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Sample records for cortical activation modulates

  1. A circuit for motor cortical modulation of auditory cortical activity.

    PubMed

    Nelson, Anders; Schneider, David M; Takatoh, Jun; Sakurai, Katsuyasu; Wang, Fan; Mooney, Richard

    2013-09-01

    Normal hearing depends on the ability to distinguish self-generated sounds from other sounds, and this ability is thought to involve neural circuits that convey copies of motor command signals to various levels of the auditory system. Although such interactions at the cortical level are believed to facilitate auditory comprehension during movements and drive auditory hallucinations in pathological states, the synaptic organization and function of circuitry linking the motor and auditory cortices remain unclear. Here we describe experiments in the mouse that characterize circuitry well suited to transmit motor-related signals to the auditory cortex. Using retrograde viral tracing, we established that neurons in superficial and deep layers of the medial agranular motor cortex (M2) project directly to the auditory cortex and that the axons of some of these deep-layer cells also target brainstem motor regions. Using in vitro whole-cell physiology, optogenetics, and pharmacology, we determined that M2 axons make excitatory synapses in the auditory cortex but exert a primarily suppressive effect on auditory cortical neuron activity mediated in part by feedforward inhibition involving parvalbumin-positive interneurons. Using in vivo intracellular physiology, optogenetics, and sound playback, we also found that directly activating M2 axon terminals in the auditory cortex suppresses spontaneous and stimulus-evoked synaptic activity in auditory cortical neurons and that this effect depends on the relative timing of motor cortical activity and auditory stimulation. These experiments delineate the structural and functional properties of a corticocortical circuit that could enable movement-related suppression of auditory cortical activity. PMID:24005287

  2. Spectrin regulates Hippo signaling by modulating cortical actomyosin activity

    PubMed Central

    Deng, Hua; Wang, Wei; Yu, Jianzhong; Zheng, Yonggang; Qing, Yun; Pan, Duojia

    2015-01-01

    The Hippo pathway controls tissue growth through a core kinase cascade that impinges on the transcription of growth-regulatory genes. Understanding how this pathway is regulated in development remains a major challenge. Recent studies suggested that Hippo signaling can be modulated by cytoskeletal tension through a Rok-myosin II pathway. How cytoskeletal tension is regulated or its relationship to the other known upstream regulators of the Hippo pathway remains poorly defined. In this study, we identify spectrin, a contractile protein at the cytoskeleton-membrane interface, as an upstream regulator of the Hippo signaling pathway. We show that, in contrast to canonical upstream regulators such as Crumbs, Kibra, Expanded, and Merlin, spectrin regulates Hippo signaling in a distinct way by modulating cortical actomyosin activity through non-muscle myosin II. These results uncover an essential mediator of Hippo signaling by cytoskeleton tension, providing a new entry point to dissecting how mechanical signals regulate Hippo signaling in living tissues. DOI: http://dx.doi.org/10.7554/eLife.06567.001 PMID:25826608

  3. Modulation of cortical oscillatory activity during transcranial magnetic stimulation.

    PubMed

    Brignani, Debora; Manganotti, Paolo; Rossini, Paolo M; Miniussi, Carlo

    2008-05-01

    Transcranial magnetic stimulation (TMS) can transiently modulate cortical excitability, with a net effect depending on the stimulation frequency (< or =1 Hz inhibition vs. > or =5 Hz facilitation, at least for the motor cortex). This possibility has generated interest in experiments aiming to improve deficits in clinical settings, as well as deficits in the cognitive domain. The aim of the present study was to investigate the on-line effects of low frequency (1 Hz) TMS on the EEG oscillatory activity in the healthy human brain, focusing particularly on the outcome of these modulatory effects in relation to the duration of the TMS stimulation. To this end, we used the event-related desynchronization/synchronization (ERD/ERS) approach to determine the patterns of oscillatory activity during two consecutive trains of sham and real TMS. Each train of stimulation was delivered to the left primary motor cortex (MI) of healthy subjects over a period of 10 min, while EEG rhythms were simultaneously recorded. Results indicated that TMS induced an increase in the power of brain rhythms that was related to the period of the stimulation, i.e. the synchronization of the alpha band increased with the duration of the stimulation, and this increase was inversely correlated with motor-evoked potentials (MEPs) amplitude. In conclusion, low frequency TMS over primary motor cortex induces a synchronization of the background oscillatory activity on the stimulated region. This induced modulation in brain oscillations seems to increase coherently with the duration of stimulation, suggesting that TMS effects may involve short-term modification of the neural circuitry sustaining MEPs characteristics. PMID:17557296

  4. Left brain cortical activity modulates stress effects on social behavior

    PubMed Central

    Lee, Eunee; Hong, Jiso; Park, Young-Gyun; Chae, Sujin; Kim, Yong; Kim, Daesoo

    2015-01-01

    When subjected to stress, some individuals develop maladaptive symptoms whereas others retain normal behavior. The medial prefrontal cortex (mPFC) is known to control these adaptive responses to stress. Here, we show that mPFC neurons in the left hemisphere control stress effects on social behavior. Mice made socially avoidant by the stress of chronic social defeats showed depressed neural activity in the left mPFC. Photoactivation of these neurons reversed social avoidance and restored social activity. Despite social defeats, resilient mice with normal sociability showed normal firing rates in the left mPFC; however, photoinhibition of these neurons induced social avoidance. The same photomodulation administered to the right mPFC caused no significant effects. These results explain how stressed individuals develop maladaptive behaviors through left cortical depression, as reported in mood and anxiety disorders. PMID:26302668

  5. Involvement of human internal globus pallidus in the early modulation of cortical error-related activity.

    PubMed

    Herrojo Ruiz, María; Huebl, Julius; Schönecker, Thomas; Kupsch, Andreas; Yarrow, Kielan; Krauss, Joachim K; Schneider, Gerd-Helge; Kühn, Andrea A

    2014-06-01

    The detection and assessment of errors are a prerequisite to adapt behavior and improve future performance. Error monitoring is afforded by the interplay between cortical and subcortical neural systems. Ample evidence has pointed to a specific cortical error-related evoked potential, the error-related negativity (ERN), during the detection and evaluation of response errors. Recent models of reinforcement learning implicate the basal ganglia (BG) in early error detection following the learning of stimulus-response associations and in the modulation of the cortical ERN. To investigate the influence of the human BG motor output activity on the cortical ERN during response errors, we recorded local field potentials from the sensorimotor area of the internal globus pallidus and scalp electroencephalogram representing activity from the posterior medial frontal cortex in patients with idiopathic dystonia (hands not affected) during a flanker task. In error trials, a specific pallidal error-related potential arose 60 ms prior to the cortical ERN. The error-related changes in pallidal activity-characterized by theta oscillations-were predictive of the cortical error-related activity as assessed by Granger causality analysis. Our findings show an early modulation of error-related activity in the human pallidum, suggesting that pallidal output influences the cortex at an early stage of error detection.

  6. Preference for Sucrose Solutions Modulates Taste Cortical Activity in Humans.

    PubMed

    Jacquin-Piques, Agnès; Mouillot, Thomas; Gigot, Vincent; Meillon, Sophie; Leloup, Corinne; Penicaud, Luc; Brondel, Laurent

    2016-09-01

    High time resolution is required to reliably measure neuronal activity in the gustatory cortex in response to taste stimuli. Hedonic aspects of gustatory processing have never been explored using gustatory evoked potentials (GEPs), a high-time-resolution technique. Our aim was to study cerebral processing of hedonic taste in humans using GEPs in response to sucrose solutions in subjects with different ratings of pleasantness regarding sucrose. In this exploratory study, 30 healthy volunteers were randomly stimulated with 3 sucrose solutions. The sucrose stimulus was presented to the tongue for 1s 20 times. GEPs were recorded from 9 cortical sites with EEG sensors at Cz, Fz, Pz, C3, C4, F3, F4, Fp1, and Fp2 (10/20 system). The main result was that subjects who preferred the high-concentration (20g/100mL) sucrose solution had higher GEP amplitudes on the Pz, Cz, and Fz electrodes than did subjects who preferred the low-concentration (5g/100mL) or the moderate-concentration (10g/100mL) solutions regardless of stimulus intensity. The difference in P1N1 amplitude on the Pz, Cz, and Fz electrodes according to sucrose preference of the subjects was described with stronger significance with stimulation by the 20 g-sucrose solution than by the 5 and 10g sucrose solutions. Using the reliable and safe GEP technique, we provide an original demonstration of variability of the gustatory response on the Pz, Cz, and Fz electrodes according to a sweet preference in humans. Further studies are needed to correlate the electric signal recorded by surface electrodes to the neural generator. PMID:27235187

  7. Subthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson’s disease

    PubMed Central

    Klotz, Rosa; Govindan, Rathinaswamy B.; Scholten, Marlieke; Naros, Georgios; Ramos-Murguialday, Ander; Bunjes, Friedemann; Meisner, Christoph; Plewnia, Christian; Krüger, Rejko

    2015-01-01

    Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson’s disease. Here, we set out to address the motor network activity and synchronization in Parkinson’s disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson’s disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with ‘stimulation on’ compared to ‘stimulation off’ on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With ‘stimulation on’, interhemispheric cortico-cortical

  8. Transcranial Direct Current Stimulation Modulates Cortical Neuronal Activity in Alzheimer's Disease.

    PubMed

    Marceglia, Sara; Mrakic-Sposta, Simona; Rosa, Manuela; Ferrucci, Roberta; Mameli, Francesca; Vergari, Maurizio; Arlotti, Mattia; Ruggiero, Fabiana; Scarpini, Elio; Galimberti, Daniela; Barbieri, Sergio; Priori, Alberto

    2016-01-01

    . Our findings disclosed that tDCS induces significant modulations in the cortical EEG activity in AD patients. The abnormal pattern of EEG activity observed in AD during memory processing is partially reversed by applying anodal tDCS, suggesting that anodal tDCS benefits in AD patients during working memory tasks are supported by the modulation of cortical activity. PMID:27065792

  9. Transcranial Direct Current Stimulation Modulates Cortical Neuronal Activity in Alzheimer's Disease

    PubMed Central

    Marceglia, Sara; Mrakic-Sposta, Simona; Rosa, Manuela; Ferrucci, Roberta; Mameli, Francesca; Vergari, Maurizio; Arlotti, Mattia; Ruggiero, Fabiana; Scarpini, Elio; Galimberti, Daniela; Barbieri, Sergio; Priori, Alberto

    2016-01-01

    . Our findings disclosed that tDCS induces significant modulations in the cortical EEG activity in AD patients. The abnormal pattern of EEG activity observed in AD during memory processing is partially reversed by applying anodal tDCS, suggesting that anodal tDCS benefits in AD patients during working memory tasks are supported by the modulation of cortical activity. PMID:27065792

  10. Modulation of cortical activity as a result of voluntary postural sway direction: an EEG study

    PubMed Central

    Slobounov, Semyon; Hallett, Mark; Cao, Cheng; Newell, Karl

    2008-01-01

    There is increasing evidence demonstrating the role of the cerebral cortex in human postural control. Modulation of EEG both in voltage and frequency domains has been observed preceding and following self-paced postural movements and those induced by external perturbations. The current study set out to provide additional evidence regarding the role of cerebral cortex in human postural control by specifically examining modulation of EEG as a function of postural sway direction. Twelve neurologically normal subjects were instructed to produce self-paced voluntary postural sways in the anterior-posterior (AP) and medial-lateral (ML) directions. The center of pressure dynamics and EEG both in voltage and frequency domains were extracted by averaging and Morlet wavelet techniques, respectively. The amplitude of movement-related cortical potentials (MRCP) was significantly higher preceding ML sways. Also, time-frequency wavelet coefficients (TF) indicated differential modulation of EEG within alpha, beta and gamma bands as a function of voluntary postural sway direction. Thus, ML sway appear to be more difficult and energy demanding tasks than the AP sway as reflected in differential modulation of EEG. These results are discussed within the conceptual framework of differential patterns of brain activation as a result of postural task complexity. PMID:18639613

  11. Luminal flow modulates H+-ATPase activity in the cortical collecting duct (CCD).

    PubMed

    Liu, Wen; Pastor-Soler, Núria M; Schreck, Carlos; Zavilowitz, Beth; Kleyman, Thomas R; Satlin, Lisa M

    2012-01-01

    Epithelial Na(+) channel (ENaC)-mediated Na(+) absorption and BK channel-mediated K(+) secretion in the cortical collecting duct (CCD) are modulated by flow, the latter requiring an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), microtubule integrity, and exocytic insertion of preformed channels into the apical membrane. As axial flow modulates HCO(3)(-) reabsorption in the proximal tubule due to changes in both luminal Na(+)/H(+) exchanger 3 and H(+)-ATPase activity (Du Z, Yan Q, Duan Y, Weinbaum S, Weinstein AM, Wang T. Am J Physiol Renal Physiol 290: F289-F296, 2006), we sought to test the hypothesis that flow also regulates H(+)-ATPase activity in the CCD. H(+)-ATPase activity was assayed in individually identified cells in microperfused CCDs isolated from New Zealand White rabbits, loaded with the pH-sensitive dye BCECF, and then subjected to an acute intracellular acid load (NH(4)Cl prepulse technique). H(+)-ATPase activity was defined as the initial rate of bafilomycin-inhibitable cell pH (pH(i)) recovery in the absence of luminal K(+), bilateral Na(+), and CO(2)/HCO(3)(-), from a nadir pH of ∼6.2. We found that 1) an increase in luminal flow rate from ∼1 to 5 nl·min(-1)·mm(-1) stimulated H(+)-ATPase activity, 2) flow-stimulated H(+) pumping was Ca(2+) dependent and required microtubule integrity, and 3) basal and flow-stimulated pH(i) recovery was detected in cells that labeled with the apical principal cell marker rhodamine Dolichos biflorus agglutinin as well as cells that did not. We conclude that luminal flow modulates H(+)-ATPase activity in the rabbit CCD and that H(+)-ATPases therein are present in both principal and intercalated cells. PMID:21957178

  12. Nicotinic modulation of cortical circuits

    PubMed Central

    Arroyo, Sergio; Bennett, Corbett; Hestrin, Shaul

    2014-01-01

    The ascending cholinergic neuromodulatory system sends projections throughout cortex and has been shown to play an important role in a number of cognitive functions including arousal, working memory, and attention. However, despite a wealth of behavioral and anatomical data, understanding how cholinergic synapses modulate cortical function has been limited by the inability to selectively activate cholinergic axons. Now, with the development of optogenetic tools and cell-type specific Cre-driver mouse lines, it has become possible to stimulate cholinergic axons from the basal forebrain (BF) and probe cholinergic synapses in the cortex for the first time. Here we review recent work studying the cell-type specificity of nicotinic signaling in the cortex, synaptic mechanisms mediating cholinergic transmission, and the potential functional role of nicotinic modulation. PMID:24734005

  13. Endogenous cholinergic tone modulates spontaneous network level neuronal activity in primary cortical cultures grown on multi-electrode arrays

    PubMed Central

    2013-01-01

    Background Cortical cultures grown long-term on multi-electrode arrays (MEAs) are frequently and extensively used as models of cortical networks in studies of neuronal firing activity, neuropharmacology, toxicology and mechanisms underlying synaptic plasticity. However, in contrast to the predominantly asynchronous neuronal firing activity exhibited by intact cortex, electrophysiological activity of mature cortical cultures is dominated by spontaneous epileptiform-like global burst events which hinders their effective use in network-level studies, particularly for neurally-controlled animat (‘artificial animal’) applications. Thus, the identification of culture features that can be exploited to produce neuronal activity more representative of that seen in vivo could increase the utility and relevance of studies that employ these preparations. Acetylcholine has a recognised neuromodulatory role affecting excitability, rhythmicity, plasticity and information flow in vivo although its endogenous production by cortical cultures and subsequent functional influence upon neuronal excitability remains unknown. Results Consequently, using MEA electrophysiological recording supported by immunohistochemical and RT-qPCR methods, we demonstrate for the first time, the presence of intrinsic cholinergic neurons and significant, endogenous cholinergic tone in cortical cultures with a characterisation of the muscarinic and nicotinic components that underlie modulation of spontaneous neuronal activity. We found that tonic muscarinic ACh receptor (mAChR) activation affects global excitability and burst event regularity in a culture age-dependent manner whilst, in contrast, tonic nicotinic ACh receptor (nAChR) activation can modulate burst duration and the proportion of spikes occurring within bursts in a spatio-temporal fashion. Conclusions We suggest that the presence of significant endogenous cholinergic tone in cortical cultures and the comparability of its modulatory effects

  14. Acute Modulation of Cortical Glutamate and GABA Content by Physical Activity.

    PubMed

    Maddock, Richard J; Casazza, Gretchen A; Fernandez, Dione H; Maddock, Michael I

    2016-02-24

    Converging evidence demonstrates that physical activity evokes a brain state characterized by distinctive changes in brain metabolism and cortical function. Human studies have shown that physical activity leads to a generalized increase in electroencephalography power across regions and frequencies, and a global increase in brain nonoxidative metabolism of carbohydrate substrates. This nonoxidative consumption of carbohydrate has been hypothesized to include increased de novo synthesis of amino acid neurotransmitters, especially glutamate and GABA. Here, we conducted a series of proton magnetic resonance spectroscopy studies in human volunteers before and after vigorous exercise (≥80% of predicted maximal heart rate). Results showed that the resonance signals of both glutamate and GABA increased significantly in the visual cortex following exercise. We further demonstrated a similar increase in glutamate following exercise in an executive region, the anterior cingulate cortex. The increase in glutamate was similar when using echo times of 30 and 144 ms, indicating that exercise-related T2 relaxation effects across this range of relaxation times did not account for the findings. In addition, we found preliminary evidence that more physical activity during the preceding week predicts higher resting glutamate levels. Overall, the results are consistent with an exercise-induced expansion of the cortical pools of glutamate and GABA, and add to a growing understanding of the distinctive brain state associated with physical activity. A more complete understanding of this brain state may reveal important insights into mechanisms underlying the beneficial effects of physical exercise in neuropsychiatric disorders, neurorehabilitation, aging, and cognition.

  15. The role of reading activity on the modulation of motor cortical outputs to the reading hand in Braille readers.

    PubMed

    Pascual-Leone, A; Wassermann, E M; Sadato, N; Hallett, M

    1995-12-01

    We studied the cortical motor output maps of the first dorsal interosseous (FDI) of both hands and the abductor digiti minimi of the reading hand in 6 blind proficient Braille readers. The maps were generated using transcranial magnetic stimulation. We compared the maps obtained on a day in which they worked as Braille proofreaders (reading Braille for approximately 6 hours) with the maps obtained on a day they took off from work. On the work day, the maps for the FDI of the reading hand were significantly larger after the working shift than in the morning after having been off work for 2 days. These changes were not seen for the same muscle on the day off work or on any of the 2 days in the other two muscles studied. These results illustrate the rapid modulation in motor cortical outputs in relation to preceding activity and emphasize the importance of precise timing in studies of the neurophysiological correlates of skill acquisition.

  16. Cortical activities of single-trial P300 amplitudes modulated by memory load using simultaneous EEG-fMRI

    NASA Astrophysics Data System (ADS)

    Zhang, Qiushi; Zhao, Xiaojie; Zhu, Chaozhe; Yang, Xueqian; Yao, Li

    2015-03-01

    The functional magnetic resonance imaging (fMRI) researches on working memory have found that activation of cortical areas appeared dependent on memory load, and event-related potentials (ERP) studies have demonstrated that amplitudes of P300 decreased significantly when working memory load increased. However, the cortical activities related with P300 amplitudes under different memory loads remains unclear. Joint fMRI and EEG analysis which fusions the time and spatial information in simultaneous EEG-fMRI recording can reveal the regional activation at each ERP time point. In this paper, we first used wavelet transform to obtain the single-trial amplitudes of P300 caused by a digital N-back task in the simultaneous EEG-fMRI recording as the ERP feature sequences. Then the feature sequences in 1-back condition and 3-back condition were introduced into general linear model (GLM) separately as parametric modulations to compare the cortical activation under different memory loads. The results showed that the average amplitudes of P300 in 3-back significantly decreased than that in 1-back, and the activities induced by ERP feature sequences in 3-back also significantly decreased than that in the 1-back, including the insular, anterior cingulate cortex, right inferior frontal gyrus, and medial frontal gyrus, which were relevant to the storage, monitoring, and manipulation of information in working memory task. Moreover, the difference in the activation caused by ERP feature showed a positive correlation with the difference in behavioral performance. These findings demonstrated the locations of P300 amplitudes differences modulated by the memory load and its relationship with the behavioral performance.

  17. Brief wide-field photostimuli evoke and modulate oscillatory reverberating activity in cortical networks.

    PubMed

    Pulizzi, Rocco; Musumeci, Gabriele; Van den Haute, Chris; Van De Vijver, Sebastiaan; Baekelandt, Veerle; Giugliano, Michele

    2016-01-01

    Cell assemblies manipulation by optogenetics is pivotal to advance neuroscience and neuroengineering. In in vivo applications, photostimulation often broadly addresses a population of cells simultaneously, leading to feed-forward and to reverberating responses in recurrent microcircuits. The former arise from direct activation of targets downstream, and are straightforward to interpret. The latter are consequence of feedback connectivity and may reflect a variety of time-scales and complex dynamical properties. We investigated wide-field photostimulation in cortical networks in vitro, employing substrate-integrated microelectrode arrays and long-term cultured neuronal networks. We characterized the effect of brief light pulses, while restricting the expression of channelrhodopsin to principal neurons. We evoked robust reverberating responses, oscillating in the physiological gamma frequency range, and found that such a frequency could be reliably manipulated varying the light pulse duration, not its intensity. By pharmacology, mathematical modelling, and intracellular recordings, we conclude that gamma oscillations likely emerge as in vivo from the excitatory-inhibitory interplay and that, unexpectedly, the light stimuli transiently facilitate excitatory synaptic transmission. Of relevance for in vitro models of (dys)functional cortical microcircuitry and in vivo manipulations of cell assemblies, we give for the first time evidence of network-level consequences of the alteration of synaptic physiology by optogenetics. PMID:27099182

  18. Brief wide-field photostimuli evoke and modulate oscillatory reverberating activity in cortical networks

    PubMed Central

    Pulizzi, Rocco; Musumeci, Gabriele; Van den Haute, Chris; Van De Vijver, Sebastiaan; Baekelandt, Veerle; Giugliano, Michele

    2016-01-01

    Cell assemblies manipulation by optogenetics is pivotal to advance neuroscience and neuroengineering. In in vivo applications, photostimulation often broadly addresses a population of cells simultaneously, leading to feed-forward and to reverberating responses in recurrent microcircuits. The former arise from direct activation of targets downstream, and are straightforward to interpret. The latter are consequence of feedback connectivity and may reflect a variety of time-scales and complex dynamical properties. We investigated wide-field photostimulation in cortical networks in vitro, employing substrate-integrated microelectrode arrays and long-term cultured neuronal networks. We characterized the effect of brief light pulses, while restricting the expression of channelrhodopsin to principal neurons. We evoked robust reverberating responses, oscillating in the physiological gamma frequency range, and found that such a frequency could be reliably manipulated varying the light pulse duration, not its intensity. By pharmacology, mathematical modelling, and intracellular recordings, we conclude that gamma oscillations likely emerge as in vivo from the excitatory-inhibitory interplay and that, unexpectedly, the light stimuli transiently facilitate excitatory synaptic transmission. Of relevance for in vitro models of (dys)functional cortical microcircuitry and in vivo manipulations of cell assemblies, we give for the first time evidence of network-level consequences of the alteration of synaptic physiology by optogenetics. PMID:27099182

  19. Lactate Modulates the Activity of Primary Cortical Neurons through a Receptor-Mediated Pathway

    PubMed Central

    Bozzo, Luigi; Puyal, Julien; Chatton, Jean-Yves

    2013-01-01

    Lactate is increasingly described as an energy substrate of the brain. Beside this still debated metabolic role, lactate may have other effects on brain cells. Here, we describe lactate as a neuromodulator, able to influence the activity of cortical neurons. Neuronal excitability of mouse primary neurons was monitored by calcium imaging. When applied in conjunction with glucose, lactate induced a decrease in the spontaneous calcium spiking frequency of neurons. The effect was reversible and concentration dependent (IC50 ∼4.2 mM). To test whether lactate effects are dependent on energy metabolism, we applied the closely related substrate pyruvate (5 mM) or switched to different glucose concentrations (0.5 or 10 mM). None of these conditions reproduced the effect of lactate. Recently, a Gi protein-coupled receptor for lactate called HCA1 has been introduced. To test if this receptor is implicated in the observed lactate sensitivity, we incubated cells with pertussis toxin (PTX) an inhibitor of Gi-protein. PTX prevented the decrease of neuronal activity by L-lactate. Moreover 3,5-dyhydroxybenzoic acid, a specific agonist of the HCA1 receptor, mimicked the action of lactate. This study indicates that lactate operates a negative feedback on neuronal activity by a receptor-mediated mechanism, independent from its intracellular metabolism. PMID:23951229

  20. Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model.

    PubMed

    Zagha, Edward; Murray, John D; McCormick, David A

    2016-01-01

    Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input-output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation. PMID:27595137

  1. Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model

    PubMed Central

    Murray, John D.; McCormick, David A.

    2016-01-01

    Abstract Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input–output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation.

  2. Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model.

    PubMed

    Zagha, Edward; Murray, John D; McCormick, David A

    2016-01-01

    Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input-output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation.

  3. Simulating Cortical Feedback Modulation as Changes in Excitation and Inhibition in a Cortical Circuit Model

    PubMed Central

    Murray, John D.; McCormick, David A.

    2016-01-01

    Abstract Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced sensory representations. However, the cellular mechanisms underlying these effects are currently unknown. In this study we use a simplified neural circuit model, which includes two recurrent excitatory populations and global inhibition, to simulate cortical modulation. First, we demonstrate how changes in the strengths of excitation and inhibition alter the input–output processing responses of our model. Second, we compare these responses with experimental findings from cortical feedback stimulation. Our analyses predict that enhanced inhibition underlies the changes in spontaneous and sensory evoked activity observed experimentally. More generally, these analyses provide a framework for relating cellular and synaptic properties to emergent circuit function and dynamic modulation. PMID:27595137

  4. Serotonin modulation of cortical neurons and networks

    PubMed Central

    Celada, Pau; Puig, M. Victoria; Artigas, Francesc

    2013-01-01

    The serotonergic pathways originating in the dorsal and median raphe nuclei (DR and MnR, respectively) are critically involved in cortical function. Serotonin (5-HT), acting on postsynaptic and presynaptic receptors, is involved in cognition, mood, impulse control and motor functions by (1) modulating the activity of different neuronal types, and (2) varying the release of other neurotransmitters, such as glutamate, GABA, acetylcholine and dopamine. Also, 5-HT seems to play an important role in cortical development. Of all cortical regions, the frontal lobe is the area most enriched in serotonergic axons and 5-HT receptors. 5-HT and selective receptor agonists modulate the excitability of cortical neurons and their discharge rate through the activation of several receptor subtypes, of which the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT3 subtypes play a major role. Little is known, however, on the role of other excitatory receptors moderately expressed in cortical areas, such as 5-HT2C, 5-HT4, 5-HT6, and 5-HT7. In vitro and in vivo studies suggest that 5-HT1A and 5-HT2A receptors are key players and exert opposite effects on the activity of pyramidal neurons in the medial prefrontal cortex (mPFC). The activation of 5-HT1A receptors in mPFC hyperpolarizes pyramidal neurons whereas that of 5-HT2A receptors results in neuronal depolarization, reduction of the afterhyperpolarization and increase of excitatory postsynaptic currents (EPSCs) and of discharge rate. 5-HT can also stimulate excitatory (5-HT2A and 5-HT3) and inhibitory (5-HT1A) receptors in GABA interneurons to modulate synaptic GABA inputs onto pyramidal neurons. Likewise, the pharmacological manipulation of various 5-HT receptors alters oscillatory activity in PFC, suggesting that 5-HT is also involved in the control of cortical network activity. A better understanding of the actions of 5-HT in PFC may help to develop treatments for mood and cognitive disorders associated with an abnormal function of the frontal lobe

  5. ACTIVITY IN CORTICAL MIDLINE STRUCTURES IS MODULATED BY SELF-CONSTRUAL CHANGES DURING ACCULTURATION

    PubMed Central

    Chen, Pin-Hao A.; Wagner, Dylan D.; Kelley, William M.; Heatherton, Todd F.

    2015-01-01

    Recent immigrants to another culture generally experience a period of acculturation during which they show self-construal changes. Here, we examine how this acculturation period alters brain activity associated with self-referential cognition. Twenty-seven native Chinese-speaking recent immigrants completed a trait-judgment task in which they judged whether a series of psychological traits applied to themselves and, separately, whether these traits applied to their mothers. Participants were scanned at two intervals: within the first two months of their arrival in the United States (Time 1), and also six months after the initial scan (Time 2). Results already revealed a significant self-vs.-mother differentiation at Time 1 in the medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC). However, at time 2, this pattern diverged depending on whether immigrants became more or less like their original culture. That is to say, for immigrants who became less like Easterners, the self vs. mother difference remained, whereas for participants who became even more like Easterners, the self vs. mother difference in cortical midline structures disappeared. These findings support the notion that self-construal changes during the process of acculturation are reflected in the relative engagement of brain structures implicated in self-referential processing (i.e., MPFC and PCC) when judging traits with reference to oneself or a close other. PMID:26236572

  6. Cortical Axons, Isolated in Channels, Display Activity-Dependent Signal Modulation as a Result of Targeted Stimulation

    PubMed Central

    Lewandowska, Marta K.; Radivojević, Miloš; Jäckel, David; Müller, Jan; Hierlemann, Andreas R.

    2016-01-01

    Mammalian cortical axons are extremely thin processes that are difficult to study as a result of their small diameter: they are too narrow to patch while intact, and super-resolution microscopy is needed to resolve single axons. We present a method for studying axonal physiology by pairing a high-density microelectrode array with a microfluidic axonal isolation device, and use it to study activity-dependent modulation of axonal signal propagation evoked by stimulation near the soma. Up to three axonal branches from a single neuron, isolated in different channels, were recorded from simultaneously using 10–20 electrodes per channel. The axonal channels amplified spikes such that propagations of individual signals along tens of electrodes could easily be discerned with high signal to noise. Stimulation from 10 up to 160 Hz demonstrated similar qualitative results from all of the cells studied: extracellular action potential characteristics changed drastically in response to stimulation. Spike height decreased, spike width increased, and latency increased, as a result of reduced propagation velocity, as the number of stimulations and the stimulation frequencies increased. Quantitatively, the strength of these changes manifested itself differently in cells at different frequencies of stimulation. Some cells' signal fidelity fell to 80% already at 10 Hz, while others maintained 80% signal fidelity at 80 Hz. Differences in modulation by axonal branches of the same cell were also seen for different stimulation frequencies, starting at 10 Hz. Potassium ion concentration changes altered the behavior of the cells causing propagation failures at lower concentrations and improving signal fidelity at higher concentrations. PMID:27013945

  7. Modulation of cortical activity in 2D versus 3D virtual reality environments: an EEG study.

    PubMed

    Slobounov, Semyon M; Ray, William; Johnson, Brian; Slobounov, Elena; Newell, Karl M

    2015-03-01

    There is a growing empirical evidence that virtual reality (VR) is valuable for education, training, entertaining and medical rehabilitation due to its capacity to represent real-life events and situations. However, the neural mechanisms underlying behavioral confounds in VR environments are still poorly understood. In two experiments, we examined the effect of fully immersive 3D stereoscopic presentations and less immersive 2D VR environments on brain functions and behavioral outcomes. In Experiment 1 we examined behavioral and neural underpinnings of spatial navigation tasks using electroencephalography (EEG). In Experiment 2, we examined EEG correlates of postural stability and balance. Our major findings showed that fully immersive 3D VR induced a higher subjective sense of presence along with enhanced success rate of spatial navigation compared to 2D. In Experiment 1 power of frontal midline EEG (FM-theta) was significantly higher during the encoding phase of route presentation in the 3D VR. In Experiment 2, the 3D VR resulted in greater postural instability and modulation of EEG patterns as a function of 3D versus 2D environments. The findings support the inference that the fully immersive 3D enriched-environment requires allocation of more brain and sensory resources for cognitive/motor control during both tasks than 2D presentations. This is further evidence that 3D VR tasks using EEG may be a promising approach for performance enhancement and potential applications in clinical/rehabilitation settings. PMID:25448267

  8. Pain modulation in waking and hypnosis in women: event-related potentials and sources of cortical activity.

    PubMed

    De Pascalis, Vilfredo; Varriale, Vincenzo; Cacace, Immacolata

    2015-01-01

    Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N

  9. Pain Modulation in Waking and Hypnosis in Women: Event-Related Potentials and Sources of Cortical Activity

    PubMed Central

    De Pascalis, Vilfredo; Varriale, Vincenzo; Cacace, Immacolata

    2015-01-01

    Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N

  10. Pain modulation in waking and hypnosis in women: event-related potentials and sources of cortical activity.

    PubMed

    De Pascalis, Vilfredo; Varriale, Vincenzo; Cacace, Immacolata

    2015-01-01

    Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N

  11. Modulation of neuronal activity and plasma membrane properties with low-power millimeter waves in organotypic cortical slices

    NASA Astrophysics Data System (ADS)

    Pikov, Victor; Arakaki, Xianghong; Harrington, Michael; Fraser, Scott E.; Siegel, Peter H.

    2010-08-01

    As millimeter waves (MMWs) are being increasingly used in communications and military applications, their potential effects on biological tissue has become an important issue for scientific inquiry. Specifically, several MMW effects on the whole-nerve activity were reported, but the underlying neuronal changes remain unexplored. This study used slices of cortical tissue to evaluate the MMW effects on individual pyramidal neurons under conditions mimicking their in vivo environment. The applied levels of MMW power are three orders of magnitude below the existing safe limit for human exposure of 1 mW cm-2. Surprisingly, even at these low power levels, MMWs were able to produce considerable changes in neuronal firing rate and plasma membrane properties. At the power density approaching 1 µW cm-2, 1 min of MMW exposure reduced the firing rate to one third of the pre-exposure level in four out of eight examined neurons. The width of the action potentials was narrowed by MMW exposure to 17% of the baseline value and the membrane input resistance decreased to 54% of the baseline value across all neurons. These effects were short lasting (2 min or less) and were accompanied by MMW-induced heating of the bath solution at 3 °C. Comparison of these results with previously published data on the effects of general bath heating of 10 °C indicated that MMW-induced effects cannot be fully attributed to heating and may involve specific MMW absorption by the tissue. Blocking of the intracellular Ca2+-mediated signaling did not significantly alter the MMW-induced neuronal responses suggesting that MMWs interacted directly with the neuronal plasma membrane. The presented results constitute the first demonstration of direct real-time monitoring of the impact of MMWs on nervous tissue at a microscopic scale. Implication of these findings for the therapeutic modulation of neuronal excitability is discussed.

  12. In search of augmentation at human SI: Somatosensory cortical responses to stimulus trains and their modulation by motor activity.

    PubMed

    Huttunen, Juha

    2010-05-17

    In many animal preparations, repeated stimulation at ca. 10 Hz in thalamic nuclei leads to rapid changes in the cortical evoked responses, known as the augmenting response. The present study was undertaken to evaluate whether anything similar to the augmenting response can be observed in awake human subjects when a peripheral nerve is stimulated, and whether a possible human correlate of augmenting would be modified when the subject is engaged in an active motor task. Somatosensory-evoked magnetic fields (SEFs) were recorded in healthy human subjects in response to stimulus trains (15 pulses at 10 Hz) applied to the left median nerve. SEFs were recorded in a resting condition and during a finger-tapping task performed with the stimulated hand. In the resting condition, the most marked change in the SEF configuration was a reduction of the P35m deflection and a concurrent enhancement of the N45m deflection during the 1st few stimuli of the trains. Another conspicuous feature was a prolongation of the latencies of the N45m and P60m deflections toward the end of the train. In the motor task, the response modulation during the pulse trains was in general similar to the resting condition. The most notable difference was that the P35m amplitude was markedly reduced already for the 1st pulse of the train when compared with rest. Also, the latencies of N45m and P60m were not prolonged during the train. We discuss the possibility that the reduction of P35m and a concurrent increase of N45m during a pulse train constitute a human analogue to the augmenting response, and suggest that these changes may reflect a decrease of inhibitory postsynaptic potentials (IPSPs, P35m) and an increase of secondary excitatory postsynaptic potentials (N45m) during stimulus train presentation. The reduction of P35m during motor activity compared with rest already at the beginning of stimulus trains suggests that postsynaptic IPSPs in response to afferent stimulation are reduced during active

  13. In search of augmentation at human SI: Somatosensory cortical responses to stimulus trains and their modulation by motor activity.

    PubMed

    Huttunen, Juha

    2010-05-17

    In many animal preparations, repeated stimulation at ca. 10 Hz in thalamic nuclei leads to rapid changes in the cortical evoked responses, known as the augmenting response. The present study was undertaken to evaluate whether anything similar to the augmenting response can be observed in awake human subjects when a peripheral nerve is stimulated, and whether a possible human correlate of augmenting would be modified when the subject is engaged in an active motor task. Somatosensory-evoked magnetic fields (SEFs) were recorded in healthy human subjects in response to stimulus trains (15 pulses at 10 Hz) applied to the left median nerve. SEFs were recorded in a resting condition and during a finger-tapping task performed with the stimulated hand. In the resting condition, the most marked change in the SEF configuration was a reduction of the P35m deflection and a concurrent enhancement of the N45m deflection during the 1st few stimuli of the trains. Another conspicuous feature was a prolongation of the latencies of the N45m and P60m deflections toward the end of the train. In the motor task, the response modulation during the pulse trains was in general similar to the resting condition. The most notable difference was that the P35m amplitude was markedly reduced already for the 1st pulse of the train when compared with rest. Also, the latencies of N45m and P60m were not prolonged during the train. We discuss the possibility that the reduction of P35m and a concurrent increase of N45m during a pulse train constitute a human analogue to the augmenting response, and suggest that these changes may reflect a decrease of inhibitory postsynaptic potentials (IPSPs, P35m) and an increase of secondary excitatory postsynaptic potentials (N45m) during stimulus train presentation. The reduction of P35m during motor activity compared with rest already at the beginning of stimulus trains suggests that postsynaptic IPSPs in response to afferent stimulation are reduced during active

  14. Modulation of Fronto-Cortical Activity by Modafinil: A Functional Imaging and Fos Study in the Rat

    PubMed Central

    Gozzi, Alessandro; Colavito, Valeria; Seke Etet, Paul F; Montanari, Dino; Fiorini, Silvia; Tambalo, Stefano; Bifone, Angelo; Zucconi, Gigliola Grassi; Bentivoglio, Marina

    2012-01-01

    Modafinil (MOD) is a wake-promoting drug with pro-cognitive properties. Despite its increasing use, the neuronal substrates of MOD action remain elusive. In particular, animal studies have highlighted a putative role of diencephalic areas as primary neuronal substrate of MOD action, with inconsistent evidence of recruitment of fronto-cortical areas despite the established pro-cognitive effects of the drug. Moreover, most animal studies have employed doses of MOD of limited clinical relevance. We used pharmacological magnetic resonance imaging (phMRI) in the anesthetized rat to map the circuitry activated by a MOD dose producing clinically relevant plasma exposure, as here ascertained by pharmacokinetic measurements. We observed prominent and sustained activation of the prefrontal and cingulate cortex, together with weaker but significant activation of the somatosensory cortex, medial thalamic domains, hippocampus, ventral striatum and dorsal raphe. Correlation analysis of phMRI data highlighted enhanced connectivity within a neural network including dopamine projections from the ventral tegmental area to the nucleus accumbens. The pro-arousing effect of MOD was assessed using electroencephalographic recording under anesthetic conditions comparable to those used for phMRI, together with the corresponding Fos immunoreactivity distribution. MOD produced electroencephalogram desynchronization, resulting in reduced delta and increased theta frequency bands, and a pattern of Fos induction largely consistent with the phMRI study. Altogether, these findings show that clinically relevant MOD doses can robustly activate fronto-cortical areas involved in higher cognitive functions and a network of pro-arousing areas, which provide a plausible substrate for the wake-promoting and pro-cognitive effects of the drug. PMID:22048464

  15. Serotoninergic modulation of cortical and respiratory responses to episodic hypoxia

    PubMed Central

    2009-01-01

    Biphasic respiratory response to hypoxia in anesthetized animals is accompanied by changes in the EEG mostly in the low EEG frequency bands. Serotonin is a potent modulator of cortical and respiratory activity through 5-HT2 receptors. Present study investigated whether 5-HT2 receptors might be involved in the EEG and respiratory relationship during normoxic and hypoxic respiration assessed from integrated phrenic (Phr) and hypoglossal (HG) nerve activities. EEG signal recorded from the frontal cortex was subjected to power spectral analysis in delta, theta, alpha, and beta frequency bands. Systemic administration of 5-HT2 agonist DOI (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane) enhanced tonic and lowered peak phasic respiratory activity, and increased frequency of bursts of Phr and HG activity. At the same time, EEG activity became desynchronized and arterial blood pressure (ABP) increased. Following DOI pretreatment, 11% hypoxia induced an augmented respiratory response in comparison with the response in the baseline condition. ABP fell less then in the control hypoxia. EEG pattern changed less than in the baseline state. Subsequent administration of ketanserin, a 5-HT2 antagonist increased respiratory activity, elicited a synchronization of EEG activity and hypotension. The respiratory response to hypoxia was attenuated and cortical response was more potent in comparison with that after DOI injection. Arterial blood pressure decreased more then during baseline hypoxic response. The results suggest that modulation of cortical synchronization and desynchronization through 5-HT2 receptor active agents may impact to hypoxic respiratory response. PMID:20156721

  16. Modulation of cortical activity during comprehension of familiar and unfamiliar text topics in speed reading and speed listening

    PubMed Central

    Buchweitz, Augusto; Mason, Robert A.; Meschyan, Gayane; Keller, Timothy A.; Just, Marcel Adam

    2014-01-01

    Brain activation associated with normal and speeded comprehension of expository texts on familiar and unfamiliar topics was investigated in reading and listening. The goal was to determine how brain activation and the comprehension processes it reflects are modulated by comprehension speed and topic familiarity. Passages on more familiar topics differentially activated a set of areas in the anterior temporal lobe and medial frontal gyrus, areas often associated with text-level integration processes, which we interpret to reflect integration of previous knowledge with the passage content. Passages presented at the faster presentation resulted in more activation of a network of frontal areas associated with strategic and working-memory processes (as well as visual or auditory sensory-related regions), which we interpret to reflect maintenance of local coherence among briefly available passage segments. The implications of this research is to demonstrate how the brain system for text comprehension adapts to varying perceptual and knowledge conditions. PMID:25463816

  17. Modulation of cortical activity during comprehension of familiar and unfamiliar text topics in speed reading and speed listening.

    PubMed

    Buchweitz, Augusto; Mason, Robert A; Meschyan, Gayane; Keller, Timothy A; Just, Marcel Adam

    2014-12-01

    Brain activation associated with normal and speeded comprehension of expository texts on familiar and unfamiliar topics was investigated in reading and listening. The goal was to determine how brain activation and the comprehension processes it reflects are modulated by comprehension speed and topic familiarity. Passages on more familiar topics differentially activated a set of areas in the anterior temporal lobe and medial frontal gyrus, areas often associated with text-level integration processes, which we interpret to reflect integration of previous knowledge with the passage content. Passages presented at the faster presentation resulted in more activation of a network of frontal areas associated with strategic and working-memory processes (as well as visual or auditory sensory-related regions), which we interpret to reflect maintenance of local coherence among briefly available passage segments. The implications of this research is that the brain system for text comprehension adapts to varying perceptual and knowledge conditions.

  18. Jealousy increased by induced relative left frontal cortical activity.

    PubMed

    Kelley, Nicholas J; Eastwick, Paul W; Harmon-Jones, Eddie; Schmeichel, Brandon J

    2015-10-01

    Asymmetric frontal cortical activity may be one key to the process linking social exclusion to jealous feelings. The current research examined the causal role of asymmetric frontal brain activity in modulating jealousy in response to social exclusion. Transcranial direct-current stimulation (tDCS) over the frontal cortex to manipulate asymmetric frontal cortical activity was combined with a modified version of the Cyberball paradigm designed to induce jealousy. After receiving 15 min of tDCS, participants were excluded by a desired partner and reported how jealous they felt. Among individuals who were excluded, tDCS to increase relative left frontal cortical activity caused greater levels of self-reported jealousy compared to tDCS to increase relative right frontal cortical activity or sham stimulation. Limitations concerning the specificity of this effect and implications for the role of the asymmetric prefrontal cortical activity in motivated behaviors are discussed. PMID:25844975

  19. Degraded attentional modulation of cortical neural populations in strabismic amblyopia

    PubMed Central

    Hou, Chuan; Kim, Yee-Joon; Lai, Xin Jie; Verghese, Preeti

    2016-01-01

    Behavioral studies have reported reduced spatial attention in amblyopia, a developmental disorder of spatial vision. However, the neural populations in the visual cortex linked with these behavioral spatial attention deficits have not been identified. Here, we use functional MRI–informed electroencephalography source imaging to measure the effect of attention on neural population activity in the visual cortex of human adult strabismic amblyopes who were stereoblind. We show that compared with controls, the modulatory effects of selective visual attention on the input from the amblyopic eye are substantially reduced in the primary visual cortex (V1) as well as in extrastriate visual areas hV4 and hMT+. Degraded attentional modulation is also found in the normal-acuity fellow eye in areas hV4 and hMT+ but not in V1. These results provide electrophysiological evidence that abnormal binocular input during a developmental critical period may impact cortical connections between the visual cortex and higher level cortices beyond the known amblyopic losses in V1 and V2, suggesting that a deficit of attentional modulation in the visual cortex is an important component of the functional impairment in amblyopia. Furthermore, we find that degraded attentional modulation in V1 is correlated with the magnitude of interocular suppression and the depth of amblyopia. These results support the view that the visual suppression often seen in strabismic amblyopia might be a form of attentional neglect of the visual input to the amblyopic eye. PMID:26885628

  20. Reliability of cortical activity during natural stimulation.

    PubMed

    Hasson, Uri; Malach, Rafael; Heeger, David J

    2010-01-01

    Response reliability is complementary to more conventional measurements of response amplitudes, and can reveal phenomena that response amplitudes do not. Here we review studies that measured reliability of cortical activity within or between human subjects in response to naturalistic stimulation (e.g. free viewing of movies). Despite the seemingly uncontrolled nature of the task, some of these complex stimuli evoke highly reliable, selective and time-locked activity in many brain areas, including some regions that show little response modulation in most conventional experimental protocols. This activity provides an opportunity to address novel questions concerning natural vision, temporal scale of processing, memory and the neural basis of inter-group differences. PMID:20004608

  1. Reliability of cortical activity during natural stimulation

    PubMed Central

    Hasson, Uri; Malach, Rafael; Heeger, David J.

    2009-01-01

    Response reliability is complementary to more conventional measurements of response amplitudes, and can reveal phenomena that response amplitudes do not. Here we review studies that measured reliability of cortical activity within or between human subjects in response to naturalistic stimulation (e.g., free viewing of movies). Despite the seemingly uncontrolled nature of the task, some of these complex stimuli evoke highly reliable, selective, and time-locked activity in many brain areas, including some brain regions that often do not show much response modulation with conventional experimental protocols. This activity provides an opportunity to address novel questions concerning natural vision, temporal scale of processing, memory, and the neural basis of inter-group differences. PMID:20004608

  2. Cortical actin regulation modulates vascular contractility and compliance in veins

    PubMed Central

    Saphirstein, Robert J; Gao, Yuan Z; Lin, Qian Qian; Morgan, Kathleen G

    2015-01-01

    Abstract The literature on arterial mechanics is extensive, but far less is known about mechanisms controlling mechanical properties of veins. We use here a multi-scale approach to identify subcellular sources of venous stiffness. Portal vein tissue displays a severalfold decrease in passive stiffness compared to aortic tissues. The α-adrenergic agonist phenylephrine (PE) increased tissue stress and stiffness, both attenuated by cytochalasin D (CytoD) and PP2, inhibitors of actin polymerization and Src activity, respectively. We quantify, for the first time, cortical cellular stiffness in freshly isolated contractile vascular smooth muscle cells using magnetic microneedle technology. Cortical stiffness is significantly increased by PE and CytoD inhibits this increase but, surprisingly, PP2 does not. No detectable change in focal adhesion size, measured by immunofluorescence of FAK and zyxin, accompanies the PE-induced changes in cortical stiffness. Probing with phospho-specific antibodies confirmed activation of FAK/Src and ERK pathways and caldesmon phosphorylation. Thus, venous tissue stiffness is regulated both at the level of the smooth muscle cell cortex, via cortical actin polymerization, and by downstream smooth muscle effectors of Src/ERK signalling pathways. These findings identify novel potential molecular targets for the modulation of venous capacitance and venous return in health and disease. Key points Most cardiovascular research focuses on arterial mechanisms of disease, largely ignoring venous mechanisms. Here we examine ex vivo venous stiffness, spanning tissue to molecular levels, using biomechanics and magnetic microneedle technology, and show for the first time that venous stiffness is regulated by a molecular actin switch within the vascular smooth muscle cell in the wall of the vein. This switch connects the contractile apparatus within the cell to adhesion structures and facilitates stiffening of the vessel wall, regulating blood flow return

  3. Higher cortical modulation of pain perception in the human brain: Psychological determinant.

    PubMed

    Chen, Andrew Cn

    2009-10-01

    Pain perception and its genesis in the human brain have been reviewed recently. In the current article, the reports on pain modulation in the human brain were reviewed from higher cortical regulation, i.e. top-down effect, particularly studied in psychological determinants. Pain modulation can be examined by gene therapy, physical modulation, pharmacological modulation, psychological modulation, and pathophysiological modulation. In psychological modulation, this article examined (a) willed determination, (b) distraction, (c) placebo, (d) hypnosis, (e) meditation, (f) qi-gong, (g) belief, and (h) emotions, respectively, in the brain function for pain modulation. In each, the operational definition, cortical processing, neuroimaging, and pain modulation were systematically deliberated. However, not all studies had featured the brain modulation processing but rather demonstrated potential effects on human pain. In our own studies on the emotional modulation on human pain, we observed that emotions could be induced from music melodies or pictures perception for reduction of tonic human pain, mainly in potentiation of the posterior alpha EEG fields, likely resulted from underneath activities of precuneous in regulation of consciousness, including pain perception. To sum, higher brain functions become the leading edge research in all sciences. How to solve the information bit of thinking and feeling in the brain can be the greatest challenge of human intelligence. Application of higher cortical modulation of human pain and suffering can lead to the progress of social humanity and civilization.

  4. TAAR1 Modulates Cortical Glutamate NMDA Receptor Function

    PubMed Central

    Espinoza, Stefano; Lignani, Gabriele; Caffino, Lucia; Maggi, Silvia; Sukhanov, Ilya; Leo, Damiana; Mus, Liudmila; Emanuele, Marco; Ronzitti, Giuseppe; Harmeier, Anja; Medrihan, Lucian; Sotnikova, Tatyana D; Chieregatti, Evelina; Hoener, Marius C; Benfenati, Fabio; Tucci, Valter; Fumagalli, Fabio; Gainetdinov, Raul R

    2015-01-01

    Trace Amine-Associated Receptor 1 (TAAR1) is a G protein-coupled receptor expressed in the mammalian brain and known to influence subcortical monoaminergic transmission. Monoamines, such as dopamine, also play an important role within the prefrontal cortex (PFC) circuitry, which is critically involved in high-o5rder cognitive processes. TAAR1-selective ligands have shown potential antipsychotic, antidepressant, and pro-cognitive effects in experimental animal models; however, it remains unclear whether TAAR1 can affect PFC-related processes and functions. In this study, we document a distinct pattern of expression of TAAR1 in the PFC, as well as altered subunit composition and deficient functionality of the glutamate N-methyl-D-aspartate (NMDA) receptors in the pyramidal neurons of layer V of PFC in mice lacking TAAR1. The dysregulated cortical glutamate transmission in TAAR1-KO mice was associated with aberrant behaviors in several tests, indicating a perseverative and impulsive phenotype of mutants. Conversely, pharmacological activation of TAAR1 with selective agonists reduced premature impulsive responses observed in the fixed-interval conditioning schedule in normal mice. Our study indicates that TAAR1 plays an important role in the modulation of NMDA receptor-mediated glutamate transmission in the PFC and related functions. Furthermore, these data suggest that the development of TAAR1-based drugs could provide a novel therapeutic approach for the treatment of disorders related to aberrant cortical functions. PMID:25749299

  5. Modulation of anxiety by cortical serotonin 1A receptors

    PubMed Central

    Piszczek, Lukasz; Piszczek, Agnieszka; Kuczmanska, Joanna; Audero, Enrica; Gross, Cornelius T.

    2015-01-01

    Serotonin (5-HT) plays an important role in the modulation of behavior across animal species. The serotonin 1A receptor (Htr1a) is an inhibitory G-protein coupled receptor that is expressed both on serotonin and non-serotonin neurons in mammals. Mice lacking Htr1a show increased anxiety behavior suggesting that its activation by serotonin has an anxiolytic effect. This outcome can be mediated by either Htr1a population present on serotonin (auto-receptor) or non-serotonin neurons (hetero-receptor), or both. In addition, both transgenic and pharmacological studies have shown that serotonin acts on Htr1a during development to modulate anxiety in adulthood, demonstrating a function for this receptor in the maturation of anxiety circuits in the brain. However, previous studies have been equivocal about which Htr1a population modulates anxiety behavior, with some studies showing a role of Htr1a hetero-receptor and others implicating the auto-receptor. In particular, cell-type specific rescue and suppression of Htr1a expression in either forebrain principal neurons or brainstem serotonin neurons reached opposite conclusions about the role of the two populations in the anxiety phenotype of the knockout. One interpretation of these apparently contradictory findings is that the modulating role of these two populations depends on each other. Here we use a novel Cre-dependent inducible allele of Htr1a in mice to show that expression of Htr1a in cortical principal neurons is sufficient to modulate anxiety. Together with previous findings, these results support a hetero/auto-receptor interaction model for Htr1a function in anxiety. PMID:25759645

  6. Modulation of Cortical Oscillations by Low-Frequency Direct Cortical Stimulation Is State-Dependent

    PubMed Central

    Alagapan, Sankaraleengam; Schmidt, Stephen L.; Lefebvre, Jérémie; Hadar, Eldad; Shin, Hae Won; Frӧhlich, Flavio

    2016-01-01

    Cortical oscillations play a fundamental role in organizing large-scale functional brain networks. Noninvasive brain stimulation with temporally patterned waveforms such as repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS) have been proposed to modulate these oscillations. Thus, these stimulation modalities represent promising new approaches for the treatment of psychiatric illnesses in which these oscillations are impaired. However, the mechanism by which periodic brain stimulation alters endogenous oscillation dynamics is debated and appears to depend on brain state. Here, we demonstrate with a static model and a neural oscillator model that recurrent excitation in the thalamo-cortical circuit, together with recruitment of cortico-cortical connections, can explain the enhancement of oscillations by brain stimulation as a function of brain state. We then performed concurrent invasive recording and stimulation of the human cortical surface to elucidate the response of cortical oscillations to periodic stimulation and support the findings from the computational models. We found that (1) stimulation enhanced the targeted oscillation power, (2) this enhancement outlasted stimulation, and (3) the effect of stimulation depended on behavioral state. Together, our results show successful target engagement of oscillations by periodic brain stimulation and highlight the role of nonlinear interaction between endogenous network oscillations and stimulation. These mechanistic insights will contribute to the design of adaptive, more targeted stimulation paradigms. PMID:27023427

  7. Cortical entrainment to music and its modulation by expertise.

    PubMed

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition.

  8. Cortical entrainment to music and its modulation by expertise.

    PubMed

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  9. Cortical entrainment to music and its modulation by expertise

    PubMed Central

    Doelling, Keith B.; Poeppel, David

    2015-01-01

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta–theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15–30 Hz)—often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  10. Cortical network models of impulse firing in the resting and active states predict cortical energetics.

    PubMed

    Bennett, Maxwell R; Farnell, Les; Gibson, William G; Lagopoulos, Jim

    2015-03-31

    Measurements of the cortical metabolic rate of glucose oxidation [CMR(glc(ox))] have provided a number of interesting and, in some cases, surprising observations. One is the decline in CMR(glc(ox)) during anesthesia and non-rapid eye movement (NREM) sleep, and another, the inverse relationship between the resting-state CMR(glc(ox)) and the transient following input from the thalamus. The recent establishment of a quantitative relationship between synaptic and action potential activity on the one hand and CMR(glc(ox)) on the other allows neural network models of such activity to probe for possible mechanistic explanations of these phenomena. We have carried out such investigations using cortical models consisting of networks of modules with excitatory and inhibitory neurons, each receiving excitatory inputs from outside the network in addition to intermodular connections. Modules may be taken as regions of cortical interest, the inputs from outside the network as arising from the thalamus, and the intermodular connections as long associational fibers. The model shows that the impulse frequency of different modules can differ from each other by less than 10%, consistent with the relatively uniform CMR(glc(ox)) observed across different regions of cortex. The model also shows that, if correlations of the average impulse rate between different modules decreases, there is a concomitant decrease in the average impulse rate in the modules, consistent with the observed drop in CMR(glc(ox)) in NREM sleep and under anesthesia. The model also explains why a transient thalamic input to sensory cortex gives rise to responses with amplitudes inversely dependent on the resting-state frequency, and therefore resting-state CMR(glc(ox)). PMID:25775588

  11. Reward-timing-dependent bidirectional modulation of cortical microcircuits during optical single-neuron operant conditioning.

    PubMed

    Hira, Riichiro; Ohkubo, Fuki; Masamizu, Yoshito; Ohkura, Masamichi; Nakai, Junichi; Okada, Takashi; Matsuzaki, Masanori

    2014-11-24

    Animals rapidly adapt to environmental change. To reveal how cortical microcircuits are rapidly reorganized when an animal recognizes novel reward contingency, we conduct two-photon calcium imaging of layer 2/3 motor cortex neurons in mice and simultaneously reinforce the activity of a single cortical neuron with water delivery. Here we show that when the target neuron is not relevant to a pre-trained forelimb movement, the mouse increases the target neuron activity and the number of rewards delivered during 15-min operant conditioning without changing forelimb movement behaviour. The reinforcement bidirectionally modulates the activity of subsets of non-target neurons, independent of distance from the target neuron. The bidirectional modulation depends on the relative timing between the reward delivery and the neuronal activity, and is recreated by pairing reward delivery and photoactivation of a subset of neurons. Reward-timing-dependent bidirectional modulation may be one of the fundamental processes in microcircuit reorganization for rapid adaptation.

  12. Broadcasting of cortical activity to the olfactory bulb.

    PubMed

    Boyd, Alison M; Kato, Hiroyuki K; Komiyama, Takaki; Isaacson, Jeffry S

    2015-02-24

    Odor representations are initially formed in the olfactory bulb, which contains a topographic glomerular map of odor molecular features. The bulb transmits sensory information directly to piriform cortex, where it is encoded by distributed ensembles of pyramidal cells without spatial order. Intriguingly, piriform cortex pyramidal cells project back to the bulb, but the information contained in this feedback projection is unknown. Here, we use imaging in awake mice to directly monitor activity in the presynaptic boutons of cortical feedback fibers. We show that the cortex provides the bulb with a rich array of information for any individual odor and that cortical feedback is dependent on brain state. In contrast to the stereotyped, spatial arrangement of olfactory bulb glomeruli, cortical inputs tuned to different odors commingle and indiscriminately target individual glomerular channels. Thus, the cortex modulates early odor representations by broadcasting sensory information diffusely onto spatially ordered bulbar circuits.

  13. Broadcasting of cortical activity to the olfactory bulb.

    PubMed

    Boyd, Alison M; Kato, Hiroyuki K; Komiyama, Takaki; Isaacson, Jeffry S

    2015-02-24

    Odor representations are initially formed in the olfactory bulb, which contains a topographic glomerular map of odor molecular features. The bulb transmits sensory information directly to piriform cortex, where it is encoded by distributed ensembles of pyramidal cells without spatial order. Intriguingly, piriform cortex pyramidal cells project back to the bulb, but the information contained in this feedback projection is unknown. Here, we use imaging in awake mice to directly monitor activity in the presynaptic boutons of cortical feedback fibers. We show that the cortex provides the bulb with a rich array of information for any individual odor and that cortical feedback is dependent on brain state. In contrast to the stereotyped, spatial arrangement of olfactory bulb glomeruli, cortical inputs tuned to different odors commingle and indiscriminately target individual glomerular channels. Thus, the cortex modulates early odor representations by broadcasting sensory information diffusely onto spatially ordered bulbar circuits. PMID:25704808

  14. Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia.

    PubMed

    Takahashi, H; Tokushige, H; Shiramatsu, T I; Noda, T; Kanzaki, R

    2015-08-01

    Very slow fluctuations of spontaneous activities significantly influence not only behavioral performance in a conscious state, but also neural activities in an unconscious state. Covariation of pupil and cortical activities may lend important insights into the state-dependent modulation of stimulus encoding, yet this phenomenon has received little attention, especially with regard to non-visual cortices. In the present study, we investigated co-fluctuation of pupil size and neural activity in the auditory cortex of rats under isoflurane anesthesia. Pupil fluctuation consisted of longitudinal irregular shifts, and 1-min cyclic modulations. Both spontaneous and auditory-evoked potentials (AEPs) covaried with the longitudinal fluctuation of pupil size, but not with the 1-min cycle. Pupil size exhibited a positive correlation with spontaneous activity and negative correlation with AEP amplitude, particularly when the pupil size was beyond the normal range. Stimulus-specific adaptation characterized using an oddball paradigm was less dependent on pupil size than AEP. In contrast to the cortical activity, heart rate covaried with pupil size with the 1-min oscillatory component, but not the non-oscillatory component. Furthermore, light exposure induced the pupil reflex through the autonomic system, but did not modify cortical activity, indicating that autonomic activity was not causing the cortical modulation. These results together suggest that cortical activities spontaneously covary with pupillary activity through central cholinergic modulation that triggers sympathetic nerve activation. Such a state-dependent property may be a confounding factor in cortical electrophysiology studies. PMID:25967265

  15. Cortical GluK1 kainate receptors modulate scratching in adult mice.

    PubMed

    Descalzi, Giannina; Chen, Tao; Koga, Kohei; Li, Xiang-Yao; Yamada, Kaori; Zhuo, Min

    2013-09-01

    Recent investigations into the mechanisms mediating itch transmission have focused on spinal mechanisms, whereas few studies have investigated the role of the cerebral cortex in itch-related behaviors. Human imaging studies show that several cortical regions are active in correspondence with itch, including the anterior cingulate cortex (ACC). We present here evidence of cortical modulation of pruritogen-induced scratching behavior. We combine pharmacological, genetic, and electrophysiological approaches to show that cortical GluK1-containing kainate (KA) receptors are involved in scratching induced by histamine and non-histamine-dependent itching stimuli. We further show that scratching corresponds with enhanced excitatory transmission in the ACC through KA receptor modulation of inhibitory circuitry. In addition, we found that inhibiting GluK1-containing KA receptors in the ACC also reduced behavioral nociceptive responses induced by formalin. Our results reveal a new role of the cortex in pruritogen-induced scratching. PMID:23786569

  16. COMMUNICATION: Folate and S-adenosylmethionine modulate synaptic activity in cultured cortical neurons: acute differential impact on normal and apolipoprotein-deficient mice

    NASA Astrophysics Data System (ADS)

    Serra, Michael; Chan, Amy; Dubey, Maya; Gilman, Vladimir; Shea, Thomas B.

    2008-12-01

    Folate deficiency is accompanied by a decline in the cognitive neurotransmitter acetylcholine and a decline in cognitive performance in mice lacking apolipoprotein E (ApoE-/- mice), a low-density lipoprotein that regulates aspects of lipid metabolism. One direct consequence of folate deficiency is a decline in S-adenosylmethionine (SAM). Since dietary SAM supplementation maintains acetylcholine levels and cognitive performance in the absence of folate, we examined herein the impact of folate and SAM on neuronal synaptic activity. Embryonic cortical neurons from mice expressing or lacking ApoE (ApoE+/+ or -/-, respectively) were cultured for 1 month on multi-electrode arrays, and signaling was recorded. ApoE+/+ cultures displayed significantly more frequent spontaneous signals than ApoE-/- cultures. Supplementation with 166 µm SAM (not normally present in culture medium) increased signal frequency and decreased signal amplitude in ApoE+/+ cultures. SAM also increased the frequency of tightly clustered signal bursts. Folate deprivation reversibly reduced signal frequency in ApoE+/+ cultures; SAM supplementation maintained signal frequency despite folate deprivation. These findings support the importance of dietary supplementation with folate and SAM on neuronal health. Supplementation with 166 µm SAM did not alter signaling in ApoE-/- cultures, which may be a reflection of the reduced SAM levels in ApoE-/- mice. The differential impact of SAM on ApoE+/+ and -/- neurons underscores the combined impact of nutritional and genetic deficiencies on neuronal homeostasis.

  17. Robust cortical encoding of slow temporal modulations of speech.

    PubMed

    Ding, Nai; Simon, Jonathan Z

    2013-01-01

    This study investigates the neural representation of speech in complex listening environments. Subjects listened to a narrated story, masked by either another speech stream or by stationary noise. Neural recordings were made using magnetoencephalography (MEG), which can measure cortical activity synchronized to the temporal envelope of speech. When two speech streams are presented simultaneously, cortical activity is predominantly synchronized to the speech stream the listener attends to, even if the unattended, competing-speech stream is more intense (up to 8 dB). When speech is presented together with spectrally matched stationary noise, cortical activity remains precisely synchronized to the temporal envelope of speech until the noise is 9 dB more intense. Critically, the precision of the neural synchronization to speech predicts subjectively rated speech intelligibility in noise. Further analysis reveals that it is longer-latency (∼100 ms) neural responses, but not shorter-latency (∼50 ms) neural responses, that show selectivity to the attended speech and invariance to background noise. This indicates a processing transition, from encoding the acoustic scene to encoding the behaviorally important auditory object, in auditory cortex. In sum, it is demonstrated that neural synchronization to the speech envelope is robust to acoustic interference, whether speech or noise, and therefore provides a strong candidate for the neural basis of acoustic-background invariant speech recognition. PMID:23716243

  18. Posture-related modulation of cortical excitability in the tibialis anterior muscle in humans.

    PubMed

    Obata, Hiroki; Sekiguchi, Hirofumi; Ohtsuki, Tatsuyuki; Nakazawa, Kimitaka

    2014-08-19

    Corticospinal excitability in the lower leg muscles is enhanced during standing as compared to other postures. In the present study, we investigated how the excitability of intracortical circuits that control the tibialis anterior muscle (TA) is modulated during standing. Short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were assessed by the paired-pulse transcranial magnetic stimulation technique during standing (STD) and sitting (SIT) with a comparable background activity level in both the soleus and the TA muscle. The results demonstrated that SICI was less effective during STD than during SIT, whereas ICF was more effective during STD than during SIT. These findings suggest that the excitabilities of these cortical neural circuits are modulated depending on posture. A decrease in SICI and an increase in ICF may reflect subliminal enhancement of the cortical excitability in the TA muscle during standing as compared with that during sitting. PMID:24978603

  19. Task-relevant modulation of primary somatosensory cortex suggests a prefrontal-cortical sensory gating system.

    PubMed

    Schaefer, Michael; Heinze, Hans-Jochen; Rotte, Michael

    2005-08-01

    Increasing evidence suggests that somatosensory information is modulated cortically for task-specific sensory inflow: Several studies report short-term adaptation of representational maps in primary somatosensory cortex (SI) due to attention or induced by task-related motor activity such as handwriting. Recently, it has been hypothesized that the frontal or prefrontal cortex may modulate SI. In order to test this hypothesis, we studied the functional organization of SI while subjects performed the Tower of Hanoi task. This task is known to be related to activation of frontal or prefrontal areas. The functional organization of SI while performing the Tower of Hanoi task was compared to the organization of SI during performing the same movements but without the Tower of Hanoi task and with rest. Topography of SI was assessed using neuromagnetic source imaging based on tactile stimulation of the first (D1) and fifth digits (D5). Performing the Tower of Hanoi task was accompanied by plastic changes in SI as indicated by significant shifts in the cortical representations of D1 and D5: They moved further apart during the Tower of Hanoi task compared to the control task containing the same movements but without the cognitive characteristic. Thus, we conclude that SI maps undergo dynamic modulation depending on motor tasks with different cognitive demands. The results suggest that this short-term plasticity may be regulated by a prefrontal-cortical sensory gating system. PMID:15886021

  20. Global segregation of cortical activity and metastable dynamics

    PubMed Central

    Stratton, Peter; Wiles, Janet

    2015-01-01

    Cortical activity exhibits persistent metastable dynamics. Assemblies of neurons transiently couple (integrate) and decouple (segregate) at multiple spatiotemporal scales; both integration and segregation are required to support metastability. Integration of distant brain regions can be achieved through long range excitatory projections, but the mechanism supporting long range segregation is not clear. We argue that the thalamocortical matrix connections, which project diffusely from the thalamus to the cortex and have long been thought to support cortical gain control, play an equally-important role in cortical segregation. We present a computational model of the diffuse thalamocortical loop, called the competitive cross-coupling (CXC) spiking network. Simulations of the model show how different levels of tonic input from the brainstem to the thalamus could control dynamical complexity in the cortex, directing transitions between sleep, wakefulness and high attention or vigilance. The model also explains how mutually-exclusive activity could arise across large portions of the cortex, such as between the default-mode and task-positive networks. It is robust to noise but does not require noise to autonomously generate metastability. We conclude that the long range segregation observed in brain activity and required for global metastable dynamics could be provided by the thalamocortical matrix, and is strongly modulated by brainstem input to the thalamus. PMID:26379514

  1. Global segregation of cortical activity and metastable dynamics.

    PubMed

    Stratton, Peter; Wiles, Janet

    2015-01-01

    Cortical activity exhibits persistent metastable dynamics. Assemblies of neurons transiently couple (integrate) and decouple (segregate) at multiple spatiotemporal scales; both integration and segregation are required to support metastability. Integration of distant brain regions can be achieved through long range excitatory projections, but the mechanism supporting long range segregation is not clear. We argue that the thalamocortical matrix connections, which project diffusely from the thalamus to the cortex and have long been thought to support cortical gain control, play an equally-important role in cortical segregation. We present a computational model of the diffuse thalamocortical loop, called the competitive cross-coupling (CXC) spiking network. Simulations of the model show how different levels of tonic input from the brainstem to the thalamus could control dynamical complexity in the cortex, directing transitions between sleep, wakefulness and high attention or vigilance. The model also explains how mutually-exclusive activity could arise across large portions of the cortex, such as between the default-mode and task-positive networks. It is robust to noise but does not require noise to autonomously generate metastability. We conclude that the long range segregation observed in brain activity and required for global metastable dynamics could be provided by the thalamocortical matrix, and is strongly modulated by brainstem input to the thalamus.

  2. Cortical control of thermoregulatory sympathetic activation.

    PubMed

    Fechir, M; Klega, A; Buchholz, H G; Pfeifer, N; Balon, S; Schlereth, T; Geber, C; Breimhorst, M; Maihöfner, C; Birklein, F; Schreckenberger, M

    2010-06-01

    Thermoregulation enables adaptation to different ambient temperatures. A complex network of central autonomic centres may be involved. In contrast to the brainstem, the role of the cortex has not been clearly evaluated. This study was therefore designed to address cerebral function during a whole thermoregulatory cycle (cold, neutral and warm stimulation) using 18-fluordeoxyglucose-PET (FDG-PET). Sympathetic activation parameters were co-registered. Ten healthy male volunteers were examined three times on three different days in a water-perfused whole-body suit. After a baseline period (32 degrees C), temperature was either decreased to 7 degrees C (cold), increased to 50 degrees C (warm) or kept constant (32 degrees C, neutral), thereafter the PET examination was performed. Cerebral glucose metabolism was increased in infrapontine brainstem and cerebellar hemispheres during cooling and warming, each compared with neutral temperature. Simultaneously, FDG uptake decreased in the bilateral anterior/mid-cingulate cortex during warming, and in the right insula during cooling and warming. Conjunction analyses revealed that right insular deactivation and brainstem activation appeared both during cold and warm stimulation. Metabolic connectivity analyses revealed positive correlations between the cortical activations, and negative correlations between these cortical areas and brainstem/cerebellar regions. Heart rate changes negatively correlated with glucose metabolism in the anterior cingulate cortex and in the middle frontal gyrus/dorsolateral prefrontal cortex, and changes of sweating with glucose metabolism in the posterior cingulate cortex. In summary, these results suggest that the cerebral cortex exerts an inhibitory control on autonomic centres located in the brainstem or cerebellum. These findings may represent reasonable explanations for sympathetic hyperactivity, which occurs, for example, after hemispheric stroke.

  3. Global cortical activity predicts shape of hand during grasping

    PubMed Central

    Agashe, Harshavardhan A.; Paek, Andrew Y.; Zhang, Yuhang; Contreras-Vidal, José L.

    2015-01-01

    Recent studies show that the amplitude of cortical field potentials is modulated in the time domain by grasping kinematics. However, it is unknown if these low frequency modulations persist and contain enough information to decode grasp kinematics in macro-scale activity measured at the scalp via electroencephalography (EEG). Further, it is unclear as to whether joint angle velocities or movement synergies are the optimal kinematics spaces to decode. In this offline decoding study, we infer from human EEG, hand joint angular velocities as well as synergistic trajectories as subjects perform natural reach-to-grasp movements. Decoding accuracy, measured as the correlation coefficient (r) between the predicted and actual movement kinematics, was r = 0.49 ± 0.02 across 15 hand joints. Across the first three kinematic synergies, decoding accuracies were r = 0.59 ± 0.04, 0.47 ± 0.06, and 0.32 ± 0.05. The spatial-temporal pattern of EEG channel recruitment showed early involvement of contralateral frontal-central scalp areas followed by later activation of central electrodes over primary sensorimotor cortical areas. Information content in EEG about the grasp type peaked at 250 ms after movement onset. The high decoding accuracies in this study are significant not only as evidence for time-domain modulation in macro-scale brain activity, but for the field of brain-machine interfaces as well. Our decoding strategy, which harnesses the neural “symphony” as opposed to local members of the neural ensemble (as in intracranial approaches), may provide a means of extracting information about motor intent for grasping without the need for penetrating electrodes and suggests that it may be soon possible to develop non-invasive neural interfaces for the control of prosthetic limbs. PMID:25914616

  4. Striatal dopamine and glutamate receptors modulate methamphetamine-induced cortical Fos expression.

    PubMed

    Gross, N B; Marshall, J F

    2009-07-21

    Methamphetamine (mAMPH) is a psychostimulant drug that increases extracellular levels of monoamines throughout the brain. It has previously been observed that a single injection of mAMPH increases immediate early gene (IEG) expression in both the striatum and cerebral cortex. Moreover, this effect is modulated by dopamine and glutamate receptors since systemic administration of dopamine or glutamate antagonists has been found to alter mAMPH-induced striatal and cortical IEG expression. However, because dopamine and glutamate receptors are found in extra-striatal as well as striatal brain regions, studies employing systemic injection of dopamine or glutamate antagonists fail to localize the effects of mAMPH-induced activation. In the present experiments, the roles of striatal dopamine and glutamate receptors in mAMPH-induced gene expression in the striatum and cerebral cortex were examined. The nuclear expression of Fos, the protein product of the IEG c-fos, was quantified in both the striatum and the cortex of animals receiving intrastriatal dopamine or glutamate antagonist administration. Intrastriatal infusion of dopamine (D1 or D2) or glutamate [N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)] antagonists affected not only mAMPH-induced striatal, but also cortical, Fos expression. Overall, the effects of the antagonists occurred dose-dependently, in both the infused and non-infused hemispheres, with greater influences occurring in the infused hemisphere. Finally, unilateral intrastriatal infusion of dopamine or glutamate antagonists changed the behavior of the rats from characteristic mAMPH-induced stereotypy to rotation ipsilateral to the infusion. These results demonstrate that mAMPH's actions on striatal dopamine and glutamate receptors modulate the widespread cortical activation induced by mAMPH. It is hypothesized that dopamine release from nigrostriatal terminals modulates activity within striatal efferent

  5. Correlation between Cortical State and Locus Coeruleus Activity: Implications for Sensory Coding in Rat Barrel Cortex

    PubMed Central

    Fazlali, Zeinab; Ranjbar-Slamloo, Yadollah; Adibi, Mehdi; Arabzadeh, Ehsan

    2016-01-01

    Cortical state modulates the background activity of cortical neurons, and their evoked response to sensory stimulation. Multiple mechanisms are involved in switching between cortical states including various neuromodulatory systems. Locus Coeruleus (LC) is one of the major neuromodulatory nuclei in the brainstem with widespread projections throughout the brain and modulates the activity of cells and networks. Here, we quantified the link between the LC spontaneous activity, cortical state and sensory processing in the rat vibrissal somatosensory “barrel” cortex (BC). We simultaneously recorded unit activity from LC and BC along with prefrontal electroencephalogram (EEG) while presenting brief whisker deflections under urethane anesthesia. The ratio of low to high frequency components of EEG (referred to as the L/H ratio) was employed to identify cortical state. We found that the spontaneous activity of LC units exhibited a negative correlation with the L/H ratio. Cross-correlation analysis revealed that changes in LC firing preceded changes in the cortical state: the correlation of the LC firing profile with the L/H ratio was maximal at an average lag of −1.2 s. We further quantified BC neuronal responses to whisker stimulation during the synchronized and desynchronized states. In the desynchronized state, BC neurons showed lower stimulus detection threshold, higher response fidelity, and shorter response latency. The most prominent change was observed in the late phase of BC evoked activity (100–400 ms post stimulus onset): almost every BC unit exhibited a greater late response during the desynchronized state. Categorization of the BC evoked responses based on LC activity (into high and low LC discharge rates) resulted in highly similar response profiles compared to categorization based on the cortical state (low and high L/H ratios). These findings provide evidence for the involvement of the LC neuromodulatory system in desynchronization of cortical state

  6. Active Chemical Thermodynamics promoted by activity of cortical actin

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Bhaswati; Chaudhuri, Abhishek; Gowrishankar, Kripa; Rao, Madan

    2011-03-01

    The spatial distribution and dynamics of formation and breakup of the nanoclusters of cell surface proteins is controlled by the active remodeling dynamics of the underlying cortical actin. To explain these observations, we have proposed a novel mechanism of nanoclustering, involving the transient binding to and advection along constitutively occuring ``asters'' of cortical actin. We study the consequences of such active actin-based clustering, in the context of chemical reactions involving conformational changes of cell surface proteins. We find that the active remodeling of cortical actin, can give rise to a dramatic increase in efficiency and extent of conformational spread, even at low levels of expression at the cell surface. We define a activity temperature (τa) arising due to actin activities which can be used to describe chemical thermodynamics of the system. We plot TTT (time-temparature-transformation) curves and compute the Arrhenius factors which depend on τa . With this, the active asters can be treated as enzymes whose enzymatic reaction rate can be related to the activity.

  7. Oscillatory entrainment of the motor cortical network during motor imagery is modulated by the feedback modality.

    PubMed

    Vukelić, Mathias; Gharabaghi, Alireza

    2015-05-01

    Neurofeedback of self-regulated brain activity in circumscribed cortical regions is used as a novel strategy to facilitate functional restoration following stroke. Basic knowledge about its impact on motor system oscillations and functional connectivity is however scarce. Specifically, a direct comparison between different feedback modalities and their neural signatures is missing. We assessed a neurofeedback training intervention of modulating β-activity in circumscribed sensorimotor regions by kinesthetic motor imagery (MI). Right-handed healthy participants received two different feedback modalities contingent to their MI-associated brain activity in a cross-over design: (I) visual feedback with a brain-computer interface (BCI) and (II) proprioceptive feedback with a brain-robot interface (BRI) orthosis attached to the right hand. High-density electroencephalography was used to examine the reactivity of the cortical motor system during the training session of each task by studying both local oscillatory power entrainment and distributed functional connectivity. Both feedback modalities activated a distributed functional connectivity network of coherent oscillations. A significantly higher skill and lower variability of self-controlled sensorimotor β-band modulation could, however, be achieved in the BRI condition. This gain in controlling regional motor oscillations was accompanied by functional coupling of remote β-band and θ-band activity in bilateral fronto-central regions and left parieto-occipital regions, respectively. The functional coupling of coherent θ-band oscillations correlated moreover with the skill of regional β-modulation thus revealing a motor learning related network. Our findings indicate that proprioceptive feedback is more suitable than visual feedback to entrain the motor network architecture during the interplay between motor imagery and feedback processing thus resulting in better volitional control of regional brain activity.

  8. Aversive learning modulates cortical representations of object categories.

    PubMed

    Dunsmoor, Joseph E; Kragel, Philip A; Martin, Alex; LaBar, Kevin S

    2014-11-01

    Experimental studies of conditioned learning reveal activity changes in the amygdala and unimodal sensory cortex underlying fear acquisition to simple stimuli. However, real-world fears typically involve complex stimuli represented at the category level. A consequence of category-level representations of threat is that aversive experiences with particular category members may lead one to infer that related exemplars likewise pose a threat, despite variations in physical form. Here, we examined the effect of category-level representations of threat on human brain activation using 2 superordinate categories (animals and tools) as conditioned stimuli. Hemodynamic activity in the amygdala and category-selective cortex was modulated by the reinforcement contingency, leading to widespread fear of different exemplars from the reinforced category. Multivariate representational similarity analyses revealed that activity patterns in the amygdala and object-selective cortex were more similar among exemplars from the threat versus safe category. Learning to fear animate objects was additionally characterized by enhanced functional coupling between the amygdala and fusiform gyrus. Finally, hippocampal activity co-varied with object typicality and amygdala activation early during training. These findings provide novel evidence that aversive learning can modulate category-level representations of object concepts, thereby enabling individuals to express fear to a range of related stimuli.

  9. Aversive Learning Modulates Cortical Representations of Object Categories

    PubMed Central

    Dunsmoor, Joseph E.; Kragel, Philip A.; Martin, Alex; LaBar, Kevin S.

    2014-01-01

    Experimental studies of conditioned learning reveal activity changes in the amygdala and unimodal sensory cortex underlying fear acquisition to simple stimuli. However, real-world fears typically involve complex stimuli represented at the category level. A consequence of category-level representations of threat is that aversive experiences with particular category members may lead one to infer that related exemplars likewise pose a threat, despite variations in physical form. Here, we examined the effect of category-level representations of threat on human brain activation using 2 superordinate categories (animals and tools) as conditioned stimuli. Hemodynamic activity in the amygdala and category-selective cortex was modulated by the reinforcement contingency, leading to widespread fear of different exemplars from the reinforced category. Multivariate representational similarity analyses revealed that activity patterns in the amygdala and object-selective cortex were more similar among exemplars from the threat versus safe category. Learning to fear animate objects was additionally characterized by enhanced functional coupling between the amygdala and fusiform gyrus. Finally, hippocampal activity co-varied with object typicality and amygdala activation early during training. These findings provide novel evidence that aversive learning can modulate category-level representations of object concepts, thereby enabling individuals to express fear to a range of related stimuli. PMID:23709642

  10. Evidence of Conjoint Activation of the Anterior Insular and Cingulate Cortices during Effortful Tasks.

    PubMed

    Engström, Maria; Karlsson, Thomas; Landtblom, Anne-Marie; Craig, A D Bud

    2014-01-01

    The ability to perform effortful tasks is a topic that has received considerable interest in the research of higher functions of the human brain. Neuroimaging studies show that the anterior insular and the anterior cingulate cortices are involved in a multitude of cognitive tasks that require mental effort. In this study, we investigated brain responses to effort using cognitive tasks with task-difficulty modulations and functional magnetic resonance imaging (fMRI). We hypothesized that effortful performance involves modulation of activation in the anterior insular and the anterior cingulate cortices, and that the modulation correlates with individual performance levels. Healthy participants performed tasks probing verbal working memory capacity using the reading span task, and visual perception speed using the inspection time task. In the fMRI analysis, we focused on identifying effort-related brain activation. The results showed that working memory and inspection time performances were directly related. The bilateral anterior insular and anterior cingulate cortices showed significantly increased activation during each task with common portions that were active across both tasks. We observed increased brain activation in the right anterior insula and the anterior cingulate cortex in participants with low working memory performance. In line with the reported results, we suggest that activation in the anterior insular and cingulate cortices is consistent with the neural efficiency hypothesis (Neubauer).

  11. D2 dopamine receptors modulate neuronal resonance in subthalamic nucleus and cortical high-voltage spindles through HCN channels.

    PubMed

    Yang, Chen; Yan, Zhiqiang; Zhao, Bo; Wang, Julei; Gao, Guodong; Zhu, Junling; Wang, Wenting

    2016-06-01

    The high-voltage spindles (HVSs), one of the characteristic oscillations that include theta frequencies in the basal ganglia (BG)-cortical system, are involved in immobile behavior and show increasing power in Parkinson's disease (PD). Our previous results suggested that the D2 dopamine receptor might be involved in HVSs modulations in a rat model of PD. Membrane resonance is one of the cellular mechanisms of network oscillation; therefore, we investigated how dopamine modulates the theta frequency membrane resonance of neurons in the subthalamic nucleus (STN), a central pacemaker of BG, and whether such changes in STN neurons subsequently alter HVSs in the BG-cortical system. In particular, we tested whether dopamine modulates HVSs through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels-dependent membrane resonance in STN neurons. We found that an antagonist of D2 receptors, but not of D1 receptors, inhibited membrane resonance and HCN currents of STN neurons through a G-protein activity in acute brain slices. Our further in vivo experiments using local injection of a D2 receptor antagonist or an HCN blocker in STNs of free-moving rats showed an increase in HVSs power and correlation in the BG-cortical system. Local injection of lamotrigine, an HCN agonist, counteracted the effect induced by the D2 antagonist. Taken together, our results revealed a potential cellular mechanism underlying HVSs activity modulation in the BG-cortical system, i.e. tuning HCN activities in STN neurons through dopamine D2 receptors. Our findings might lead to a new direction in PD treatment by providing promising new drug targets for HVSs activity modulation.

  12. Early development of synchrony in cortical activations in the human

    PubMed Central

    Koolen, N.; Dereymaeker, A.; Räsänen, O.; Jansen, K.; Vervisch, J.; Matic, V.; Naulaers, G.; De Vos, M.; Van Huffel, S.; Vanhatalo, S.

    2016-01-01

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates. PMID:26876605

  13. Cortical entrainment of human hypoglossal motor unit activities

    PubMed Central

    Laine, Christopher M.; Nickerson, Laura A.

    2012-01-01

    Output from the primary motor cortex contains oscillations that can have frequency-specific effects on the firing of motoneurons (MNs). Whereas much is known about the effects of oscillatory cortical drive on the output of spinal MN pools, considerably less is known about the effects on cranial motor nuclei, which govern speech/oromotor control. Here, we investigated cortical input to one such motor pool, the hypoglossal motor nucleus (HMN), which controls muscles of the tongue. We recorded intramuscular genioglossus electromyogram (EMG) and scalp EEG from healthy adult subjects performing a tongue protrusion task. Cortical entrainment of HMN population activity was assessed by measuring coherence between EEG and multiunit EMG activity. In addition, cortical entrainment of individual MN firing activity was assessed by measuring phase locking between single motor unit (SMU) action potentials and EEG oscillations. We found that cortical entrainment of multiunit activity was detectable within the 15- to 40-Hz frequency range but was inconsistent across recordings. By comparison, cortical entrainment of SMU spike timing was reliable within the same frequency range. Furthermore, this effect was found to be intermittent over time. Our study represents an important step in understanding corticomuscular synchronization in the context of human oromotor control and is the first study to document SMU entrainment by cortical oscillations in vivo. PMID:22049332

  14. tDCS modulates cortical nociceptive processing but has little to no impact on pain perception.

    PubMed

    Ihle, Kristin; Rodriguez-Raecke, Rea; Luedtke, Kerstin; May, Arne

    2014-10-01

    Transcranial direct current stimulation (tDCS) effectively modulates cortical excitability. Several studies suggest clinical efficacy in chronic pain syndromes. However, little is known regarding its effects on cortical pain processing. In this double-blind, randomized, cross-over, sham controlled study, we examined the effects of anodal, cathodal, and sham stimulation of the left motor cortex in 16 healthy volunteers using functional imaging during an acute heat pain paradigm as well as pain thresholds, pain intensity ratings, and quantitative sensory testing. tDCS was applied at 1 mA for 15 minutes. Neither cathodal nor anodal tDCS significantly changed brain activation in response to nociceptive stimulation when compared with sham stimulation. However, contrasting the interaction of stimulation modes (anodal/cathodal) resulted in a significant decrease of activation in the hypothalamus, inferior parietal cortex, inferior parietal lobule, anterior insula, and precentral gyrus, contralateral to the stimulation site after anodal stimulation, which showed the opposite behavior after cathodal stimulation. Pain ratings and heat hyperalgesia showed only a subclinical pain reduction after anodal tDCS. Larger-scale clinical trials using higher tDCS intensities or longer durations are necessary to assess the neurophysiological effect and subsequently the therapeutic potential of tDCS.

  15. Non-linear Membrane Properties in Entorhinal Cortical Stellate Cells Reduce Modulation of Input-Output Responses by Voltage Fluctuations

    PubMed Central

    Fernandez, Fernando R.; Malerba, Paola; White, John A.

    2015-01-01

    The presence of voltage fluctuations arising from synaptic activity is a critical component in models of gain control, neuronal output gating, and spike rate coding. The degree to which individual neuronal input-output functions are modulated by voltage fluctuations, however, is not well established across different cortical areas. Additionally, the extent and mechanisms of input-output modulation through fluctuations have been explored largely in simplified models of spike generation, and with limited consideration for the role of non-linear and voltage-dependent membrane properties. To address these issues, we studied fluctuation-based modulation of input-output responses in medial entorhinal cortical (MEC) stellate cells of rats, which express strong sub-threshold non-linear membrane properties. Using in vitro recordings, dynamic clamp and modeling, we show that the modulation of input-output responses by random voltage fluctuations in stellate cells is significantly limited. In stellate cells, a voltage-dependent increase in membrane resistance at sub-threshold voltages mediated by Na+ conductance activation limits the ability of fluctuations to elicit spikes. Similarly, in exponential leaky integrate-and-fire models using a shallow voltage-dependence for the exponential term that matches stellate cell membrane properties, a low degree of fluctuation-based modulation of input-output responses can be attained. These results demonstrate that fluctuation-based modulation of input-output responses is not a universal feature of neurons and can be significantly limited by subthreshold voltage-gated conductances. PMID:25909971

  16. Non-linear Membrane Properties in Entorhinal Cortical Stellate Cells Reduce Modulation of Input-Output Responses by Voltage Fluctuations.

    PubMed

    Fernandez, Fernando R; Malerba, Paola; White, John A

    2015-04-01

    The presence of voltage fluctuations arising from synaptic activity is a critical component in models of gain control, neuronal output gating, and spike rate coding. The degree to which individual neuronal input-output functions are modulated by voltage fluctuations, however, is not well established across different cortical areas. Additionally, the extent and mechanisms of input-output modulation through fluctuations have been explored largely in simplified models of spike generation, and with limited consideration for the role of non-linear and voltage-dependent membrane properties. To address these issues, we studied fluctuation-based modulation of input-output responses in medial entorhinal cortical (MEC) stellate cells of rats, which express strong sub-threshold non-linear membrane properties. Using in vitro recordings, dynamic clamp and modeling, we show that the modulation of input-output responses by random voltage fluctuations in stellate cells is significantly limited. In stellate cells, a voltage-dependent increase in membrane resistance at sub-threshold voltages mediated by Na+ conductance activation limits the ability of fluctuations to elicit spikes. Similarly, in exponential leaky integrate-and-fire models using a shallow voltage-dependence for the exponential term that matches stellate cell membrane properties, a low degree of fluctuation-based modulation of input-output responses can be attained. These results demonstrate that fluctuation-based modulation of input-output responses is not a universal feature of neurons and can be significantly limited by subthreshold voltage-gated conductances.

  17. Oxytocin modulates female sociosexual behavior through a specific class of prefrontal cortical interneurons

    PubMed Central

    Nakajima, Miho; Görlich, Andreas; Heintz, Nathaniel

    2014-01-01

    SUMMARY Human imaging studies have revealed that intranasal administration of the “prosocial” hormone oxytocin (OT) activates the frontal cortex, and that this action of OT correlates with enhanced brain function in autism. Here we report the discovery of a population of somatostatin (Sst) positive, regular spiking interneurons that express the oxytocin receptor (OxtrINs). Silencing of OxtrINs in the medial prefrontal cortex (mPFC) of female mice resulted in loss of social interest in male mice specifically during the sexually receptive phase of the estrous cycle. This sociosexual deficit was also present in mice in which the Oxtr gene was conditionally deleted from the mPFC, and in control mice infused with an Oxtr antagonist. Our data demonstrate a gender, cell type and state specific role for OT/Oxtr signaling in the mPFC, and identify a latent cortical circuit element that may modulate other complex social behaviors in response to OT. PMID:25303526

  18. Trigeminal nerve stimulation modulates brainstem more than cortical excitability in healthy humans.

    PubMed

    Mercante, B; Pilurzi, G; Ginatempo, F; Manca, A; Follesa, P; Tolu, E; Deriu, F

    2015-11-01

    Multiple sites in the central nervous system (CNS) have been hypothesized to explain the beneficial effects of transcutaneous trigeminal nerve stimulation (TNS) on several disorders. This work investigated the acute effects of TNS on the excitability of brainstem and intracortical circuits, as well as on sensorimotor integration processes at cortical level in physiological conditions. Brainstem excitability was evaluated in seventeen healthy subjects measuring the R1 and R2 areas of the blink reflex (BR) and its recovery cycle, with cortical excitability and sensorimotor integration assessed by probing short-interval (SICI) and long-interval (LICI) intracortical inhibition, with short-interval (SICF), intracortical facilitation (ICF), short-latency (SAI) and long-latency (LAI) inhibition measuring motor potentials evoked in the first dorsal interosseous muscle by TMS of the contralateral motor cortex. Neurophysiological parameters were assessed, in seventeen healthy subjects, before and after cyclic 20-min TNS delivered bilaterally to the infraorbital nerve. After TNS, the area of the R2 was significantly reduced (p = 0.018). By contrast, R1 area and R2 recovery cycle were unaffected. Similarly, SICI, ICF, LICI, SICF, SAI and LAI appeared unaltered after TNS. These data suggest that, in normal subjects, TNS mainly acts on brainstem polysynaptic circuits mediating the R2 component of the BR and plays a minor role in modifying the activity of higher-level structures involved in the R2 recovery cycle and in modulation of cortical excitability. A further investigation of a chronic TNS-induced effect may disclose a higher potential for TNS in producing measurable after effects on its CNS targets. PMID:26259748

  19. Formation and Dynamics of Waves in a Cortical Model of Cholinergic Modulation.

    PubMed

    Roach, James P; Ben-Jacob, Eshel; Sander, Leonard M; Zochowski, Michal R

    2015-08-01

    Acetylcholine (ACh) is a regulator of neural excitability and one of the neurochemical substrates of sleep. Amongst the cellular effects induced by cholinergic modulation are a reduction in spike-frequency adaptation (SFA) and a shift in the phase response curve (PRC). We demonstrate in a biophysical model how changes in neural excitability and network structure interact to create three distinct functional regimes: localized asynchronous, traveling asynchronous, and traveling synchronous. Our results qualitatively match those observed experimentally. Cortical activity during slow wave sleep (SWS) differs from that during REM sleep or waking states. During SWS there are traveling patterns of activity in the cortex; in other states stationary patterns occur. Our model is a network composed of Hodgkin-Huxley type neurons with a M-current regulated by ACh. Regulation of ACh level can account for dynamical changes between functional regimes. Reduction of the magnitude of this current recreates the reduction in SFA the shift from a type 2 to a type 1 PRC observed in the presence of ACh. When SFA is minimal (in waking or REM sleep state, high ACh) patterns of activity are localized and easily pinned by network inhomogeneities. When SFA is present (decreasing ACh), traveling waves of activity naturally arise. A further decrease in ACh leads to a high degree of synchrony within traveling waves. We also show that the level of ACh determines how sensitive network activity is to synaptic heterogeneity. These regimes may have a profound functional significance as stationary patterns may play a role in the proper encoding of external input as memory and traveling waves could lead to synaptic regularization, giving unique insights into the role and significance of ACh in determining patterns of cortical activity and functional differences arising from the patterns.

  20. Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration.

    PubMed

    Halgren, Eric; Kaestner, Erik; Marinkovic, Ksenija; Cash, Sydney S; Wang, Chunmao; Schomer, Donald L; Madsen, Joseph R; Ulbert, Istvan

    2015-09-01

    Theta may play a central role during language understanding and other extended cognitive processing, providing an envelope for widespread integration of participating cortical areas. We used linear microelectrode arrays in epileptics to define the circuits generating theta in inferotemporal, perirhinal, entorhinal, prefrontal and anterior cingulate cortices. In all locations, theta was generated by excitatory current sinks in middle layers which receive predominantly feedforward inputs, alternating with sinks in superficial layers which receive mainly feedback/associative inputs. Baseline and event-related theta were generated by indistinguishable laminar profiles of transmembrane currents and unit-firing. Word presentation could reset theta phase, permitting theta to contribute to late event-related potentials, even when theta power decreases relative to baseline. Limited recordings during sentence reading are consistent with rhythmic theta activity entrained by a given word modulating the neural background for the following word. These findings show that theta occurs spontaneously, and can be momentarily suppressed, reset and synchronized by words. Theta represents an alternation between feedforward/divergent and associative/convergent processing modes that may temporally organize sustained processing and optimize the timing of memory formation. We suggest that words are initially encoded via a ventral feedforward stream which is lexicosemantic in the anteroventral temporal lobe; its arrival may trigger a widespread theta rhythm which integrates the word within a larger context. PMID:25801916

  1. Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration.

    PubMed

    Halgren, Eric; Kaestner, Erik; Marinkovic, Ksenija; Cash, Sydney S; Wang, Chunmao; Schomer, Donald L; Madsen, Joseph R; Ulbert, Istvan

    2015-09-01

    Theta may play a central role during language understanding and other extended cognitive processing, providing an envelope for widespread integration of participating cortical areas. We used linear microelectrode arrays in epileptics to define the circuits generating theta in inferotemporal, perirhinal, entorhinal, prefrontal and anterior cingulate cortices. In all locations, theta was generated by excitatory current sinks in middle layers which receive predominantly feedforward inputs, alternating with sinks in superficial layers which receive mainly feedback/associative inputs. Baseline and event-related theta were generated by indistinguishable laminar profiles of transmembrane currents and unit-firing. Word presentation could reset theta phase, permitting theta to contribute to late event-related potentials, even when theta power decreases relative to baseline. Limited recordings during sentence reading are consistent with rhythmic theta activity entrained by a given word modulating the neural background for the following word. These findings show that theta occurs spontaneously, and can be momentarily suppressed, reset and synchronized by words. Theta represents an alternation between feedforward/divergent and associative/convergent processing modes that may temporally organize sustained processing and optimize the timing of memory formation. We suggest that words are initially encoded via a ventral feedforward stream which is lexicosemantic in the anteroventral temporal lobe; its arrival may trigger a widespread theta rhythm which integrates the word within a larger context.

  2. Mesoscopic Patterns of Neural Activity Support Songbird Cortical Sequences

    PubMed Central

    Guitchounts, Grigori; Velho, Tarciso; Lois, Carlos; Gardner, Timothy J.

    2015-01-01

    Time-locked sequences of neural activity can be found throughout the vertebrate forebrain in various species and behavioral contexts. From “time cells” in the hippocampus of rodents to cortical activity controlling movement, temporal sequence generation is integral to many forms of learned behavior. However, the mechanisms underlying sequence generation are not well known. Here, we describe a spatial and temporal organization of the songbird premotor cortical microcircuit that supports sparse sequences of neural activity. Multi-channel electrophysiology and calcium imaging reveal that neural activity in premotor cortex is correlated with a length scale of 100 µm. Within this length scale, basal-ganglia–projecting excitatory neurons, on average, fire at a specific phase of a local 30 Hz network rhythm. These results show that premotor cortical activity is inhomogeneous in time and space, and that a mesoscopic dynamical pattern underlies the generation of the neural sequences controlling song. PMID:26039895

  3. Contributions of Subsurface Cortical Modulations to Discrimination of Executed and Imagined Grasp Forces through Stereoelectroencephalography

    PubMed Central

    Murphy, Brian A.; Miller, Jonathan P.; Gunalan, Kabilar; Ajiboye, A. Bolu

    2016-01-01

    Stereoelectroencephalographic (SEEG) depth electrodes have the potential to record neural activity from deep brain structures not easily reached with other intracranial recording technologies. SEEG electrodes were placed through deep cortical structures including central sulcus and insular cortex. In order to observe changes in frequency band modulation, participants performed force matching trials at three distinct force levels using two different grasp configurations: a power grasp and a lateral pinch. Signals from these deeper structures were found to contain information useful for distinguishing force from rest trials as well as different force levels in some participants. High frequency components along with alpha and beta bands recorded from electrodes located near the primary motor cortex wall of central sulcus and electrodes passing through sensory cortex were found to be the most useful for classification of force versus rest although one participant did have significant modulation in the insular cortex. This study electrophysiologically corroborates with previous imaging studies that show force-related modulation occurs inside of central sulcus and insular cortex. The results of this work suggest that depth electrodes could be useful tools for investigating the functions of deeper brain structures as well as showing that central sulcus and insular cortex may contain neural signals that could be used for control of a grasp force BMI. PMID:26963246

  4. Input-Dependent Frequency Modulation of Cortical Gamma Oscillations Shapes Spatial Synchronization and Enables Phase Coding

    PubMed Central

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-01-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25–80Hz) may play a significant role in information processing, for example by neural grouping (‘binding’) and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency

  5. Activation of 5-HT2A/2C receptors reduces the excitability of cultured cortical neurons.

    PubMed

    Hu, Lingli; Liu, Chunhua; Dang, Minyan; Luo, Bin; Guo, Yiping; Wang, Haitao

    2016-10-01

    The abundant forebrain serotonergic projections are believed to modulate the activities of cortical neurons. 5-HT2 receptor among multiple subtypes of serotonin receptors contributes to the modulation of excitability, synaptic transmissions and plasticity. In the present study, whole-cell patch-clamp recording was adopted to examine whether activation of 5-HT2A/2C receptors would have any impact on the excitability of cultured cortical neurons. We found that 2,5-Dimethoxy-4-iodoamphetamine (DOI), a selective 5-HT2A/2C receptor agonist, rapidly and reversibly depressed spontaneous action potentials mimicking the effect of serotonin. The decreased excitability was also observed for current-evoked firing. Additionally DOI increased neuronal input resistance. Hyperpolarization-activated cyclic nucleotide-gated cationic channels (HCN) did not account for the inhibition of spontaneous firing. The synaptic contribution was ruled out in that DOI augmented excitation and attenuated inhibition to actually favor an increase in the excitability. Our findings revealed that activation of 5-HT2A/2C receptors reduces neuronal excitability, which would deepen our understanding of serotonergic modulation of cortical activities. PMID:27585751

  6. Altered visual feedback modulates cortical excitability in a mirror-box-like paradigm.

    PubMed

    Senna, Irene; Russo, Cristina; Parise, Cesare Valerio; Ferrario, Irene; Bolognini, Nadia

    2015-06-01

    Watching self-generated unilateral hand movements reflected in a mirror-oriented along the midsagittal plane-enhances the excitability of the primary motor cortex (M1) ipsilateral to the moving hand of the observer. Mechanisms detecting sensory-motor conflicts generated by the mirror reflection of such movements might mediate this effect; if so, cortical excitability should be modulated by the magnitude of sensory-motor conflict. To this end, we explored the modulatory effects of an altered visual feedback on M1 excitability in a mirror-box-like paradigm, by increasing or decreasing the speed of the observed movement. Healthy subjects performed movements with their left index finger while watching a video of a hand superimposed to their right static hand, which was hidden from view. The hand observed in the video executed the same movement as the observer's left hand, but at slower, same, or faster paces. Motor evoked potentials (MEPs) induced by transcranial magnetic stimulation were measured from the first dorsal interosseous and the abductor digiti minimi of the participant's hidden resting hand. The excitability of the M1 ipsilateral to the moving hand was systematically modulated by the speed of the observed hand movement: the slower the observed movement, the greater the MEP amplitude from both muscles. This evidence shows that the magnitude of the visual-motor conflicts can be used to adjust the activity of the observer's motor system. Hence, an appropriate alteration of the visual feedback, here the reduction in the movement speed, may be useful to increase its modulatory effect on motor cortical excitability. PMID:25850405

  7. Altered visual feedback modulates cortical excitability in a mirror-box-like paradigm.

    PubMed

    Senna, Irene; Russo, Cristina; Parise, Cesare Valerio; Ferrario, Irene; Bolognini, Nadia

    2015-06-01

    Watching self-generated unilateral hand movements reflected in a mirror-oriented along the midsagittal plane-enhances the excitability of the primary motor cortex (M1) ipsilateral to the moving hand of the observer. Mechanisms detecting sensory-motor conflicts generated by the mirror reflection of such movements might mediate this effect; if so, cortical excitability should be modulated by the magnitude of sensory-motor conflict. To this end, we explored the modulatory effects of an altered visual feedback on M1 excitability in a mirror-box-like paradigm, by increasing or decreasing the speed of the observed movement. Healthy subjects performed movements with their left index finger while watching a video of a hand superimposed to their right static hand, which was hidden from view. The hand observed in the video executed the same movement as the observer's left hand, but at slower, same, or faster paces. Motor evoked potentials (MEPs) induced by transcranial magnetic stimulation were measured from the first dorsal interosseous and the abductor digiti minimi of the participant's hidden resting hand. The excitability of the M1 ipsilateral to the moving hand was systematically modulated by the speed of the observed hand movement: the slower the observed movement, the greater the MEP amplitude from both muscles. This evidence shows that the magnitude of the visual-motor conflicts can be used to adjust the activity of the observer's motor system. Hence, an appropriate alteration of the visual feedback, here the reduction in the movement speed, may be useful to increase its modulatory effect on motor cortical excitability.

  8. The plasticity of the mirror system: How reward learning modulates cortical motor simulation of others

    PubMed Central

    Trilla Gros, Irene; Panasiti, Maria Serena; Chakrabarti, Bhismadev

    2015-01-01

    Cortical motor simulation supports the understanding of others' actions and intentions. This mechanism is thought to rely on the mirror neuron system (MNS), a brain network that is active both during action execution and observation. Indirect evidence suggests that (alpha/beta) mu suppression, an electroencephalographic (EEG) index of MNS activity, is modulated by reward. In this study we aimed to test the plasticity of the MNS by directly investigating the link between (alpha/beta) mu suppression and reward. 40 individuals from a general population sample took part in an evaluative conditioning experiment, where different neutral faces were associated with high or low reward values. In the test phase, EEG was recorded while participants viewed videoclips of happy expressions made by the conditioned faces. Alpha/beta mu suppression (identified using event-related desynchronisation of specific independent components) in response to rewarding faces was found to be greater than for non-rewarding faces. This result provides a mechanistic insight into the plasticity of the MNS and, more generally, into the role of reward in modulating physiological responses linked to empathy. PMID:25744871

  9. Interactions between autonomic cardiovascular regulation and cortical activity: a CNV study.

    PubMed

    Duschek, Stefan; Wörsching, Jana; Reyes del Paso, Gustavo A

    2013-04-01

    The study investigated interactions between autonomic cardiovascular regulation and cortical activity. In 54 healthy subjects, baroreflex sensitivity (BRS) and respiratory sinus arrhythmia (RSA) were assessed at resting conditions. As an EEG indicator of cortical excitability, the contingent negative variation (CNV) was induced using a constant foreperiod reaction time task. At bivariate level, only RSA showed a moderate positive correlation with the CNV recorded at frontal electrodes. However, when common variance of BRS and RSA was controlled for in multiple regression analysis, an inverse association between BRS and the frontal CNV also arose. The inverse association between BRS and the CNV is discussed as reflecting bottom-up modulation of cortical excitability by baroreceptor afferents. The positive correlation between RSA and the CNV may relate to the interplay between prefrontal processing and cardiac vagal tone. PMID:23351157

  10. Ghrelin accelerates synapse formation and activity development in cultured cortical networks

    PubMed Central

    2014-01-01

    Background While ghrelin was initially related to appetite stimulation and growth hormone secretion, it also has a neuroprotective effect in neurodegenerative diseases and regulates cognitive function. The cellular basis of those processes is related to synaptic efficacy and plasticity. Previous studies have shown that ghrelin not only stimulates synapse formation in cultured cortical neurons and hippocampal slices, but also alters some of the electrophysiological properties of neurons in the hypothalamus, amygdala and other subcortical areas. However, direct evidence for ghrelin’s ability to modulate the activity in cortical neurons is not available yet. In this study, we investigated the effect of acylated ghrelin on the development of the activity level and activity patterns in cortical neurons, in relation to its effect on synaptogenesis. Additionally, we quantitatively evaluated the expression of the receptor for acylated ghrelin – growth hormone secretagogue receptor-1a (GHSR-1a) during development. Results We performed electrophysiology and immunohistochemistry on dissociated cortical cultures from neonates, treated chronically with acylated ghrelin. On average 76 ± 4.6% of the cortical neurons expressed GHSR-1a. Synapse density was found to be much higher in ghrelin treated cultures than in controls across all age groups (1, 2 or 3 weeks). In all cultures (control and ghrelin treated), network activity gradually increased until it reached a maximum after approximately 3 weeks, followed by a slight decrease towards a plateau. During early developmental stages (1–2 weeks), the activity was much higher in ghrelin treated cultures and consequently, they reached the plateau value almost a week earlier than controls. Conclusions Acylated ghrelin leads to earlier network formation and activation in cultured cortical neuronal networks, the latter being a possibly consequence of accelerated synaptogenesis. PMID:24742241

  11. Existence of high-order correlations in cortical activity

    NASA Astrophysics Data System (ADS)

    Benucci, Andrea; Verschure, Paul F.; König, Peter

    2003-10-01

    Neurons collect signals originating from a large number of other cells. The variability of this integrated population activity at the millisecond time scale is a critical constraint on the degree of signal integration and processing performed by single neurons. Optical imaging, EEG, and fMRI studies have indicated that cortical activity shows a high degree of variability at a time scale of hundreds of ms. However, currently no experimental methods are available to directly assess the variability in the activity of populations of neurons at a time scale closer to that of the characteristic time constants of neurons, i.e., around 10 ms. Here we integrate pertinent experimental data in one rigorous mathematical framework to demonstrate that (1) the high temporal variability in the spiking activity of individual neurons, (2) the second-order correlation properties of the spiking activity of cortical neurons, and (3) the correlations of the subthreshold dynamics, all impose high amplitude, fast variability in the population activity of cortical neurons. This implies that higher order correlations, a necessary condition for temporal coding models, must be a central feature of cortical dynamics.

  12. Cortical Network Models of Firing Rates in the Resting and Active States Predict BOLD Responses.

    PubMed

    Bennett, Maxwell R; Farnell, Les; Gibson, William G; Lagopoulos, Jim

    2015-01-01

    Measurements of blood oxygenation level dependent (BOLD) signals have produced some surprising observations. One is that their amplitude is proportional to the entire activity in a region of interest and not just the fluctuations in this activity. Another is that during sleep and anesthesia the average BOLD correlations between regions of interest decline as the activity declines. Mechanistic explanations of these phenomena are described here using a cortical network model consisting of modules with excitatory and inhibitory neurons, taken as regions of cortical interest, each receiving excitatory inputs from outside the network, taken as subcortical driving inputs in addition to extrinsic (intermodular) connections, such as provided by associational fibers. The model shows that the standard deviation of the firing rate is proportional to the mean frequency of the firing when the extrinsic connections are decreased, so that the mean BOLD signal is proportional to both as is observed experimentally. The model also shows that if these extrinsic connections are decreased or the frequency of firing reaching the network from the subcortical driving inputs is decreased, or both decline, there is a decrease in the mean firing rate in the modules accompanied by decreases in the mean BOLD correlations between the modules, consistent with the observed changes during NREM sleep and under anesthesia. Finally, the model explains why a transient increase in the BOLD signal in a cortical area, due to a transient subcortical input, gives rises to responses throughout the cortex as observed, with these responses mediated by the extrinsic (intermodular) connections.

  13. Secondary instabilities modulate cortical complexity in the mammalian brain

    NASA Astrophysics Data System (ADS)

    Budday, Silvia; Steinmann, Paul; Kuhl, Ellen

    2015-10-01

    Disclosing the origin of convolutions in the mammalian brain remains a scientific challenge. Primary folds form before we are born: they are static, well defined and highly preserved across individuals. Secondary folds occur and disappear throughout our entire lifetime: they are dynamic, irregular and highly variable among individuals. While extensive research has improved our understanding of primary folding in the mammalian brain, secondary folding remains understudied and poorly understood. Here, we show that secondary instabilities can explain the increasing complexity of our brain surface as we age. Using the nonlinear field theories of mechanics supplemented by the theory of finite growth, we explore the critical conditions for secondary instabilities. We show that with continuing growth, our brain surface continues to bifurcate into increasingly complex morphologies. Our results suggest that even small geometric variations can have a significant impact on surface morphogenesis. Secondary bifurcations, and with them morphological changes during childhood and adolescence, are closely associated with the formation and loss of neuronal connections. Understanding the correlation between neuronal connectivity, cortical thickness, surface morphology and ultimately behaviour, could have important implications on the diagnostics, classification and treatment of neurological disorders.

  14. Age-Related Variability in Cortical Activity during Language Processing

    ERIC Educational Resources Information Center

    Fridriksson, Julius; Morrow, K. Leigh; Moser, Dana; Baylis, Gordon C.

    2006-01-01

    Purpose: The present study investigated the extent of cortical activity during overt picture naming using functional magnetic resonance imaging (fMRI). Method: Participants comprised 20 healthy, adult participants with ages ranging from 20 to 82 years. While undergoing fMRI, participants completed a picture-naming task consisting of 60…

  15. Enhancement of Cortical Network Activity in vitro and Promotion of GABAergic Neurogenesis by Stimulation with an Electromagnetic Field with a 150 MHz Carrier Wave Pulsed with an Alternating 10 and 16 Hz Modulation.

    PubMed

    Gramowski-Voß, Alexandra; Schwertle, Hans-Joachim; Pielka, Anna-Maria; Schultz, Luise; Steder, Anne; Jügelt, Konstantin; Axmann, Jürgen; Pries, Wolfgang

    2015-01-01

    In recent years, various stimuli were identified capable of enhancing neurogenesis, a process which is dysfunctional in the senescent brain and in neurodegenerative and certain neuropsychiatric diseases. Applications of electromagnetic fields to brain tissue have been shown to affect cellular properties and their importance for therapies in medicine is recognized. In this study, differentiating murine cortical networks on multiwell microelectrode arrays were repeatedly exposed to an extremely low-electromagnetic field (ELEMF) with alternating 10 and 16 Hz frequencies piggy backed onto a 150 MHz carrier frequency. The ELEMF exposure stimulated the electrical network activity and intensified the structure of bursts. Further, the exposure to electromagnetic fields within the first 28 days in vitro of the differentiation of the network activity induced also reorganization within the burst structure. This effect was already most pronounced at 14 days in vitro after 10 days of exposure. Overall, the development of cortical activity under these conditions was accelerated. These functional electrophysiological changes were accompanied by morphological ones. The percentage of neurons in the neuron glia co-culture was increased without affecting the total number of cells, indicating an enhancement of neurogenesis. The ELEMF exposure selectively promoted the proliferation of a particular population of neurons, evidenced by the increased proportion of GABAergic neurons. The results support the initial hypothesis that this kind of ELEMF stimulation could be a treatment option for specific indications with promising potential for CNS applications, especially for degenerative diseases, such as Alzheimer's disease and other dementias.

  16. Targeted, noninvasive blockade of cortical neuronal activity

    NASA Astrophysics Data System (ADS)

    McDannold, Nathan; Zhang, Yongzhi; Power, Chanikarn; Arvanitis, Costas D.; Vykhodtseva, Natalia; Livingstone, Margaret

    2015-11-01

    Here we describe a novel method to noninvasively modulate targeted brain areas through the temporary disruption of the blood-brain barrier (BBB) via focused ultrasound, enabling focal delivery of a neuroactive substance. Ultrasound was used to locally disrupt the BBB in rat somatosensory cortex, and intravenous administration of GABA then produced a dose-dependent suppression of somatosensory-evoked potentials in response to electrical stimulation of the sciatic nerve. No suppression was observed 1-5 days afterwards or in control animals where the BBB was not disrupted. This method has several advantages over existing techniques: it is noninvasive; it is repeatable via additional GABA injections; multiple brain regions can be affected simultaneously; suppression magnitude can be titrated by GABA dose; and the method can be used with freely behaving subjects. We anticipate that the application of neuroactive substances in this way will be a useful tool for noninvasively mapping brain function, and potentially for surgical planning or novel therapies.

  17. Dynamical activities of primary somatosensory cortices studied by magnetoencephalography

    NASA Astrophysics Data System (ADS)

    Kishida, Kuniharu

    2009-11-01

    A blind identification method of transfer functions in feedback systems is introduced for examination of dynamical activities of cortices by magnetoencephalography study. Somatosensory activities are examined in 5 Hz periodical median nerve stimulus. In the present paper, we will try two careful preprocessing procedures for the identification method to obtain impulse responses between primary somatosensory cortices. Time series data of the somatosensory evoked field are obtained by using a blind source separation of the T/k type (fractional) decorrelation method. Time series data of current dipoles of primary somatosensory cortices are transformed from the time series data of the somatosensory evoked field by the inverse problem. Fluctuations of current dipoles of them are obtained after elimination of deterministic periodical evoked waveforms. An identification method based on feedback system theory is used for estimation of transfer functions in a feedback model from obtained fluctuations of currents dipoles of primary somatosensory cortices. Dynamical activities between them are presented by Bode diagrams of transfer functions and their impulse responses: the time delay of about 30 ms via corpus callosum is found in the impulse response of identified transfer function.

  18. Stimuli Reduce the Dimensionality of Cortical Activity

    PubMed Central

    Mazzucato, Luca; Fontanini, Alfredo; La Camera, Giancarlo

    2016-01-01

    The activity of ensembles of simultaneously recorded neurons can be represented as a set of points in the space of firing rates. Even though the dimension of this space is equal to the ensemble size, neural activity can be effectively localized on smaller subspaces. The dimensionality of the neural space is an important determinant of the computational tasks supported by the neural activity. Here, we investigate the dimensionality of neural ensembles from the sensory cortex of alert rats during periods of ongoing (inter-trial) and stimulus-evoked activity. We find that dimensionality grows linearly with ensemble size, and grows significantly faster during ongoing activity compared to evoked activity. We explain these results using a spiking network model based on a clustered architecture. The model captures the difference in growth rate between ongoing and evoked activity and predicts a characteristic scaling with ensemble size that could be tested in high-density multi-electrode recordings. Moreover, we present a simple theory that predicts the existence of an upper bound on dimensionality. This upper bound is inversely proportional to the amount of pair-wise correlations and, compared to a homogeneous network without clusters, it is larger by a factor equal to the number of clusters. The empirical estimation of such bounds depends on the number and duration of trials and is well predicted by the theory. Together, these results provide a framework to analyze neural dimensionality in alert animals, its behavior under stimulus presentation, and its theoretical dependence on ensemble size, number of clusters, and correlations in spiking network models. PMID:26924968

  19. Stimuli Reduce the Dimensionality of Cortical Activity.

    PubMed

    Mazzucato, Luca; Fontanini, Alfredo; La Camera, Giancarlo

    2016-01-01

    The activity of ensembles of simultaneously recorded neurons can be represented as a set of points in the space of firing rates. Even though the dimension of this space is equal to the ensemble size, neural activity can be effectively localized on smaller subspaces. The dimensionality of the neural space is an important determinant of the computational tasks supported by the neural activity. Here, we investigate the dimensionality of neural ensembles from the sensory cortex of alert rats during periods of ongoing (inter-trial) and stimulus-evoked activity. We find that dimensionality grows linearly with ensemble size, and grows significantly faster during ongoing activity compared to evoked activity. We explain these results using a spiking network model based on a clustered architecture. The model captures the difference in growth rate between ongoing and evoked activity and predicts a characteristic scaling with ensemble size that could be tested in high-density multi-electrode recordings. Moreover, we present a simple theory that predicts the existence of an upper bound on dimensionality. This upper bound is inversely proportional to the amount of pair-wise correlations and, compared to a homogeneous network without clusters, it is larger by a factor equal to the number of clusters. The empirical estimation of such bounds depends on the number and duration of trials and is well predicted by the theory. Together, these results provide a framework to analyze neural dimensionality in alert animals, its behavior under stimulus presentation, and its theoretical dependence on ensemble size, number of clusters, and correlations in spiking network models. PMID:26924968

  20. Stereotypic wheel running decreases cortical activity in mice

    PubMed Central

    Fisher, Simon P.; Cui, Nanyi; McKillop, Laura E.; Gemignani, Jessica; Bannerman, David M.; Oliver, Peter L.; Peirson, Stuart N.; Vyazovskiy, Vladyslav V.

    2016-01-01

    Prolonged wakefulness is thought to gradually increase ‘sleep need' and influence subsequent sleep duration and intensity, but the role of specific waking behaviours remains unclear. Here we report the effect of voluntary wheel running during wakefulness on neuronal activity in the motor and somatosensory cortex in mice. We find that stereotypic wheel running is associated with a substantial reduction in firing rates among a large subpopulation of cortical neurons, especially at high speeds. Wheel running also has longer-term effects on spiking activity across periods of wakefulness. Specifically, cortical firing rates are significantly higher towards the end of a spontaneous prolonged waking period. However, this increase is abolished when wakefulness is dominated by running wheel activity. These findings indicate that wake-related changes in firing rates are determined not only by wake duration, but also by specific waking behaviours. PMID:27748455

  1. Orbitofrontal cortical activity during repeated free choice.

    PubMed

    Campos, Michael; Koppitch, Kari; Andersen, Richard A; Shimojo, Shinsuke

    2012-06-01

    Neurons in the orbitofrontal cortex (OFC) have been shown to encode subjective values, suggesting a role in preference-based decision-making, although the precise relation to choice behavior is unclear. In a repeated two-choice task, subjective values of each choice can account for aggregate choice behavior, which is the overall likelihood of choosing one option over the other. Individual choices, however, are impossible to predict with knowledge of relative subjective values alone. In this study we investigated the role of internal factors in choice behavior with a simple but novel free-choice task and simultaneous recording from individual neurons in nonhuman primate OFC. We found that, first, the observed sequences of choice behavior included periods of exceptionally long runs of each of two available options and periods of frequent switching. Neither a satiety-based mechanism nor a random selection process could explain the observed choice behavior. Second, OFC neurons encode important features of the choice behavior. These features include activity selective for exceptionally long runs of a given choice (stay selectivity) as well as activity selective for switches between choices (switch selectivity). These results suggest that OFC neural activity, in addition to encoding subjective values on a long timescale that is sensitive to satiety, also encodes a signal that fluctuates on a shorter timescale and thereby reflects some of the statistically improbable aspects of free-choice behavior.

  2. Influence of spiking activity on cortical local field potentials

    PubMed Central

    Waldert, Stephan; Lemon, Roger N; Kraskov, Alexander

    2013-01-01

    The intra-cortical local field potential (LFP) reflects a variety of electrophysiological processes including synaptic inputs to neurons and their spiking activity. It is still a common assumption that removing high frequencies, often above 300 Hz, is sufficient to exclude spiking activity from LFP activity prior to analysis. Conclusions based on such supposedly spike-free LFPs can result in false interpretations of neurophysiological processes and erroneous correlations between LFPs and behaviour or spiking activity. Such findings might simply arise from spike contamination rather than from genuine changes in synaptic input activity. Although the subject of recent studies, the extent of LFP contamination by spikes is unclear, and the fundamental problem remains. Using spikes recorded in the motor cortex of the awake monkey, we investigated how different factors, including spike amplitude, duration and firing rate, together with the noise statistic, can determine the extent to which spikes contaminate intra-cortical LFPs. We demonstrate that such contamination is realistic for LFPs with a frequency down to ∼10 Hz. For LFP activity below ∼10 Hz, such as movement-related potential, contamination is theoretically possible but unlikely in real situations. Importantly, LFP frequencies up to the (high-) gamma band can remain unaffected. This study shows that spike–LFP crosstalk in intra-cortical recordings should be assessed for each individual dataset to ensure that conclusions based on LFP analysis are valid. To this end, we introduce a method to detect and to visualise spike contamination, and provide a systematic guide to assess spike contamination of intra-cortical LFPs. PMID:23981719

  3. Computational Study of Subdural Cortical Stimulation: Effects of Simulating Anisotropic Conductivity on Activation of Cortical Neurons

    PubMed Central

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2015-01-01

    Subdural cortical stimulation (SuCS) is an appealing method in the treatment of neurological disorders, and computational modeling studies of SuCS have been applied to determine the optimal design for electrotherapy. To achieve a better understanding of computational modeling on the stimulation effects of SuCS, the influence of anisotropic white matter conductivity on the activation of cortical neurons was investigated in a realistic head model. In this paper, we constructed pyramidal neuronal models (layers 3 and 5) that showed primary excitation of the corticospinal tract, and an anatomically realistic head model reflecting complex brain geometry. The anisotropic information was acquired from diffusion tensor magnetic resonance imaging (DT-MRI) and then applied to the white matter at various ratios of anisotropic conductivity. First, we compared the isotropic and anisotropic models; compared to the isotropic model, the anisotropic model showed that neurons were activated in the deeper bank during cathodal stimulation and in the wider crown during anodal stimulation. Second, several popular anisotropic principles were adapted to investigate the effects of variations in anisotropic information. We observed that excitation thresholds varied with anisotropic principles, especially with anodal stimulation. Overall, incorporating anisotropic conductivity into the anatomically realistic head model is critical for accurate estimation of neuronal responses; however, caution should be used in the selection of anisotropic information. PMID:26057524

  4. Molecular Correlates of Cortical Network Modulation by Long-Term Sensory Experience in the Adult Rat Barrel Cortex

    ERIC Educational Resources Information Center

    Vallès, Astrid; Granic, Ivica; De Weerd, Peter; Martens, Gerard J. M.

    2014-01-01

    Modulation of cortical network connectivity is crucial for an adaptive response to experience. In the rat barrel cortex, long-term sensory stimulation induces cortical network modifications and neuronal response changes of which the molecular basis is unknown. Here, we show that long-term somatosensory stimulation by enriched environment…

  5. Correlated activity supports efficient cortical processing

    PubMed Central

    Hung, Chou P.; Cui, Ding; Chen, Yueh-peng; Lin, Chia-pei; Levine, Matthew R.

    2015-01-01

    Visual recognition is a computational challenge that is thought to occur via efficient coding. An important concept is sparseness, a measure of coding efficiency. The prevailing view is that sparseness supports efficiency by minimizing redundancy and correlations in spiking populations. Yet, we recently reported that “choristers”, neurons that behave more similarly (have correlated stimulus preferences and spontaneous coincident spiking), carry more generalizable object information than uncorrelated neurons (“soloists”) in macaque inferior temporal (IT) cortex. The rarity of choristers (as low as 6% of IT neurons) indicates that they were likely missed in previous studies. Here, we report that correlation strength is distinct from sparseness (choristers are not simply broadly tuned neurons), that choristers are located in non-granular output layers, and that correlated activity predicts human visual search efficiency. These counterintuitive results suggest that a redundant correlational structure supports efficient processing and behavior. PMID:25610392

  6. Perceptual expectation evokes category-selective cortical activity.

    PubMed

    Esterman, Michael; Yantis, Steven

    2010-05-01

    Selective visual attention directed to a location (even in the absence of a stimulus) increases activity in the corresponding regions of visual cortex and enhances the speed and accuracy of target perception. We further explored top-down influences on perceptual representations by manipulating observers' expectations about the category of an upcoming target. Observers viewed a display in which an object (either a face or a house) gradually emerged from a state of phase-scrambled noise; a cue established expectation about the object category. Observers were faster to categorize faces (gender discrimination) or houses (structural discrimination) when the category of the partially scrambled object matched their expectation. Functional magnetic resonance imaging revealed that this expectation was associated with anticipatory increases in category-specific visual cortical activity, even in the absence of object- or category-specific visual information. Expecting a face evoked increased activity in face-selective cortical regions in the fusiform gyrus and superior temporal sulcus. Conversely, expecting a house increased activity in parahippocampal gyrus. These results suggest that visual anticipation facilitates subsequent perception by recruiting, in advance, the same cortical mechanisms as those involved in perception. PMID:19759124

  7. Attention selectively modulates cortical entrainment in different regions of the speech spectrum.

    PubMed

    Baltzell, Lucas S; Horton, Cort; Shen, Yi; Richards, Virginia M; D'Zmura, Michael; Srinivasan, Ramesh

    2016-08-01

    Recent studies have uncovered a neural response that appears to track the envelope of speech, and have shown that this tracking process is mediated by attention. It has been argued that this tracking reflects a process of phase-locking to the fluctuations of stimulus energy, ensuring that this energy arrives during periods of high neuronal excitability. Because all acoustic stimuli are decomposed into spectral channels at the cochlea, and this spectral decomposition is maintained along the ascending auditory pathway and into auditory cortex, we hypothesized that the overall stimulus envelope is not as relevant to cortical processing as the individual frequency channels; attention may be mediating envelope tracking differentially across these spectral channels. To test this we reanalyzed data reported by Horton et al. (2013), where high-density EEG was recorded while adults attended to one of two competing naturalistic speech streams. In order to simulate cochlear filtering, the stimuli were passed through a gammatone filterbank, and temporal envelopes were extracted at each filter output. Following Horton et al. (2013), the attended and unattended envelopes were cross-correlated with the EEG, and local maxima were extracted at three different latency ranges corresponding to distinct peaks in the cross-correlation function (N1, P2, and N2). We found that the ratio between the attended and unattended cross-correlation functions varied across frequency channels in the N1 latency range, consistent with the hypothesis that attention differentially modulates envelope-tracking activity across spectral channels. PMID:27195825

  8. Stochastic Resonance Modulates Neural Synchronization within and between Cortical Sources

    PubMed Central

    Ward, Lawrence M.; MacLean, Shannon E.; Kirschner, Aaron

    2010-01-01

    Neural synchronization is a mechanism whereby functionally specific brain regions establish transient networks for perception, cognition, and action. Direct addition of weak noise (fast random fluctuations) to various neural systems enhances synchronization through the mechanism of stochastic resonance (SR). Moreover, SR also occurs in human perception, cognition, and action. Perception, cognition, and action are closely correlated with, and may depend upon, synchronized oscillations within specialized brain networks. We tested the hypothesis that SR-mediated neural synchronization occurs within and between functionally relevant brain areas and thus could be responsible for behavioral SR. We measured the 40-Hz transient response of the human auditory cortex to brief pure tones. This response arises when the ongoing, random-phase, 40-Hz activity of a group of tuned neurons in the auditory cortex becomes synchronized in response to the onset of an above-threshold sound at its “preferred” frequency. We presented a stream of near-threshold standard sounds in various levels of added broadband noise and measured subjects' 40-Hz response to the standards in a deviant-detection paradigm using high-density EEG. We used independent component analysis and dipole fitting to locate neural sources of the 40-Hz response in bilateral auditory cortex, left posterior cingulate cortex and left superior frontal gyrus. We found that added noise enhanced the 40-Hz response in all these areas. Moreover, added noise also increased the synchronization between these regions in alpha and gamma frequency bands both during and after the 40-Hz response. Our results demonstrate neural SR in several functionally specific brain regions, including areas not traditionally thought to contribute to the auditory 40-Hz transient response. In addition, we demonstrated SR in the synchronization between these brain regions. Thus, both intra- and inter-regional synchronization of neural activity are

  9. Network-State Modulation of Power-Law Frequency-Scaling in Visual Cortical Neurons

    PubMed Central

    Béhuret, Sébastien; Baudot, Pierre; Yger, Pierre; Bal, Thierry; Destexhe, Alain; Frégnac, Yves

    2009-01-01

    Various types of neural-based signals, such as EEG, local field potentials and intracellular synaptic potentials, integrate multiple sources of activity distributed across large assemblies. They have in common a power-law frequency-scaling structure at high frequencies, but it is still unclear whether this scaling property is dominated by intrinsic neuronal properties or by network activity. The latter case is particularly interesting because if frequency-scaling reflects the network state it could be used to characterize the functional impact of the connectivity. In intracellularly recorded neurons of cat primary visual cortex in vivo, the power spectral density of Vm activity displays a power-law structure at high frequencies with a fractional scaling exponent. We show that this exponent is not constant, but depends on the visual statistics used to drive the network. To investigate the determinants of this frequency-scaling, we considered a generic recurrent model of cortex receiving a retinotopically organized external input. Similarly to the in vivo case, our in computo simulations show that the scaling exponent reflects the correlation level imposed in the input. This systematic dependence was also replicated at the single cell level, by controlling independently, in a parametric way, the strength and the temporal decay of the pairwise correlation between presynaptic inputs. This last model was implemented in vitro by imposing the correlation control in artificial presynaptic spike trains through dynamic-clamp techniques. These in vitro manipulations induced a modulation of the scaling exponent, similar to that observed in vivo and predicted in computo. We conclude that the frequency-scaling exponent of the Vm reflects stimulus-driven correlations in the cortical network activity. Therefore, we propose that the scaling exponent could be used to read-out the “effective” connectivity responsible for the dynamical signature of the population signals measured

  10. Network-state modulation of power-law frequency-scaling in visual cortical neurons.

    PubMed

    El Boustani, Sami; Marre, Olivier; Béhuret, Sébastien; Baudot, Pierre; Yger, Pierre; Bal, Thierry; Destexhe, Alain; Frégnac, Yves

    2009-09-01

    Various types of neural-based signals, such as EEG, local field potentials and intracellular synaptic potentials, integrate multiple sources of activity distributed across large assemblies. They have in common a power-law frequency-scaling structure at high frequencies, but it is still unclear whether this scaling property is dominated by intrinsic neuronal properties or by network activity. The latter case is particularly interesting because if frequency-scaling reflects the network state it could be used to characterize the functional impact of the connectivity. In intracellularly recorded neurons of cat primary visual cortex in vivo, the power spectral density of V(m) activity displays a power-law structure at high frequencies with a fractional scaling exponent. We show that this exponent is not constant, but depends on the visual statistics used to drive the network. To investigate the determinants of this frequency-scaling, we considered a generic recurrent model of cortex receiving a retinotopically organized external input. Similarly to the in vivo case, our in computo simulations show that the scaling exponent reflects the correlation level imposed in the input. This systematic dependence was also replicated at the single cell level, by controlling independently, in a parametric way, the strength and the temporal decay of the pairwise correlation between presynaptic inputs. This last model was implemented in vitro by imposing the correlation control in artificial presynaptic spike trains through dynamic-clamp techniques. These in vitro manipulations induced a modulation of the scaling exponent, similar to that observed in vivo and predicted in computo. We conclude that the frequency-scaling exponent of the V(m) reflects stimulus-driven correlations in the cortical network activity. Therefore, we propose that the scaling exponent could be used to read-out the "effective" connectivity responsible for the dynamical signature of the population signals measured

  11. Amygdala activation for eye contact despite complete cortical blindness.

    PubMed

    Burra, Nicolas; Hervais-Adelman, Alexis; Kerzel, Dirk; Tamietto, Marco; de Gelder, Beatrice; Pegna, Alan J

    2013-06-19

    Cortical blindness refers to the loss of vision that occurs after destruction of the primary visual cortex. Although there is no sensory cortex and hence no conscious vision, some cortically blind patients show amygdala activation in response to facial or bodily expressions of emotion. Here we investigated whether direction of gaze could also be processed in the absence of any functional visual cortex. A well-known patient with bilateral destruction of his visual cortex and subsequent cortical blindness was investigated in an fMRI paradigm during which blocks of faces were presented either with their gaze directed toward or away from the viewer. Increased right amygdala activation was found in response to directed compared with averted gaze. Activity in this region was further found to be functionally connected to a larger network associated with face and gaze processing. The present study demonstrates that, in human subjects, the amygdala response to eye contact does not require an intact primary visual cortex. PMID:23785160

  12. Medial prefrontal cortical lesions modulate baroreflex sensitivity in the rat.

    PubMed

    Verberne, A J; Lewis, S J; Worland, P J; Beart, P M; Jarrott, B; Christie, M J; Louis, W J

    1987-11-24

    Previous neuroanatomical studies in rats have demonstrated that the medial prefrontal cortex sends projections to the nucleus of the solitary tract which also receives the bulk of baroreceptor information from primary afferents within the IXth and Xth cranial nerves. The present study examines the influence of the prefrontal cortex on baroreceptor heart rate reflex in conscious rats. Baroreceptor reflex activity was examined in rats with bilateral excitotoxin (N-methyl-D-aspartate)-induced lesions of the medial prefrontal cortex and in control rats (artificial cerebrospinal fluid). Seventeen to eighteen days after lesioning, reflex heart rate responses were recorded following intravenous bolus doses of the pressor agent phenylephrine and the depressor agent sodium nitroprusside. Baroreceptor reflex parameters i.e., maximum and average baroreceptor reflex gain (or sensitivity): minimum and maximum heart rate plateaus; heart rate range; upper and lower reflex thresholds, were determined by sigmoidal computerized curve-fitting. Lesioning the medial prefrontal cortex did not affect resting mean arterial pressure and heart rate. However, the lesion reduced maximum and average baroreceptor reflex gain and produced a small reduction in lower reflex threshold. The other parameters were unaffected by the lesion. These observations suggest that although the medial prefrontal cortex does not exert a tonic influence on brainstem vasomotor neurons, there may be a descending excitatory projection from this brain region to medullary neurones involved in the baroreceptor reflex arc. PMID:3319045

  13. Smoking experience modulates the cortical integration of vision and haptics.

    PubMed

    Yalachkov, Yavor; Kaiser, Jochen; Görres, Andreas; Seehaus, Arne; Naumer, Marcus J

    2012-01-01

    Human neuroplasticity of multisensory integration has been studied mainly in the context of natural or artificial training situations in healthy subjects. However, regular smokers also offer the opportunity to assess the impact of intensive daily multisensory interactions with smoking-related objects on the neural correlates of crossmodal object processing. The present functional magnetic resonance imaging study revealed that smokers show a comparable visuo-haptic integration pattern for both smoking paraphernalia and control objects in the left lateral occipital complex, a region playing a crucial role in crossmodal object recognition. Moreover, the degree of nicotine dependence correlated positively with the magnitude of visuo-haptic integration in the left lateral occipital complex (LOC) for smoking-associated but not for control objects. In contrast, in the left LOC non-smokers displayed a visuo-haptic integration pattern for control objects, but not for smoking paraphernalia. This suggests that prolonged smoking-related multisensory experiences in smokers facilitate the merging of visual and haptic inputs in the lateral occipital complex for the respective stimuli. Studying clinical populations who engage in compulsive activities may represent an ecologically valid approach to investigating the neuroplasticity of multisensory integration.

  14. Acupuncture modulates cortical thickness and functional connectivity in knee osteoarthritis patients

    PubMed Central

    Chen, Xiaoyan; Spaeth, Rosa B.; Retzepi, Kallirroi; Ott, Daniel; Kong, Jian

    2014-01-01

    In this study, we investigated cortical thickness and functional connectivity across longitudinal acupuncture treatments in patients with knee osteoarthritis (OA). Over a period of four weeks (six treatments), we collected resting state functional magnetic resonance imaging (fMRI) scans from 30 patients before their first, third and sixth treatments. Clinical outcome showed a significantly greater Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score (improvement) with verum acupuncture compared to the sham acupuncture. Longitudinal cortical thickness analysis showed that the cortical thickness at left posterior medial prefrontal cortex (pMPFC) decreased significantly in the sham group across treatment sessions as compared with verum group. Resting state functional connectivity (rsFC) analysis using the left pMPFC as a seed showed that after longitudinal treatments, the rsFC between the left pMPFC and the rostral anterior cingulate cortex (rACC), medial frontal pole (mFP) and periaquiduct grey (PAG) are significantly greater in the verum acupuncture group as compared with the sham group. Our results suggest that acupuncture may achieve its therapeutic effect on knee OA pain by preventing cortical thinning and decreases in functional connectivity in major pain related areas, therefore modulating pain in the descending pain modulatory pathway. PMID:25258037

  15. Golli Myelin Basic Proteins Modulate Voltage-Operated Ca(++) Influx and Development in Cortical and Hippocampal Neurons.

    PubMed

    Vt, Cheli; DA, Santiago González; V, Spreuer; V, Handley; At, Campagnoni; Pm, Paez

    2016-10-01

    The golli proteins, products of the myelin basic protein gene, are widely expressed in oligodendrocyte progenitor cells and neurons during the postnatal development of the brain. While golli appears to be important for oligodendrocyte migration and differentiation, its function in neuronal development is completely unknown. We have found that golli proteins function as new and novel modulators of voltage-operated Ca(++) channels (VOCCs) in neurons. In vitro, golli knock-out (KO) neurons exhibit decreased Ca(++) influx after plasma membrane depolarization and a substantial maturational delay. Increased expression of golli proteins enhances L-type Ca(++) entry and processes outgrowth in cortical neurons, and pharmacological activation of L-type Ca(++) channels stimulates maturation and prevents cell death in golli-KO neurons. In situ, Ca(++) influx mediated by L-type VOCCs was significantly decreased in cortical and hippocampal neurons of the golli-KO brain. These Ca(++) alterations affect cortical and hippocampal development and the proliferation and survival of neural progenitor cells during the postnatal development of the golli-KO brain. The CA1/3 sections and the dentate gyrus of the hippocampus were reduced in the golli-KO mice as well as the density of dendrites in the somatosensory cortex. Furthermore, the golli-KO mice display abnormal behavior including deficits in episodic memory and reduced anxiety. Because of the expression of the golli proteins within neurons in learning and memory centers of the brain, this work has profound implication in neurodegenerative diseases and neurological disorders.

  16. Serotonin signaling modulates the effects of familial risk for depression on cortical thickness.

    PubMed

    Bansal, Ravi; Peterson, Bradley S; Gingrich, Jay; Hao, Xuejun; Odgerel, Zagaa; Warner, Virginia; Wickramaratne, Priya J; Talati, Ardesheer; Ansorge, Mark; Brown, Alan S; Sourander, Andre; Weissman, Myrna M

    2016-02-28

    Depression is a highly familial and a heritable illness that is more prevalent in the biological offspring of the depressed individuals than in the general population. In a 3-generation, 30-year, longitudinal study of individuals at either a high(HR) or a low(LR) familial risk for depression, we previously showed cortical thinning in the right hemisphere was an endophenotype for the familial risk. In this study, we assessed whether the effects of familial risk were modulated by the serotonin-transporter-linked polymorphic region (5-HTTLPR). We measured cortical thickness using MRI of the brain and associated it with 5-HTTLPR polymorphism in 76 HR and 53 LR individuals. We studied the effects of genotype and gene-by-risk interaction on cortical thickness while controlling for the confounding effects of age and gender, and for the familial relatedness by applying a variance component model with random effects for genotype. The results showed significant effects of gene-by-risk interaction on thickness: The "s" allele was associated with thinner cortex in the LR individuals whereas with thicker cortex in the HR individuals. The opposing gene effects across the two risk groups were likely due to either epistatic effects and/or differing modulation of the neural plasticity by the altered 5-HT signaling in utero.

  17. Dopamine replacement modulates oscillatory coupling between premotor and motor cortical areas in Parkinson's disease.

    PubMed

    Herz, Damian Marc; Florin, Esther; Christensen, Mark Schram; Reck, Christiane; Barbe, Michael Thomas; Tscheuschler, Maike Karoline; Tittgemeyer, Marc; Siebner, Hartwig Roman; Timmermann, Lars

    2014-11-01

    Efficient neural communication between premotor and motor cortical areas is critical for manual motor control. Here, we used high-density electroencephalography to study cortical connectivity in patients with Parkinson's disease (PD) and age-matched healthy controls while they performed repetitive movements of the right index finger at maximal repetition rate. Multiple source beamformer analysis and dynamic causal modeling were used to assess oscillatory coupling between the lateral premotor cortex (lPM), supplementary motor area (SMA), and primary motor cortex (M1) in the contralateral hemisphere. Elderly healthy controls showed task-related modulation in connections from lPM to SMA and M1, mainly within the γ-band (>30 Hz). Nonmedicated PD patients also showed task-related γ-γ coupling from lPM to M1, but γ coupling from lPM to SMA was absent. Levodopa reinstated physiological γ-γ coupling from lPM to SMA and significantly strengthened coupling in the feedback connection from M1 to lPM expressed as β-β as well as θ-β coupling. Enhancement in cross-frequency θ-β coupling from M1 to lPM was correlated with levodopa-induced improvement in motor function. The results show that PD is associated with an altered neural communication between premotor and motor cortical areas, which can be modulated by dopamine replacement. PMID:23733911

  18. Different categories of living and non-living sound-sources activate distinct cortical networks

    PubMed Central

    Engel, Lauren R.; Frum, Chris; Puce, Aina; Walker, Nathan A.; Lewis, James W.

    2009-01-01

    With regard to hearing perception, it remains unclear as to whether, or the extent to which, different conceptual categories of real-world sounds and related categorical knowledge are differentially represented in the brain. Semantic knowledge representations are reported to include the major divisions of living versus non-living things, plus more specific categories including animals, tools, biological motion, faces, and places—categories typically defined by their characteristic visual features. Here, we used functional magnetic resonance imaging (fMRI) to identify brain regions showing preferential activity to four categories of action sounds, which included non-vocal human and animal actions (living), plus mechanical and environmental sound-producing actions (non-living). The results showed a striking antero-posterior division in cortical representations for sounds produced by living versus non-living sources. Additionally, there were several significant differences by category, depending on whether the task was category-specific (e.g. human or not) versus non-specific (detect end-of-sound). In general, (1) human-produced sounds yielded robust activation in the bilateral posterior superior temporal sulci independent of task. Task demands modulated activation of left-lateralized fronto-parietal regions, bilateral insular cortices, and subcortical regions previously implicated in observation-execution matching, consistent with “embodied” and mirror-neuron network representations subserving recognition. (2) Animal action sounds preferentially activated the bilateral posterior insulae. (3) Mechanical sounds activated the anterior superior temporal gyri and parahippocampal cortices. (4) Environmental sounds preferentially activated dorsal occipital and medial parietal cortices. Overall, this multi-level dissociation of networks for preferentially representing distinct sound-source categories provides novel support for grounded cognition models that may

  19. Chaos-induced modulation of reliability boosts output firing rate in downstream cortical areas

    NASA Astrophysics Data System (ADS)

    Tiesinga, P. H.

    2004-03-01

    The reproducibility of neural spike train responses to an identical stimulus across different presentations (trials) has been studied extensively. Reliability, the degree of reproducibility of spike trains, was found to depend in part on the amplitude and frequency content of the stimulus [J. Hunter and J. Milton, J. Neurophysiol. 90, 387 (2003)]. The responses across different trials can sometimes be interpreted as the response of an ensemble of similar neurons to a single stimulus presentation. How does the reliability of the activity of neural ensembles affect information transmission between different cortical areas? We studied a model neural system consisting of two ensembles of neurons with Hodgkin-Huxley-type channels. The first ensemble was driven by an injected sinusoidal current that oscillated in the gamma-frequency range (40 Hz) and its output spike trains in turn drove the second ensemble by fast excitatory synaptic potentials with short term depression. We determined the relationship between the reliability of the first ensemble and the response of the second ensemble. In our paradigm the neurons in the first ensemble were initially in a chaotic state with unreliable and imprecise spike trains. The neurons became entrained to the oscillation and responded reliably when the stimulus power was increased by less than 10%. The firing rate of the first ensemble increased by 30%, whereas that of the second ensemble could increase by an order of magnitude. We also determined the response of the second ensemble when its input spike trains, which had non-Poisson statistics, were replaced by an equivalent ensemble of Poisson spike trains. The resulting output spike trains were significantly different from the original response, as assessed by the metric introduced by Victor and Purpura [J. Neurophysiol. 76, 1310 (1996)]. These results are a proof of principle that weak temporal modulations in the power of gamma-frequency oscillations in a given cortical area

  20. The Beat Goes on: Rhythmic Modulation of Cortical Potentials by Imagined Tapping

    ERIC Educational Resources Information Center

    Osman, Allen; Albert, Robert; Ridderinkhof, K. Richard; Band, Guido; van der Molen, Maurits

    2006-01-01

    A frequency analysis was used to tag cortical activity from imagined rhythmic movements. Participants synchronized overt and imagined taps with brief visual stimuli presented at a constant rate, alternating between left and right index fingers. Brain potentials were recorded from across the scalp and topographic maps made of their power at the…

  1. Acoustic change responses to amplitude modulation: a method to quantify cortical temporal processing and hemispheric asymmetry

    PubMed Central

    Han, Ji Hye; Dimitrijevic, Andrew

    2015-01-01

    Objective: Sound modulation is a critical temporal cue for the perception of speech and environmental sounds. To examine auditory cortical responses to sound modulation, we developed an acoustic change stimulus involving amplitude modulation (AM) of ongoing noise. The AM transitions in this stimulus evoked an acoustic change complex (ACC) that was examined parametrically in terms of rate and depth of modulation and hemispheric symmetry. Methods: Auditory cortical potentials were recorded from 64 scalp electrodes during passive listening in two conditions: (1) ACC from white noise to 4, 40, 300 Hz AM, with varying AM depths of 100, 50, 25% lasting 1 s and (2) 1 s AM noise bursts at the same modulation rate. Behavioral measures included AM detection from an attend ACC condition and AM depth thresholds (i.e., a temporal modulation transfer function, TMTF). Results: The N1 response of the ACC was large to 4 and 40 Hz and small to the 300 Hz AM. In contrast, the opposite pattern was observed with bursts of AM showing larger responses with increases in AM rate. Brain source modeling showed significant hemispheric asymmetry such that 4 and 40 Hz ACC responses were dominated by right and left hemispheres respectively. Conclusion: N1 responses to the ACC resembled a low pass filter shape similar to a behavioral TMTF. In the ACC paradigm, the only stimulus parameter that changes is AM and therefore the N1 response provides an index for this AM change. In contrast, an AM burst stimulus contains both AM and level changes and is likely dominated by the rise time of the stimulus. The hemispheric differences are consistent with the asymmetric sampling in time hypothesis suggesting that the different hemispheres preferentially sample acoustic time across different time windows. Significance: The ACC provides a novel approach to studying temporal processing at the level of cortex and provides further evidence of hemispheric specialization for fast and slow stimuli. PMID:25717291

  2. Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice.

    PubMed

    Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

    2016-01-01

    Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  3. Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice

    PubMed Central

    Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

    2016-01-01

    Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  4. Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice.

    PubMed

    Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

    2016-01-01

    Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  5. Late cortical disinhibition in relaxed versus active hand muscles.

    PubMed

    Caux-Dedeystère, A; Derambure, P; Devanne, H

    2015-07-01

    Recent research suggests that long-interval intracortical inhibition (LICI) is followed by a transitory period of late cortical disinhibition (LCD) that can even lead to a net increase in cortical excitability. The relationship between LICI/LCD and voluntary drive remains poorly understood. Our study aims at investigating the influence of index abduction on LICI and LCD in an actively engaged muscle and a neighboring muscle, while varying the intensity of the conditioning stimulus (CS). Motor-evoked potentials (MEPs) were recorded from the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles in 13 subjects. Paired-pulses were delivered with 10 different interstimulus intervals (ranging from 60 to 290 ms). Whatever the condition (relaxed or active FDI), the test stimulus was set to evoke an MEP of 1mV. The time course of conditioned MEP amplitude was compared for relaxed and active conditions when the CS intensity was set to (i) 130% of the rest motor threshold (RMT) or (ii) to evoke the same size of MEP under both conditions. LICI lasted longer (i.e. disinhibition occurred later) at rest than during abduction when evoked either by similar or matched conditioning stimuli. No post-LICI facilitation was observed at rest - even when the CS intensity was set to 160% RMT. In contrast, long-interval intracortical facilitation (LICF) was observed in the quiescent ADM when FDI was active. LICF may then be associated with voluntary activity albeit with lack of topographic specificity. PMID:25888934

  6. Olanzapine Treatment of Adolescent Rats Alters Adult D2 Modulation of Cortical Inputs to the Ventral Striatum

    PubMed Central

    Brooks, Julie M.; Frost, Douglas O.

    2016-01-01

    Background: The striatal dopamine system undergoes vast ontogenetic changes during adolescence, making the brain vulnerable to drug treatments that target this class of neurotransmitters. Atypical antipsychotic drugs are often prescribed to children and adolescents for off-label treatment of neuropsychiatric disorders, yet the long-term impact this treatment has on brain development remains largely unknown. Methods: Adolescent male rats were treated with olanzapine or vehicle for 3 weeks (during postnatal day 28–49) using a dosing condition designed to approximate closely D2 receptor occupancies in the human therapeutic range. We assessed D2 receptor modulation of corticostriatal inputs onto medium spiny neurons in the adult ventral striatum using in vitro whole-cell current clamp recordings. Results: The D2/D3 agonist quinpirole (5 µM) enhanced cortically driven medium spiny neuron synaptic responses in slices taken from adult rats treated with vehicle during adolescence, as in untreated adult rats. However, in slices from mature rats treated with olanzapine during adolescence, quinpirole reduced medium spiny neuron activation. The magnitude of decrease was similar to previous observations in untreated, prepubertal rats. These changes may reflect alterations in local inhibitory circuitry, as the GABA-A antagonist picrotoxin (100 µM) reversed the effects of quinpirole in vehicle-treated slices but had no impact on cortically evoked responses in olanzapine-treated slices. Conclusions: These data suggest that adolescent atypical antipsychotic drug treatment leads to enduring changes in dopamine modulation of corticostriatal synaptic function. PMID:27207908

  7. Magnetoencephalographic evidence for the modulation of cortical swallowing processing by transcranial direct current stimulation.

    PubMed

    Suntrup, Sonja; Teismann, Inga; Wollbrink, Andreas; Winkels, Martin; Warnecke, Tobias; Flöel, Agnes; Pantev, Christo; Dziewas, Rainer

    2013-12-01

    Swallowing is a complex neuromuscular task that is processed within multiple regions of the human brain. Rehabilitative treatment options for dysphagia due to neurological diseases are limited. Because the potential for adaptive cortical changes in compensation of disturbed swallowing is recognized, neuromodulation techniques like transcranial direct current stimulation (tDCS) are currently considered as a treatment option. Here we evaluate the effect of tDCS on cortical swallowing network activity and behavior. In a double-blind crossover study, anodal tDCS (20 min, 1 mA) or sham stimulation was administered over the left or right swallowing motor cortex in 21 healthy subjects in separate sessions. Cortical activation was measured using magnetoencephalography (MEG) before and after tDCS during cued "simple", "fast" and "challenged" swallow tasks with increasing levels of difficulty. Swallowing response times and accuracy were measured. Significant bilateral enhancement of cortical swallowing network activation was found in the theta frequency range after left tDCS in the fast swallow task (p=0.006) and following right tDCS in the challenged swallow task (p=0.007), but not after sham stimulation. No relevant behavioral effects were observed on swallow response time, but swallow precision improved after left tDCS (p<0.05). Anodal tDCS applied over the swallowing motor cortex of either hemisphere was able to increase bilateral swallow-related cortical network activation in a frequency specific manner. These neuroplastic effects were associated with subtle behavioral gains during complex swallow tasks in healthy individuals suggesting that tDCS deserves further evaluation as a treatment tool for dysphagia.

  8. Multi-dimensional modulations of α and γ cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder.

    PubMed

    Schoenberg, Poppy L A; Speckens, Anne E M

    2015-02-01

    To illuminate candidate neural working mechanisms of Mindfulness-Based Cognitive Therapy (MBCT) in the treatment of recurrent depressive disorder, parallel to the potential interplays between modulations in electro-cortical dynamics and depressive symptom severity and self-compassionate experience. Linear and nonlinear α and γ EEG oscillatory dynamics were examined concomitant to an affective Go/NoGo paradigm, pre-to-post MBCT or natural wait-list, in 51 recurrent depressive patients. Specific EEG variables investigated were; (1) induced event-related (de-) synchronisation (ERD/ERS), (2) evoked power, and (3) inter-/intra-hemispheric coherence. Secondary clinical measures included depressive severity and experiences of self-compassion. MBCT significantly downregulated α and γ power, reflecting increased cortical excitability. Enhanced α-desynchronisation/ERD was observed for negative material opposed to attenuated α-ERD towards positively valenced stimuli, suggesting activation of neural networks usually hypoactive in depression, related to positive emotion regulation. MBCT-related increase in left-intra-hemispheric α-coherence of the fronto-parietal circuit aligned with these synchronisation dynamics. Ameliorated depressive severity and increased self-compassionate experience pre-to-post MBCT correlated with α-ERD change. The multi-dimensional neural mechanisms of MBCT pertain to task-specific linear and non-linear neural synchronisation and connectivity network dynamics. We propose MBCT-related modulations in differing cortical oscillatory bands have discrete excitatory (enacting positive emotionality) and inhibitory (disengaging from negative material) effects, where mediation in the α and γ bands relates to the former. PMID:26052359

  9. Quantifying attentional modulation of auditory-evoked cortical responses from single-trial electroencephalography

    PubMed Central

    Choi, Inyong; Rajaram, Siddharth; Varghese, Lenny A.; Shinn-Cunningham, Barbara G.

    2013-01-01

    Selective auditory attention is essential for human listeners to be able to communicate in multi-source environments. Selective attention is known to modulate the neural representation of the auditory scene, boosting the representation of a target sound relative to the background, but the strength of this modulation, and the mechanisms contributing to it, are not well understood. Here, listeners performed a behavioral experiment demanding sustained, focused spatial auditory attention while we measured cortical responses using electroencephalography (EEG). We presented three concurrent melodic streams; listeners were asked to attend and analyze the melodic contour of one of the streams, randomly selected from trial to trial. In a control task, listeners heard the same sound mixtures, but performed the contour judgment task on a series of visual arrows, ignoring all auditory streams. We found that the cortical responses could be fit as weighted sum of event-related potentials evoked by the stimulus onsets in the competing streams. The weighting to a given stream was roughly 10 dB higher when it was attended compared to when another auditory stream was attended; during the visual task, the auditory gains were intermediate. We then used a template-matching classification scheme to classify single-trial EEG results. We found that in all subjects, we could determine which stream the subject was attending significantly better than by chance. By directly quantifying the effect of selective attention on auditory cortical responses, these results reveal that focused auditory attention both suppresses the response to an unattended stream and enhances the response to an attended stream. The single-trial classification results add to the growing body of literature suggesting that auditory attentional modulation is sufficiently robust that it could be used as a control mechanism in brain–computer interfaces (BCIs). PMID:23576968

  10. Modulation of Cortical Inhibitory Circuits after Cathodal Transcranial Direct Current Stimulation over the Primary Motor Cortex

    PubMed Central

    Sasaki, Ryoki; Miyaguchi, Shota; Kotan, Shinichi; Kojima, Sho; Kirimoto, Hikari; Onishi, Hideaki

    2016-01-01

    Here, we aimed to evaluate whether cathodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) and primary somatosensory cortex (S1) can modulate cortical inhibitory circuits. Sixteen healthy subjects participated in this study. Cathodal tDCS was positioned over the left M1 (M1 cathodal) or left S1 (S1 cathodal) with an intensity of 1 mA for 10 min. Sham tDCS was applied for 10 min over the left M1 (sham). Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) were recorded from the right abductor pollicis brevis (APB) muscle before the intervention (pre) and 10 and 30 min after the intervention (post 1 and post 2, respectively). Cortical inhibitory circuits were evaluated using short-interval intracortical inhibition (SICI) and short-latency afferent inhibition (SAI). M1 cathodal decreased single-pulse MEP amplitudes at post 1 and decreased SAI at post 1 and post 2; however, SICI did not exhibit any change. S1 cathodal and sham did not show any changes in MEP amplitudes at any of the three time points. These results demonstrated that cathodal tDCS over the M1 not only decreases the M1 excitability but also affects the cortical inhibitory circuits related to SAI. PMID:26869909

  11. Alteration of Electro-Cortical Activity in Microgravity

    NASA Astrophysics Data System (ADS)

    Schneider, Stefan; Brummer, Vera; Carnahan, Heather; Askew, Christopher D.; Guardiera, Simon; Struder, Heiko K.

    2008-06-01

    There is growing interest in the effects of weightlessness on central nervous system (CNS) activity. Due to technical and logistical limitations it presently seems impossible to apply imaging techniques as fMRI or PET in weightless environments e.g. on ISS or during parabolic flights. Within this study we evaluated changes in brain cortical activity using low resolution brain electromagnetic tomography (LORETA) during parabolic flights. Results showed a distinct inhibition of right frontal area activity >12Hz during phases of microgravity compared to normal gravity. We conclude that the inhibition of high frequency frontal activity during microgravity may serve as a marker of emotional anxiety and/or indisposition associated with weightlessness. This puts a new light on the debate as to whether cognitive and sensorimotor impairments are attributable to primary physiological effects or secondary psychological effects of a weightless environment.

  12. Functional roles of 10 Hz alpha-band power modulating engagement and disengagement of cortical networks in a complex visual motion task.

    PubMed

    Rana, Kunjan D; Vaina, Lucia M

    2014-01-01

    Alpha band power, particularly at the 10 Hz frequency, is significantly involved in sensory inhibition, attention modulation, and working memory. However, the interactions between cortical areas and their relationship to the different functional roles of the alpha band oscillations are still poorly understood. Here we examined alpha band power and the cortico-cortical interregional phase synchrony in a psychophysical task involving the detection of an object moving in depth by an observer in forward self-motion. Wavelet filtering at the 10 Hz frequency revealed differences in the profile of cortical activation in the visual processing regions (occipital and parietal lobes) and in the frontoparietal regions. The alpha rhythm driving the visual processing areas was found to be asynchronous with the frontoparietal regions. These findings suggest a decoupling of the 10 Hz frequency into separate functional roles: sensory inhibition in the visual processing regions and spatial attention in the frontoparietal regions.

  13. Spontaneous cortical activity in awake monkeys composed of neuronal avalanches.

    PubMed

    Petermann, Thomas; Thiagarajan, Tara C; Lebedev, Mikhail A; Nicolelis, Miguel A L; Chialvo, Dante R; Plenz, Dietmar

    2009-09-15

    Spontaneous neuronal activity is an important property of the cerebral cortex but its spatiotemporal organization and dynamical framework remain poorly understood. Studies in reduced systems--tissue cultures, acute slices, and anesthetized rats--show that spontaneous activity forms characteristic clusters in space and time, called neuronal avalanches. Modeling studies suggest that networks with this property are poised at a critical state that optimizes input processing, information storage, and transfer, but the relevance of avalanches for fully functional cerebral systems has been controversial. Here we show that ongoing cortical synchronization in awake rhesus monkeys carries the signature of neuronal avalanches. Negative LFP deflections (nLFPs) correlate with neuronal spiking and increase in amplitude with increases in local population spike rate and synchrony. These nLFPs form neuronal avalanches that are scale-invariant in space and time and with respect to the threshold of nLFP detection. This dimension, threshold invariance, describes a fractal organization: smaller nLFPs are embedded in clusters of larger ones without destroying the spatial and temporal scale-invariance of the dynamics. These findings suggest an organization of ongoing cortical synchronization that is scale-invariant in its three fundamental dimensions--time, space, and local neuronal group size. Such scale-invariance has ontogenetic and phylogenetic implications because it allows large increases in network capacity without a fundamental reorganization of the system.

  14. Abstract art and cortical motor activation: an EEG study

    PubMed Central

    Umilta', M. Alessandra; Berchio, Cristina; Sestito, Mariateresa; Freedberg, David; Gallese, Vittorio

    2012-01-01

    The role of the motor system in the perception of visual art remains to be better understood. Earlier studies on the visual perception of abstract art (from Gestalt theory, as in Arnheim, 1954 and 1988, to balance preference studies as in Locher and Stappers, 2002, and more recent work by Locher et al., 2007; Redies, 2007, and Taylor et al., 2011), neglected the question, while the field of neuroesthetics (Ramachandran and Hirstein, 1999; Zeki, 1999) mostly concentrated on figurative works. Much recent work has demonstrated the multimodality of vision, encompassing the activation of motor, somatosensory, and viscero-motor brain regions. The present study investigated whether the observation of high-resolution digitized static images of abstract paintings by Lucio Fontana is associated with specific cortical motor activation in the beholder's brain. Mu rhythm suppression was evoked by the observation of original art works but not by control stimuli (as in the case of graphically modified versions of these works). Most interestingly, previous visual exposure to the stimuli did not affect the mu rhythm suppression induced by their observation. The present results clearly show the involvement of the cortical motor system in the viewing of static abstract art works. PMID:23162456

  15. Motor-related cortical activity after cervical spinal cord injury: multifaceted EEG analysis of isometric elbow flexion contractions.

    PubMed

    Cremoux, Sylvain; Tallet, Jessica; Berton, Eric; Dal Maso, Fabien; Amarantini, David

    2013-10-01

    Electroencephalographic (EEG) studies have well established that motor cortex (M1) activity ~20 Hz decreases during muscular contraction and increases as soon as contraction stops, which are known as event-related desynchronization (ERD) and event-related synchronization (ERS), respectively. ERD is supposed to reflect M1 activation, sending information to recruited muscles, while the process underlying ERS is interpreted either as active cortical inhibition or as processing of sensory inputs. Investigation of the process behind ERD/ERS in people with spinal cord injury (SCI) would be particularly relevant since their M1 remains effective despite decreased sensorimotor abilities. In this study, we recorded net joint torque and EEG in 6 participants with cervical SCI and 8 healthy participants who performed isometric elbow flexion at 3 force levels. Multifaceted EEG analysis was introduced to assess ERD/ERS according to their amplitude, frequency range and duration. The results revealed that net joint torque increased with the required force level for all participants and time to contraction inhibition was longer in the SCI group. At the cortical level, ERD/ERS frequency ranges increased with the required force level in all participants, indicating that the modulation of cortical activity with force level is preserved after SCI. However, ERS amplitude decreased only in SCI participants, which may be linked to delayed contraction inhibition. All in all, cortical modulation of frequency range and amplitude could reflect two different kinds of neural communication. PMID:23939224

  16. EEG frequency tagging to explore the cortical activity related to the tactile exploration of natural textures

    PubMed Central

    Moungou, Athanasia; Thonnard, Jean-Louis; Mouraux, André

    2016-01-01

    When sliding our fingertip against a textured surface, complex vibrations are produced in the skin. It is increasingly recognised that the neural transduction and processing of these vibrations plays an important role in the dynamic tactile perception of textures. The aim of the present study was to develop a novel means to tag the cortical activity related to the processing of these vibrations, by periodically modulating the amplitude of texture exploration-induced vibrations such as to record a steady-state evoked potential (SS-EP). The EEG was recorded while the right index fingertip was scanned against four different textures using a constant exploration velocity. Amplitude modulation of the elicited vibrations was achieved by periodically modulating the force applied against the finger. Frequency analysis of the recorded EEG signals showed that modulation of the vibrations induced by the fingertip-texture interactions elicited an SS-EP at the frequency of modulation (3 Hz) as well as its second harmonic (6 Hz), maximal over parietal regions contralateral to the stimulated side. Textures generating stronger vibrations also generated SS-EPs of greater magnitude. Our results suggest that frequency tagging using SS-EPs can be used to isolate and explore the brain activity related to the tactile exploration of natural textures. PMID:26853820

  17. Macroeconomic Activity Module - NEMS Documentation

    EIA Publications

    2016-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 2016 (AEO2016). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code

  18. Developmental regulation of spatio-temporal patterns of cortical circuit activation

    PubMed Central

    Griffen, Trevor C.; Wang, Lang; Fontanini, Alfredo; Maffei, Arianna

    2013-01-01

    Neural circuits are refined in an experience-dependent manner during early postnatal development. How development modulates the spatio-temporal propagation of activity through cortical circuits is poorly understood. Here we use voltage-sensitive dye imaging (VSD) to show that there are significant changes in the spatio-temporal patterns of intracortical signals in primary visual cortex (V1) from postnatal day 13 (P13), eye opening, to P28, the peak of the critical period for rodent visual cortical plasticity. Upon direct stimulation of layer 4 (L4), activity spreads to L2/3 and to L5 at all ages. However, while from eye opening to the peak of the critical period, the amplitude and persistence of the voltage signal decrease, peak activation is reached more quickly and the interlaminar gain increases with age. The lateral spread of activation within layers remains unchanged throughout the time window under analysis. These developmental changes in spatio-temporal patterns of intracortical circuit activation are mediated by differences in the contributions of excitatory and inhibitory synaptic components. Our results demonstrate that after eye opening the circuit in V1 is refined through a progression of changes that shape the spatio-temporal patterns of circuit activation. Signals become more efficiently propagated across layers through developmentally regulated changes in interlaminar gain. PMID:23316135

  19. Diaphragmatic activity induced by cortical stimulation: surface versus esophageal electrodes.

    PubMed

    Gea, J; Espadaler, J M; Guiu, R; Aran, X; Seoane, L; Broquetas, J M

    1993-02-01

    Evoked responses of the diaphragm can be induced by magnetic cortical stimulation and recorded by either surface or esophageal electrodes. The former recording system is tolerated better by the patient but has potential problems with the specificity of the diaphragmatic signal. This study compares the responses of the diaphragm to cortical stimulation that were recorded simultaneously with surface and esophageal electrodes on seven patients (61 +/- 4 yr) with chronic obstructive pulmonary diseases. Stimuli were delivered in three ventilatory conditions: at baseline, during deep breathing, and during voluntary panting. No differences were observed between results recorded by surface and esophageal electrodes [amplitude of the compound motor of the action potential (CMAP), 0.8 +/- 0.1 vs. 0.8 +/- 0.1 mV, NS; latency, 13.1 +/- 0.4 vs. 12.6 +/- 0.5 ms, NS]. In addition, significant correlations were found (CMAP, r = 0.77, P < 0.001; latency, r = 0.71, P = 0.002). The concordance analysis, however, indicated some dissimilarity between the recordings of the electrodes (CMAP, R1 = 0.31; latency, R1 = 0.26). These differences may be due to the area of the muscle mainly recorded by each electrode and/or to the additional activity from other muscles recorded by surface electrodes. On the other hand, the diaphragmatic responses observed in these patients with chronic obstructive pulmonary diseases were similar to those previously reported in healthy subjects. PMID:8458780

  20. Response reliability observed with voltage-sensitive dye imaging of cortical layer 2/3: the probability of activation hypothesis.

    PubMed

    Gollnick, Clare A; Millard, Daniel C; Ortiz, Alexander D; Bellamkonda, Ravi V; Stanley, Garrett B

    2016-06-01

    A central assertion in the study of neural processing is that our perception of the environment directly reflects the activity of our sensory neurons. This assertion reinforces the intuition that the strength of a sensory input directly modulates the amount of neural activity observed in response to that sensory feature: an increase in the strength of the input yields a graded increase in the amount of neural activity. However, cortical activity across a range of sensory pathways can be sparse, with individual neurons having remarkably low firing rates, often exhibiting suprathreshold activity on only a fraction of experimental trials. To compensate for this observed apparent unreliability, it is assumed that instead the local population of neurons, although not explicitly measured, does reliably represent the strength of the sensory input. This assumption, however, is largely untested. In this study, using wide-field voltage-sensitive dye (VSD) imaging of the somatosensory cortex in the anesthetized rat, we show that whisker deflection velocity, or stimulus strength, is not encoded by the magnitude of the population response at the level of cortex. Instead, modulation of whisker deflection velocity affects the likelihood of the cortical response, impacting the magnitude, rate of change, and spatial extent of the cortical response. An ideal observer analysis of the cortical response points to a probabilistic code based on repeated sampling across cortical columns and/or time, which we refer to as the probability of activation hypothesis. This hypothesis motivates a range of testable predictions for both future electrophysiological and future behavioral studies. PMID:26864758

  1. Loss of Consciousness Is Associated with Stabilization of Cortical Activity

    PubMed Central

    Solovey, Guillermo; Alonso, Leandro M.; Yanagawa, Toru; Fujii, Naotaka; Magnasco, Marcelo O.; Cecchi, Guillermo A.

    2015-01-01

    What aspects of neuronal activity distinguish the conscious from the unconscious brain? This has been a subject of intense interest and debate since the early days of neurophysiology. However, as any practicing anesthesiologist can attest, it is currently not possible to reliably distinguish a conscious state from an unconscious one on the basis of brain activity. Here we approach this problem from the perspective of dynamical systems theory. We argue that the brain, as a dynamical system, is self-regulated at the boundary between stable and unstable regimes, allowing it in particular to maintain high susceptibility to stimuli. To test this hypothesis, we performed stability analysis of high-density electrocorticography recordings covering an entire cerebral hemisphere in monkeys during reversible loss of consciousness. We show that, during loss of consciousness, the number of eigenmodes at the edge of instability decreases smoothly, independently of the type of anesthetic and specific features of brain activity. The eigenmodes drift back toward the unstable line during recovery of consciousness. Furthermore, we show that stability is an emergent phenomenon dependent on the correlations among activity in different cortical regions rather than signals taken in isolation. These findings support the conclusion that dynamics at the edge of instability are essential for maintaining consciousness and provide a novel and principled measure that distinguishes between the conscious and the unconscious brain. SIGNIFICANCE STATEMENT What distinguishes brain activity during consciousness from that observed during unconsciousness? Answering this question has proven difficult because neither consciousness nor lack thereof have universal signatures in terms of most specific features of brain activity. For instance, different anesthetics induce different patterns of brain activity. We demonstrate that loss of consciousness is universally and reliably associated with stabilization

  2. Quantifying cortical activity during general anesthesia using wavelet analysis.

    PubMed

    Zikov, Tatjana; Bibian, Stéphane; Dumont, Guy A; Huzmezan, Mihai; Ries, Craig R

    2006-04-01

    This paper reports on a novel method for quantifying the cortical activity of a patient during general anesthesia as a surrogate measure of the patient's level of consciousness. The proposed technique is based on the analysis of a single-channel (frontal) electroencephalogram (EEG) signal using stationary wavelet transform (SWT). The wavelet coefficients calculated from the EEG are pooled into a statistical representation, which is then compared to two well-defined states: the awake state with normal EEG activity, and the isoelectric state with maximal cortical depression. The resulting index, referred to as the wavelet-based anesthetic value for central nervous system monitoring (WAV(CNS)), quantifies the depth of consciousness between these two extremes. To validate the proposed technique, we present a clinical study which explores the advantages of the WAV(CNS) in comparison with the BIS monitor (Aspect Medical Systems, MA), currently a reference in consciousness monitoring. Results show that the WAV(CNS) and BIS are well correlated (r = 0.969) during periods of steady-state despite fundamental algorithmic differences. However, in terms of dynamic behavior, the WAV(CNS) offers faster tracking of transitory changes at induction and emergence, with an average lead of 15-30 s. Furthermore, and conversely to the BIS, the WAV(CNS) regains its preinduction baseline value when patients are responding to verbal command after emergence from anesthesia. We conclude that the proposed analysis technique is an attractive alternative to BIS monitoring. In addition, we show that the WAV(CNS) dynamics can be modeled as a linear time invariant transfer function. This index is, therefore, well suited for use as a feedback sensor in advisory systems, closed-loop control schemes, and for the identification of the pharmacodynamic models of anesthetic drugs.

  3. Local and thalamic origins of correlated ongoing and sensory-evoked cortical activities

    PubMed Central

    Cohen-Kashi Malina, Katayun; Mohar, Boaz; Rappaport, Akiva N.; Lampl, Ilan

    2016-01-01

    Thalamic inputs of cells in sensory cortices are outnumbered by local connections. Thus, it was suggested that robust sensory response in layer 4 emerges due to synchronized thalamic activity. To investigate the role of both inputs in the generation of correlated cortical activities, we isolated the thalamic excitatory inputs of cortical cells by optogenetically silencing cortical firing. In anaesthetized mice, we measured the correlation between isolated thalamic synaptic inputs of simultaneously patched nearby layer 4 cells of the barrel cortex. Here we report that in contrast to correlated activity of excitatory synaptic inputs in the intact cortex, isolated thalamic inputs exhibit lower variability and asynchronous spontaneous and sensory-evoked inputs. These results are further supported in awake mice when we recorded the excitatory inputs of individual cortical cells simultaneously with the local field potential in a nearby site. Our results therefore indicate that cortical synchronization emerges by intracortical coupling. PMID:27615520

  4. Sensory stimuli reduce the dimensionality of cortical activity

    NASA Astrophysics Data System (ADS)

    Mazzucato, Luca; Fontanini, Alfredo; La Camera, Giancarlo

    Neural ensembles in alert animals generate complex patterns of activity. Although cortical activity unfolds in a space whose dimension is equal to the number of neurons, it is often restricted to a lower dimensional subspace. Dimensionality is the minimal number of dimensions that accurately capture neural dynamics, and may be related to the computational tasks supported by the neural circuit. Here, we investigate the dimensionality of neural ensembles from the insular cortex of alert rats during periods of `ongoing' (spontaneous) and stimulus-evoked activity. We find that the dimensionality grows with ensemble size, and does so significantly faster during ongoing compared to evoked activity. We explain both results using a recurrent spiking network with clustered architecture, and obtain analytical results on the dependence of dimensionality on ensemble size, number of clusters, and pair-wise noise correlations. The theory predicts a characteristic scaling with ensemble size and the existence of an upper bound on dimensionality, which grows with the number of clusters and decreases with the amount of noise correlations. To our knowledge, this is the first mechanistic model of neural dimensionality in cortex during both spontaneous and evoked activity.

  5. Dopamine D1/D5 receptor modulates state-dependent switching of soma-dendritic Ca2+ potentials via differential protein kinase A and C activation in rat prefrontal cortical neurons.

    PubMed

    Young, Clint E; Yang, Charles R

    2004-01-01

    To determine the nature of dopamine modulation of dendritic Ca2+ signaling in layers V-VI prefrontal cortex (PFC) neurons, whole-cell Ca2+ potentials were evoked after blockade of Na+ and K+ channels. Soma-dendritic Ca2+ spikes evoked by suprathreshold depolarizing pulses, which could be terminated by superimposed brief intrasomatic hyperpolarizing pulses, are blocked by the L-type Ca2+ channel antagonist nimodipine (1 microM). The D1/D5 receptor agonist dihydrexidine (DHX) (0.01-10 microM; 5 min) or R-(+)SKF81291 (10 microM) induced a prolonged (>30 min) dose-dependent peak suppression of these Ca2+ spikes. This effect was dependent on [Ca2+]i- and protein kinase C (PKC)-dependent mechanisms because [Ca2+]i chelation by BAPTA or inhibition of PKC by bisindolymaleimide (BiM1), but not inhibition of [Ca2+]i release with heparin or Xestospongin C, prevented the D1-mediated suppression of Ca2+ spikes. Depolarizing pulses subthreshold to activating a Ca2+ spike evoked a nimodipine-sensitive Ca2+ "hump" potential. D1/D5 stimulation induced an N-[2-((o-bromocinamyl)amino)ethyl]-5-isoquinolinesulfonamide (H-89)- or internal PKA inhibitory peptide[5-24]-sensitive (PKA-dependent) transient (approximately 7 min) potentiation of the hump potential to full Ca2+ spike firing. Furthermore, application of DHX in the presence of the PKC inhibitor BiM1 or internal PKC inhibitory peptide[19-36] resulted in persistent firing of full Ca2+ spike bursts, suggesting that a D1/D5-PKA mechanism switches subthreshold Ca2+ hump potential to fire full Ca2+ spikes, which are eventually turned off by a D1/D5-Ca2+-dependent PKC mechanism. This depolarizing state-dependent, D1/D5-activated, bi-directional switching of soma-dendritic L-type Ca2+ channels via PKA-dependent potentiation and PKC-dependent suppression may provide spatiotemporal regulation of synaptic integration and plasticity in PFC. PMID:14715933

  6. Anatomical organization of descending cortical projections orchestrating the patterns of cortically induced rhythmical jaw muscle activity in guinea pigs.

    PubMed

    Kato, Takafumi; Seki, Shinichiro; Higashiyama, Makoto; Masuda, Yuji; Kitamura, Seiichiro; Yoshida, Atsushi

    2015-10-01

    Repetitive electrical microstimulation to the cortical masticatory area (CMA) evokes distinct patterns of rhythmical jaw muscle activities (RJMAs) in animals. This study aimed to investigate the characteristics of the descending projections from the CMA, associated with distinct patterns of RJMAs, to the thalamus, midbrain, pons and medulla in guinea pigs. RJMAs with continuous masseter and digastric bursts (CB-RJMAs) and stimulus-locked digastric sub-bursts (SLB-RJMAs) were induced from the anterior and posterior areas of the rostral region of the lateral agranular cortex, and chewing-like RJMAs from the rostral region of the granular cortex. Anterograde tracer, biotinylated dextran amine, was injected into the three cortical areas. The cortical area inducing CB-RJMAs had strong ipsilateral projections to the motor thalamus, red nucleus, midbrain reticular formation, superior colliculus, parabrachial nucleus, and supratrigeminal region, and contralateral projections mainly to the lateral reticular formation around the trigeminal motor nucleus (Vmo). The cortical area inducing SLB-RJMAs had moderate projections to the motor thalamus and lateral reticular formation around the Vmo, but few projections to the midbrain nuclei. The cortical area inducing chewing-like RJMAs had strong projections to the ipsilateral sensory thalamus and contralateral trigeminal sensory nuclei, and moderate projections to the lateral reticular formation. The three cortical areas consistently had few projections to the ventromedial reticular formation. The present study demonstrates that multiple direct and indirect descending projections from the CMA onto the premotor systems connecting the trigeminal motoneurons represent the neuroanatomical repertoires for generating RJMAs during the distinct phases of natural ingestive behavior.

  7. Baicalein reverts L-valine-induced persistent sodium current up-modulation in primary cortical neurons.

    PubMed

    Caioli, Silvia; Candelotti, Elena; Pedersen, Jens Z; Saba, Luana; Antonini, Alessia; Incerpi, Sandra; Zona, Cristina

    2016-04-01

    L-valine is a branched-chain amino acid (BCAA) largely used as dietary integrator by athletes and involved in some inherited rare diseases such as maple syrup urine disease. This pathology is caused by an altered BCAA metabolism with the accumulation of toxic keto acids in tissues and body fluids with consequent severe neurological symptoms. In animal models of BCAA accumulation, increased oxidative stress levels and lipid peroxidation have been reported. The aim of this study was to analyze both whether high BCAA concentrations in neurons induce reactive oxygen species (ROS) production and whether, by performing electrophysiological recordings, the neuronal functional properties are modified. Our results demonstrate that in primary cortical cultures, a high dose of valine increases ROS production and provokes neuronal hyperexcitability because the action potential frequencies and the persistent sodium current amplitudes increase significantly compared to non-treated neurons. Since Baicalein, a flavone obtained from the Scutellaria root, has been shown to act as a strong antioxidant with neuroprotective effects, we evaluated its possible antioxidant activity in primary cortical neurons chronically exposed to L-valine. The preincubation of cortical neurons with Baicalein prevents the ROS production and is able to revert both the neuronal hyperexcitability and the increase of the persistent sodium current, indicating a direct correlation between the ROS production and the altered physiological parameters. In conclusion, our data show that the electrophysiological alterations of cortical neurons elicited by high valine concentration are due to the increase in ROS production, suggesting much caution in the intake of BCAA dietary integrators. PMID:26721313

  8. Baicalein reverts L-valine-induced persistent sodium current up-modulation in primary cortical neurons.

    PubMed

    Caioli, Silvia; Candelotti, Elena; Pedersen, Jens Z; Saba, Luana; Antonini, Alessia; Incerpi, Sandra; Zona, Cristina

    2016-04-01

    L-valine is a branched-chain amino acid (BCAA) largely used as dietary integrator by athletes and involved in some inherited rare diseases such as maple syrup urine disease. This pathology is caused by an altered BCAA metabolism with the accumulation of toxic keto acids in tissues and body fluids with consequent severe neurological symptoms. In animal models of BCAA accumulation, increased oxidative stress levels and lipid peroxidation have been reported. The aim of this study was to analyze both whether high BCAA concentrations in neurons induce reactive oxygen species (ROS) production and whether, by performing electrophysiological recordings, the neuronal functional properties are modified. Our results demonstrate that in primary cortical cultures, a high dose of valine increases ROS production and provokes neuronal hyperexcitability because the action potential frequencies and the persistent sodium current amplitudes increase significantly compared to non-treated neurons. Since Baicalein, a flavone obtained from the Scutellaria root, has been shown to act as a strong antioxidant with neuroprotective effects, we evaluated its possible antioxidant activity in primary cortical neurons chronically exposed to L-valine. The preincubation of cortical neurons with Baicalein prevents the ROS production and is able to revert both the neuronal hyperexcitability and the increase of the persistent sodium current, indicating a direct correlation between the ROS production and the altered physiological parameters. In conclusion, our data show that the electrophysiological alterations of cortical neurons elicited by high valine concentration are due to the increase in ROS production, suggesting much caution in the intake of BCAA dietary integrators.

  9. Extended cortical activations during evaluating successive pain stimuli.

    PubMed

    Lötsch, Jörn; Walter, Carmen; Felden, Lisa; Preibisch, Christine; Nöth, Ulrike; Martin, Till; Anti, Sandra; Deichmann, Ralf; Oertel, Bruno G

    2012-08-01

    Comparing pain is done in daily life and involves short-term memorizing and attention focusing. This event-related functional magnetic resonance imaging study investigated the short-term brain activations associated with the comparison of pain stimuli using a delayed discrimination paradigm. Fourteen healthy young volunteers compared two successive pain stimuli administered at a 10 s interval to the same location at the nasal mucosa. Fourteen age- and sex-matched subjects received similar pain stimuli without performing the comparison task. With the comparison task, the activations associated with the second pain stimulus were significantly greater than with the first stimulus in the anterior insular cortex and the primary somatosensory area. This was observed on the background of a generally increased stimulus-associated brain activation in the presence of the comparison task that included regions of the pain matrix (insular cortex, primary and secondary somatosensory area, midcingulate cortex, supplemental motor area) and regions associated with attention, decision making, working memory and body recognition (frontal and temporal gyri, inferior parietal lobule, precuneus, lingual cortices). This data provides a cerebral correlate for the role of pain as a biological alerting system that gains the subject's attention and then dominates most other perceptions and activities involving pain-specific and non-pain-specific brain regions.

  10. Exercising self-control increases relative left frontal cortical activation.

    PubMed

    Schmeichel, Brandon J; Crowell, Adrienne; Harmon-Jones, Eddie

    2016-02-01

    Self-control refers to the capacity to override or alter a predominant response tendency. The current experiment tested the hypothesis that exercising self-control temporarily increases approach motivation, as revealed by patterns of electrical activity in the prefrontal cortex. Participants completed a writing task that did vs did not require them to exercise self-control. Then they viewed pictures known to evoke positive, negative or neutral affect. We assessed electroencephalographic (EEG) activity while participants viewed the pictures, and participants reported their trait levels of behavioral inhibition system (BIS) and behavioral activation system (BAS) sensitivity at the end of the study. We found that exercising (vs not exercising) self-control increased relative left frontal cortical activity during picture viewing, particularly among individuals with relatively higher BAS than BIS, and particularly during positive picture viewing. A similar but weaker pattern emerged during negative picture viewing. The results suggest that exercising self-control temporarily increases approach motivation, which may help to explain the aftereffects of self-control (i.e. ego depletion).

  11. Phase advancement and nucleus-specific timing of thalamocortical activity during slow cortical oscillation

    PubMed Central

    Slézia, Andrea; Hangya, Balázs; Ulbert, István; Acsády, László

    2011-01-01

    The exact timing of cortical afferent activity is instrumental for the correct coding and retrieval of internal and external stimuli. Thalamocortical inputs represent the most significant subcortical pathway to the cortex, but the precise timing and temporal variability of thalamocortical activity is not known. To examine this question, we studied the phase of thalamic action potentials relative to cortical oscillations and established correlations among phase, the nuclear location of the thalamocortical neurons and the frequency of cortical activity. The phase of thalamic action potentials depended on the exact frequency of the slow cortical oscillation both on long (minutes) and short (single wave) time scales. Faster waves were accompanied by phase advancement in both cases. Thalamocortical neurons located in different nuclei fired at significantly different phases of the slow waves but were active at similar phase of spindle oscillations. Different thalamic nuclei displayed distinct burst patterns. Bursts with higher number of action potentials displayed progressive phase advancement in a nucleus-specific manner. Thalamic neurons located along nuclear borders were characterized by mixed burst and phase properties. Our data demonstrate that the temporal relationship between cortical and thalamic activity is not fixed but displays dynamic changes during oscillatory activity. The timing depends on the precise location and exact activity of thalamocortical cells and the ongoing cortical network pattern. This variability of thalamic output and its coupling to cortical activity can enable thalamocortical neurons to actively participate in the coding and retrieval of complex cortical signals. PMID:21228169

  12. Attention Modulates the Auditory Cortical Processing of Spatial and Category Cues in Naturalistic Auditory Scenes

    PubMed Central

    Renvall, Hanna; Staeren, Noël; Barz, Claudia S.; Ley, Anke; Formisano, Elia

    2016-01-01

    This combined fMRI and MEG study investigated brain activations during listening and attending to natural auditory scenes. We first recorded, using in-ear microphones, vocal non-speech sounds, and environmental sounds that were mixed to construct auditory scenes containing two concurrent sound streams. During the brain measurements, subjects attended to one of the streams while spatial acoustic information of the scene was either preserved (stereophonic sounds) or removed (monophonic sounds). Compared to monophonic sounds, stereophonic sounds evoked larger blood-oxygenation-level-dependent (BOLD) fMRI responses in the bilateral posterior superior temporal areas, independent of which stimulus attribute the subject was attending to. This finding is consistent with the functional role of these regions in the (automatic) processing of auditory spatial cues. Additionally, significant differences in the cortical activation patterns depending on the target of attention were observed. Bilateral planum temporale and inferior frontal gyrus were preferentially activated when attending to stereophonic environmental sounds, whereas when subjects attended to stereophonic voice sounds, the BOLD responses were larger at the bilateral middle superior temporal gyrus and sulcus, previously reported to show voice sensitivity. In contrast, the time-resolved MEG responses were stronger for mono- than stereophonic sounds in the bilateral auditory cortices at ~360 ms after the stimulus onset when attending to the voice excerpts within the combined sounds. The observed effects suggest that during the segregation of auditory objects from the auditory background, spatial sound cues together with other relevant temporal and spectral cues are processed in an attention-dependent manner at the cortical locations generally involved in sound recognition. More synchronous neuronal activation during monophonic than stereophonic sound processing, as well as (local) neuronal inhibitory mechanisms in

  13. Modulation of cortical midline structures by implicit and explicit self-relevance evaluation.

    PubMed

    Moran, Joseph M; Heatherton, Todd F; Kelley, William M

    2009-01-01

    Recent neuroimaging work has observed activity in cortical midline structures (CMS) such as medial prefrontal and posterior cingulate cortices during self-referential processing. Moreover, items rated as self-relevant produce increased activity in these regions relative to items that are deemed not self-relevant. A common thread among previous reports has been reliance on experimental tasks that encourage or require online self-referential processing. In this paper, we report findings from two experiments that manipulated requirements for self-reflection. In Experiment 1, subjects rated trait adjectives for social desirability and for self-relevance. Results revealed increasing activity in CMS with increasing self-relevance, but only during explicit ratings of self-relevance. In Experiment 2, we examined CMS activity during passive viewing of personal semantic facts (such as subjects' own first names). Taken together, these results suggest that highly self-relevant information captures attention through neural mechanisms that are comparable to those engaged during explicit self-reflection, namely via recruitment of CMS structures. PMID:19424905

  14. Valence of physical stimuli, not housing conditions, affects behaviour and frontal cortical brain activity in sheep.

    PubMed

    Vögeli, Sabine; Lutz, Janika; Wolf, Martin; Wechsler, Beat; Gygax, Lorenz

    2014-07-01

    Modulation of short-term emotions by long-term mood is little understood but relevant to understand the affective system and of importance in respect to animal welfare: a negative mood might taint experiences, whilst a positive mood might alleviate single negative events. To induce different mood states in sheep housing conditions were varied. Fourteen ewes were group-housed in an unpredictable, stimulus-poor and 15 ewes in a predictable, stimulus-rich environment. Sheep were tested individually for mood in a behavioural cognitive bias paradigm. Also, their reactions to three physical stimuli thought to differ in their perceived valence were observed (negative: pricking, intermediate: slight pressure, positive: kneading). General behaviour, activity, ear movements and positions, and haemodynamic changes in the cortical brain were recorded during stimulations. Generalised mixed-effects models and model probabilities based on the BIC (Bayesian information criterion) were used. Only weak evidence for mood difference was found. Sheep from the unpredictable, stimulus-poor housing condition had a somewhat more negative cognitive bias, showed slightly more aversive behaviour, were slightly more active and moved their ears somewhat more. Sheep most clearly differentiated the negative from the intermediate and positive stimulus in that they exhibited more aversive behaviour, less nibbling, were more active, showed more ear movements, more forward ear postures, fewer backward ear postures, and a stronger decrease in deoxyhaemoglobin when subjected to the negative stimulus. In conclusion, sheep reacted towards stimuli according to their presumed valence but their mood was not strongly influenced by housing conditions. Therefore, behavioural reactions and cortical brain activity towards the stimuli were hardly modulated by housing conditions.

  15. Cortical Activation During Levitation and Tentacular Movements of Corticobasal Syndrome

    PubMed Central

    Onofrj, Marco; Bonanni, Laura; Pizzi, Stefano Delli; Caulo, Massimo; Onofrj, Valeria; Thomas, Astrid; Tartaro, Armando; Franciotti, Raffaella

    2015-01-01

    Abstract Levitation and tentacular movements (LTM) are considered specific, yet rare (30%), features of Corticobasal Syndrome (CBS), and are erroneously classified as alien hand. Our study focuses on these typical involuntary movements and aims to highlight possible neural correlates. LTM were recognizable during functional magnetic resonance imaging (fMRI) in 4 of 19 CBS patients. FMRI activity was evaluated with an activation recognition program for movements, during LTM, consisting of levitaton and finger writhing, and compared with the absence of movement (rest) and voluntary movements (VM), similar to LTM, of affected and unaffected arm-hand. FMRI acquisition blocks were balanced in order to match LTM blocks with rest and VM conditions. In 1 of the 4 patients, fMRI was acquired only during LTM and with a different equipment. Despite variable intensity and range of involuntary movements, evidenced by videos, fMRI showed, during LTM, a significant (P<0.05–0.001) activation only of the contralateral primary motor cortex (M1). Voluntary movements of the affected and unaffected arm elicited the known network including frontal, supplementary, sensory-motor cortex, and cerebellum. Willed movements of the LTM-affected arm induced higher and wider activation of contralateral M1 compared with the unaffected arm. The isolated activation of M1 suggests that LTM is a cortical disinhibition symptom, not involving a network. Higher activation of M1 during VM confirms that M1 excitability changes occur in CBS. Our study calls, finally, attention to the necessity to separate LTM from other alien hand phenomena. PMID:26559277

  16. Cortical Activation During Levitation and Tentacular Movements of Corticobasal Syndrome.

    PubMed

    Onofrj, Marco; Bonanni, Laura; Delli Pizzi, Stefano; Caulo, Massimo; Onofrj, Valeria; Thomas, Astrid; Tartaro, Armando; Franciotti, Raffaella

    2015-11-01

    Levitation and tentacular movements (LTM) are considered specific, yet rare (30%), features of Corticobasal Syndrome (CBS), and are erroneously classified as alien hand. Our study focuses on these typical involuntary movements and aims to highlight possible neural correlates.LTM were recognizable during functional magnetic resonance imaging (fMRI) in 4 of 19 CBS patients. FMRI activity was evaluated with an activation recognition program for movements, during LTM, consisting of levitaton and finger writhing, and compared with the absence of movement (rest) and voluntary movements (VM), similar to LTM, of affected and unaffected arm-hand. FMRI acquisition blocks were balanced in order to match LTM blocks with rest and VM conditions. In 1 of the 4 patients, fMRI was acquired only during LTM and with a different equipment.Despite variable intensity and range of involuntary movements, evidenced by videos, fMRI showed, during LTM, a significant (P<0.05-0.001) activation only of the contralateral primary motor cortex (M1). Voluntary movements of the affected and unaffected arm elicited the known network including frontal, supplementary, sensory-motor cortex, and cerebellum. Willed movements of the LTM-affected arm induced higher and wider activation of contralateral M1 compared with the unaffected arm.The isolated activation of M1 suggests that LTM is a cortical disinhibition symptom, not involving a network. Higher activation of M1 during VM confirms that M1 excitability changes occur in CBS. Our study calls, finally, attention to the necessity to separate LTM from other alien hand phenomena. PMID:26559277

  17. Stimulus-dependency and mechanisms of surround modulation in cortical area MT

    PubMed Central

    Huang, Xin; Albright, Thomas D.; Stoner, Gene R.

    2009-01-01

    The perceptual interpretation of a given visual feature depends on the surrounding context. To explore the neural mechanisms underlying such contextual interactions in the motion domain, we studied responses of neurons in cortical area MT of macaque monkeys while presenting a variety of center-surround stimuli that stimulated both the classical receptive visual field (CRF) and the receptive field surround. In human psychophysical experiments, the perceptual impact of the surround stimulus on the center stimulus varied from motion capture (“integration”) to motion contrast (“segmentation”). In our neurophysiological experiments, the directional tuning of surround modulation with these stimuli ranged from antagonistic (consistent with motion contrast) to integrative (consistent with motion capture) and agreed qualitatively with perception under some but not all conditions. Most strikingly, for a stimulus that elicited perceptual motion contrast, surround modulation was integrative if the CRF stimulus was ambiguous due to the aperture problem. In addition, we found that surround modulation was linked to response magnitude: stimuli eliciting the largest responses yielded the strongest antagonism and those eliciting the smallest responses yielded the strongest integration. We developed a neural network model that accounts for this finding as well as a previous finding that surround suppression in area MT is contrast-dependent. Our findings suggest that changes in MT surround modulation result from shifts in the balance between directionally-tuned excitation and inhibition mediated by changes in input strength. We speculate that input strength is, in turn, linked with the ambiguity of the motion present within the CRF. PMID:19091978

  18. Differential involvement of two cortical masticatory areas in modulation of the swallowing reflex in rats.

    PubMed

    Tsujimura, Takanori; Tsuji, Kojun; Ariyasinghe, Sajjiv; Fukuhara, Takako; Yamada, Aki; Hayashi, Hirokazu; Nakamura, Yuki; Iwata, Koichi; Inoue, Makoto

    2012-10-24

    To clarify the functional role of cortical descending inputs involved in the swallowing reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and swallowing reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and swallowing reflex. The number of evoked swallows was significantly lower, and swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the swallowing reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the swallowing CPG.

  19. HTR2 Receptors in a Songbird Premotor Cortical-Like Area Modulate Spectral Characteristics of Zebra Finch Song

    PubMed Central

    Wood, William E.; Roseberry, Thomas K.; Perkel, David J.

    2013-01-01

    Serotonin [5-hydroxytryptamine (5-HT)] is involved in modulating an array of complex behaviors including learning, depression, and circadian rhythms. Additionally, HTR2 receptors on layer V pyramidal neurons are thought to mediate the actions of psychedelic drugs; the native function of these receptors at this site, however, remains unknown. Previously, we found that activation of HTR2 receptors in the zebra finch forebrain song premotor structure the robust nucleus of the arcopallium (RA) led to increased excitation, and that endogenous 5-HT could roughly double spontaneous firing rate. Here, using in vivo single-unit recordings, we found that direct application of 5-HT to these same RA projection neurons, which are analogous to layer V cortical pyramidal neurons, caused a significant increase in the number of action potentials per song-related burst, and a dramatic decrease in signal-to-noise ratio. Injection of the serotonergic neurotoxin 5,7-dihydroxytryptamine into the third ventricle greatly reduced telencephalic 5-HT and resulted in decreased fundamental frequency of harmonic syllables as well as increased goodness of pitch. Both of these results can be explained by the observed actions of 5-HT on RA projection neurons, and both effects recovered to baseline within 2 weeks following the toxin injection. These results show that 5-HT is involved in modulating spectral properties of song, likely via effects on RA projection neurons, but that adult zebra finches can partially compensate for this deficit within 7 d. PMID:23407949

  20. HTR2 receptors in a songbird premotor cortical-like area modulate spectral characteristics of zebra finch song.

    PubMed

    Wood, William E; Roseberry, Thomas K; Perkel, David J

    2013-02-13

    Serotonin [5-hydroxytryptamine (5-HT)] is involved in modulating an array of complex behaviors including learning, depression, and circadian rhythms. Additionally, HTR2 receptors on layer V pyramidal neurons are thought to mediate the actions of psychedelic drugs; the native function of these receptors at this site, however, remains unknown. Previously, we found that activation of HTR2 receptors in the zebra finch forebrain song premotor structure the robust nucleus of the arcopallium (RA) led to increased excitation, and that endogenous 5-HT could roughly double spontaneous firing rate. Here, using in vivo single-unit recordings, we found that direct application of 5-HT to these same RA projection neurons, which are analogous to layer V cortical pyramidal neurons, caused a significant increase in the number of action potentials per song-related burst, and a dramatic decrease in signal-to-noise ratio. Injection of the serotonergic neurotoxin 5,7-dihydroxytryptamine into the third ventricle greatly reduced telencephalic 5-HT and resulted in decreased fundamental frequency of harmonic syllables as well as increased goodness of pitch. Both of these results can be explained by the observed actions of 5-HT on RA projection neurons, and both effects recovered to baseline within 2 weeks following the toxin injection. These results show that 5-HT is involved in modulating spectral properties of song, likely via effects on RA projection neurons, but that adult zebra finches can partially compensate for this deficit within 7 d. PMID:23407949

  1. Cortical Modulation of Motor Control Biofeedback among the Elderly with High Fall Risk during a Posture Perturbation Task with Augmented Reality.

    PubMed

    Chang, Chun-Ju; Yang, Tsui-Fen; Yang, Sai-Wei; Chern, Jen-Suh

    2016-01-01

    The cerebral cortex provides sensorimotor integration and coordination during motor control of daily functional activities. Power spectrum density based on electroencephalography (EEG) has been employed as an approach that allows an investigation of the spatial-temporal characteristics of neuromuscular modulation; however, the biofeedback mechanism associated with cortical activation during motor control remains unclear among elderly individuals. Thirty one community-dwelling elderly participants were divided into low fall-risk potential (LF) and high fall-risk potential (HF) groups based upon the results obtained from a receiver operating characteristic analysis of the ellipse area of the center of pressure. Electroencephalography (EEG) was performed while the participants stood on a 6-degree-of-freedom Stewart platform, which generated continuous perturbations and done either with or without the virtual reality scene. The present study showed that when there was visual stimulation and poor somatosensory coordination, a higher level of cortical response was activated in order to keep postural balance. The elderly participants in the LF group demonstrated a significant and strong correlation between postural-related cortical regions; however, the elderly individuals in the HF group did not show such a relationship. Moreover, we were able to clarify the roles of various brainwave bands functioning in motor control. Specifically, the gamma and beta bands in the parietal-occipital region facilitate the high-level cortical modulation and sensorimotor integration, whereas the theta band in the frontal-central region is responsible for mediating error detection during perceptual motor tasks. Finally, the alpha band is associated with processing visual challenges in the occipital lobe.With a variety of motor control demands, increment in brainwave band coordination is required to maintain postural stability. These investigations shed light on the cortical modulation of

  2. Cortical Modulation of Motor Control Biofeedback among the Elderly with High Fall Risk during a Posture Perturbation Task with Augmented Reality

    PubMed Central

    Chang, Chun-Ju; Yang, Tsui-Fen; Yang, Sai-Wei; Chern, Jen-Suh

    2016-01-01

    The cerebral cortex provides sensorimotor integration and coordination during motor control of daily functional activities. Power spectrum density based on electroencephalography (EEG) has been employed as an approach that allows an investigation of the spatial–temporal characteristics of neuromuscular modulation; however, the biofeedback mechanism associated with cortical activation during motor control remains unclear among elderly individuals. Thirty one community-dwelling elderly participants were divided into low fall-risk potential (LF) and high fall-risk potential (HF) groups based upon the results obtained from a receiver operating characteristic analysis of the ellipse area of the center of pressure. Electroencephalography (EEG) was performed while the participants stood on a 6-degree-of-freedom Stewart platform, which generated continuous perturbations and done either with or without the virtual reality scene. The present study showed that when there was visual stimulation and poor somatosensory coordination, a higher level of cortical response was activated in order to keep postural balance. The elderly participants in the LF group demonstrated a significant and strong correlation between postural-related cortical regions; however, the elderly individuals in the HF group did not show such a relationship. Moreover, we were able to clarify the roles of various brainwave bands functioning in motor control. Specifically, the gamma and beta bands in the parietal–occipital region facilitate the high-level cortical modulation and sensorimotor integration, whereas the theta band in the frontal–central region is responsible for mediating error detection during perceptual motor tasks. Finally, the alpha band is associated with processing visual challenges in the occipital lobe.With a variety of motor control demands, increment in brainwave band coordination is required to maintain postural stability. These investigations shed light on the cortical modulation

  3. Cortical Modulation of Motor Control Biofeedback among the Elderly with High Fall Risk during a Posture Perturbation Task with Augmented Reality.

    PubMed

    Chang, Chun-Ju; Yang, Tsui-Fen; Yang, Sai-Wei; Chern, Jen-Suh

    2016-01-01

    The cerebral cortex provides sensorimotor integration and coordination during motor control of daily functional activities. Power spectrum density based on electroencephalography (EEG) has been employed as an approach that allows an investigation of the spatial-temporal characteristics of neuromuscular modulation; however, the biofeedback mechanism associated with cortical activation during motor control remains unclear among elderly individuals. Thirty one community-dwelling elderly participants were divided into low fall-risk potential (LF) and high fall-risk potential (HF) groups based upon the results obtained from a receiver operating characteristic analysis of the ellipse area of the center of pressure. Electroencephalography (EEG) was performed while the participants stood on a 6-degree-of-freedom Stewart platform, which generated continuous perturbations and done either with or without the virtual reality scene. The present study showed that when there was visual stimulation and poor somatosensory coordination, a higher level of cortical response was activated in order to keep postural balance. The elderly participants in the LF group demonstrated a significant and strong correlation between postural-related cortical regions; however, the elderly individuals in the HF group did not show such a relationship. Moreover, we were able to clarify the roles of various brainwave bands functioning in motor control. Specifically, the gamma and beta bands in the parietal-occipital region facilitate the high-level cortical modulation and sensorimotor integration, whereas the theta band in the frontal-central region is responsible for mediating error detection during perceptual motor tasks. Finally, the alpha band is associated with processing visual challenges in the occipital lobe.With a variety of motor control demands, increment in brainwave band coordination is required to maintain postural stability. These investigations shed light on the cortical modulation of

  4. Asymmetric frontal cortical activity predicts effort expenditure for reward.

    PubMed

    Hughes, David M; Yates, Mark J; Morton, Emma E; Smillie, Luke D

    2015-07-01

    An extensive literature shows that greater left, relative to right, frontal cortical activity (LFA) is involved in approach-motivated affective states and reflects stable individual differences in approach motivation. However, relatively few studies have linked LFA to behavioral indices of approach motivation. In this study, we examine the relation between LFA and effort expenditure for reward, a behavioral index of approach motivation. LFA was calculated for 51 right-handed participants (55% female) using power spectral analysis of electroencephalogram recorded at rest. Participants also completed the effort expenditure for rewards task (EEfRT), which presents a series of trials requiring a choice between a low-reward low-effort task and a high-reward high-effort task. We found that individuals with greater resting LFA were more willing to expend greater effort in the pursuit of larger rewards, particularly when reward delivery was less likely. Our findings offer a more nuanced understanding of the motivational significance of LFA, in terms of processes that mitigate the effort- and uncertainty-related costs of pursuing rewarding goals. PMID:25479792

  5. Human temporal cortical single neuron activity during working memory maintenance.

    PubMed

    Zamora, Leona; Corina, David; Ojemann, George

    2016-06-01

    The Working Memory model of human memory, first introduced by Baddeley and Hitch (1974), has been one of the most influential psychological constructs in cognitive psychology and human neuroscience. However the neuronal correlates of core components of this model have yet to be fully elucidated. Here we present data from two studies where human temporal cortical single neuron activity was recorded during tasks differentially affecting the maintenance component of verbal working memory. In Study One we vary the presence or absence of distracting items for the entire period of memory storage. In Study Two we vary the duration of storage so that distractors filled all, or only one-third of the time the memory was stored. Extracellular single neuron recordings were obtained from 36 subjects undergoing awake temporal lobe resections for epilepsy, 25 in Study one, 11 in Study two. Recordings were obtained from a total of 166 lateral temporal cortex neurons during performance of one of these two tasks, 86 study one, 80 study two. Significant changes in activity with distractor manipulation were present in 74 of these neurons (45%), 38 Study one, 36 Study two. In 48 (65%) of those there was increased activity during the period when distracting items were absent, 26 Study One, 22 Study Two. The magnitude of this increase was greater for Study One, 47.6%, than Study Two, 8.1%, paralleling the reduction in memory errors in the absence of distracters, for Study One of 70.3%, Study Two 26.3% These findings establish that human lateral temporal cortex is part of the neural system for working memory, with activity during maintenance of that memory that parallels performance, suggesting it represents active rehearsal. In 31 of these neurons (65%) this activity was an extension of that during working memory encoding that differed significantly from the neural processes recorded during overt and silent language tasks without a recent memory component, 17 Study one, 14 Study two

  6. Human temporal cortical single neuron activity during working memory maintenance.

    PubMed

    Zamora, Leona; Corina, David; Ojemann, George

    2016-06-01

    The Working Memory model of human memory, first introduced by Baddeley and Hitch (1974), has been one of the most influential psychological constructs in cognitive psychology and human neuroscience. However the neuronal correlates of core components of this model have yet to be fully elucidated. Here we present data from two studies where human temporal cortical single neuron activity was recorded during tasks differentially affecting the maintenance component of verbal working memory. In Study One we vary the presence or absence of distracting items for the entire period of memory storage. In Study Two we vary the duration of storage so that distractors filled all, or only one-third of the time the memory was stored. Extracellular single neuron recordings were obtained from 36 subjects undergoing awake temporal lobe resections for epilepsy, 25 in Study one, 11 in Study two. Recordings were obtained from a total of 166 lateral temporal cortex neurons during performance of one of these two tasks, 86 study one, 80 study two. Significant changes in activity with distractor manipulation were present in 74 of these neurons (45%), 38 Study one, 36 Study two. In 48 (65%) of those there was increased activity during the period when distracting items were absent, 26 Study One, 22 Study Two. The magnitude of this increase was greater for Study One, 47.6%, than Study Two, 8.1%, paralleling the reduction in memory errors in the absence of distracters, for Study One of 70.3%, Study Two 26.3% These findings establish that human lateral temporal cortex is part of the neural system for working memory, with activity during maintenance of that memory that parallels performance, suggesting it represents active rehearsal. In 31 of these neurons (65%) this activity was an extension of that during working memory encoding that differed significantly from the neural processes recorded during overt and silent language tasks without a recent memory component, 17 Study one, 14 Study two

  7. The EEG signal: a window on the cortical brain activity.

    PubMed

    Constant, Isabelle; Sabourdin, Nada

    2012-06-01

    The accurate assessment of the depth of anesthesia, allowing a more accurate adaptation of the doses of hypnotics, is an important end point for the anesthesiologist. It is a particularly crucial issue in pediatric anesthesia, in the context of the recent controversies about the potential neurological consequences of the main anesthetic drugs on the developing brain. The electroencephalogram signal reflects the electrical activity of the neurons in the cerebral cortex. It is thus the key to assessment of the level of hypnosis. Beyond visual analysis, several monitoring devices allow an automated treatment of the electroencephalographic (EEG) signal, combining time and frequency domain analysis. Each of these monitors focuses on a specific combination of characteristics of the signal and provides the clinician with useful information that remains, however, partial. For a comprehensive approach of the EEG-derived indices, the main features of the normal EEG, in adults and children, will be presented in the awake state and during sleep. Age-related modifications accompanying cerebral maturation during infancy and childhood will be detailed. Then, this review will provide an update on how anesthetic drugs, particularly hypnotics, influence the EEG signal, and how the main available monitors analyze these drug-induced modifications. The relationships between pain, memory, and the EEG will be discussed. Finally, this review will focus on some specific EEG features such as the electrical epileptoid activity observed under sevoflurane anesthesia. The EEG signal is the best window we have on cortical brain activity and provides a fair pharmacodynamic feedback of the effects of hypnotics. However, the cortex is only one of several targets of anesthesia. Hypnotics and opiates, have also subcortical primary targets, and the EEG performances in the evaluation or prediction of nociception are poor. Monitoring subcortical structures in combination with the EEG might in the future

  8. Kv1.2 mediates heterosynaptic modulation of direct cortical synaptic inputs in CA3 pyramidal cells

    PubMed Central

    Hyun, Jung Ho; Eom, Kisang; Lee, Kyu-Hee; Bae, Jin Young; Bae, Yong Chul; Kim, Myoung-Hwan; Kim, Sooyun; Ho, Won-Kyung; Lee, Suk-Ho

    2015-01-01

    A short high frequency stimulation of mossy fibres (MFs) induces long-term potentiation (LTP) of direct cortical or perforant path (PP) synaptic inputs in hippocampal CA3 pyramidal cells (CA3-PCs). However, the cellular mechanism underlying this heterosynaptic modulation remains elusive. Previously, we reported that repetitive somatic firing at 10 Hz downregulates Kv1.2 in the CA3-PCs. Here, we show that MF inputs induce similar somatic firing and downregulation of Kv1.2 in the CA3-PCs. The effect of Kv1.2 downregulation was specific to PP synaptic inputs that arrive at distal apical dendrites. We found that the somatodendritic expression of Kv1.2 is polarized to distal apical dendrites. Compartmental simulations based on this finding suggested that passive normalization of synaptic inputs and polarized distributions of dendritic ionic channels may facilitate the activation of dendritic Na+ channels preferentially at distal apical dendrites. Indeed, partial block of dendritic Na+ channels using 10 nm tetrodotoxin brought back the enhanced PP-evoked excitatory postsynaptic potentials (PP-EPSPs) to the baseline level. These results indicate that activity-dependent downregulation of Kv1.2 in CA3-PCs mediates MF-induced heterosynaptic LTP of PP-EPSPs by facilitating activation of Na+ channels at distal apical dendrites. PMID:26047212

  9. Knowledge About Sounds-Context-Specific Meaning Differently Activates Cortical Hemispheres, Auditory Cortical Fields, and Layers in House Mice.

    PubMed

    Geissler, Diana B; Schmidt, H Sabine; Ehret, Günter

    2016-01-01

    Activation of the auditory cortex (AC) by a given sound pattern is plastic, depending, in largely unknown ways, on the physiological state and the behavioral context of the receiving animal and on the receiver's experience with the sounds. Such plasticity can be inferred when house mouse mothers respond maternally to pup ultrasounds right after parturition and naïve females have to learn to respond. Here we use c-FOS immunocytochemistry to quantify highly activated neurons in the AC fields and layers of seven groups of mothers and naïve females who have different knowledge about and are differently motivated to respond to acoustic models of pup ultrasounds of different behavioral significance. Profiles of FOS-positive cells in the AC primary fields (AI, AAF), the ultrasonic field (UF), the secondary field (AII), and the dorsoposterior field (DP) suggest that activation reflects in AI, AAF, and UF the integration of sound properties with animal state-dependent factors, in the higher-order field AII the news value of a given sound in the behavioral context, and in the higher-order field DP the level of maternal motivation and, by left-hemisphere activation advantage, the recognition of the meaning of sounds in the given context. Anesthesia reduced activation in all fields, especially in cortical layers 2/3. Thus, plasticity in the AC is field-specific preparing different output of AC fields in the process of perception, recognition and responding to communication sounds. Further, the activation profiles of the auditory cortical fields suggest the differentiation between brains hormonally primed to know (mothers) and brains which acquired knowledge via implicit learning (naïve females). In this way, auditory cortical activation discriminates between instinctive (mothers) and learned (naïve females) cognition.

  10. Knowledge About Sounds—Context-Specific Meaning Differently Activates Cortical Hemispheres, Auditory Cortical Fields, and Layers in House Mice

    PubMed Central

    Geissler, Diana B.; Schmidt, H. Sabine; Ehret, Günter

    2016-01-01

    Activation of the auditory cortex (AC) by a given sound pattern is plastic, depending, in largely unknown ways, on the physiological state and the behavioral context of the receiving animal and on the receiver's experience with the sounds. Such plasticity can be inferred when house mouse mothers respond maternally to pup ultrasounds right after parturition and naïve females have to learn to respond. Here we use c-FOS immunocytochemistry to quantify highly activated neurons in the AC fields and layers of seven groups of mothers and naïve females who have different knowledge about and are differently motivated to respond to acoustic models of pup ultrasounds of different behavioral significance. Profiles of FOS-positive cells in the AC primary fields (AI, AAF), the ultrasonic field (UF), the secondary field (AII), and the dorsoposterior field (DP) suggest that activation reflects in AI, AAF, and UF the integration of sound properties with animal state-dependent factors, in the higher-order field AII the news value of a given sound in the behavioral context, and in the higher-order field DP the level of maternal motivation and, by left-hemisphere activation advantage, the recognition of the meaning of sounds in the given context. Anesthesia reduced activation in all fields, especially in cortical layers 2/3. Thus, plasticity in the AC is field-specific preparing different output of AC fields in the process of perception, recognition and responding to communication sounds. Further, the activation profiles of the auditory cortical fields suggest the differentiation between brains hormonally primed to know (mothers) and brains which acquired knowledge via implicit learning (naïve females). In this way, auditory cortical activation discriminates between instinctive (mothers) and learned (naïve females) cognition. PMID:27013959

  11. Visual Experience Modulates Spatio-Temporal Dynamics of Circuit Activation

    PubMed Central

    Wang, Lang; Fontanini, Alfredo; Maffei, Arianna

    2011-01-01

    Persistent reduction in sensory drive in early development results in multiple plastic changes of different cortical synapses. How these experience-dependent modifications affect the spatio-temporal dynamics of signal propagation in neocortical circuits is poorly understood. Here we demonstrate that brief visual deprivation significantly affects the propagation of electrical signals in the primary visual cortex. The spatio-temporal spread of circuit activation upon direct stimulation of its input layer (Layer 4) is reduced, as is the activation of L2/3 – the main recipient of the output from L4. Our data suggest that the decrease in spatio-temporal activation of L2/3 depends on reduced L4 output, and is not intrinsically generated within L2/3. The data shown here suggest that changes in the synaptic components of the visual cortical circuit result not only in alteration of local integration of excitatory and inhibitory inputs, but also in a significant decrease in overall circuit activation. Furthermore, our data indicate a differential effect of visual deprivation on L4 and L2/3, suggesting that while feedforward activation of L2/3 is reduced, its activation by long range, within layer inputs is unaltered. Thus, brief visual deprivation induces experience-dependent circuit re-organization by modulating not only circuit excitability, but also the spatio-temporal patterns of cortical activation within and between layers. PMID:21743804

  12. Modulation of cortical excitability induced by repetitive transcranial magnetic stimulation: influence of timing and geometrical parameters and underlying mechanisms.

    PubMed

    Pell, Gaby S; Roth, Yiftach; Zangen, Abraham

    2011-01-01

    Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that activates neurons via generation of brief pulses of high-intensity magnetic field. If these pulses are applied in a repetitive fashion (rTMS), persistent modulation of neural excitability can be achieved. The technique has proved beneficial in the treatment of a number of neurological and psychiatric conditions. However, the effect of rTMS on excitability and the other performance indicators shows a considerable degree of variability across different sessions and subjects. The frequency of stimulation has always been considered as the main determinant of the direction of excitability modulation. However, interactions exist between frequency and several other stimulation parameters that also influence the degree of modulation. In addition, the spatial interaction of the transient electric field induced by the TMS pulse with the cortical neurons is another contributor to variability. Consideration of all of these factors is necessary in order to improve the consistency of the conditioning effect and to better understand the outcomes of investigations with rTMS. These user-controlled sources of variability are discussed against the background of the mechanisms that are believed to drive the excitability changes. The mechanism behind synaptic plasticity is commonly accepted as the driver of sustained excitability modulation for rTMS and indeed, plasticity and rTMS share many characteristics, but definitive evidence is lacking for this. It is more likely that there is a multiplicity of mechanisms behind the action of rTMS. The different mechanisms interact with each other and this will contribute to the variability of rTMS-induced excitability changes. This review investigates the links between rTMS and synaptic plasticity, describes their similarities and differences, and highlights a neglected contribution of the membrane potential. In summary, the principal aims of this review

  13. Bidirectional radial Ca2+ activity regulates neurogenesis and migration during early cortical column formation

    PubMed Central

    Rash, Brian G.; Ackman, James B.; Rakic, Pasko

    2016-01-01

    Cortical columns are basic cellular and functional units of the cerebral cortex that are malformed in many brain disorders, but how they initially develop is not well understood. Using an optogenetic sensor in the mouse embryonic forebrain, we demonstrate that Ca2+ fluxes propagate bidirectionally within the elongated fibers of radial glial cells (RGCs), providing a novel communication mechanism linking the proliferative and postmitotic zones before the onset of synaptogenesis. Our results indicate that Ca2+ activity along RGC fibers provides feedback information along the radial migratory pathway, influencing neurogenesis and migration during early column development. Furthermore, we find that this columnar Ca2+ propagation is induced by Notch and fibroblast growth factor activities classically implicated in cortical expansion and patterning. Thus, cortical morphogens and growth factors may influence cortical column assembly in part by regulating long-distance Ca2+ communication along the radial axis of cortical development. PMID:26933693

  14. Cortical State and Attention

    PubMed Central

    Harris, Kenneth D.; Thiele, Alexander

    2012-01-01

    Preface The brain continuously adapts its processing machinery to behavioural demands. To achieve this it rapidly modulates the operating mode of cortical circuits, controlling the way information is transformed and routed. This article will focus on two experimental approaches by which the control of cortical information processing has been investigated: the study of state-dependent cortical processing in rodents, and attention in the primate visual system. Both processes involve a modulation of low-frequency activity fluctuations and spiking correlation, and are mediated by common receptor systems. We suggest that selective attention involves processes similar to state change, operating at a local columnar level to enhance the representation of otherwise nonsalient features while suppressing internally generated activity patterns. PMID:21829219

  15. Accommodative response and cortical activity during sustained attention.

    PubMed

    Poltavski, Dmitri V; Biberdorf, David; Petros, Thomas V

    2012-06-15

    Greater accommodative lag and vergence deficits have been linked to attentional deficits similar to those observed in Attention Deficit Hyperactivity Disorder (ADHD). The purpose of the present study was to assess the effect of accommodative-vergence stress on a measure of sustained attention (Conners CPT) used in the diagnosis of ADHD. Twenty-seven normal non-ADHD adults completed the Conners CPT twice: wearing -2.00 D lenses and normally (without the -2.00 D lenses) in a counterbalanced order with at least 24 h between the sessions. Simultaneous recording of participants' dynamic accommodative responses was performed from the right eye using the Grand Seiko WAM-5500 auto-refractor and electroencephalographic activity (EEG) in the left prefrontal region using the Neurosky Mindset headset. The results demonstrated a significantly greater accommodative lag in the -2.00 D stress condition and a significantly poorer performance on the Conners CPT as indexed by slower reaction time, greater standard error of hit reaction time, grater response variability, poorer stimulus detectability and a greater number of perseverations. No differences were observed on measures of EEG in the theta (4-7 Hz), alpha (8-12 Hz), and beta (12-20 Hz) bands. Moreover, when directly juxtaposed with each EEG band in multiple linear regression analyses, greater accommodative lag in the stress condition was significantly associated with a greater probability of clinical classification on the Conners CPT, and was also marginally predictive of the number of omissions recorded in the stress condition. The results demonstrated that sustained attention can be influenced by such factors as accommodative-vergence stress and suggest that bottom-up processes can contribute to and potentially exacerbate attentional problems in individuals with ADHD. The study also showed that cortical dysfunction (while sufficient) may not be a necessary condition for attentional deficits.

  16. Dopamine modulation of emotional processing in cortical and subcortical neural circuits: evidence for a final common pathway in schizophrenia?

    PubMed

    Laviolette, Steven R

    2007-07-01

    The neural regulation of emotional perception, learning, and memory is essential for normal behavioral and cognitive functioning. Many of the symptoms displayed by individuals with schizophrenia may arise from fundamental disturbances in the ability to accurately process emotionally salient sensory information. The neurotransmitter dopamine (DA) and its ability to modulate neural regions involved in emotional learning, perception, and memory formation has received considerable research attention as a potential final common pathway to account for the aberrant emotional regulation and psychosis present in the schizophrenic syndrome. Evidence from both human neuroimaging studies and animal-based research using neurodevelopmental, behavioral, and electrophysiological techniques have implicated the mesocorticolimbic DA circuit as a crucial system for the encoding and expression of emotionally salient learning and memory formation. While many theories have examined the cortical-subcortical interactions between prefrontal cortical regions and subcortical DA substrates, many questions remain as to how DA may control emotional perception and learning and how disturbances linked to DA abnormalities may underlie the disturbed emotional processing in schizophrenia. Beyond the mesolimbic DA system, increasing evidence points to the amygdala-prefrontal cortical circuit as an important processor of emotionally salient information and how neurodevelopmental perturbances within this circuitry may lead to dysregulation of DAergic modulation of emotional processing and learning along this cortical-subcortical emotional processing circuit. PMID:17519393

  17. Effects of Spectral Degradation on Attentional Modulation of Cortical Auditory Responses to Continuous Speech.

    PubMed

    Kong, Ying-Yee; Somarowthu, Ala; Ding, Nai

    2015-12-01

    This study investigates the effect of spectral degradation on cortical speech encoding in complex auditory scenes. Young normal-hearing listeners were simultaneously presented with two speech streams and were instructed to attend to only one of them. The speech mixtures were subjected to noise-channel vocoding to preserve the temporal envelope and degrade the spectral information of speech. Each subject was tested with five spectral resolution conditions (unprocessed speech, 64-, 32-, 16-, and 8-channel vocoder conditions) and two target-to-masker ratio (TMR) conditions (3 and 0 dB). Ongoing electroencephalographic (EEG) responses and speech comprehension were measured in each spectral and TMR condition for each subject. Neural tracking of each speech stream was characterized by cross-correlating the EEG responses with the envelope of each of the simultaneous speech streams at different time lags. Results showed that spectral degradation and TMR both significantly influenced how top-down attention modulated the EEG responses to the attended and unattended speech. That is, the EEG responses to the attended and unattended speech streams differed more for the higher (unprocessed, 64 ch, and 32 ch) than the lower (16 and 8 ch) spectral resolution conditions, as well as for the higher (3 dB) than the lower TMR (0 dB) condition. The magnitude of differential neural modulation responses to the attended and unattended speech streams significantly correlated with speech comprehension scores. These results suggest that severe spectral degradation and low TMR hinder speech stream segregation, making it difficult to employ top-down attention to differentially process different speech streams. PMID:26362546

  18. Effects of Spectral Degradation on Attentional Modulation of Cortical Auditory Responses to Continuous Speech.

    PubMed

    Kong, Ying-Yee; Somarowthu, Ala; Ding, Nai

    2015-12-01

    This study investigates the effect of spectral degradation on cortical speech encoding in complex auditory scenes. Young normal-hearing listeners were simultaneously presented with two speech streams and were instructed to attend to only one of them. The speech mixtures were subjected to noise-channel vocoding to preserve the temporal envelope and degrade the spectral information of speech. Each subject was tested with five spectral resolution conditions (unprocessed speech, 64-, 32-, 16-, and 8-channel vocoder conditions) and two target-to-masker ratio (TMR) conditions (3 and 0 dB). Ongoing electroencephalographic (EEG) responses and speech comprehension were measured in each spectral and TMR condition for each subject. Neural tracking of each speech stream was characterized by cross-correlating the EEG responses with the envelope of each of the simultaneous speech streams at different time lags. Results showed that spectral degradation and TMR both significantly influenced how top-down attention modulated the EEG responses to the attended and unattended speech. That is, the EEG responses to the attended and unattended speech streams differed more for the higher (unprocessed, 64 ch, and 32 ch) than the lower (16 and 8 ch) spectral resolution conditions, as well as for the higher (3 dB) than the lower TMR (0 dB) condition. The magnitude of differential neural modulation responses to the attended and unattended speech streams significantly correlated with speech comprehension scores. These results suggest that severe spectral degradation and low TMR hinder speech stream segregation, making it difficult to employ top-down attention to differentially process different speech streams.

  19. Refractory period modulates the spatiotemporal evolution of cortical spreading depression: a computational study.

    PubMed

    Li, Bing; Chen, Shangbin; Li, Pengcheng; Luo, Qingming; Gong, Hui

    2014-01-01

    Cortical spreading depression (CSD) is a pathophysiological phenomenon, which underlies some neurological disorders, such as migraine and stroke, but its mechanisms are still not completely understood. One of the striking facts is that the spatiotemporal evolution of CSD wave is varying. Observations in experiments reveal that a CSD wave may propagate through the entire cortex, or just bypass some areas of the cortex. In this paper, we have applied a 2D reaction-diffusion equation with recovery term to study the spatiotemporal evolution of CSD. By modulating the recovery rate from CSD in the modeled cortex, CSD waves with different spatiotemporal evolutions, either bypassing some areas or propagating slowly in these areas, were present. Moreover, spiral CSD waves could also be induced in case of the transiently altered recovery rate, i.e. block release from the absolute refractory period. These results suggest that the refractory period contributes to the different propagation patterns of CSD, which may help to interpret the mechanisms of CSD propagation. PMID:24400104

  20. Cortical Spectral Activity and Connectivity during Active and Viewed Arm and Leg Movement

    PubMed Central

    Kline, Julia E.; Huang, Helen J.; Snyder, Kristine L.; Ferris, Daniel P.

    2016-01-01

    Active and viewed limb movement activate many similar neural pathways, however, to date most comparison studies have focused on subjects making small, discrete movements of the hands and feet. The purpose of this study was to determine if high-density electroencephalography (EEG) could detect differences in cortical activity and connectivity during active and viewed rhythmic arm and leg movements in humans. Our primary hypothesis was that we would detect similar but weaker electrocortical spectral fluctuations and effective connectivity fluctuations during viewed limb exercise compared to active limb exercise due to the similarities in neural recruitment. A secondary hypothesis was that we would record stronger cortical spectral fluctuations for arm exercise compared to leg exercise, because rhythmic arm exercise would be more dependent on supraspinal control than rhythmic leg exercise. We recorded EEG data while ten young healthy subjects exercised on a recumbent stepper with: (1) both arms and legs, (2) just legs, and (3) just arms. Subjects also viewed video playback of themselves or another individual performing the same exercises. We performed independent component analysis, dipole fitting, spectral analysis, and effective connectivity analysis on the data. Cortical areas comprising the premotor and supplementary motor cortex, the anterior cingulate, the posterior cingulate, and the parietal cortex exhibited significant spectral fluctuations during rhythmic limb exercise. These fluctuations tended to be greater for the arms exercise conditions than for the legs only exercise condition, which suggests that human rhythmic arm movements are under stronger cortical control than rhythmic leg movements. We did not find consistent spectral fluctuations in these areas during the viewed conditions, but effective connectivity fluctuated at harmonics of the exercise frequency during both active and viewed rhythmic limb exercise. The right premotor and supplementary motor

  1. Functional MRI of neuronal activation in epilepsy patients with malformations of cortical development.

    PubMed

    Nikolova, Simona; Bartha, Robert; Parrent, Andrew G; Steven, David A; Diosy, David; Burneo, Jorge G

    2015-10-01

    Malformations of cortical development are disturbances in brain formation that arise from abnormalities affecting the processes of cortical development. Surgical treatment of intractable epilepsy in patients with malformations of cortical development requires localization of both epileptogenic and eloquent cortices. Functional magnetic resonance imaging has been shown to detect the reorganization of activation patterns in such patients. The purpose of this study was to determine whether functional reorganization of the primary sensory and motor cortices occurs in patients with epileptogenic malformations of cortical development. Functional MRI data were obtained for 11 patients (four male, seven female) with a mean age of 36 years (range 18-55 years). The mean age at epilepsy onset was 23 years (range 3-55 years). Twelve healthy controls (six male, six female) with mean age of 33 years (range 28-51 years) were also recruited for comparison. High resolution anatomical MRI was used to confirm the presence and the location of the malformation. All imaging experiments were performed using a 3.0T Siemens Tim Trio whole body MRI. Each subject performed four block-paradigm fMRI experiments to study motor and sensory activation for each hand. A total of 132 image sets were collected for each paradigm over 5.5min (2.5s per image). Each paradigm consisted of seven stimulus periods lasting 30s (12 images) and stimulus onset of 30, 90, 150, 210 and 270s. Functional data were obtained from all eligible patients and compared to those of controls. Reorganization and reduction in function in the motor and sensory areas were observed in patients with cortical dysplasia. Patients with polymicrogyria did not present with significant functional reorganization and patients with heterotopias and coexisting polymicrogyria and/or cortical dysplasia had variable patterns of activation. In summary, this study showed evidence of functional reorganization of sensory and motor cortices in

  2. Assessments of Muscle Oxygenation and Cortical Activity Using Functional Near-infrared Spectroscopy in Healthy Adults During Hybrid Activation.

    PubMed

    Lin, Tai-You; Wu, Jin-Shang; Lin, Linda L; Ho, Ting-Chuan; Lin, Pei-Yi; Chen, Jia-Jin J

    2016-01-01

    Hybrid activation (HA), patterned electrical stimulation (ES) superimposed on attempted voluntary movement in close synchrony, can augment muscle force output. It has been proposed for limb function restoration and neuromodulation. Limited studies have been performed to investigate the influences of HA on muscle oxygenation and brain cortical activity. The present study investigates muscle oxygenation and cortical activity during isometric knee extension tasks with voluntary contraction (VOL) only, ES only, and with HA at three stimulation intensities, namely 10 mA (HA-I), 30 mA (HA-II), and 50 mA (HA-III). A frequency-domain near-infrared spectroscopy system was employed to assess the muscle oxygenation in the vastus lateralis as well as the cortical activity from the bilateral sensorimotor cortices (SMCs), premotor cortices (PMCs), and supplementary motor areas (SMAs). Our results show that the increased ES contribution during HA significantly increased O2 demand in working muscle, implying that the intervention of ES accelerates the muscle metabolism during muscle contraction. For cortical activation, ES only had a similar cortical activation pattern to that during VOL but with lower activation in SMCs, PMCs, and SMAs. Augmented sensorimotor activation was observed during the HA-II condition. The enhanced level of cortical activation during HA was not only affected by the ES contribution within HA but also related to the functional specificity of cortical areas. Our results suggest that HA can effectively enhance the muscle oxygen demand as well as the activation of cortical regions, and that the ES contribution within HA is a key factor.

  3. Correlation of fingertip shear force direction with somatosensory cortical activity in monkey.

    PubMed

    Fortier-Poisson, Pascal; Langlais, Jean-Sébastien; Smith, Allan M

    2016-01-01

    To examine the activity of somatosensory cortex (S1) neurons to self-generated shear forces on the index and thumb, two monkeys were trained to grasp a stationary metal tab with a key grip and exert forces without the fingers slipping in one of four orthogonal directions for 1 s. A majority (∼85%) of slowly adapting and rapidly adapting (RA) S1 neurons had activity modulated with shear force direction. The cells were recorded mainly in areas 1 and 2 of the S1, although some area 3b neurons also responded to shear direction or magnitude. The preferred shear vectors were distributed in every direction, with tuning arcs varying from 50° to 170°. Some RA neurons sensitive to dynamic shear force direction also responded to static shear force but within a narrower range, suggesting that the direction of the shear force may influence the adaptation rate. Other neurons were modulated with shear forces in diametrically opposite directions. The directional sensitivity of S1 cortical neurons is consistent with recordings from cutaneous afferents showing that shear direction, even without slip, is a powerful stimulus to S1 neurons. PMID:26467520

  4. Human thalamus regulates cortical activity via spatially specific and structurally constrained phase-amplitude coupling.

    PubMed

    Malekmohammadi, Mahsa; Elias, W Jeff; Pouratian, Nader

    2015-06-01

    Although the thalamus is believed to regulate and coordinate cortical activity both within and across functional regions, such as motor and visual cortices, direct evidence for such regulation and the mechanism of regulation remains poorly described. Using simultaneous invasive recordings of cortical and thalamic electrophysiological activity in 2 awake and spontaneously behaving human subjects, we provide direct evidence of thalamic regulation of cortical activity through a mechanism of phase-amplitude coupling (PAC), in which the phase of low frequency oscillations regulates the amplitude of higher frequency oscillations. Specifically, we show that cortical PAC between the theta phase and beta amplitude is spatially dependent on and time variant with the magnitude of thalamocortical theta coherence. Moreover, using causality analysis and MR diffusion tractography, we provide evidence that thalamic theta activity drives cortical theta oscillations and PAC across structures and that these thalamocortical relationships are structurally constrained by anatomic pathways. This relationship allows for new evidence of thalamocortical PAC. Given the diffuse connectivity of the thalamus with the cerebral cortex, thalamocortical PAC may play an important role in addressing the binding problem, including both integration and segregation of information within and across cortical areas.

  5. Orexin-dependent activation of layer VIb enhances cortical network activity and integration of non-specific thalamocortical inputs.

    PubMed

    Hay, Y Audrey; Andjelic, Sofija; Badr, Sammy; Lambolez, Bertrand

    2015-11-01

    Neocortical layer VI is critically involved in thalamocortical activity changes during the sleep/wake cycle. It receives dense projections from thalamic nuclei sensitive to the wake-promoting neuropeptides orexins, and its deepest part, layer VIb, is the only cortical lamina reactive to orexins. This convergence of wake-promoting inputs prompted us to investigate how layer VIb can modulate cortical arousal, using patch-clamp recordings and optogenetics in rat brain slices. We found that the majority of layer VIb neurons were excited by nicotinic agonists and orexin through the activation of nicotinic receptors containing α4-α5-β2 subunits and OX2 receptor, respectively. Specific effects of orexin on layer VIb neurons were potentiated by low nicotine concentrations and we used this paradigm to explore their intracortical projections. Co-application of nicotine and orexin increased the frequency of excitatory post-synaptic currents in the ipsilateral cortex, with maximal effect in infragranular layers and minimal effect in layer IV, as well as in the contralateral cortex. The ability of layer VIb to relay thalamocortical inputs was tested using photostimulation of channelrhodopsin-expressing fibers from the orexin-sensitive rhomboid nucleus in the parietal cortex. Photostimulation induced robust excitatory currents in layer VIa neurons that were not pre-synaptically modulated by orexin, but exhibited a delayed, orexin-dependent, component. Activation of layer VIb by orexin enhanced the reliability and spike-timing precision of layer VIa responses to rhomboid inputs. These results indicate that layer VIb acts as an orexin-gated excitatory feedforward loop that potentiates thalamocortical arousal.

  6. Active modulation of nanorod plasmons.

    PubMed

    Khatua, Saumyakanti; Chang, Wei-Shun; Swanglap, Pattanawit; Olson, Jana; Link, Stephan

    2011-09-14

    Confining visible light to nanoscale dimensions has become possible with surface plasmons. Many plasmonic elements have already been realized. Nanorods, for example, function as efficient optical antennas. However, active control of the plasmonic response remains a roadblock for building optical analogues of electronic circuits. We present a new approach to modulate the polarized scattering intensities of individual gold nanorods by 100% using liquid crystals with applied voltages as low as 4 V. This novel effect is based on the transition from a homogeneous to a twisted nematic phase of the liquid crystal covering the nanorods. With our method it will be possible to actively control optical antennas as well as other plasmonic elements.

  7. Contrasting early visual cortical activation states causally involved in visual imagery and short-term memory.

    PubMed

    Cattaneo, Zaira; Vecchi, Tomaso; Pascual-Leone, Alvaro; Silvanto, Juha

    2009-10-01

    Whether visual imagery and visual short-term memory (STM) share the same neural resources, and the extent to which the early visual cortex (V1/V2) is involved in these processes, has been the subject of much debate. Here, we used transcranial magnetic stimulation (TMS) in two separate experiments to contrast the neural states associated with visual imagery and visual STM in the early visual cortex. In Experiment 1, we investigated V1/V2 activation states at the end of the retention phase in a visual imagery and a visual STM task. V1/V2 TMS facilitated performance in both tasks; the finding that imagery and STM interacted with TMS in the same way suggests that the two processes have similar effects on early visual cortical excitability. In Experiment 2, we investigated V1/V2 activation states at the beginning of the retention phase. V1/V2 TMS impaired performance in the visual STM task, whereas it had no effect on the imagery task. Taken together, our findings show that the late phases of the early visual cortical activation state associated with visual imagery and visual STM are similar; differences between the two processes are apparent in the early phases of the tasks. Our results also suggest that the causal role of the early visual cortex in visual STM includes both the initial translation of the visual input into working memory and the subsequent maintenance of the mental representation. Finally, our findings indicate that visual STM sensory recruitment in working memory might act via excitability modulation of V1/V2 neurons.

  8. Cortical Activity during a Highly-Trained Resistance Exercise Movement Emphasizing Force, Power or Volume.

    PubMed

    Flanagan, Shawn D; Dunn-Lewis, Courtenay; Comstock, Brett A; Maresh, Carl M; Volek, Jeff S; Denegar, Craig R; Kraemer, William J

    2012-11-20

    Cortical activity is thought to reflect the biomechanical properties of movement (e.g., force or velocity of movement), but fatigue and movement familiarity are important factors that require additional consideration in electrophysiological research. The purpose of this within-group quantitative electroencephalogram (EEG) investigation was to examine changes in cortical activity amplitude and location during four resistance exercise movement protocols emphasizing rate (PWR), magnitude (FOR), or volume (VOL) of force production, while accounting for movement familiarity and fatigue. EEG signals were recorded during each complete repetition and were then grouped by functional region, processed to eliminate artifacts, and averaged to compare overall differences in the magnitude and location of cortical activity between protocols over the course of six sets. Biomechanical, biochemical, and exertional data were collected to contextualize electrophysiological data. The most fatiguing protocols were accompanied by the greatest increases in cortical activity. Furthermore, despite non-incremental loading and lower force levels, VOL displayed the largest increases in cortical activity over time and greatest motor and sensory activity overall. Our findings suggest that cortical activity is strongly related to aspects of fatigue during a high intensity resistance exercise movement.

  9. Cortical Activity during a Highly-Trained Resistance Exercise Movement Emphasizing Force, Power or Volume

    PubMed Central

    Flanagan, Shawn D.; Dunn-Lewis, Courtenay; Comstock, Brett A.; Maresh, Carl M.; Volek, Jeff S.; Denegar, Craig R.; Kraemer, William J.

    2012-01-01

    Cortical activity is thought to reflect the biomechanical properties of movement (e.g., force or velocity of movement), but fatigue and movement familiarity are important factors that require additional consideration in electrophysiological research. The purpose of this within-group quantitative electroencephalogram (EEG) investigation was to examine changes in cortical activity amplitude and location during four resistance exercise movement protocols emphasizing rate (PWR), magnitude (FOR), or volume (VOL) of force production, while accounting for movement familiarity and fatigue. EEG signals were recorded during each complete repetition and were then grouped by functional region, processed to eliminate artifacts, and averaged to compare overall differences in the magnitude and location of cortical activity between protocols over the course of six sets. Biomechanical, biochemical, and exertional data were collected to contextualize electrophysiological data. The most fatiguing protocols were accompanied by the greatest increases in cortical activity. Furthermore, despite non-incremental loading and lower force levels, VOL displayed the largest increases in cortical activity over time and greatest motor and sensory activity overall. Our findings suggest that cortical activity is strongly related to aspects of fatigue during a high intensity resistance exercise movement. PMID:24961265

  10. Traumatic Brain Injury Increases Cortical Glutamate Network Activity by Compromising GABAergic Control

    PubMed Central

    Cantu, David; Walker, Kendall; Andresen, Lauren; Taylor-Weiner, Amaro; Hampton, David; Tesco, Giuseppina; Dulla, Chris G.

    2015-01-01

    Traumatic brain injury (TBI) is a major risk factor for developing pharmaco-resistant epilepsy. Although disruptions in brain circuitry are associated with TBI, the precise mechanisms by which brain injury leads to epileptiform network activity is unknown. Using controlled cortical impact (CCI) as a model of TBI, we examined how cortical excitability and glutamatergic signaling was altered following injury. We optically mapped cortical glutamate signaling using FRET-based glutamate biosensors, while simultaneously recording cortical field potentials in acute brain slices 2–4 weeks following CCI. Cortical electrical stimulation evoked polyphasic, epileptiform field potentials and disrupted the input–output relationship in deep layers of CCI-injured cortex. High-speed glutamate biosensor imaging showed that glutamate signaling was significantly increased in the injured cortex. Elevated glutamate responses correlated with epileptiform activity, were highest directly adjacent to the injury, and spread via deep cortical layers. Immunoreactivity for markers of GABAergic interneurons were significantly decreased throughout CCI cortex. Lastly, spontaneous inhibitory postsynaptic current frequency decreased and spontaneous excitatory postsynaptic current increased after CCI injury. Our results suggest that specific cortical neuronal microcircuits may initiate and facilitate the spread of epileptiform activity following TBI. Increased glutamatergic signaling due to loss of GABAergic control may provide a mechanism by which TBI can give rise to post-traumatic epilepsy. PMID:24610117

  11. Cortical alpha activity predicts the confidence in an impending action

    PubMed Central

    Kubanek, Jan; Hill, N. Jeremy; Snyder, Lawrence H.; Schalk, Gerwin

    2015-01-01

    When we make a decision, we experience a degree of confidence that our choice may lead to a desirable outcome. Recent studies in animals have probed the subjective aspects of the choice confidence using confidence-reporting tasks. These studies showed that estimates of the choice confidence substantially modulate neural activity in multiple regions of the brain. Building on these findings, we investigated the neural representation of the confidence in a choice in humans who explicitly reported the confidence in their choice. Subjects performed a perceptual decision task in which they decided between choosing a button press or a saccade while we recorded EEG activity. Following each choice, subjects indicated whether they were sure or unsure about the choice. We found that alpha activity strongly encodes a subject's confidence level in a forthcoming button press choice. The neural effect of the subjects' confidence was independent of the reaction time and independent of the sensory input modeled as a decision variable. Furthermore, the effect is not due to a general cognitive state, such as reward expectation, because the effect was specifically observed during button press choices and not during saccade choices. The neural effect of the confidence in the ensuing button press choice was strong enough that we could predict, from independent single trial neural signals, whether a subject was going to be sure or unsure of an ensuing button press choice. In sum, alpha activity in human cortex provides a window into the commitment to make a hand movement. PMID:26283892

  12. Beyond the amygdala: Linguistic threat modulates peri-sylvian semantic access cortices.

    PubMed

    Weisholtz, Daniel S; Root, James C; Butler, Tracy; Tüscher, Oliver; Epstein, Jane; Pan, Hong; Protopopescu, Xenia; Goldstein, Martin; Isenberg, Nancy; Brendel, Gary; LeDoux, Joseph; Silbersweig, David A; Stern, Emily

    2015-12-01

    In this study, healthy volunteers were scanned using functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in processing the threatening content conveyed via visually presented "threat words." The neural responses elicited by these words were compared to those elicited by matched neutral control words. The results demonstrate that linguistic threat, when presented in written form, can selectively engage areas of lateral temporal and inferior frontal cortex, distinct from the core language areas implicated in aphasia. Additionally, linguistic threat modulates neural activity in visceral/emotional systems (amygdala, parahippocampal gyrus and periaqueductal gray), and at earlier stages of the visual-linguistic processing stream involved in visual word form representations (ventral occipitotemporal cortex). We propose a model whereby limbic activation modulates activity at multiple nodes along the visual-linguistic-semantic processing stream, including a perisylvian "semantic access network" involved in decoding word meaning, suggesting a dynamic interplay between feedforward and feedback processes. PMID:26575986

  13. Pharmacological and ionic characterizations of the muscarinic receptors modulating (/sup 3/H)acetylcholine release from rat cortical synaptosomes

    SciTech Connect

    Meyer, E.M.; Otero, D.H.

    1985-05-01

    The muscarinic receptors that modulate acetylcholine release from rat cortical synaptosomes were characterized with respect to sensitivity to drugs that act selectively at M1 or M2 receptor subtypes, as well as to changes in ionic strength and membrane potential. The modulatory receptors appear to be of the M2 type, since they are activated by carbachol, acetylcholine, methacholine, oxotremorine, and bethanechol, but not by pilocarpine, and are blocked by atropine, scopolamine, and gallamine (at high concentrations), but not by pirenzepine or dicyclomine. The ED50S for carbachol, acetylcholine, and oxotremorine are less than 10 microM, suggesting that the high affinity state of the receptor is functional. High ionic strength induced by raising the NaCl concentration has no effect on agonist (oxotremorine) potency, but increases the efficacy of this compound, which disagrees with receptor-binding studies. On the other hand, depolarization with either KCl or with veratridine (20 microM) reduces agonist potencies by approximately an order of magnitude, suggesting a potential mechanism for receptor regulation.

  14. Different Modulation of Common Motor Information in Rat Primary and Secondary Motor Cortices

    PubMed Central

    Saiki, Akiko; Kimura, Rie; Samura, Toshikazu; Fujiwara-Tsukamoto, Yoko; Sakai, Yutaka; Isomura, Yoshikazu

    2014-01-01

    Rodents have primary and secondary motor cortices that are involved in the execution of voluntary movements via their direct and parallel projections to the spinal cord. However, it is unclear whether the rodent secondary motor cortex has any motor function distinct from the primary motor cortex to properly control voluntary movements. In the present study, we quantitatively examined neuronal activity in the caudal forelimb area (CFA) of the primary motor cortex and rostral forelimb area (RFA) of the secondary motor cortex in head-fixed rats performing forelimb movements (pushing, holding, and pulling a lever). We found virtually no major differences between CFA and RFA neurons, regardless of neuron subtypes, not only in their basal spiking properties but also in the time-course, amplitude, and direction preference of their functional activation for simple forelimb movements. However, the RFA neurons, as compared with the CFA neurons, showed obviously a greater susceptibility of their functional activation to an alteration in a behavioral situation, a 'rewarding' response that leads to reward or a 'consummatory' response that follows reward water, which might be accompanied by some internal adaptations without affecting the motor outputs. Our results suggest that, although the CFA and RFA neurons commonly process fundamental motor information to properly control forelimb movements, the RFA neurons may be functionally differentiated to integrate motor information with internal state information for an adaptation to goal-directed behaviors. PMID:24893154

  15. Dynamic modulation of shared sensory and motor cortical rhythms mediates speech and non-speech discrimination performance

    PubMed Central

    Bowers, Andrew L.; Saltuklaroglu, Tim; Harkrider, Ashley; Wilson, Matt; Toner, Mary A.

    2014-01-01

    Oscillatory models of speech processing have proposed that rhythmic cortical oscillations in sensory and motor regions modulate speech sound processing from the bottom-up via phase reset at low frequencies (3–10 Hz) and from the top-down via the disinhibition of alpha/beta rhythms (8–30 Hz). To investigate how the proposed rhythms mediate perceptual performance, electroencephalographic (EEG) was recorded while participants passively listened to or actively identified speech and tone-sweeps in a two-force choice in noise discrimination task presented at high and low signal-to-noise ratios. EEG data were decomposed using independent component analysis and clustered across participants using principle component methods in EEGLAB. Left and right hemisphere sensorimotor and posterior temporal lobe clusters were identified. Alpha and beta suppression was associated with active tasks only in sensorimotor and temporal clusters. In posterior temporal clusters, increases in phase reset at low frequencies were driven by the quality of bottom-up acoustic information for speech and non-speech stimuli, whereas phase reset in sensorimotor clusters was associated with top-down active task demands. A comparison of correct discrimination trials to those identified at chance showed an earlier performance related effect for the left sensorimotor cluster relative to the left-temporal lobe cluster during the syllable discrimination task only. The right sensorimotor cluster was associated with performance related differences for tone–sweep stimuli only. Findings are consistent with internal model accounts suggesting that early efferent sensorimotor models transmitted along alpha and beta channels reflect a release from inhibition related to active attention to auditory discrimination. Results are discussed in the broader context of dynamic, oscillatory models of cognition proposing that top-down internally generated states interact with bottom-up sensory processing to enhance task

  16. Task-dependent and polarity-specific effects of prefrontal transcranial direct current stimulation on cortical activation during word fluency.

    PubMed

    Ehlis, Ann-Christine; Haeussinger, Florian B; Gastel, Alex; Fallgatter, Andreas J; Plewnia, Christian

    2016-10-15

    Targeted modulation of cortical functions by non-invasive brain stimulation is widely used for the investigation of the neurophysiological signatures of executive functions and put forward as a potential specific treatment for its disorders. To further investigate the underlying mechanisms, we performed two experiments involving 46 subjects that performed a semantic and a phonological verbal fluency task (VFT) as well as a simple speech-production task after application of 1mA anodal or cathodal transcranial direct current stimulation (tDCS) to the left inferior frontal gyrus (IFG). Brain activation was measured by functional near-infrared spectroscopy (fNIRS) during task performance. Neither preceding anodal nor cathodal tDCS was found to modulate VFT performance of either difficulty. However, preconditioning with anodal tDCS increased brain activity during the VFT whereas a trendwise decrease of activation was found after cathodal stimulation. Notably, this difference was not found with simple speech production. These findings support the notion of a polarity-specific malleability of neuronal network activity underlying speech production by tDCS. Most importantly, the task-specificity of the modulatory effect observed after the end of stimulation demonstrates lasting neurophysiological effects of tDCS that are reflected in modifications of cortical excitability by challenging cognitive tasks. PMID:26748077

  17. Comparison of visual cortical activations induced by electro-acupuncture at vision and nonvision-related acupoints.

    PubMed

    Zhang, Yi; Liang, Jimin; Qin, Wei; Liu, Peng; von Deneen, Karen M; Chen, Peng; Bai, Lijun; Tian, Jie; Liu, Yijun

    2009-07-10

    In the current study, we investigated whether or not stimulation at vision and nonvision-related acupoints was able to induce similarity in the time domain, although stimulation at different acupoints could produce similar spatial distributions. This phenomenon still remains uncertain and contradictory. We introduced a novel experimental paradigm using a modified non-repeated event-related (NRER) design, and utilized the methods of independent component analysis (ICA) combined with seed correlated functional connectivity analysis to locate visual cortical activations and to study their temporal characteristics during electro-acupuncture (EAS) at vision-related acupoint GB 37 and nonvision-related acupoint KI 8. Results showed that strong activations were present in the visual cortical areas (BA 17/18/19) at both acupoints, but temporal correlation analysis indicated that they were modulated in opposite directions during the resting state after acupuncture. Our results revealed that acupuncture at vision and nonvision-related acupoints can induce similar activations in spatial distribution but different modulation effects temporally.

  18. Caloric restriction stimulates autophagy in rat cortical neurons through neuropeptide Y and ghrelin receptors activation

    PubMed Central

    Carmo-Silva, Sara; Botelho, Mariana; de Almeida, Luís Pereira; Cavadas, Cláudia

    2016-01-01

    Caloric restriction is an anti-aging intervention known to extend lifespan in several experimental models, at least in part, by stimulating autophagy. Caloric restriction increases neuropeptide Y (NPY) in the hypothalamus and plasma ghrelin, a peripheral gut hormone that acts in hypothalamus to modulate energy homeostasis. NPY and ghrelin have been shown to be neuroprotective in different brain areas and to induce several physiological modifications similar to those induced by caloric restriction. However, the effect of NPY and ghrelin in autophagy in cortical neurons is currently not known. Using a cell culture of rat cortical neurons we investigate the involvement of NPY and ghrelin in caloric restriction-induced autophagy. We observed that a caloric restriction mimetic cell culture medium stimulates autophagy in rat cortical neurons and NPY or ghrelin receptor antagonists blocked this effect. On the other hand, exogenous NPY or ghrelin stimulate autophagy in rat cortical neurons. Moreover, NPY mediates the stimulatory effect of ghrelin on autophagy in rat cortical neurons. Since autophagy impairment occurs in aging and age-related neurodegenerative diseases, NPY and ghrelin synergistic effect on autophagy stimulation may suggest a new strategy to delay aging process. PMID:27441412

  19. Vestibular activation differentially modulates human early visual cortex and V5/MT excitability and response entropy.

    PubMed

    Seemungal, Barry M; Guzman-Lopez, Jessica; Arshad, Qadeer; Schultz, Simon R; Walsh, Vincent; Yousif, Nada

    2013-01-01

    Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC.

  20. Mitochondrial activity and brain functions during cortical depolarization

    NASA Astrophysics Data System (ADS)

    Mayevsky, Avraham; Sonn, Judith

    2008-12-01

    Cortical depolarization (CD) of the cerebral cortex could be developed under various pathophysiological conditions. In animal models, CD was recorded under partial or complete ischemia as well as when cortical spreading depression (SD) was induced externally or by internal stimulus. The development of CD in patients and the changes in various metabolic parameters, during CD, was rarely reported. Brain metabolic, hemodynamic, ionic and electrical responses to the CD event are dependent upon the O2 balance in the tissue. When the O2 balance is negative (i.e. ischemia), the CD process will be developed due to mitochondrial dysfunction, lack of energy and the inhibition of Na+-K+-ATPase. In contradiction, when oxygen is available (i.e. normoxia) the development of CD after induction of SD will accelerate mitochondrial respiration for retaining ionic homeostasis and normal brain functions. We used the multiparametric monitoring approach that enable real time monitoring of mitochondrial NADH redox state, microcirculatory blood flow and oxygenation, extracellular K+, Ca2+, H+ levels, DC steady potential and electrocorticogram (ECoG). This monitoring approach, provide a unique tool that has a significant value in analyzing the pathophysiology of the brain when SD developed under normoxia, ischemia, or hypoxia. We applied the same monitoring approach to patients suffered from severe head injury or exposed to neurosurgical procedures.

  1. Nitric Oxide Modulation of GABAergic Synaptic Transmission in Mechanically Isolated Rat Auditory Cortical Neurons

    PubMed Central

    2009-01-01

    The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic K+ channels by 4-aminopyridine, a K+ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic Ca2+ channels by Cd2+, a general voltage-dependent Ca2+ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic Ca2+ channels in the presynaptic nerve terminals of A1 neurons. PMID:20054493

  2. Nanoscale laminin coating modulates cortical scarring response around implanted silicon microelectrode arrays

    NASA Astrophysics Data System (ADS)

    He, Wei; McConnell, George C.; Bellamkonda, Ravi V.

    2006-12-01

    Neural electrodes could significantly enhance the quality of life for patients with sensory and/or motor deficits as well as improve our understanding of brain functions. However, long-term electrical connectivity between neural tissue and recording sites is compromised by the development of astroglial scar around the recording probes. In this study we investigate the effect of a nanoscale laminin (LN) coating on Si-based neural probes on chronic cortical tissue reaction in a rat model. Tissue reaction was evaluated after 1 day, 1 week, and 4 weeks post-implant for coated and uncoated probes using immunohistochemical techniques to evaluate activated microglia/macrophages (ED-1), astrocytes (GFAP) and neurons (NeuN). The coating did not have an observable effect on neuronal density or proximity to the electrode surface. However, the response of microglia/macrophages and astrocytes was altered by the coating. One day post-implant, we observed an ~60% increase in ED-1 expression near LN-coated probe sites compared with control uncoated probe sites. Four weeks post-implant, we observed an ~20% reduction in ED-1 expression along with an ~50% reduction in GFAP expression at coated relative to uncoated probe sites. These results suggest that LN has a stimulatory effect on early microglia activation, accelerating the phagocytic function of these cells. This hypothesis is further supported by the increased mRNA expression of several pro-inflammatory cytokines (TNF-α, IL-1 and IL-6) in cultured microglia on LN-bound Si substrates. LN immunostaining of coated probes immediately after insertion and retrieval demonstrates that the coating integrity is not compromised by the shear force during insertion. We speculate, based on these encouraging results, that LN coating of Si neural probes could potentially improve chronic neural recordings through dispersion of the astroglial scar.

  3. Shifts of Gamma Phase across Primary Visual Cortical Sites Reflect Dynamic Stimulus-Modulated Information Transfer

    PubMed Central

    Besserve, Michel; Lowe, Scott C.; Logothetis, Nikos K.; Schölkopf, Bernhard; Panzeri, Stefano

    2015-01-01

    Distributed neural processing likely entails the capability of networks to reconfigure dynamically the directionality and strength of their functional connections. Yet, the neural mechanisms that may allow such dynamic routing of the information flow are not yet fully understood. We investigated the role of gamma band (50–80 Hz) oscillations in transient modulations of communication among neural populations by using measures of direction-specific causal information transfer. We found that the local phase of gamma-band rhythmic activity exerted a stimulus-modulated and spatially-asymmetric directed effect on the firing rate of spatially separated populations within the primary visual cortex. The relationships between gamma phases at different sites (phase shifts) could be described as a stimulus-modulated gamma-band wave propagating along the spatial directions with the largest information transfer. We observed transient stimulus-related changes in the spatial configuration of phases (compatible with changes in direction of gamma wave propagation) accompanied by a relative increase of the amount of information flowing along the instantaneous direction of the gamma wave. These effects were specific to the gamma-band and suggest that the time-varying relationships between gamma phases at different locations mark, and possibly causally mediate, the dynamic reconfiguration of functional connections. PMID:26394205

  4. Altered Theta Oscillations and Aberrant Cortical Excitatory Activity in the 5XFAD Model of Alzheimer's Disease

    PubMed Central

    Siwek, Magdalena Elisabeth; Müller, Ralf; Henseler, Christina; Trog, Astrid; Lundt, Andreas; Wormuth, Carola; Broich, Karl; Weiergräber, Marco; Papazoglou, Anna

    2015-01-01

    Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by impairment of memory function. The 5XFAD mouse model was analyzed and compared with wild-type (WT) controls for aberrant cortical excitability and hippocampal theta oscillations by using simultaneous video-electroencephalogram (EEG) monitoring. Seizure staging revealed that 5XFAD mice exhibited cortical hyperexcitability whereas controls did not. In addition, 5XFAD mice displayed a significant increase in hippocampal theta activity from the light to dark phase during nonmotor activity. We also observed a reduction in mean theta frequency in 5XFAD mice compared to controls that was again most prominent during nonmotor activity. Transcriptome analysis of hippocampal probes and subsequent qPCR validation revealed an upregulation of Plcd4 that might be indicative of enhanced muscarinic signalling. Our results suggest that 5XFAD mice exhibit altered cortical excitability, hippocampal dysrhythmicity, and potential changes in muscarinic signaling. PMID:25922768

  5. Spatiotemporal regulation of chemical reaction kinetics of cell surface molecules by active remodeling of cortical actin

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Bhaswati; Chaudhuri, Abhishek; Gowrishankar, Kripa; Mayor, Satyajit; Rao, Madan

    2010-03-01

    Cell surface proteins such as lipid tethered GPI-anchored proteins and Ras-proteins are distributed as monomers and nanoclusters on the surface of living cells. Recent work from our laboratory suggests that the spatial distribution and dynamics of formation and breakup of these nanoclusters is controlled by the active remodeling dynamics of the underlying cortical actin. To explain these observations, we propose a novel mechanism of nanoclustering, involving the transient binding to and advection along constitutively occuring ``asters'' of cortical actin. Here we study the consequences of such active actin based clustering, in the context of chemical reactions involving conformational changes of cell surface proteins. We find that active remodeling of cortical actin, can give rise to a dramatic increase in the reaction efficiency and output levels. In general, such actin driven clustering of membrane proteins could be a cellular mechanism to spatiotemporally regulate and amplify local chemical reaction rates, in the context of signalling and endocytosis.

  6. Migration Speed of Cajal-Retzius Cells Modulated by Vesicular Trafficking Controls the Size of Higher-Order Cortical Areas.

    PubMed

    Barber, Melissa; Arai, Yoko; Morishita, Yoshihiro; Vigier, Lisa; Causeret, Frédéric; Borello, Ugo; Ledonne, Fanny; Coppola, Eva; Contremoulins, Vincent; Pfrieger, Frank W; Tissir, Fadel; Govindan, Subashika; Jabaudon, Denis; Proux-Gillardeaux, Véronique; Galli, Thierry; Pierani, Alessandra

    2015-10-01

    In the neocortex, higher-order areas are essential to integrate sensory-motor information and have expanded in size during evolution. How higher-order areas are specified, however, remains largely unknown. Here, we show that the migration and distribution of early-born neurons, the Cajal-Retzius cells (CRs), controls the size of higher-order areas in the mouse somatosensory, auditory, and visual cortex. Using live imaging, genetics, and in silico modeling, we show that subtype-specific differences in the onset, speed, and directionality of CR migration determine their differential invasion of the developing cortical surface. CR migration speed is cell autonomously modulated by vesicle-associated membrane protein 3 (VAMP3), a classically non-neuronal mediator of endosomal recycling. Increasing CR migration speed alters their distribution in the developing cerebral cortex and leads to an expansion of postnatal higher-order areas and congruent rewiring of thalamo-cortical input. Our findings thus identify novel roles for neuronal migration and VAMP3-dependent vesicular trafficking in cortical wiring.

  7. Age-Related Differences in Cortical Activity during a Visuo-Spatial Working Memory Task with Facial Stimuli

    PubMed Central

    Belham, Flávia Schechtman; Satler, Corina; Garcia, Ana; Tomaz, Carlos; Gasbarri, Antonella; Rego, Artur; Tavares, Maria Clotilde H.

    2013-01-01

    Emotion, importantly displayed by facial expressions, is one of the most significant memory modulators. The interaction between memory and the different emotional valences change across lifespan, while young adults (YA) are expected to better recall negative events (Negativity Bias Hypothesis), older adults (OA) tend to focus on positive stimuli (Positivity Effect Hypothesis). This research work aims at verifying whether cortical electrical activity of these two age groups would also be differently influenced by emotional valences in a visuo-spatial working memory task. 27 YA (13 males) and 25 OA (14 males), all healthy volunteers, underwent electroencephalographic recordings (21 scalp electrodes montage), while performing the Spatial Delayed Recognition Span Task using a touch screen with different stimuli categories: neutral, positive and negative faces and geometric pictures. YA obtained higher scores than OA, and showed higher activation of theta and alpha bands in the frontal and midline regions, besides a more evident right-hemispheric asymmetry on alpha band when compared to OA. For both age groups, performance in the task was worse for positive faces than to negative and to neutral faces. Facial stimuli induced a better performance and higher alpha activation on the pre-frontal region for YA, and on the midline, occipital and left temporal regions for OA when compared to geometric figures. The superior performance of YA was expected due to the natural cognitive deficits connected to ageing, as was a better performance with facial stimuli due to the evolutionary importance of faces. These results were related to cortical activity on areas of importance for action-planning, decision making and sustained attention. Taken together, they are in accordance with the Negativity Bias but do not support the Positivity Effect. The methodology used was able to identify age-related differences in cortical activity during emotional mnemonic processing and may be

  8. Auditory cortical activity during cochlear implant-mediated perception of spoken language, melody, and rhythm.

    PubMed

    Limb, Charles J; Molloy, Anne T; Jiradejvong, Patpong; Braun, Allen R

    2010-03-01

    Despite the significant advances in language perception for cochlear implant (CI) recipients, music perception continues to be a major challenge for implant-mediated listening. Our understanding of the neural mechanisms that underlie successful implant listening remains limited. To our knowledge, this study represents the first neuroimaging investigation of music perception in CI users, with the hypothesis that CI subjects would demonstrate greater auditory cortical activation than normal hearing controls. H(2) (15)O positron emission tomography (PET) was used here to assess auditory cortical activation patterns in ten postlingually deafened CI patients and ten normal hearing control subjects. Subjects were presented with language, melody, and rhythm tasks during scanning. Our results show significant auditory cortical activation in implant subjects in comparison to control subjects for language, melody, and rhythm. The greatest activity in CI users compared to controls was seen for language tasks, which is thought to reflect both implant and neural specializations for language processing. For musical stimuli, PET scanning revealed significantly greater activation during rhythm perception in CI subjects (compared to control subjects), and the least activation during melody perception, which was the most difficult task for CI users. These results may suggest a possible relationship between auditory performance and degree of auditory cortical activation in implant recipients that deserves further study.

  9. Endocannabinoids modulate cortical development by configuring Slit2/Robo1 signalling.

    PubMed

    Alpár, Alán; Tortoriello, Giuseppe; Calvigioni, Daniela; Niphakis, Micah J; Milenkovic, Ivan; Bakker, Joanne; Cameron, Gary A; Hanics, János; Morris, Claudia V; Fuzik, János; Kovacs, Gabor G; Cravatt, Benjamin F; Parnavelas, John G; Andrews, William D; Hurd, Yasmin L; Keimpema, Erik; Harkany, Tibor

    2014-07-17

    Local environmental cues are indispensable for axonal growth and guidance during brain circuit formation. Here, we combine genetic and pharmacological tools, as well as systems neuroanatomy in human fetuses and mouse models, to study the role of endocannabinoid and Slit/Robo signalling in axonal growth. We show that excess 2-arachidonoylglycerol, an endocannabinoid affecting directional axonal growth, triggers corpus callosum enlargement due to the errant CB1 cannabinoid receptor-containing corticofugal axon spreading. This phenotype mechanistically relies on the premature differentiation and end-feet proliferation of CB2R-expressing oligodendrocytes. We further show the dependence of both axonal Robo1 positioning and oligodendroglial Slit2 production on cell-type-specific cannabinoid receptor activation. Accordingly, Robo1 and/or Slit2 manipulation limits endocannabinoid modulation of axon guidance. We conclude that endocannabinoids can configure focal Slit2/Robo1 signalling to modulate directional axonal growth, which may provide a basis for understanding impaired brain wiring associated with metabolic deficits and prenatal drug exposure.

  10. Endocannabinoids modulate cortical development by configuring Slit2/Robo1 signaling

    PubMed Central

    Alpár, Alán; Tortoriello, Giuseppe; Calvigioni, Daniela; Niphakis, Micah J; Milenkovic, Ivan; Bakker, Joanne; Cameron, Gary A; Hanics, János; Morris, Claudia V; Fuzik, János; Kovacs, Gabor G; Cravatt, Benjamin F; Parnavelas, John G; Andrews, William D; Hurd, Yasmin L; Keimpema, Erik; Harkany, Tibor

    2014-01-01

    Local environmental cues are indispensable for axonal growth and guidance during brain circuit formation. Here, we combine genetic and pharmacological tools, as well as systems neuroanatomy in human fetuses and mouse models, to study the role of endocannabinoid and Slit/Robo signaling in axonal growth. We show that excess 2-arachidonoylglycerol, an endocannabinoid affecting directional axonal growth, triggers corpus callosum enlargement due to errant CB1 cannabinoid receptor (CB1R)-containing corticofugal axon spreading. This phenotype mechanistically relies on the premature differentiation and end-feet proliferation of CB2R-expressing oligodendrocytes. We further show the dependence of both axonal Robo1 positioning and oligodendroglial Slit2 production on cell-type specific cannabinoid receptor activation. Accordingly, Robo1 and/or Slit2 manipulation limits endocannabinoid modulation of axon guidance. We conclude that endocannabinoids can configure focal Slit2/Robo1 signaling to modulate directional axonal growth, which may provide a basis for understanding impaired brain wiring associated with metabolic deficits and prenatal drug exposure. PMID:25030704

  11. Observation of implied motion in a work of art modulates cortical connectivity and plasticity

    PubMed Central

    Concerto, Carmen; Infortuna, Carmenrita; Mineo, Ludovico; Pereira, Manuel; Freedberg, David; Chusid, Eileen; Aguglia, Eugenio; Battaglia, Fortunato

    2016-01-01

    Following the discovery of mirror neurons, much attention has been de-voted to understanding the neural responses evoked by observation of implied motion in works of art. Neuroimaging studies have demonstrated that dorsal premotor cortex (PMd) is commonly involved during observation of movements but the role of the inhibitory and excitatory connections between PMd and primary motor cortex (M1) during observation of implied motion remains uncertain. In this study, using high and low frequency repetitive transcranial magnetic stimulation (rTMS), we examined PMd–M1 connectivity and plasticity during observation of Michelangelo’s frescos with and without implied motion (Sistine Chapel, 1508–1512). We found that observation of implied motion in a painting specifically reduces the activity of inhibitory PMd–M1 connections. On the contrary PMd–M1 facilitatory connections, as examined by means of 5-Hz rTMS, were not modulated during observation of the painting. Our data suggest that observation of implied motion in a painting modulates PMd–M1 connectivity and plasticity. These results are consistent with the hypothesis that art with implied motion might be used as a plasticity-based intervention in rehabilitation. PMID:27807519

  12. Spatiotemporal patterns of cortical activity with bilateral cochlear implants in congenital deafness.

    PubMed

    Kral, Andrej; Tillein, Jochen; Hubka, Peter; Schiemann, Dorrit; Heid, Silvia; Hartmann, Rainer; Engel, Andreas Karl

    2009-01-21

    Congenital deafness affects developmental processes in the auditory cortex. In this study, local field potentials (LFPs) were mapped at the cortical surface with microelectrodes in response to cochlear implant stimulation. LFPs were compared between hearing controls and congenitally deaf cats (CDCs). Pulsatile electrical stimulation initially evoked cortical activity in the rostral parts of the primary auditory field (A1). This progressed both in the approximate dorsoventral direction (along the isofrequency stripe) and in the rostrocaudal direction. The dorsal branch of the wavefront split into a caudal branch (propagating in A1) and another smaller one propagating rostrally into the AAF (anterior auditory field). After the front reached the caudal border of A1, a "reflection wave" appeared, propagating back rostrally. In total, the waves took approximately 13-15 ms to propagate along A1 and return back. In CDCs, the propagation pattern was significantly disturbed, with a more synchronous activation of distant cortical regions. The maps obtained from contralateral and ipsilateral stimulation overlapped in both groups of animals. Although controls showed differences in the latency-amplitude patterns, cortical waves evoked by contralateral and ipsilateral stimulation were more similar in CDCs. Additionally, in controls, LFPs with contralateral and ipsilateral stimulation were more similar in caudal A1 than in rostral A1. This dichotomy was lost in deaf animals. In conclusion, propagating cortical waves are specific for the contralateral ear, they are affected by auditory deprivation, and the specificity of the cortex for stimulation of the contralateral ear is reduced by deprivation.

  13. Natural stimuli from three coherent modalities enhance behavioral responses and electrophysiological cortical activity in humans.

    PubMed

    Sella, Irit; Reiner, Miriam; Pratt, Hillel

    2014-07-01

    Cues that involve a number of sensory modalities are processed in the brain in an interactive multimodal manner rather than independently for each modality. We studied multimodal integration in a natural, yet fully controlled scene, implemented as an interactive game in an auditory-haptic-visual virtual environment. In this imitation of a natural scene, the targets of perception were ecologically valid uni-, bi- and tri-modal manifestations of a simple event-a ball hitting a wall. Subjects were engaged in the game while their behavioral and early cortical electrophysiological responses were measured. Behavioral results confirmed that tri-modal cues were detected faster and more accurately than bi-modal cues, which, likewise, showed advantages over unimodal responses. Event-Related Potentials (ERPs) were recorded, and the first 200 ms following stimulus onset was analyzed to reveal the latencies of cortical multimodal interactions as estimated by sLORETA. These electrophysiological findings indicated bi-modal as well as tri-modal interactions beginning very early (~30 ms), uniquely for each multimodal combination. The results suggest that early cortical multimodal integration accelerates cortical activity and, in turn, enhances performance measures. This acceleration registers on the scalp as sub-additive cortical activation.

  14. Submillimeter Confocal Imaging Active Module

    NASA Technical Reports Server (NTRS)

    Hong, John; Mehdi, Imran; Siegel, Peter; Chattopadhyay, Goutam; Cwik, Thomas; Rowell, Mark; Hacker, John

    2009-01-01

    The term submillimeter confocal imaging active module (SCIAM) denotes a proposed airborne coherent imaging radar system that would be suitable for use in reconnaissance, surveillance, and navigation. The development of the SCIAM would include utilization and extension of recent achievements in monolithic microwave integrated circuits capable of operating at frequencies up to and beyond a nominal radio frequency of 340 GHz. Because the SCIAM would be primarily down-looking (in contradistinction to primarily side-looking), it could be useful for imaging shorter objects located between taller ones (for example, objects on streets between buildings). The SCIAM would utilize a confocal geometry to obtain high cross-track resolution, and would be amenable to synthetic-aperture processing of its output to obtain high along-track resolution. The SCIAM (see figure) would include multiple (two in the initial version) antenna apertures, separated from each other by a cross-track baseline of suitable length (e.g., 1.6 m). These apertures would both transmit the illuminating radar pulses and receive the returns. A common reference oscillator would generate a signal at a controllable frequency of (340 GHz + (Delta)f)/N, where (Delta)f is an instantaneous swept frequency difference and N is an integer. The output of this oscillator would be fed to a frequency- multiplier-and-power-amplifier module to obtain a signal, at 340 GHz + (Delta)f, that would serve as both the carrier signal for generating the transmitted pulses and a local-oscillator (LO) signal for a receiver associated with each antenna aperture. Because duplexers in the form of circulators or transmit/receive (T/R) switches would be lossy and extremely difficult to implement, the antenna apertures would be designed according to a spatial-diplexing scheme, in which signals would be coupled in and out via separate, adjacent transmitting and receiving feed horns. This scheme would cause the transmitted and received beams

  15. Alzheimer risk genes modulate the relationship between plasma apoE and cortical PiB binding

    PubMed Central

    Lazaris, Andreas; Hwang, Kristy S.; Goukasian, Naira; Ramirez, Leslie M.; Eastman, Jennifer; Blanken, Anna E.; Teng, Edmond; Gylys, Karen; Cole, Greg; Saykin, Andrew J.; Shaw, Leslie M.; Trojanowski, John Q.; Jagust, William J.; Weiner, Michael W.

    2015-01-01

    Objective: We investigated the association between apoE protein plasma levels and brain amyloidosis and the effect of the top 10 Alzheimer disease (AD) risk genes on this association. Methods: Our dataset consisted of 18 AD, 52 mild cognitive impairment, and 3 cognitively normal Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) participants with available [11C]-Pittsburgh compound B (PiB) and peripheral blood protein data. We used cortical pattern matching to study associations between plasma apoE and cortical PiB binding and the effect of carrier status for the top 10 AD risk genes. Results: Low plasma apoE was significantly associated with high PiB SUVR, except in the sensorimotor and entorhinal cortex. For BIN1 rs744373, the association was observed only in minor allele carriers. For CD2AP rs9349407 and CR1 rs3818361, the association was preserved only in minor allele noncarriers. We did not find evidence for modulation by CLU, PICALM, ABCA7, BIN1, and MS4A6A. Conclusions: Our data show that BIN1 rs744373, CD2AP rs9349407, and CR1 rs3818361 genotypes modulate the association between apoE protein plasma levels and brain amyloidosis, implying a potential epigenetic/downstream interaction. PMID:27066559

  16. Investigating Emotional Top Down Modulation of Ambiguous Faces by Single Pulse TMS on Early Visual Cortices.

    PubMed

    Yaple, Zachary A; Vakhrushev, Roman

    2016-01-01

    Top-down processing is a mechanism in which memory, context and expectation are used to perceive stimuli. For this study we investigated how emotion content, induced by music mood, influences perception of happy and sad emoticons. Using single pulse TMS we stimulated right occipital face area (rOFA), primary visual cortex (V1) and vertex while subjects performed a face-detection task and listened to happy and sad music. At baseline, incongruent audio-visual pairings decreased performance, demonstrating dependence of emotion while perceiving ambiguous faces. However, performance of face identification decreased during rOFA stimulation regardless of emotional content. No effects were found between Cz and V1 stimulation. These results suggest that while rOFA is important for processing faces regardless of emotion, V1 stimulation had no effect. Our findings suggest that early visual cortex activity may not integrate emotional auditory information with visual information during emotion top-down modulation of faces. PMID:27445674

  17. Investigating Emotional Top Down Modulation of Ambiguous Faces by Single Pulse TMS on Early Visual Cortices

    PubMed Central

    Yaple, Zachary A.; Vakhrushev, Roman

    2016-01-01

    Top-down processing is a mechanism in which memory, context and expectation are used to perceive stimuli. For this study we investigated how emotion content, induced by music mood, influences perception of happy and sad emoticons. Using single pulse TMS we stimulated right occipital face area (rOFA), primary visual cortex (V1) and vertex while subjects performed a face-detection task and listened to happy and sad music. At baseline, incongruent audio-visual pairings decreased performance, demonstrating dependence of emotion while perceiving ambiguous faces. However, performance of face identification decreased during rOFA stimulation regardless of emotional content. No effects were found between Cz and V1 stimulation. These results suggest that while rOFA is important for processing faces regardless of emotion, V1 stimulation had no effect. Our findings suggest that early visual cortex activity may not integrate emotional auditory information with visual information during emotion top-down modulation of faces. PMID:27445674

  18. Sensorimotor cortical influences on cuneate nucleus rhythmic activity in the anesthetized cat.

    PubMed

    Marino, J; Canedo, A; Aguilar, J

    2000-01-01

    This work aimed to study whether the sensorimotor cerebral cortex spreads down its rhythmic patterns of activity to the dorsal column nuclei. Extracellular and intracellular recordings were obtained from the cuneate nucleus of chloralose-anesthetized cats. From a total of 140 neurons tested (106 cuneolemniscal), 72 showed spontaneous rhythmic activity within the slow (< 1 Hz), delta (1-4 Hz), spindle (5-15 Hz) and higher frequencies, with seven cells having the delta rhythm coupled to slow oscillations. The spindle activity recorded in the cuneate was tightly coupled to the thalamo-cortico-thalamic spindle rhythmicity. Bilateral or contralateral removal of the frontoparietal cortex abolished the cuneate slow and spindle oscillations. Oscillatory paroxysmal activity generated by fast electrical stimulation (50-100 Hz/1-2 s) of the sensorimotor cortex induced burst firing synchronized with the paroxysmal cortical "spike" on all the non-lemniscal neurons, and inhibitory responses also coincident with the cortical paroxysmal "spike" in the majority (71%) of the cuneolemniscal cells. The remaining lemniscal-projecting neurons showed bursting activity (11%) or sequences of excitation-inhibition (18%) also time-locked to the cortical paroxysmal "spike". Additionally, the cerebral cortex induced coherent oscillatory activity between thalamic ventroposterolateral and cuneate neurons. Electrolytic lesion of the pyramidal tract abolished the cortically induced effects on the contralateral cuneate nucleus, as well as on the ipsilateral medial lemniscus. The results demonstrate that the sensorimotor cortex imposes its rhythmic patterns on the cuneate nucleus through the pyramidal tract, and that the corticocuneate network can generate normal and abnormal patterns of synchronized activity, such as delta waves, spindles and spike-and-wave complexes. The cuneate neurons, however, are able to generate oscillatory activity above 1 Hz in the absence of cortical input, which implies

  19. Applications of brain blood flow imaging in behavioral neurophysiology: cortical field activation hypothesis

    SciTech Connect

    Roland, P.E.

    1985-01-01

    The /sup 133/xenon intracarotid method for rCBF measurements has been a very useful method for functional mapping and functional dissection of the cerebral cortex in humans. With this method it has been shown that different types of cortical information treatment activate different cortical areas and furthermore that sensory and motor functions of the cerebral cortex could be dissected into anatomical and informational subcomponents by behavioral manipulations. The brain organizes its own activity. One of the principles of organization was that the brain could recruit in advance cortical fields that were expected to participate in a certain type of information operation. During brain work in awake human beings the cerebral cortex was activated in fields that, projected on the cerebral surface, most often had a size greater than 3 CM/sup 2/. Such activated fields appeared no matter which type of information processing was going on in the brain: during planning and execution of voluntary movements, during preparation for sensory information processing, and during sensory information processing, as well as during cognitive brain work and retrieval of specific memories. Therefore, it was hypothesized that cortical field activation was the physiological manifestation of normal brain work in awake humans.

  20. Theta-Modulated Gamma-Band Synchronization Among Activated Regions During a Verb Generation Task

    PubMed Central

    Doesburg, Sam M.; Vinette, Sarah A.; Cheung, Michael J.; Pang, Elizabeth W.

    2012-01-01

    Expressive language is complex and involves processing within a distributed network of cortical regions. Functional MRI and magnetoencephalography (MEG) have identified brain areas critical for expressive language, but how these regions communicate across the network remains poorly understood. It is thought that synchronization of oscillations between neural populations, particularly at a gamma rate (>30 Hz), underlies functional integration within cortical networks. Modulation of gamma rhythms by theta-band oscillations (4–8 Hz) has been proposed as a mechanism for the integration of local cell coalitions into large-scale networks underlying cognition and perception. The present study tested the hypothesis that these oscillatory mechanisms of functional integration were present within the expressive language network. We recorded MEG while subjects performed a covert verb generation task. We localized activated cortical regions using beamformer analysis, calculated inter-regional phase locking between activated areas, and measured modulation of inter-regional gamma synchronization by theta phase. The results show task-dependent gamma-band synchronization among regions activated during the performance of the verb generation task, and we provide evidence that these transient and periodic instances of high-frequency connectivity were modulated by the phase of cortical theta oscillations. These findings suggest that oscillatory synchronization and cross-frequency interactions are mechanisms for functional integration among distributed brain areas supporting expressive language processing. PMID:22707946

  1. Interaction of electrically evoked activity with intrinsic dynamics of cultured cortical networks with and without functional fast GABAergic synaptic transmission

    PubMed Central

    Baltz, Thomas; Voigt, Thomas

    2015-01-01

    The modulation of neuronal activity by means of electrical stimulation is a successful therapeutic approach for patients suffering from a variety of central nervous system disorders. Prototypic networks formed by cultured cortical neurons represent an important model system to gain general insights in the input–output relationships of neuronal tissue. These networks undergo a multitude of developmental changes during their maturation, such as the excitatory–inhibitory shift of the neurotransmitter GABA. Very few studies have addressed how the output properties to a given stimulus change with ongoing development. Here, we investigate input–output relationships of cultured cortical networks by probing cultures with and without functional GABAAergic synaptic transmission with a set of stimulation paradigms at various stages of maturation. On the cellular level, low stimulation rates (<15 Hz) led to reliable neuronal responses; higher rates were increasingly ineffective. Similarly, on the network level, lowest stimulation rates (<0.1 Hz) lead to maximal output rates at all ages, indicating a network wide refractory period after each stimulus. In cultures aged 3 weeks and older, a gradual recovery of the network excitability within tens of milliseconds was in contrast to an abrupt recovery after about 5 s in cultures with absent GABAAergic synaptic transmission. In these GABA deficient cultures evoked responses were prolonged and had multiple discharges. Furthermore, the network excitability changed periodically, with a very slow spontaneous change of the overall network activity in the minute range, which was not observed in cultures with absent GABAAergic synaptic transmission. The electrically evoked activity of cultured cortical networks, therefore, is governed by at least two potentially interacting mechanisms: A refractory period in the order of a few seconds and a very slow GABA dependent oscillation of the network excitability. PMID:26236196

  2. Nicotinic agonists modulate basal forebrain control of cortical cerebral blood flow in anesthetized rats.

    PubMed

    Linville, D G; Williams, S; Raszkiewicz, J L; Arneric, S P

    1993-10-01

    Previous studies have indicated that electrical microstimulation of the cholinergic (basal forebrain, BF) elicits profound increases in cortical cerebral blood flow (CBF) that are selectively attenuated by nicotinic receptor antagonists. This study sought to determine whether nicotinic receptor agonists such as (-)-nicotine, and related agents, can enhance the increases in CBF elicited by electrical stimulation of the BF of urethane-anesthetized rats. The magnitude of cortical CBF responses, measured by laser-Doppler flowmetry, increased progressively with higher frequencies (range = 6.25-50 Hz) to a maximum of 248% of control. (-)-Nicotine and (-)-lobeline each further enhanced the responses to BF stimulation, with (-)-nicotine having the most potent effect (up to 350%). (+)-Nicotine and (-)-cotinine were without effect, suggesting stereoselectivity and that the effects were not mediated by the major metabolite of (-)-nicotine. In contrast, (-)-cystisine, another nicotinic receptor agonist, modestly inhibited the BF-elicited increase in CBF suggesting nicotinic receptor subtype selectivity in mediating the response. Arecoline, a potent muscarinic agonist, was without effect suggesting that muscarinic mechanisms are not involved in the mediation of this response. None of the nicotinic agents had overt effects on heart rate or blood pressure in the dose ranges examined. In experiments targeting the site of action of the nicotinically mediated enhancement, (-)-nicotine microinjections into the BF elicited profound increases in cortical CBF, whereas similar injections into the cerebral cortex were without effect suggesting that nicotine receptors mediating CBF increases are localized to the BF.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8229773

  3. Effects of L-dopa priming on cortical high beta and high gamma oscillatory activity in a rodent model of Parkinson’s disease

    PubMed Central

    Dupre, Kristin B.; Cruz, Ana V.; McCoy, Alex J.; Delaville, Claire; Gerber, Colin M.; Eyring, Katherine W.; Walters, Judith R.

    2016-01-01

    Prolonged L-dopa treatment in Parkinson’s disease (PD) often leads to the expression of abnormal involuntary movements known as L-dopa-induced dyskinesia. Recently, dramatic 80 Hz oscillatory local field potential (LFP) activity within the primary motor cortex has been linked to dyskinetic symptoms in a rodent model of PD and attributed to stimulation of cortical dopamine D1 receptors. To characterize the relationship between high gamma (70–110 Hz) cortical activity and the development of L-dopa-induced dyskinesia, cortical LFP and spike signals were recorded in hemiparkinsonian rats treated with L-dopa for 7 days, and dyskinesia was quantified using the abnormal involuntary movements (AIMs) scale. The relationship between high gamma and dyskinesia was further probed by assessment of the effects of pharmacological agents known to induce or modulate dyskinesia expression. Findings demonstrate that AIMs and high gamma LFP power increase between days 1 and 7 of L-dopa priming. Notably, high beta (25–35 Hz) power associated with parkinsonian bradykinesia decreased as AIMs and high gamma LFP power increased during priming. After priming, rats were treated with the D1 agonist SKF81297 and the D2 agonist quinpirole. Both dopamine agonists independently induced AIMs and high gamma cortical activity that were similar to that induced by L-dopa, showing that this LFP activity is neither D1 nor D2 receptor specific. The serotonin 1A receptor agonist 8-OH-DPAT reduced L-dopa- and DA agonist-induced AIMs and high gamma power to varying degrees, while the serotonin 1A antagonist WAY100635 reversed these effects. Unexpectedly, as cortical high gamma power increased, phase locking of cortical pyramidal spiking to high gamma oscillations decreased, raising questions regarding the neural substrate(s) responsible for high gamma generation and the functional correlation between high gamma and dyskinesia. PMID:26586558

  4. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    NASA Astrophysics Data System (ADS)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  5. Cortical Activity Differs During Nicotine Deprivation versus Satiation in Heavy Smokers

    PubMed Central

    Evans, David E.; Sutton, Steven K.; Oliver, Jason A.; Drobes, David J.

    2015-01-01

    Rationale Research suggests that nicotine deprivation among smokers is associated with lesser resting cortical activity (i.e., greater power density in theta and alpha-1 EEG bands and lesser power in beta bands). These changes in cortical activity may be indicative of withdrawal-related cognitive deficits, yet the markers of differences in cortical activity are not well-established. Objective To clarify the EEG frequency bands affected by nicotine deprivation and assess prospective moderators Method 124 heavy smokers visited the laboratory on two occasions following overnight smoking/nicotine deprivation. Prior to collecting three minutes of resting EEG data, participants smoked two very low nicotine cigarettes (< .05 mg nicotine yield) at one session and two moderate nicotine cigarettes (.60 mg nicotine yield) at the other. Results Theta and alpha-1 band (4–7 & 8–10 Hz) was greater in the very low nicotine (deprivation) relative to higher nicotine (satiation) condition. There were no condition differences in the beta-1 and beta-2 bands (14–20 & 21–30 Hz). Conclusions Greater slow wave resting EEG may serve as a reliable marker of decreased cortical activity during smoking deprivation and, in turn, of withdrawal-related deficits in cognitive functioning. This research may inform the development of adjunct strategies for smoking cessation. PMID:25491928

  6. Sex Differences in Mental Rotation and Cortical Activation Patterns: Can Training Change Them?

    ERIC Educational Resources Information Center

    Jausovec, Norbert; Jausovec, Ksenija

    2012-01-01

    In two experiments the neuronal mechanisms of sex differences in mental rotation were investigated. In Experiment 1 cortical activation was studied in women and men with similar levels of mental rotation ability (high, and average to low), who were equalized with respect to general intelligence. Sex difference in neuroelectric patterns of brain…

  7. The estimation of cortical activity for brain-computer interface: applications in a domotic context.

    PubMed

    Babiloni, F; Cincotti, F; Marciani, M; Salinari, S; Astolfi, L; Tocci, A; Aloise, F; De Vico Fallani, F; Bufalari, S; Mattia, D

    2007-01-01

    In order to analyze whether the use of the cortical activity, estimated from noninvasive EEG recordings, could be useful to detect mental states related to the imagination of limb movements, we estimate cortical activity from high-resolution EEG recordings in a group of healthy subjects by using realistic head models. Such cortical activity was estimated in region of interest associated with the subject's Brodmann areas by using a depth-weighted minimum norm technique. Results showed that the use of the cortical-estimated activity instead of the unprocessed EEG improves the recognition of the mental states associated to the limb movement imagination in the group of normal subjects. The BCI methodology presented here has been used in a group of disabled patients in order to give them a suitable control of several electronic devices disposed in a three-room environment devoted to the neurorehabilitation. Four of six patients were able to control several electronic devices in this domotic context with the BCI system.

  8. Magnetoencephalographic Analysis of Cortical Activity in Adults with and without Down Syndrome

    ERIC Educational Resources Information Center

    Virji-Babul, N.; Cheung, T.; Weeks, D.; Herdman, A. T.; Cheyne, D.

    2007-01-01

    Background: This preliminary study served as a pilot for an ongoing analysis of spectral power in adults with Down syndrome (DS) using a 151 channel whole head magnetoencephalography (MEG). The present study is the first step for examining and comparing cortical responses during spontaneous and task related activity in DS. Method: Cortical…

  9. The Estimation of Cortical Activity for Brain-Computer Interface: Applications in a Domotic Context

    PubMed Central

    Babiloni, F.; Cincotti, F.; Marciani, M.; Salinari, S.; Astolfi, L.; Tocci, A.; Aloise, F.; Fallani, F. De Vico; Bufalari, S.; Mattia, D.

    2007-01-01

    In order to analyze whether the use of the cortical activity, estimated from noninvasive EEG recordings, could be useful to detect mental states related to the imagination of limb movements, we estimate cortical activity from high-resolution EEG recordings in a group of healthy subjects by using realistic head models. Such cortical activity was estimated in region of interest associated with the subject's Brodmann areas by using a depth-weighted minimum norm technique. Results showed that the use of the cortical-estimated activity instead of the unprocessed EEG improves the recognition of the mental states associated to the limb movement imagination in the group of normal subjects. The BCI methodology presented here has been used in a group of disabled patients in order to give them a suitable control of several electronic devices disposed in a three-room environment devoted to the neurorehabilitation. Four of six patients were able to control several electronic devices in this domotic context with the BCI system. PMID:18350134

  10. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing

    PubMed Central

    Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Ávila, César

    2010-01-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  11. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing.

    PubMed

    Barrós-Loscertales, Alfonso; Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Avila, César

    2010-03-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS.

  12. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing.

    PubMed

    Barrós-Loscertales, Alfonso; Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Avila, César

    2010-03-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  13. Turning a Negative into a Positive: Ascending GABAergic Control of Cortical Activation and Arousal

    PubMed Central

    Brown, Ritchie E.; McKenna, James T.

    2015-01-01

    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain. Recent technological advances have illuminated the role of GABAergic neurons in control of cortical arousal and sleep. Sleep-promoting GABAergic neurons in the preoptic hypothalamus are well-known. Less well-appreciated are GABAergic projection neurons in the brainstem, midbrain, hypothalamus, and basal forebrain, which paradoxically promote arousal and fast electroencephalographic (EEG) rhythms. Thus, GABA is not purely a sleep-promoting neurotransmitter. GABAergic projection neurons in the brainstem nucleus incertus and ventral tegmental nucleus of Gudden promote theta (4–8 Hz) rhythms. Ventral tegmental area GABAergic neurons, neighboring midbrain dopamine neurons, project to the frontal cortex and nucleus accumbens. They discharge faster during cortical arousal and regulate reward. Thalamic reticular nucleus GABAergic neurons initiate sleep spindles in non-REM sleep. In addition, however, during wakefulness, they tonically regulate the activity of thalamocortical neurons. Other GABAergic inputs to the thalamus arising in the globus pallidus pars interna, substantia nigra pars reticulata, zona incerta, and basal forebrain regulate motor activity, arousal, attention, and sensory transmission. Several subpopulations of cortically projecting GABAergic neurons in the basal forebrain project to the thalamus and neocortex and preferentially promote cortical gamma-band (30–80 Hz) activity and wakefulness. Unlike sleep-active GABAergic neurons, these ascending GABAergic neurons are fast-firing neurons which disinhibit and synchronize the activity of their forebrain targets, promoting the fast EEG rhythms typical of conscious states. They are prominent targets of GABAergic hypnotic agents. Understanding the properties of ascending GABAergic neurons may lead to novel treatments for diseases involving disorders of cortical activation and wakefulness. PMID:26124745

  14. Active combustion flow modulation valve

    DOEpatents

    Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

    2013-09-24

    A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

  15. Diffusion of GPI-anchored proteins is influenced by the activity of dynamic cortical actin.

    PubMed

    Saha, Suvrajit; Lee, Il-Hyung; Polley, Anirban; Groves, Jay T; Rao, Madan; Mayor, Satyajit

    2015-11-01

    Molecular diffusion at the surface of living cells is believed to be predominantly driven by thermal kicks. However, there is growing evidence that certain cell surface molecules are driven by the fluctuating dynamics of cortical cytoskeleton. Using fluorescence correlation spectroscopy, we measure the diffusion coefficient of a variety of cell surface molecules over a temperature range of 24-37 °C. Exogenously incorporated fluorescent lipids with short acyl chains exhibit the expected increase of diffusion coefficient over this temperature range. In contrast, we find that GPI-anchored proteins exhibit temperature-independent diffusion over this range and revert to temperature-dependent diffusion on cell membrane blebs, in cells depleted of cholesterol, and upon acute perturbation of actin dynamics and myosin activity. A model transmembrane protein with a cytosolic actin-binding domain also exhibits the temperature-independent behavior, directly implicating the role of cortical actin. We show that diffusion of GPI-anchored proteins also becomes temperature dependent when the filamentous dynamic actin nucleator formin is inhibited. However, changes in cortical actin mesh size or perturbation of branched actin nucleator Arp2/3 do not affect this behavior. Thus cell surface diffusion of GPI-anchored proteins and transmembrane proteins that associate with actin is driven by active fluctuations of dynamic cortical actin filaments in addition to thermal fluctuations, consistent with expectations from an "active actin-membrane composite" cell surface.

  16. Diffusion of GPI-anchored proteins is influenced by the activity of dynamic cortical actin

    PubMed Central

    Saha, Suvrajit; Lee, Il-Hyung; Polley, Anirban; Groves, Jay T.; Rao, Madan; Mayor, Satyajit

    2015-01-01

    Molecular diffusion at the surface of living cells is believed to be predominantly driven by thermal kicks. However, there is growing evidence that certain cell surface molecules are driven by the fluctuating dynamics of cortical cytoskeleton. Using fluorescence correlation spectroscopy, we measure the diffusion coefficient of a variety of cell surface molecules over a temperature range of 24–37°C. Exogenously incorporated fluorescent lipids with short acyl chains exhibit the expected increase of diffusion coefficient over this temperature range. In contrast, we find that GPI-anchored proteins exhibit temperature-independent diffusion over this range and revert to temperature-dependent diffusion on cell membrane blebs, in cells depleted of cholesterol, and upon acute perturbation of actin dynamics and myosin activity. A model transmembrane protein with a cytosolic actin-binding domain also exhibits the temperature-independent behavior, directly implicating the role of cortical actin. We show that diffusion of GPI-anchored proteins also becomes temperature dependent when the filamentous dynamic actin nucleator formin is inhibited. However, changes in cortical actin mesh size or perturbation of branched actin nucleator Arp2/3 do not affect this behavior. Thus cell surface diffusion of GPI-anchored proteins and transmembrane proteins that associate with actin is driven by active fluctuations of dynamic cortical actin filaments in addition to thermal fluctuations, consistent with expectations from an “active actin-membrane composite” cell surface. PMID:26378258

  17. Simultaneous measurement of neuronal activity and cortical hemodynamics by unshielded magnetoencephalography and near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Seki, Yusuke; Miyashita, Tsuyoshi; Kandori, Akihiko; Maki, Atsushi; Koizumi, Hideaki

    2012-10-01

    The correlation between neuronal activity and cortical hemodynamics, namely, neurovascular coupling (NVC), is important to shed light on the mechanism of a variety of brain functions or neuronal diseases. NVC can be studied by simultaneously measuring neuronal activity and cortical hemodynamics. Consequently, noninvasive measurements of the NVC have been widely studied using both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). However, electromagnetic interference between EEG and fMRI is still a major problem. On the other hand, near-infrared spectroscopy (NIRS) is another promising tool for detecting cortical hemodynamics because it can be combined with EEG or magnetoencephalography (MEG) without any electromagnetic interference. Accordingly, in the present study, a simultaneous measurement system-combining an unshielded MEG using a two-dimensional gradiometer based on a low-T superconducting quantum interference device (SQUID) and an NIRS using nonmagnetic thin probes-was developed. This combined system was used to simultaneously measure both an auditory-evoked magnetic field and blood flow change in the auditory cortex. It was experimentally demonstrated that the combined unshielded MEG/NIRS system can simultaneously measure neuronal activity and cortical hemodynamics.

  18. Auditory cortical activation in severe-to-profound hearing-impaired patients monitored by SPET.

    PubMed

    Di Nardo, W; Di Giuda, D; Scarano, E; Picciotti, P M; Galla, S; De Rossi, G

    2006-08-01

    Single photon emission tomography was used to map blood flow increase in temporal and parietal cortex after auditory stimulation in 25 subjects: 10 normal-hearing, 10 severe-profound hearing-impaired and 5 totally deaf. After a 500 Hz pure tone stimulation, a marked perfusion increase was observed, particularly at the level of the contralateral auditory temporal cortex. Blood flow increase in temporal and parietal cortical areas of normal subjects was significantly higher than that observed in severe-to-profound hearing-impaired patients. In all cases, following 500 Hz pure tone acoustic stimulation, the most lateral sagittal slice tomograms (48.75 and 56.25 mm) showed the highest blood flow increase. Statistically significant differences were also observed between normal subjects and hearing-impaired patients in the 48.75 mm sagittal tomogram. In 2 hearing-impaired patients, the single photon emission tomography pattern showed activation of the intermediate sagittal tomogram, suggesting a possible new tonotopic cortical arrangement. No significant activation was present in totally deaf patients. In conclusion, Single Photon Emission Tomography appears to be a useful tool in the evaluation of auditory cortical activation and cortical plasticity, in severe-to-profound hearing-impaired patients. Moreover, it could be a useful test for the study of auditory central pathways.

  19. Delayed synchronization of activity in cortex and subthalamic nucleus following cortical stimulation in the rat

    PubMed Central

    Magill, Peter J; Sharott, Andrew; Bolam, J Paul; Brown, Peter

    2006-01-01

    Oscillations may play a role in the functional organization of cortico-basal ganglia-thalamocortical circuits, and it is important to understand their underlying mechanisms. The cortex often drives basal ganglia (BG) activity, and particularly, oscillatory activity in the subthalamic nucleus (STN). However, the STN may also indirectly influence cortex. The aim of this study was to characterize the delayed (>200 ms) responses of STN neurons to synchronized cortical inputs, focusing on their relationship with oscillatory cortical activity. We recorded the short-latency and delayed responses of STN units and frontal electrocorticogram (ECoG) to cortical stimulation in anaesthetized rats. Similar to previous studies, stimulation of ipsilateral frontal cortex, but not temporal cortex, evoked a short-latency triphasic response, followed by a sustained reduction or pause in firing, in rostral STN units. Caudal STN units did not show the short-latency triphasic response but often displayed a prolonged firing reduction. Oscillations in STN unit activity and ECoG were common after this sustained firing reduction, particularly between 200 and 600 ms after frontal cortical stimulation. These delayed oscillations were significantly coherent in a broad frequency band of 5–30 Hz. Coherence with ECoG at 5–15 Hz was observed throughout STN, though coherence at 15–30 Hz was largely restricted to rostral STN. Furthermore, oscillatory responses at 5–30 Hz in rostral STN predominantly led those in cortex (mean latency of 29 ms) after frontal cortical stimulation. These findings suggest that STN neurons responding to corticosubthalamic inputs may provide a delayed input to cortex, via BG output nuclei, and thence, thalamocortical pathways. PMID:16709634

  20. Physical activity when young provides lifelong benefits to cortical bone size and strength in men.

    PubMed

    Warden, Stuart J; Mantila Roosa, Sara M; Kersh, Mariana E; Hurd, Andrea L; Fleisig, Glenn S; Pandy, Marcus G; Fuchs, Robyn K

    2014-04-01

    The skeleton shows greatest plasticity to physical activity-related mechanical loads during youth but is more at risk for failure during aging. Do the skeletal benefits of physical activity during youth persist with aging? To address this question, we used a uniquely controlled cross-sectional study design in which we compared the throwing-to-nonthrowing arm differences in humeral diaphysis bone properties in professional baseball players at different stages of their careers (n = 103) with dominant-to-nondominant arm differences in controls (n = 94). Throwing-related physical activity introduced extreme loading to the humeral diaphysis and nearly doubled its strength. Once throwing activities ceased, the cortical bone mass, area, and thickness benefits of physical activity during youth were gradually lost because of greater medullary expansion and cortical trabecularization. However, half of the bone size (total cross-sectional area) and one-third of the bone strength (polar moment of inertia) benefits of throwing-related physical activity during youth were maintained lifelong. In players who continued throwing during aging, some cortical bone mass and more strength benefits of the physical activity during youth were maintained as a result of less medullary expansion and cortical trabecularization. These data indicate that the old adage of "use it or lose it" is not entirely applicable to the skeleton and that physical activity during youth should be encouraged for lifelong bone health, with the focus being optimization of bone size and strength rather than the current paradigm of increasing mass. The data also indicate that physical activity should be encouraged during aging to reduce skeletal structural decay.

  1. Dampened hippocampal oscillations and enhanced spindle activity in an asymptomatic model of developmental cortical malformations

    PubMed Central

    Cid, Elena; Gomez-Dominguez, Daniel; Martin-Lopez, David; Gal, Beatriz; Laurent, François; Ibarz, Jose M.; Francis, Fiona; Menendez de la Prida, Liset

    2014-01-01

    Developmental cortical malformations comprise a large spectrum of histopathological brain abnormalities and syndromes. Their genetic, developmental and clinical complexity suggests they should be better understood in terms of the complementary action of independently timed perturbations (i.e., the multiple-hit hypothesis). However, understanding the underlying biological processes remains puzzling. Here we induced developmental cortical malformations in offspring, after intraventricular injection of methylazoxymethanol (MAM) in utero in mice. We combined extensive histological and electrophysiological studies to characterize the model. We found that MAM injections at E14 and E15 induced a range of cortical and hippocampal malformations resembling histological alterations of specific genetic mutations and transplacental mitotoxic agent injections. However, in contrast to most of these models, intraventricularly MAM-injected mice remained asymptomatic and showed no clear epilepsy-related phenotype as tested in long-term chronic recordings and with pharmacological manipulations. Instead, they exhibited a non-specific reduction of hippocampal-related brain oscillations (mostly in CA1); including theta, gamma and HFOs; and enhanced thalamocortical spindle activity during non-REM sleep. These data suggest that developmental cortical malformations do not necessarily correlate with epileptiform activity. We propose that the intraventricular in utero MAM approach exhibiting a range of rhythmopathies is a suitable model for multiple-hit studies of associated neurological disorders. PMID:24782720

  2. Maturation-Promoting Activity of SATB1 in MGE-Derived Cortical Interneurons

    PubMed Central

    Denaxa, Myrto; Kalaitzidou, Melanie; Garefalaki, Anna; Achimastou, Angeliki; Lasrado, Reena; Maes, Tamara; Pachnis, Vassilis

    2012-01-01

    Summary The generation of cortical interneuron subtypes is controlled by genetic programs that are activated in the ventral forebrain and unfold during the prolonged period of inhibitory neuron development. The LIM-homeodomain protein LHX6 is critical for the development of all cortical interneurons originating in the medial ganglionic eminence, but the molecular mechanisms that operate downstream of LHX6 to control the terminal differentiation of somatostatin- and parvalbumin-expressing interneurons within the cortex remain unknown. Here, we provide evidence that the nuclear matrix and genome organizer protein SATB1 is induced by neuronal activity and functions downstream of Lhx6 to control the transition of tangentially migrating immature interneurons into the terminally differentiated Somatostatin (SST)-expressing subtype. Our experiments provide a molecular framework for understanding the genetic and epigenetic mechanisms by which specified but immature cortical interneurons acquire the subtype-defining molecular and morphophysiological characteristics that allow them to integrate and function within cortical circuits. PMID:23142661

  3. Cullin 5 regulates cortical layering by modulating the speed and duration of Dab1-dependent neuronal migration

    PubMed Central

    Simo, Sergi; Jossin, Yves; Cooper, Jonathan A.

    2010-01-01

    The multi-layered mammalian neocortex develops by the coordinated immigration and differentiation of cells that are produced at distant sites. Correct layering requires an extracellular protein, Reelin (Reln), an intracellular signaling molecule, Disabled-1 (Dab1), and an E3 ubiquitin ligase, Cullin-5 (Cul5). Reln activates Dab1, which is then degraded by Cul5. Here we test whether Cul5 regulates neuron layering by affecting Dab1 stability or other mechanisms. We find that a stabilized mutant Dab1, which resists Cul5-dependent degradation, causes a similar phenotype to Cul5-deficiency. Moreover, Cul5 has no effect when Dab1 is absent. The effects of Cul5 and Dab1 are cell autonomous and Cul5 regulates movement of early as well as late cortical neurons. Removing Cul5 increases the speed at which neurons migrate through the cortical plate by reducing the time spent stationary and increasing the speed of individual steps. These results show that Cul5 regulates neuron layering by stimulating Dab1 degradation, that Cul5 controls migration speed and stopping point, and demonstrate the importance of negative feedback in signaling during cortical development. PMID:20410119

  4. Health Activities Project (HAP): Breathing Fitness Module.

    ERIC Educational Resources Information Center

    Buller, Dave; And Others

    Contained within this Health Activities Project (HAP) learning packet are activities for children in grades 5-8. Design of the activities centers around the idea that students can control their own health and safety. Within this module are teacher and student folios describing four activities which involve students in learning how to measure their…

  5. Cerebral Activations Related to Ballistic, Stepwise Interrupted and Gradually Modulated Movements in Parkinson Patients

    PubMed Central

    Toxopeus, Carolien M.; Maurits, Natasha M.; Valsan, Gopal; Conway, Bernard A.; Leenders, Klaus L.; de Jong, Bauke M.

    2012-01-01

    Patients with Parkinson’s disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced

  6. Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in Parkinson patients.

    PubMed

    Toxopeus, Carolien M; Maurits, Natasha M; Valsan, Gopal; Conway, Bernard A; Leenders, Klaus L; de Jong, Bauke M

    2012-01-01

    Patients with Parkinson's disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced

  7. Endogenous sequential cortical activity evoked by visual stimuli.

    PubMed

    Carrillo-Reid, Luis; Miller, Jae-Eun Kang; Hamm, Jordan P; Jackson, Jesse; Yuste, Rafael

    2015-06-10

    Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

  8. Endogenous Sequential Cortical Activity Evoked by Visual Stimuli

    PubMed Central

    Miller, Jae-eun Kang; Hamm, Jordan P.; Jackson, Jesse; Yuste, Rafael

    2015-01-01

    Although the functional properties of individual neurons in primary visual cortex have been studied intensely, little is known about how neuronal groups could encode changing visual stimuli using temporal activity patterns. To explore this, we used in vivo two-photon calcium imaging to record the activity of neuronal populations in primary visual cortex of awake mice in the presence and absence of visual stimulation. Multidimensional analysis of the network activity allowed us to identify neuronal ensembles defined as groups of cells firing in synchrony. These synchronous groups of neurons were themselves activated in sequential temporal patterns, which repeated at much higher proportions than chance and were triggered by specific visual stimuli such as natural visual scenes. Interestingly, sequential patterns were also present in recordings of spontaneous activity without any sensory stimulation and were accompanied by precise firing sequences at the single-cell level. Moreover, intrinsic dynamics could be used to predict the occurrence of future neuronal ensembles. Our data demonstrate that visual stimuli recruit similar sequential patterns to the ones observed spontaneously, consistent with the hypothesis that already existing Hebbian cell assemblies firing in predefined temporal sequences could be the microcircuit substrate that encodes visual percepts changing in time. PMID:26063915

  9. Modulation of motor cortical outputs to the reading hand of braille readers.

    PubMed

    Pascual-Leone, A; Cammarota, A; Wassermann, E M; Brasil-Neto, J P; Cohen, L G; Hallett, M

    1993-07-01

    We used focal transcranial magnetic stimulation to map the motor cortical areas targeting the first dorsal interosseous and the abductor digiti minimi muscles bilaterally in 10 proficient braille readers and 10 blind controls who were matched for age (mean, 50.6 yr) and age at time of blindness (mean, 7.5 yr). The proficient braille readers had learned braille at age 8 to 14 years and used it daily for 5 to 10 hours. Controls had not learned braille until age 17 to 21 years and used it daily for < 1 hour. In the controls, motor representations of the right and left first dorsal interosseous and abductor digiti minimi muscles were not significantly different. However, in the proficient braille readers, the representation of the first dorsal interosseous muscle in the reading hand was significantly larger than that in the nonreading hand or in either hand of the controls. Conversely, the representation of the abductor digiti minimi muscle in the reading hand was significantly smaller than that in the nonreading hand or in either hand of the controls. These differences were not due to differences in motor thresholds. Our results suggest that the cortical representation of the reading finger in proficient braille readers is enlarged at the expense of the representation of other fingers.

  10. Similarity of Cortical Activity Patterns Predicts generalization Behavior

    PubMed Central

    Engineer, Crystal T.; Perez, Claudia A.; Carraway, Ryan S.; Chang, Kevin Q.; Roland, Jarod L.; Sloan, Andrew M.; Kilgard, Michael P.

    2013-01-01

    Humans and animals readily generalize previously learned knowledge to new situations. Determining similarity is critical for assigning category membership to a novel stimulus. We tested the hypothesis that category membership is initially encoded by the similarity of the activity pattern evoked by a novel stimulus to the patterns from known categories. We provide behavioral and neurophysiological evidence that activity patterns in primary auditory cortex contain sufficient information to explain behavioral categorization of novel speech sounds by rats. Our results suggest that category membership might be encoded by the similarity of the activity pattern evoked by a novel speech sound to the patterns evoked by known sounds. Categorization based on featureless pattern matching may represent a general neural mechanism for ensuring accurate generalization across sensory and cognitive systems. PMID:24147140

  11. Altered cortical activation patterns associated with baroreflex unloading following 24 h of physical deconditioning.

    PubMed

    Shoemaker, J K; Usselman, C W; Rothwell, A; Wong, S W

    2012-12-01

    Cardiovascular arousal is associated with patterned cortical activity changes. Head-down-tilt bed rest (HDBR) dimishes the baroreflex-mediated cardiac control. The present study tested the hypothesis that HDBR deconditioning would modify the forebrain organization for heart rate (HR) control during baroreflex unloading. Heart rate variability (HRV), blood pressure and plasma hormones were analysed at rest, whereas HR and cortical autonomic activation patterns (functional magnetic resonance imaging) were measured during graded and randomly assigned lower body negative pressure treatments (LBNP, -15 and -35 mmHg) both before (Pre) and after (Post) a 24 h HDBR protocol (study 1; n = 8). An additional group was tested before and following diuretic-induced hypovolaemia (study 2; n = 9; spironolactone, 100 mg day(-1) for 3 days) that mimicked the plasma volume lost during HDBR (-15% in both studies; P < 0.05). Head-down bed rest with hypovolaemia did not affect baseline HR, mean arterial pressure, HRV or plasma catecholamines. Head-down bed rest augmented the LBNP-induced HR response (P < 0.05), and this was associated with bed-rest-induced development of the following changes: (i) enhanced activation within the genual anterior cingulate cortex and the right anterior insular cortex; and (ii) deactivation patterns within the subgenual regions of the anterior cingulate cortex. Diuretic treatment (without HDBR) did not affect baseline HR and mean arterial pressure, but did reduce resting HRV and elevated circulating noradrenaline and plasma renin activity (P < 0.05). The greater HR response to LBNP following diuretic (P < 0.05) was associated with diminished activation of the right anterior insula. Our findings indicate that 24 h of HDBR minimized the impact of diuretic treatment on baseline autonomic and cardiovascular variables. The findings also indicate that despite the similar augmentation of HR responses to LBNP and despite similar pre-intervention cortical activation

  12. Altered cortical activation patterns associated with baroreflex unloading following 24 h of physical deconditioning.

    PubMed

    Shoemaker, J K; Usselman, C W; Rothwell, A; Wong, S W

    2012-12-01

    Cardiovascular arousal is associated with patterned cortical activity changes. Head-down-tilt bed rest (HDBR) dimishes the baroreflex-mediated cardiac control. The present study tested the hypothesis that HDBR deconditioning would modify the forebrain organization for heart rate (HR) control during baroreflex unloading. Heart rate variability (HRV), blood pressure and plasma hormones were analysed at rest, whereas HR and cortical autonomic activation patterns (functional magnetic resonance imaging) were measured during graded and randomly assigned lower body negative pressure treatments (LBNP, -15 and -35 mmHg) both before (Pre) and after (Post) a 24 h HDBR protocol (study 1; n = 8). An additional group was tested before and following diuretic-induced hypovolaemia (study 2; n = 9; spironolactone, 100 mg day(-1) for 3 days) that mimicked the plasma volume lost during HDBR (-15% in both studies; P < 0.05). Head-down bed rest with hypovolaemia did not affect baseline HR, mean arterial pressure, HRV or plasma catecholamines. Head-down bed rest augmented the LBNP-induced HR response (P < 0.05), and this was associated with bed-rest-induced development of the following changes: (i) enhanced activation within the genual anterior cingulate cortex and the right anterior insular cortex; and (ii) deactivation patterns within the subgenual regions of the anterior cingulate cortex. Diuretic treatment (without HDBR) did not affect baseline HR and mean arterial pressure, but did reduce resting HRV and elevated circulating noradrenaline and plasma renin activity (P < 0.05). The greater HR response to LBNP following diuretic (P < 0.05) was associated with diminished activation of the right anterior insula. Our findings indicate that 24 h of HDBR minimized the impact of diuretic treatment on baseline autonomic and cardiovascular variables. The findings also indicate that despite the similar augmentation of HR responses to LBNP and despite similar pre-intervention cortical activation

  13. Sensory and decision-related activity propagate in a cortical feedback loop during touch perception.

    PubMed

    Kwon, Sung Eun; Yang, Hongdian; Minamisawa, Genki; O'Connor, Daniel H

    2016-09-01

    The brain transforms physical sensory stimuli into meaningful perceptions. In animals making choices about sensory stimuli, neuronal activity in successive cortical stages reflects a progression from sensation to decision. Feedforward and feedback pathways connecting cortical areas are critical for this transformation. However, the computational functions of these pathways are poorly understood because pathway-specific activity has rarely been monitored during a perceptual task. Using cellular-resolution, pathway-specific imaging, we measured neuronal activity across primary (S1) and secondary (S2) somatosensory cortices of mice performing a tactile detection task. S1 encoded the stimulus better than S2, while S2 activity more strongly reflected perceptual choice. S1 neurons projecting to S2 fed forward activity that predicted choice. Activity encoding touch and choice propagated in an S1-S2 loop along feedforward and feedback axons. Our results suggest that sensory inputs converge into a perceptual outcome as feedforward computations are reinforced in a feedback loop. PMID:27437910

  14. Selection of independent components based on cortical mapping of electromagnetic activity

    NASA Astrophysics Data System (ADS)

    Chan, Hui-Ling; Chen, Yong-Sheng; Chen, Li-Fen

    2012-10-01

    Independent component analysis (ICA) has been widely used to attenuate interference caused by noise components from the electromagnetic recordings of brain activity. However, the scalp topographies and associated temporal waveforms provided by ICA may be insufficient to distinguish functional components from artifactual ones. In this work, we proposed two component selection methods, both of which first estimate the cortical distribution of the brain activity for each component, and then determine the functional components based on the parcellation of brain activity mapped onto the cortical surface. Among all independent components, the first method can identify the dominant components, which have strong activity in the selected dominant brain regions, whereas the second method can identify those inter-regional associating components, which have similar component spectra between a pair of regions. For a targeted region, its component spectrum enumerates the amplitudes of its parceled brain activity across all components. The selected functional components can be remixed to reconstruct the focused electromagnetic signals for further analysis, such as source estimation. Moreover, the inter-regional associating components can be used to estimate the functional brain network. The accuracy of the cortical activation estimation was evaluated on the data from simulation studies, whereas the usefulness and feasibility of the component selection methods were demonstrated on the magnetoencephalography data recorded from a gender discrimination study.

  15. Metabotropic glutamate receptor modulation of voltage-gated Ca2+ channels involves multiple receptor subtypes in cortical neurons.

    PubMed

    Choi, S; Lovinger, D M

    1996-01-01

    Metabotropic glutamate receptor (mGluR) modulation of voltage-gated Ca2+ channels was examined in isolated deep layer frontoparietal cortical neurons under conditions designed to isolate calcium-independent modulatory pathways. Trans-1-aminocyclopentane-1,3-dicarboxylate (t-ACPD), a nonspecific mGluR agonist, produced rapid and reversible inhibition of Ca2+ channels. This effect was mimicked by agonists for group I and group II, but not group III, mGluRs. Effects of group I and II agonists often were observed in the same neurons, but separate subgroups of neurons were unresponsive to the group I agonist quisqualate or the group II agonist 2-(2,3-dicarboxycyclopropyl) glycine (DCG-IV). Inhibition by quisqualate and DCG-IV was nonocclusive in neurons responding to both agonists. These agonists thus appear to act on different mGluRs. The mGluR antagonist alpha-methyl-4-carboxylphenylglycine attenuated inhibition by t-ACPD, quisqualate, and DCG-IV. Inhibition by quisqualate and DCG-IV was voltage-dependent. Although the effects of both agonists were greatly reduced by N-ethylmaleimide (NEM), inhibition by DCG-IV was more sensitive to NEM than inhibition by quisqualate. t-ACPD-induced inhibition was reduced by omega-conotoxin GVIA (omega-CgTx) and omega-agatoxin IVA (omega-AgTx) but was affected little by nifedipine. Inhibition by DCG-IV and quisqualate also was reduced by omega-CgTx. We conclude that multiple mGluR subtypes inhibit Ca2+ channels in cortical neurons and that N- and possibly P-type channels are inhibited. Modulation is via a rapid-onset, voltage-dependent mechanism that likely involves a pertussis toxin (PTX)-sensitive G-protein. Type I mGluRs may work via additional PTX-insensitive pathways.

  16. Do Male And Female Cyclists' Cortical Activity Differ Before and During Cycling Exercise?

    PubMed

    Ludyga, Sebastian; Gronwald, Thomas; Hottenrott, Kuno

    2015-12-01

    Although men and women are suggested to vary in resistance to fatigue, possible sex difference in its central component have rarely been investigated via electroencephalography (EEG). Therefore, we examined differences in cortical activity between male and female cyclists (n = 26) during cycling exercise. Participants performed an incremental test to derive the anaerobic threshold from the lactate power curve. In addition, cyclists' cortical activity was recorded with EEG before and during cycling exercise. Whereas women showed higher frontal alpha and beta activity at rest, no sex-specific differences of relative EEG spectral power occurred during cycling at higher intensity. Women and men's brains respond similarly during submaximal cycling, as both sexes show an inverted U-shaped curve of alpha power. Therefore, sex differences observable at rest vanish after the onset of exercise. PMID:26866769

  17. Do Male And Female Cyclists' Cortical Activity Differ Before and During Cycling Exercise?

    PubMed

    Ludyga, Sebastian; Gronwald, Thomas; Hottenrott, Kuno

    2015-12-01

    Although men and women are suggested to vary in resistance to fatigue, possible sex difference in its central component have rarely been investigated via electroencephalography (EEG). Therefore, we examined differences in cortical activity between male and female cyclists (n = 26) during cycling exercise. Participants performed an incremental test to derive the anaerobic threshold from the lactate power curve. In addition, cyclists' cortical activity was recorded with EEG before and during cycling exercise. Whereas women showed higher frontal alpha and beta activity at rest, no sex-specific differences of relative EEG spectral power occurred during cycling at higher intensity. Women and men's brains respond similarly during submaximal cycling, as both sexes show an inverted U-shaped curve of alpha power. Therefore, sex differences observable at rest vanish after the onset of exercise.

  18. Molecular Mechanisms and Timing of Cortical Immune Activation in Schizophrenia

    PubMed Central

    Volk, David W.; Chitrapu, Anjani; Edelson, Jessica R.; Roman, Kaitlyn M.; Moroco, Annie E.; Lewis, David A.

    2016-01-01

    Objective Immune-related abnormalities are commonly reported in schizophrenia, including higher mRNA levels for the viral restriction factor interferon-induced transmembrane protein (IFITM) in the prefrontal cortex. The authors sought to clarify whether higher IFITM mRNA levels and other immune-related disturbances in the prefrontal cortex are the consequence of an ongoing molecular cascade contributing to immune activation or the reflection of a long-lasting maladaptive response to an in utero immune-related insult. Method Quantitative polymerase chain reaction was employed to measure mRNA levels for immune-related cytokines and transcriptional regulators, including those reported to regulate IFITM expression, in the prefrontal cortex from 62 schizophrenia and 62 healthy subjects and from adult mice exposed prenatally to maternal immune activation or in adulthood to the immune stimulant poly(I:C). Results Schizophrenia subjects had markedly higher mRNA levels for interleukin 6 (IL-6) (+379%) and interferon-β (+29%), which induce IFITM expression; lower mRNA levels for Schnurri-2 (−10%), a transcriptional inhibitor that lowers IFITM expression; and higher mRNA levels for nuclear factor-κB (+86%), a critical transcription factor that mediates cytokine regulation of immune-related gene expression. In adult mice that received daily poly(I:C) injections, but not in offspring with prenatal exposure to maternal immune activation, frontal cortex mRNA levels were also markedly elevated for IFITM (+304%), multiple cytokines including IL-6 (+493%), and nuclear factor-κB (+151%). Conclusions These data suggest that higher prefrontal cortex IFITM mRNA levels in schizophrenia may be attributable to adult, but not prenatal, activation of multiple immune markers and encourage further investigation into the potential role of these and other immune markers as therapeutic targets in schizophrenia. PMID:26133963

  19. Auditory and visual modulation of temporal lobe neurons in voice-sensitive and association cortices.

    PubMed

    Perrodin, Catherine; Kayser, Christoph; Logothetis, Nikos K; Petkov, Christopher I

    2014-02-12

    Effective interactions between conspecific individuals can depend upon the receiver forming a coherent multisensory representation of communication signals, such as merging voice and face content. Neuroimaging studies have identified face- or voice-sensitive areas (Belin et al., 2000; Petkov et al., 2008; Tsao et al., 2008), some of which have been proposed as candidate regions for face and voice integration (von Kriegstein et al., 2005). However, it was unclear how multisensory influences occur at the neuronal level within voice- or face-sensitive regions, especially compared with classically defined multisensory regions in temporal association cortex (Stein and Stanford, 2008). Here, we characterize auditory (voice) and visual (face) influences on neuronal responses in a right-hemisphere voice-sensitive region in the anterior supratemporal plane (STP) of Rhesus macaques. These results were compared with those in the neighboring superior temporal sulcus (STS). Within the STP, our results show auditory sensitivity to several vocal features, which was not evident in STS units. We also newly identify a functionally distinct neuronal subpopulation in the STP that appears to carry the area's sensitivity to voice identity related features. Audiovisual interactions were prominent in both the STP and STS. However, visual influences modulated the responses of STS neurons with greater specificity and were more often associated with congruent voice-face stimulus pairings than STP neurons. Together, the results reveal the neuronal processes subserving voice-sensitive fMRI activity patterns in primates, generate hypotheses for testing in the visual modality, and clarify the position of voice-sensitive areas within the unisensory and multisensory processing hierarchies. PMID:24523543

  20. Investigating the cortical regions involved in MEP modulation in tDCS

    PubMed Central

    Salvador, Ricardo; Wenger, Cornelia; Miranda, Pedro C.

    2015-01-01

    Transcranial magnetic stimulation (TMS) is used in several studies to evaluate cortical excitability changes induced by transcranial direct current stimulation (tDCS) of the primary motor cortex. Interpretation of these results, however, is hindered by the very different spatial distribution of the electric field (E-field) induced by the two techniques and by the different target neurons that they might act upon. In this study we used the finite element method to calculate the E-field distribution induced by TMS and tDCS in a realistically shaped model of a human head. A model of a commercially available figure-8 coil was placed over a position above the identified hand knob (HK) region. We also modeled two configurations of bipolar tDCS montages with one of the electrodes placed over the HK and a return electrode over the contralateral orbital region. The electrodes over the HK were either rectangular in shape, with an area of 35 cm2 or cylindrical with an area of π cm2 (1 cm radius). To compare the E-field distribution in TMS and the two tDCS models, average values of the E-field's magnitude as well as the polar and azimuthal angle were investigated in the HK region and premotor areas. The results show that both techniques induce fields with different magnitudes and directions in the HK: the field in tDCS is predominantly perpendicular to the cortical surface, contrary to what happens in TMS where the field is mostly parallel to it. In the premotor areas, the magnitude of the E-field induced in TMS was well below the accepted threshold for MEP generation, 100 V/m. In tDCS, the magnitude of the field in these areas was comparable to that induced at the HK with a significant component perpendicular to the cortical surface. These results indicate that tDCS and TMS target preferentially different neuronal structures at the HK. Besides, they show that premotor areas may play a role in the tDCS-induced after effects on motor cortex excitability. PMID:26528134

  1. Optogenetic micro-electrocorticography for modulating and localizing cerebral cortex activity

    PubMed Central

    Richner, Thomas J.; Thongpang, Sanitta; Brodnick, Sarah K.; Schendel, Amelia A.; Falk, Ryan W.; Krugner-Higby, Lisa A.; Pashaie, Ramin; Williams, Justin C.

    2014-01-01

    Objective Spatial localization of neural activity from within the brain with electrocorticography (ECoG) and electroencephalography (EEG) remains a challenge in clinical and research settings, and while microfabricated ECoG (micro-ECoG) array technology continues to improve, complimentary methods to simultaneously modulate cortical activity while recording are needed. Approach We developed a neural interface utilizing optogenetics, cranial windowing, and micro-ECoG arrays fabricated on a transparent polymer. This approach enabled us to directly modulate neural activity at known locations around micro-ECoG arrays in mice expressing Channelrhodopsin-2 (ChR2). We applied photostimuli varying in time, space and frequency to the cortical surface, and we targeted multiple depths within the cortex using an optical fiber while recording micro-ECoG signals. Main Results Negative potentials of up to 1.5 mV were evoked by photostimuli applied to the entire cortical window, while focally applied photostimuli evoked spatially localized micro-ECoG potentials. Two simultaneously applied focal stimuli could be separated, depending on the distance between them. Photostimuli applied within the cortex with an optical fiber evoked more complex micro-ECoG potentials with multiple positive and negative peaks whose relative amplitudes depended on the depth of the fiber. Significance Optogenetic ECoG has potential applications in the study of epilepsy, cortical dynamics, and neuroprostheses. PMID:24445482

  2. Optogenetic micro-electrocorticography for modulating and localizing cerebral cortex activity

    NASA Astrophysics Data System (ADS)

    Richner, Thomas J.; Thongpang, Sanitta; Brodnick, Sarah K.; Schendel, Amelia A.; Falk, Ryan W.; Krugner-Higby, Lisa A.; Pashaie, Ramin; Williams, Justin C.

    2014-02-01

    Objective. Spatial localization of neural activity from within the brain with electrocorticography (ECoG) and electroencephalography remains a challenge in clinical and research settings, and while microfabricated ECoG (micro-ECoG) array technology continues to improve, complementary methods to simultaneously modulate cortical activity while recording are needed. Approach. We developed a neural interface utilizing optogenetics, cranial windowing, and micro-ECoG arrays fabricated on a transparent polymer. This approach enabled us to directly modulate neural activity at known locations around micro-ECoG arrays in mice expressing Channelrhodopsin-2. We applied photostimuli varying in time, space and frequency to the cortical surface, and we targeted multiple depths within the cortex using an optical fiber while recording micro-ECoG signals. Main results. Negative potentials of up to 1.5 mV were evoked by photostimuli applied to the entire cortical window, while focally applied photostimuli evoked spatially localized micro-ECoG potentials. Two simultaneously applied focal stimuli could be separated, depending on the distance between them. Photostimuli applied within the cortex with an optical fiber evoked more complex micro-ECoG potentials with multiple positive and negative peaks whose relative amplitudes depended on the depth of the fiber. Significance. Optogenetic ECoG has potential applications in the study of epilepsy, cortical dynamics, and neuroprostheses.

  3. Matrix stiffness modulates formation and activity of neuronal networks of controlled architectures.

    PubMed

    Lantoine, Joséphine; Grevesse, Thomas; Villers, Agnès; Delhaye, Geoffrey; Mestdagh, Camille; Versaevel, Marie; Mohammed, Danahe; Bruyère, Céline; Alaimo, Laura; Lacour, Stéphanie P; Ris, Laurence; Gabriele, Sylvain

    2016-05-01

    The ability to construct easily in vitro networks of primary neurons organized with imposed topologies is required for neural tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. However, accumulating evidence suggests that the mechanical properties of the culture matrix can modulate important neuronal functions such as growth, extension, branching and activity. Here we designed robust and reproducible laminin-polylysine grid micropatterns on cell culture substrates that have similar biochemical properties but a 100-fold difference in Young's modulus to investigate the role of the matrix rigidity on the formation and activity of cortical neuronal networks. We found that cell bodies of primary cortical neurons gradually accumulate in circular islands, whereas axonal extensions spread on linear tracks to connect circular islands. Our findings indicate that migration of cortical neurons is enhanced on soft substrates, leading to a faster formation of neuronal networks. Furthermore, the pre-synaptic density was two times higher on stiff substrates and consistently the number of action potentials and miniature synaptic currents was enhanced on stiff substrates. Taken together, our results provide compelling evidence to indicate that matrix stiffness is a key parameter to modulate the growth dynamics, synaptic density and electrophysiological activity of cortical neuronal networks, thus providing useful information on scaffold design for neural tissue engineering.

  4. Emotional expressions modulate low α and β oscillations in a cortically blind patient.

    PubMed

    Del Zotto, Marzia; Deiber, Marie-Pierre; Legrand, Lore Billie; De Gelder, Beatrice; Pegna, Alan John

    2013-12-01

    Studies of cortical blindness have suggested that some residual visual function may persist without perceptual awareness, a condition known as blindsight. To investigate electrophysiological evidence of unconscious processing of emotional stimuli, we examined the event-related oscillations (EROs) in a 62year-old male patient (TN) with affective blindsight during random stimulation of three facial expressions (fearful, happy and neutral). Spectral power analysis in response to the different emotions revealed significant differences between fearful and happy faces over the right frontal regions at 7-8Hz (low α), and between emotional and neutral faces over the left frontal sites at 12-13Hz (low β) in a time period between 100-400ms after visual stimulus onset. These results demonstrate that emotional face processing occurs very early in time in the absence of any functional striate cortex, and further reveals the existence of specific oscillatory frequencies that reflect unconscious processing of facial expressions in affective blindsight. PMID:24144636

  5. Performance Based Education. Technology Activity Modules.

    ERIC Educational Resources Information Center

    Custer, Rodney L., Ed.

    These Technology Activity Modules are designed to serve as an implementation resource for technology education teachers as they integrate technology education with Missouri's Academic Performance Standards and provide a source of activities and activity ideas that can be used to integrate and reinforce learning across the curriculum. The modules…

  6. Relationship Between Cortical Thickness and Functional Activation in the Early Blind

    PubMed Central

    Anurova, Irina; Renier, Laurent A.; De Volder, Anne G.; Carlson, Synnöve; Rauschecker, Josef P.

    2015-01-01

    Early blindness results in both structural and functional changes of the brain. However, these changes have rarely been studied in relation to each other. We measured alterations in cortical thickness (CT) caused by early visual deprivation and their relationship with cortical activity. Structural and functional magnetic resonance imaging was performed in 12 early blind (EB) humans and 12 sighted controls (SC). Experimental conditions included one-back tasks for auditory localization and pitch identification, and a simple sound-detection task. Structural and functional data were analyzed in a whole-brain approach and within anatomically defined regions of interest in sensory areas of the spared (auditory) and deprived (visual) modalities. Functional activation during sound-localization or pitch-identification tasks correlated negatively with CT in occipital areas of EB (calcarine sulcus, lingual gyrus, superior and middle occipital gyri, and cuneus) and in nonprimary auditory areas of SC. These results suggest a link between CT and activation and demonstrate that the relationship between cortical structure and function may depend on early sensory experience, probably via selective pruning of exuberant connections. Activity-dependent effects of early sensory deprivation and long-term practice are superimposed on normal maturation and aging. Together these processes shape the relationship between brain structure and function over the lifespan. PMID:24518755

  7. DETECTION AND IDENTIFICATION OF SPEECH SOUNDS USING CORTICAL ACTIVITY PATTERNS

    PubMed Central

    Centanni, T.M.; Sloan, A.M.; Reed, A.C.; Engineer, C.T.; Rennaker, R.; Kilgard, M.P.

    2014-01-01

    We have developed a classifier capable of locating and identifying speech sounds using activity from rat auditory cortex with an accuracy equivalent to behavioral performance without the need to specify the onset time of the speech sounds. This classifier can identify speech sounds from a large speech set within 40 ms of stimulus presentation. To compare the temporal limits of the classifier to behavior, we developed a novel task that requires rats to identify individual consonant sounds from a stream of distracter consonants. The classifier successfully predicted the ability of rats to accurately identify speech sounds for syllable presentation rates up to 10 syllables per second (up to 17.9 ± 1.5 bits/sec), which is comparable to human performance. Our results demonstrate that the spatiotemporal patterns generated in primary auditory cortex can be used to quickly and accurately identify consonant sounds from a continuous speech stream without prior knowledge of the stimulus onset times. Improved understanding of the neural mechanisms that support robust speech processing in difficult listening conditions could improve the identification and treatment of a variety of speech processing disorders. PMID:24286757

  8. Model of multi-modal cortical processing: coherent learning in self-organizing modules.

    PubMed

    Ménard, Olivier; Frezza-Buet, Hervé

    2005-01-01

    In this paper (An abbreviated version of some portions of this article appeared in reference Menard and Frezza-Buet (Menard, O., & Frezza-Buet, H. (2004). Rewarded multi-modal neuronal self-organization: Example of the arm reaching movement. In: Proceedings of international conference on advances in intelligent systems theory and application.), as part of the IJCNN 2005 conference proceedings, published under the IEEE copyright.), an original self-organizing model is presented, with experiments highlighting its ability to be used in different frameworks, as phonetic coding dependent on semantics and arm-reaching. The model relies on the coupling of the learning processes that stand at different self-organizing modules, and exhibits dynamics that can be discussed in terms of the binding of different modalities, scattered over the different modules. Such a binding property is based on an emerging constraint of keeping consistency between the modules. This process is induced by partial connectivity and appropriate neural field competition mechanisms.

  9. TRPV1 Activation in Primary Cortical Neurons Induces Calcium-Dependent Programmed Cell Death.

    PubMed

    Song, Juhyun; Lee, Jun Hong; Lee, Sung Ho; Park, Kyung Ah; Lee, Won Taek; Lee, Jong Eun

    2013-03-01

    Transient receptor potential cation channel, subfamily V, member 1 (TRPV1, also known as vanilloid receptor 1) is a receptor that detects capsaicin, a pungent component of chili peppers, and noxious heat. Although its function in the primary nociceptor as a pain receptor is well established, whether TRPV1 is expressed in the brain is still under debate. In this study, the responses of primary cortical neurons were investigated. Here, we report that 1) capsaicin induces caspase-3-dependent programmed cell death, which coincides with increased production of nitric oxide and peroxynitrite ; that 2) the prolonged capsaicin treatment induces a steady increase in the degree of capase-3 activation, which is prevented by the removal of capsaicin; 3) and that blocking calcium entry and calcium-mediated signaling prevents capsaicin-induced cell death. These results indicate that cortical neurons express TRPV1 whose prolonged activation causes cell death. PMID:23585723

  10. Simultaneous modulation of retrieval by dopaminergic D(1), beta-noradrenergic, serotonergic-1A and cholinergic muscarinic receptors in cortical structures of the rat.

    PubMed

    Barros, D M; Mello e Souza, T; De David, T; Choi, H; Aguzzoli, A; Madche, C; Ardenghi, P; Medina, J H; Izquierdo, I

    2001-09-28

    Retrieval of inhibitory avoidance has been recently shown to require intact glutamate receptors, protein kinases A and C and mitogen-activated protein kinase in the CA1 region of the rat hippocampus and in the entorhinal, posterior parietal and anterior cingulate cortex. These enzymatic activities are known to be modulated by dopamine D(1), beta-noradrenergic, 5HT1A and cholinergic muscarinic receptors. Here we study the effect on retrieval of this task of well-known agonists and antagonists of these receptors infused in the same brain cortical regions and into the basolateral amygdala, in rats. The drugs used were SKF38393 (D(1) agonist), noradrenaline, 8-HO-DPAT (5HT1A agonist), oxotremorine (muscarinic agonist), SCH23390 (D(1) antagonist), timolol (beta antagonist), NAN-190 (5HT1A antagonist) and scopolamine (muscarinic antagonist). All were studied at two different dose levels. The localised infusion of SKF38393, noradrenaline, NAN-190 and oxotremorine into any of the cortical structures mentioned 10 min prior to a 24-h retention test session of one-trial step-down inhibitory avoidance enhanced retention test performance. SCH2330, timolol, 8-HO-DPAT and scopolamine hindered retention test performance. In the basolateral amygdala only an enhancing effect of noradrenaline and an inhibitory effect of timolol were seen. Three hours after the infusions, retention test performance returned to normal in all cases. None of the treatments affected locomotion or rearing in an open field or behaviour in the elevated plus maze. Therefore, their effects on retention testing can be attributed to an influence on retrieval. In conclusion, memory retrieval of this apparently simple task requires the participation of CA1, entorhinal, posterior parietal and anterior cingulate cortex, and is strongly modulated by, dopaminergic D(1), beta-noradrenergic, muscarinic cholinergic and 5HT1A receptors in the four areas. The first three types of receptor enhance, and the latter inhibits

  11. Reversible Information Flow across the Medial Temporal Lobe: The Hippocampus Links Cortical Modules during Memory Retrieval

    PubMed Central

    Cooper, Elisa; Henson, Richard N.

    2013-01-01

    A simple cue can be sufficient to elicit vivid recollection of a past episode. Theoretical models suggest that upon perceiving such a cue, disparate episodic elements held in neocortex are retrieved through hippocampal pattern completion. We tested this fundamental assumption by applying functional magnetic resonance imaging (fMRI) while objects or scenes were used to cue participants' recall of previously paired scenes or objects, respectively. We first demonstrate functional segregation within the medial temporal lobe (MTL), showing domain specificity in perirhinal and parahippocampal cortices (for object-processing vs scene-processing, respectively), but domain generality in the hippocampus (retrieval of both stimulus types). Critically, using fMRI latency analysis and dynamic causal modeling, we go on to demonstrate functional integration between these MTL regions during successful memory retrieval, with reversible signal flow from the cue region to the target region via the hippocampus. This supports the claim that the human hippocampus provides the vital associative link that integrates information held in different parts of cortex. PMID:23986252

  12. Enhanced cortical excitability in grapheme-color synesthesia and its modulation.

    PubMed

    Terhune, Devin Blair; Tai, Sarah; Cowey, Alan; Popescu, Tudor; Cohen Kadosh, Roi

    2011-12-01

    Synesthesia is an unusual condition characterized by the over-binding of two or more features and the concomitant automatic and conscious experience of atypical, ancillary images or perceptions. Previous research suggests that synesthetes display enhanced modality-specific perceptual processing, but it remains unclear whether enhanced processing contributes to conscious awareness of color photisms. In three experiments, we investigated whether grapheme-color synesthesia is characterized by enhanced cortical excitability in primary visual cortex and the role played by this hyperexcitability in the expression of synesthesia. Using transcranial magnetic stimulation, we show that synesthetes display 3-fold lower phosphene thresholds than controls during stimulation of the primary visual cortex. We next used transcranial direct current stimulation to discriminate between two competing hypotheses of the role of hyperexcitability in the expression of synesthesia. We demonstrate that synesthesia can be selectively augmented with cathodal stimulation and attenuated with anodal stimulation of primary visual cortex. A control task revealed that the effect of the brain stimulation was specific to the experience of synesthesia. These results indicate that hyperexcitability acts as a source of noise in visual cortex that influences the availability of the neuronal signals underlying conscious awareness of synesthetic photisms.

  13. Activity-dependent potentiation and depression of visual cortical responses to optic nerve stimulation in kittens.

    PubMed

    Tamura, H; Tsumoto, T; Hata, Y

    1992-11-01

    1. To see whether long-lasting changes in synaptic efficacy are induced in the developing visual cortex (VC), field potentials evoked by test stimulation given alternatively to each of the optic nerves (ONs) were recorded from VC of kittens ranging in age from 4 to 8 wk. In some experiments, field potentials were recorded simultaneously from the dorsal lateral geniculate nucleus (LGN) in addition to VC. 2. Tetanic stimulation was applied to one of the ONs for 1-60 min at 5 Hz. Homosynaptic potentiation of cortical responses, defined as an increase lasting > 2.5 h in the cortical field potential evoked by test stimulation of the ON that was tetanized, was induced without any changes in LGN responses in 3 of the 12 kittens tested. Heterosynaptic depression, defined as a decrease lasting > 0.5 h in the field potential evoked by stimulation of the ON that was not tetanized, was also induced in two of those three kittens. 3. To elucidate a role of inputs originating from spontaneous activity of retinal ganglion cells in induction of potentiation and depression in the cortex, tetrodotoxin (TTX) was injected into both eyes of 11 kittens. After we confirmed the suppression of retinal activity by TTX, tetanic stimulation was applied to ON. Homosynaptic potentiation of cortical responses was induced in 6 of the 11 kittens, and the ratio of the mean amplitude of posttetanic responses to that of pretetanic responses for the 11 kittens was on average larger than that for the 12 control kittens. Heterosynaptic depression was not observed in any of the 11 kittens. 4. To see a role of postsynaptic activity in induction of potentiation and depression, gamma-aminobutyric acid (GABA) was applied continuously to the VC by an infusion pump in 10 kittens. Tetanic stimulation was given to ON while cortical activities were suppressed by GABA. After recovery of cortical activities, homosynaptic depression was found to be induced in 3 of the 10 kittens, but homosynaptic potentiation was not

  14. A novel inhibitory nucleo-cortical circuit controls cerebellar Golgi cell activity

    PubMed Central

    Ankri, Lea; Husson, Zoé; Pietrajtis, Katarzyna; Proville, Rémi; Léna, Clément; Yarom, Yosef; Dieudonné, Stéphane; Uusisaari, Marylka Yoe

    2015-01-01

    The cerebellum, a crucial center for motor coordination, is composed of a cortex and several nuclei. The main mode of interaction between these two parts is considered to be formed by the inhibitory control of the nuclei by cortical Purkinje neurons. We now amend this view by showing that inhibitory GABA-glycinergic neurons of the cerebellar nuclei (CN) project profusely into the cerebellar cortex, where they make synaptic contacts on a GABAergic subpopulation of cerebellar Golgi cells. These spontaneously firing Golgi cells are inhibited by optogenetic activation of the inhibitory nucleo-cortical fibers both in vitro and in vivo. Our data suggest that the CN may contribute to the functional recruitment of the cerebellar cortex by decreasing Golgi cell inhibition onto granule cells. DOI: http://dx.doi.org/10.7554/eLife.06262.001 PMID:25965178

  15. Cerebral cortical activity associated with non-experts' most accurate motor performance.

    PubMed

    Dyke, Ford; Godwin, Maurice M; Goel, Paras; Rehm, Jared; Rietschel, Jeremy C; Hunt, Carly A; Miller, Matthew W

    2014-10-01

    This study's specific aim was to determine if non-experts' most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation. To assess this, EEG was recorded from non-expert golfers executing putts; EEG spectral power and coherence were calculated for the epoch preceding putt execution; and spectral power and coherence for the five most accurate putts were contrasted with that for the five least accurate. Results revealed marked power in the theta frequency bandwidth at all cerebral cortical regions for the most accurate putts relative to the least accurate, and considerable power in the low-beta frequency bandwidth at the left temporal region for the most accurate compared to the least. As theta power is associated with working memory and low-beta power at the left temporal region with verbal analysis, results suggest non-experts' most accurate motor performance is associated with verbal-analytic- and working memory-related cerebral cortical activity during motor preparation. PMID:25058623

  16. Left anterior temporal cortex actively engages in speech perception: A direct cortical stimulation study.

    PubMed

    Matsumoto, Riki; Imamura, Hisaji; Inouchi, Morito; Nakagawa, Tomokazu; Yokoyama, Yohei; Matsuhashi, Masao; Mikuni, Nobuhiro; Miyamoto, Susumu; Fukuyama, Hidenao; Takahashi, Ryosuke; Ikeda, Akio

    2011-04-01

    Recent neuroimaging studies proposed the importance of the anterior auditory pathway for speech comprehension. Its clinical significance is implicated by semantic dementia or pure word deafness. Neurodegenerative or cerebrovascular nature, however, precluded precise localization of the cortex responsible for speech perception. Electrical cortical stimulation could delineate such localization by producing transient, functional impairment. We investigated engagement of the left anterior temporal cortex in speech perception by means of direct electrical cortical stimulation. Subjects were two partial epilepsy patients, who underwent direct cortical stimulation as a part of invasive presurgical evaluations. Stimulus sites were coregistered to presurgical 3D-MRI, and then to MNI standard space for anatomical localization. Separate from the posterior temporal language area, electrical cortical stimulation revealed a well-restricted language area in the anterior part of the superior temporal sulcus and gyrus (aSTS/STG) in both patients. Auditory sentence comprehension was impaired upon electrical stimulation of aSTS/STG. In one patient, additional investigation revealed that the functional impairment was restricted to auditory sentence comprehension with preserved visual sentence comprehension and perception of music and environmental sounds. Both patients reported that they could hear the voice but not understand the sentence well (e.g., heard as a series of meaningless utterance). The standard coordinates of this restricted area at left aSTS/STG well corresponded with the coordinates of speech perception reported in neuroimaging activation studies in healthy subjects. The present combined anatomo-functional case study, for the first time, demonstrated that aSTS/STG in the language dominant hemisphere actively engages in speech perception.

  17. Enhanced Somatosensory Feedback Reduces Prefrontal Cortical Activity During Walking in Older Adults

    PubMed Central

    Christou, Evangelos A.; Ring, Sarah A.; Williamson, John B.; Doty, Leilani

    2014-01-01

    Background. The coordination of steady state walking is relatively automatic in healthy humans, such that active attention to the details of task execution and performance (controlled processing) is low. Somatosensation is a crucial input to the spinal and brainstem circuits that facilitate this automaticity. Impaired somatosensation in older adults may reduce automaticity and increase controlled processing, thereby contributing to deficits in walking function. The primary objective of this study was to determine if enhancing somatosensory feedback can reduce controlled processing during walking, as assessed by prefrontal cortical activation. Methods. Fourteen older adults (age 77.1±5.56 years) with mild mobility deficits and mild somatosensory deficits participated in this study. Functional near-infrared spectroscopy was used to quantify metabolic activity (tissue oxygenation index, TOI) in the prefrontal cortex. Prefrontal activity and gait spatiotemporal data were measured during treadmill walking and overground walking while participants wore normal shoes and under two conditions of enhanced somatosensation: wearing textured insoles and no shoes. Results. Relative to walking with normal shoes, textured insoles yielded a bilateral reduction of prefrontal cortical activity for treadmill walking (ΔTOI = −0.85 and −1.19 for left and right hemispheres, respectively) and for overground walking (ΔTOI = −0.51 and −0.66 for left and right hemispheres, respectively). Relative to walking with normal shoes, no shoes yielded lower prefrontal cortical activity for treadmill walking (ΔTOI = −0.69 and −1.13 for left and right hemispheres, respectively), but not overground walking. Conclusions. Enhanced somatosensation reduces prefrontal activity during walking in older adults. This suggests a less intensive utilization of controlled processing during walking. PMID:25112494

  18. Physiologically motivated multiplex Kuramoto model describes phase diagram of cortical activity

    NASA Astrophysics Data System (ADS)

    Sadilek, Maximilian; Thurner, Stefan

    2015-05-01

    We derive a two-layer multiplex Kuramoto model from Wilson-Cowan type physiological equations that describe neural activity on a network of interconnected cortical regions. This is mathematically possible due to the existence of a unique, stable limit cycle, weak coupling, and inhibitory synaptic time delays. We study the phase diagram of this model numerically as a function of the inter-regional connection strength that is related to cerebral blood flow, and a phase shift parameter that is associated with synaptic GABA concentrations. We find three macroscopic phases of cortical activity: background activity (unsynchronized oscillations), epileptiform activity (highly synchronized oscillations) and resting-state activity (synchronized clusters/chaotic behaviour). Previous network models could hitherto not explain the existence of all three phases. We further observe a shift of the average oscillation frequency towards lower values together with the appearance of coherent slow oscillations at the transition from resting-state to epileptiform activity. This observation is fully in line with experimental data and could explain the influence of GABAergic drugs both on gamma oscillations and epileptic states. Compared to previous models for gamma oscillations and resting-state activity, the multiplex Kuramoto model not only provides a unifying framework, but also has a direct connection to measurable physiological parameters.

  19. Altered Cortical Activation in Adolescents With Acute Migraine: A Magnetoencephalography Study

    PubMed Central

    Xiang, Jing; deGrauw, Xinyao; Korostenskaja, Milena; Korman, Abraham M.; O’Brien, Hope L.; Kabbouche, Marielle A.; Powers, Scott W.; Hershey, Andrew D.

    2013-01-01

    To quantitatively assess cortical dysfunction in pediatric migraine, 31 adolescents with acute migraine and age- and gender-matched controls were studied using a magnetoencephalography (MEG) system at a sampling rate of 6,000 Hz. Neuromagnetic brain activation was elicited by a finger-tapping task. The spectral and spatial signatures of magnetoencephalography data in 5 to 2,884 Hz were analyzed using Morlet wavelet and beamformers. Compared with controls, 31 migraine subjects during their headache attack phases (ictal) showed significantly prolonged latencies of neuromagnetic activation in 5 to 30 Hz, increased spectral power in 100 to 200 Hz, and a higher likelihood of neuromagnetic activation in the supplementary motor area, the occipital and ipsilateral sensorimotor cortices, in 2,200 to 2,800 Hz. Of the 31 migraine subjects, 16 migraine subjects during their headache-free phases (interictal) showed that there were no significant differences between interictal and control MEG data except that interictal spectral power in 100 to 200 Hz was significantly decreased. The results demonstrated that migraine subjects had significantly aberrant ictal brain activation, which can normalize interictally. The spread of abnormal ictal brain activation in both low- and high-frequency ranges triggered by movements may play a key role in the cascade of migraine attacks. Perspective This is the first study focusing on the spectral and spatial signatures of cortical dysfunction in adolescents with migraine using MEG signals in a frequency range of 5 to 2,884 Hz. This analyzing aberrant brain activation may be important for developing new therapeutic interventions for migraine in the future. PMID:23792072

  20. Cerebellar theta burst stimulation modulates the neural activity of interconnected parietal and motor areas

    PubMed Central

    Casula, Elias Paolo; Pellicciari, Maria Concetta; Ponzo, Viviana; Stampanoni Bassi, Mario; Veniero, Domenica; Caltagirone, Carlo; Koch, Giacomo

    2016-01-01

    Voluntary movement control and execution are regulated by the influence of the cerebellar output over different interconnected cortical areas, through dentato-thalamo connections. In the present study we applied transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess the effects of cerebellar theta-burst stimulation (TBS) over the controlateral primary motor cortex (M1) and posterior parietal cortex (PPC) in a group of healthy volunteers. We found a TBS-dependent bidirectional modulation over TMS-evoked activity; specifically, cTBS increased whereas iTBS decreased activity between 100 and 200 ms after TMS, in a similar manner over both M1 and PPC areas. On the oscillatory domain, TBS induced specific changes over M1 natural frequencies of oscillation: TMS-evoked alpha activity was decreased by cTBS whereas beta activity was enhanced by iTBS. No effects were observed after sham stimulation. Our data provide novel evidence showing that the cerebellum exerts its control on the cortex likely by impinging on specific set of interneurons dependent on GABA-ergic activity. We show that cerebellar TBS modulates cortical excitability of distant interconnected cortical areas by acting through common temporal, spatial and frequency domains. PMID:27796359

  1. Prefrontal cortical neuregulin-ErbB modulation of inhibitory control in rats.

    PubMed

    Loos, Maarten; Schetters, Dustin; Hoogeland, Myrthe; Spijker, Sabine; de Vries, Taco J; Pattij, Tommy

    2016-06-15

    Impulse control disturbances are key features of various neuropsychiatric and neurological disorders, such as attention-deficit/hyperactivity disorder, drug addiction, Parkinson disease and schizophrenia. Whereas over the last years accumulating evidence has highlighted monoaminergic modulation of the processes underlying impulse control, investigating novel mechanisms beyond monoamines may provide new intervention strategies to ameliorate impulse control disturbances. Recent work has associated the neuregulin (Nrg)-ErbB pathway with several neuropsychiatric diseases, as well as indicated its involvement in murine measures of impulse control. The aim of the present study was to investigate whether this Nrg-ErbB signaling pathway also modulates impulsive action in rats. To this end, a group of rats was trained in the 5-choice serial reaction time task (5-CSRTT), an operant paradigm that provides measures of visuospatial attention and inhibitory control processes. Upon stable baseline performance, the ErbB tyrosine kinase receptor inhibitor JNJ-28871063 (JNJ) was intracranially infused into the medioprefrontal cortex prior to test sessions. Results showed that JNJ dose-dependently improved measures of impulsive action. Importantly, other measures in the 5-CSRTT reflecting visuospatial attention or aspects of motivational behavior were not altered by JNJ. In conclusion, the present data strengthen a role for the Nrg-ErbB4 pathway in the prefrontal cortex in cognitive functioning, and in particular point towards involvement in the processes underlying impulse control. PMID:27079641

  2. Cortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5.

    PubMed

    Viggiano, Emanuela; Monda, Vincenzo; Messina, Antonietta; Moscatelli, Fiorenzo; Valenzano, Anna; Tafuri, Domenico; Cibelli, Giuseppe; De Luca, Bruno; Messina, Giovanni; Monda, Marcellino

    2016-01-01

    Depression of electrocorticogram propagating over the cortex surface results in cortical spreading depression (CSD), which is probably related to the pathophysiology of stroke, epilepsy, and migraine. However, preconditioning with CSD produces neuroprotection to subsequent ischemic episodes. Such effects require the expression or activation of several genes, including neuroprotective ones. Recently, it has been demonstrated that the expression of the uncoupling proteins (UCPs) 2 and 5 is amplified during brain ischemia and their expression exerts a long-term effect upon neuron protection. To evaluate the neuroprotective consequence of CSD, the expression of UCP-5 in the brain cortex was measured following CSD induction. CSD was evoked in four samples of rats, which were sacrificed after 2 hours, 4 hours, 6 hours, and 24 hours. Western blot analyses were carried out to measure UCP-5 concentrations in the prefrontal cortices of both hemispheres, and immunohistochemistry was performed to determine the localization of UCP-5 in the brain cortex. The results showed a significant elevation in UCP-5 expression at 24 hours in all cortical strata. Moreover, UCP-5 was triggered by CSD, indicating that UCP-5 production can have a neuroprotective effect. PMID:27468234

  3. Cortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5

    PubMed Central

    Viggiano, Emanuela; Monda, Vincenzo; Messina, Antonietta; Moscatelli, Fiorenzo; Valenzano, Anna; Tafuri, Domenico; Cibelli, Giuseppe; De Luca, Bruno; Messina, Giovanni; Monda, Marcellino

    2016-01-01

    Depression of electrocorticogram propagating over the cortex surface results in cortical spreading depression (CSD), which is probably related to the pathophysiology of stroke, epilepsy, and migraine. However, preconditioning with CSD produces neuroprotection to subsequent ischemic episodes. Such effects require the expression or activation of several genes, including neuroprotective ones. Recently, it has been demonstrated that the expression of the uncoupling proteins (UCPs) 2 and 5 is amplified during brain ischemia and their expression exerts a long-term effect upon neuron protection. To evaluate the neuroprotective consequence of CSD, the expression of UCP-5 in the brain cortex was measured following CSD induction. CSD was evoked in four samples of rats, which were sacrificed after 2 hours, 4 hours, 6 hours, and 24 hours. Western blot analyses were carried out to measure UCP-5 concentrations in the prefrontal cortices of both hemispheres, and immunohistochemistry was performed to determine the localization of UCP-5 in the brain cortex. The results showed a significant elevation in UCP-5 expression at 24 hours in all cortical strata. Moreover, UCP-5 was triggered by CSD, indicating that UCP-5 production can have a neuroprotective effect. PMID:27468234

  4. Chondroitinase enhances cortical map plasticity and increases functionally active sprouting axons after brain injury.

    PubMed

    Harris, Neil G; Nogueira, Marcia S M; Verley, Derek R; Sutton, Richard L

    2013-07-15

    The beneficial effect of interventions with chondroitinase ABC enzyme to reduce axon growth-inhibitory chondroitin sulphate side chains after central nervous system injuries has been mainly attributed to enhanced axonal sprouting. After traumatic brain injury (TBI), it is unknown whether newly sprouting axons that occur as a result of interventional strategies are able to functionally contribute to existing circuitry, and it is uncertain whether maladaptive sprouting occurs to increase the well-known risk for seizure activity after TBI. Here, we show that after a controlled cortical impact injury in rats, chondroitinase infusion into injured cortex at 30 min and 3 days reduced c-Fos⁺ cell staining resulting from the injury alone at 1 week postinjury, indicating that at baseline, abnormal spontaneous activity is likely to be reduced, not increased, with this type of intervention. c-Fos⁺ cell staining elicited by neural activity from stimulation of the affected forelimb 1 week after injury was significantly enhanced by chondroitinase, indicating a widespread effect on cortical map plasticity. Underlying this map plasticity was a larger contribution of neuronal, rather than glial cells and an absence of c-Fos⁺ cells surrounded by perineuronal nets that were normally present in stimulated naïve rats. After injury, chondroitin sulfate proteoglycan digestion produced the expected increase in growth-associated protein 43-positive axons and perikarya, of which a significantly greater number were double labeled for c-Fos after intervention with chondroitinase, compared to vehicle. These data indicate that chondroitinase produces significant gains in cortical map plasticity after TBI, and that either axonal sprouting and/or changes in perineuronal nets may underlie this effect. Chondroitinase dampens, rather than increases nonspecific c-Fos activity after brain injury, and induction of axonal sprouting is not maladaptive because greater numbers are functionally

  5. High gamma power in ECoG reflects cortical electrical stimulation effects on unit activity in layers V/VI

    NASA Astrophysics Data System (ADS)

    Yazdan-Shahmorad, Azadeh; Kipke, Daryl R.; Lehmkuhle, Mark J.

    2013-12-01

    Objective. Cortical electrical stimulation (CES) has been used extensively in experimental neuroscience to modulate neuronal or behavioral activity, which has led this technique to be considered in neurorehabilitation. Because the cortex and the surrounding anatomy have irregular geometries as well as inhomogeneous and anisotropic electrical properties, the mechanism by which CES has therapeutic effects is poorly understood. Therapeutic effects of CES can be improved by optimizing the stimulation parameters based on the effects of various stimulation parameters on target brain regions. Approach. In this study we have compared the effects of CES pulse polarity, frequency, and amplitude on unit activity recorded from rat primary motor cortex with the effects on the corresponding local field potentials (LFP), and electrocorticograms (ECoG). CES was applied at the surface of the cortex and the unit activity and LFPs were recorded using a penetrating electrode array, which was implanted below the stimulation site. ECoGs were recorded from the vicinity of the stimulation site. Main results. Time-frequency analysis of LFPs following CES showed correlation of gamma frequencies with unit activity response in all layers. More importantly, high gamma power of ECoG signals only correlated with the unit activity in lower layers (V-VI) following CES. Time-frequency correlations, which were found between LFPs, ECoGs and unit activity, were frequency- and amplitude-dependent. Significance. The signature of the neural activity observed in LFP and ECoG signals provides a better understanding of the effects of stimulation on network activity, representative of large numbers of neurons responding to stimulation. These results demonstrate that the neurorehabilitation and neuroprosthetic applications of CES targeting layered cortex can be further improved by using field potential recordings as surrogates to unit activity aimed at optimizing stimulation efficacy. Likewise, the signatures

  6. Reward modulates the effect of visual cortical microstimulation on perceptual decisions.

    PubMed

    Cicmil, Nela; Cumming, Bruce G; Parker, Andrew J; Krug, Kristine

    2015-01-01

    Effective perceptual decisions rely upon combining sensory information with knowledge of the rewards available for different choices. However, it is not known where reward signals interact with the multiple stages of the perceptual decision-making pathway and by what mechanisms this may occur. We combined electrical microstimulation of functionally specific groups of neurons in visual area V5/MT with performance-contingent reward manipulation, while monkeys performed a visual discrimination task. Microstimulation was less effective in shifting perceptual choices towards the stimulus preferences of the stimulated neurons when available reward was larger. Psychophysical control experiments showed this result was not explained by a selective change in response strategy on microstimulated trials. A bounded accumulation decision model, applied to analyse behavioural performance, revealed that the interaction of expected reward with microstimulation can be explained if expected reward modulates a sensory representation stage of perceptual decision-making, in addition to the better-known effects at the integration stage. PMID:26402458

  7. fNIRS: An Emergent Method to Document Functional Cortical Activity during Infant Movements

    PubMed Central

    Nishiyori, Ryota

    2016-01-01

    The neural basis underlying the emergence of goal-directed actions in infants has been severely understudied, with minimal empirical evidence for hypotheses proposed. This was largely due to the technological constraints of traditional neuroimaging techniques. Recently, functional near-infrared spectroscopy (fNIRS) technology has emerged as a tool developmental scientists are finding useful to examine cortical activity, particularly in young children and infants due to its greater tolerance to movements than other neuroimaging techniques. fNIRS provides an opportunity to finally begin to examine the neural underpinnings as infants develop goal-directed actions. In this methodological paper, I will outline the utility, challenges, and outcomes of using fNIRS to measure the changes in cortical activity as infants reach for an object. I will describe the advantages and limitations of the technology, the setup I used to study primary motor cortex activity during infant reaching, and example steps in the analyses processes. I will present exemplar data to illustrate the feasibility of this technique to quantify changes in hemodynamic activity as infants move. The viability of this research method opens the door to expanding studies of the development of neural activity related to goal-directed actions in infants. I encourage others to share details of techniques used, as well, including analyticals, to help this neuroimaging technology grow as others, such as EEG and fMRI have. PMID:27148141

  8. Correlated activity of cortical neurons survives extensive removal of feedforward sensory input

    PubMed Central

    Shapcott, Katharine A.; Schmiedt, Joscha T.; Saunders, Richard C.; Maier, Alexander; Leopold, David A.; Schmid, Michael C.

    2016-01-01

    A fundamental property of brain function is that the spiking activity of cortical neurons is variable and that some of this variability is correlated between neurons. Correlated activity not due to the stimulus arises from shared input but the neuronal circuit mechanisms that result in these noise correlations are not fully understood. Here we tested in the visual system if correlated variability in mid-level area V4 of visual cortex is altered following extensive lesions of primary visual cortex (V1). To this end we recorded longitudinally the neuronal correlations in area V4 of two behaving macaque monkeys before and after a V1 lesion while the monkeys fixated a grey screen. We found that the correlations of neuronal activity survived the lesions in both monkeys. In one monkey, the correlation of multi-unit spiking signals was strongly increased in the first week post-lesion, while in the second monkey, correlated activity was slightly increased, but not greater than some week-by-week fluctuations observed. The typical drop-off of inter-neuronal correlations with cortical distance was preserved after the lesion. Therefore, as V4 noise correlations remain without feedforward input from V1, these results suggest instead that local and/or feedback input seem to be necessary for correlated activity. PMID:27721468

  9. Cortical activation changes underlying stimulation-induced behavioural gains in chronic stroke

    PubMed Central

    Bachtiar, Velicia; O'Shea, Jacinta; Allman, Claire; Bosnell, Rosemary Ann; Kischka, Udo; Matthews, Paul McMahan; Johansen-Berg, Heidi

    2012-01-01

    Transcranial direct current stimulation, a form of non-invasive brain stimulation, is showing increasing promise as an adjunct therapy in rehabilitation following stroke. However, although significant behavioural improvements have been reported in proof-of-principle studies, the underlying mechanisms are poorly understood. The rationale for transcranial direct current stimulation as therapy for stroke is that therapeutic stimulation paradigms increase activity in ipsilesional motor cortical areas, but this has not previously been directly tested for conventional electrode placements. This study was performed to test directly whether increases in ipsilesional cortical activation with transcranial direct current stimulation are associated with behavioural improvements in chronic stroke patients. Patients at least 6 months post-first stroke participated in a behavioural experiment (n = 13) or a functional magnetic resonance imaging experiment (n = 11), each investigating the effects of three stimulation conditions in separate sessions: anodal stimulation to the ipsilesional hemisphere; cathodal stimulation to the contralesional hemisphere; and sham stimulation. Anodal (facilitatory) stimulation to the ipsilesional hemisphere led to significant improvements (5–10%) in response times with the affected hand in both experiments. This improvement was associated with an increase in movement-related cortical activity in the stimulated primary motor cortex and functionally interconnected regions. Cathodal (inhibitory) stimulation to the contralesional hemisphere led to a functional improvement only when compared with sham stimulation. We show for the first time that the significant behavioural improvements produced by anodal stimulation to the ipsilesional hemisphere are associated with a functionally relevant increase in activity within the ipsilesional primary motor cortex in patients with a wide range of disabilities following stroke. PMID:22155982

  10. Cortical activation changes underlying stimulation-induced behavioural gains in chronic stroke.

    PubMed

    Stagg, Charlotte Jane; Bachtiar, Velicia; O'Shea, Jacinta; Allman, Claire; Bosnell, Rosemary Ann; Kischka, Udo; Matthews, Paul McMahan; Johansen-Berg, Heidi

    2012-01-01

    Transcranial direct current stimulation, a form of non-invasive brain stimulation, is showing increasing promise as an adjunct therapy in rehabilitation following stroke. However, although significant behavioural improvements have been reported in proof-of-principle studies, the underlying mechanisms are poorly understood. The rationale for transcranial direct current stimulation as therapy for stroke is that therapeutic stimulation paradigms increase activity in ipsilesional motor cortical areas, but this has not previously been directly tested for conventional electrode placements. This study was performed to test directly whether increases in ipsilesional cortical activation with transcranial direct current stimulation are associated with behavioural improvements in chronic stroke patients. Patients at least 6 months post-first stroke participated in a behavioural experiment (n = 13) or a functional magnetic resonance imaging experiment (n = 11), each investigating the effects of three stimulation conditions in separate sessions: anodal stimulation to the ipsilesional hemisphere; cathodal stimulation to the contralesional hemisphere; and sham stimulation. Anodal (facilitatory) stimulation to the ipsilesional hemisphere led to significant improvements (5-10%) in response times with the affected hand in both experiments. This improvement was associated with an increase in movement-related cortical activity in the stimulated primary motor cortex and functionally interconnected regions. Cathodal (inhibitory) stimulation to the contralesional hemisphere led to a functional improvement only when compared with sham stimulation. We show for the first time that the significant behavioural improvements produced by anodal stimulation to the ipsilesional hemisphere are associated with a functionally relevant increase in activity within the ipsilesional primary motor cortex in patients with a wide range of disabilities following stroke.

  11. Patterns of brain activity distinguishing free and forced actions: contribution from sensory cortices

    PubMed Central

    Kostelecki, Wojciech; Mei, Ye; Garcia Dominguez, Luis; Pérez Velázquez, José L.

    2012-01-01

    The neural basis of decision-making is extremely complex due to the large number of factors that contribute to the outcome of even the most basic actions as well as the range of appropriate responses within many behavioral contexts. To better understand the neural processes underlying basic forms of decision-making, this study utilized an experiment that required a choice about whether to press a button with the right or left hand. These instances of decision-making were compared to identical button presses that were experimentally specified rather than selected by the subject. Magnetoencephalography (MEG) was used to record neural activity during these—what are being termed—free and forced actions and differences in the MEG signal between these two conditions were attributed to the distinct forms of neural activity required to carry out the two types of actions. To produce instances of free and forced behavior, cued button-pressing experiments were performed that use visual, aural, and memorized cues to instruct experimental subjects of the expected outcome of individual trials. Classification analysis of the trials revealed that cortical regions that allowed for the most accurate classification of free and forced actions primarily handle sensory input for the modality used to cue the trials: occipital cortex for visually cued trials, temporal cortex for aurally cued trials, and minor non-localized differences in MEG activity for trials initiated from memory. The differential roles of visual and auditory sensory cortices during free and forced actions provided insight into the neural processing steps that were engaged to initiate cued actions. Specifically, it suggested that detectable differences exist in the activity of sensory cortices and their target sites when subjects performed free and forced actions in response to sensory cues. PMID:23060760

  12. Treadmill exercise training and estradiol differentially modulate hypothalamic-pituitary-adrenal cortical responses to acute running and immobilization.

    PubMed

    White-Welkley, J E; Bunnell, B N; Mougey, E H; Meyerhoff, J L; Dishman, R K

    1995-03-01

    It is generally believed that physical fitness promotes health by attenuating responsiveness to other stressors. The experimental evidence for this belief is limited and does not extend to interactions between the hypothalamic-pituitary-adrenal cortical (HPA) and hypothalamic-pituitary-gonadal (HPG) axes. We tested the hypothesis that treadmill exercise training would lead to an estrogen-dependent hyporesponsiveness of the HPA axis that would generalize to immobilization stress. Ovariectomized female Sprague-Dawley rats (N = 74) that had been treadmill trained (TT) or sedentary for 6 weeks received intramuscular injections of estradiol benzoate (Eb) or sesame oil on each of 3 days prior to 15 min of acute treadmill running or immobilization. Plasma (adrenocorticotrophin) (ACTH), (corticosterone) (B) and (prolactin) (PRL) were determined from trunk blood by radioimmunoassay and compared in a 2 group (TT vs. sedentary)-by-2 treatment (Eb vs. oil)-by-2 acute stressor (running vs. immobilization) design. Home-cage (HC) animals (N = 24) provided baseline hormone levels. ACTH and B levels were elevated after stressors in animals treated with either Eb or oil compared to HC, but increases in PRL after stressors were dependent on Eb. Treadmill exercise training led to an attenuation of ACTH and prolactin to running, but the attenuation did not generalize to immobilization. In contrast, treadmill exercise training led to a hyperresponsiveness of ACTH. Treadmill training did not modulate prolactin responses to immobilization. The modulating effects of the estradiol treatment are consistent with an interaction of the HPA and HPG axes in response to stress.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Venlafaxine treatment after endothelin-1-induced cortical stroke modulates growth factor expression and reduces tissue damage in rats.

    PubMed

    Zepeda, Rodrigo; Contreras, Valentina; Pissani, Claudia; Stack, Katherine; Vargas, Macarena; Owen, Gareth I; Lazo, Oscar M; Bronfman, Francisca C

    2016-08-01

    Neuromodulators, such as antidepressants, may contribute to neuroprotection by modulating growth factor expression to exert anti-inflammatory effects and to support neuronal plasticity after stroke. Our objective was to study whether early treatment with venlafaxine, a serotonin-norepinephrine reuptake inhibitor, modulates growth factor expression and positively contributes to reducing the volume of infarcted brain tissue resulting in increased functional recovery. We studied the expression of BDNF, FGF2 and TGF-β1 by examining their mRNA and protein levels and cellular distribution using quantitative confocal microscopy at 5 days after venlafaxine treatment in control and infarcted brains. Venlafaxine treatment did not change the expression of these growth factors in sham rats. In infarcted rats, BDNF mRNA and protein levels were reduced, while the mRNA and protein levels of FGF2 and TGF-β1 were increased. Venlafaxine treatment potentiated all of the changes that were induced by cortical stroke alone. In particular, increased levels of FGF2 and TGF-β1 were observed in astrocytes at 5 days after stroke induction, and these increases were correlated with decreased astrogliosis (measured by GFAP) and increased synaptophysin immunostaining at twenty-one days after stroke in venlafaxine-treated rats. Finally, we show that venlafaxine reduced infarct volume after stroke resulting in increased functional recovery, which was measured using ladder rung motor tests, at 21 days after stroke. Our results indicate that the early oral administration of venlafaxine positively contributes to neuroprotection during the acute and late events that follow stroke. PMID:26965219

  14. Consequences of Laughter Upon Trunk Compression and Cortical Activation: Linear and Polynomial Relations.

    PubMed

    Svebak, Sven

    2016-08-01

    Results from two studies of biological consequences of laughter are reported. A proposed inhibitory brain mechanism was tested in Study 1. It aims to protect against trunk compression that can cause health hazards during vigorous laughter. Compression may be maximal during moderate durations and, for protective reasons, moderate in enduring vigorous laughs. Twenty-five university students volunteered to see a candid camera film. Laughter responses (LR) and the superimposed ha-responses were operationally assessed by mercury-filled strain gauges strapped around the trunk. On average, the thorax compression amplitudes exceeded those of the abdomen, and greater amplitudes were seen in the males than in the females after correction for resting trunk circumference. Regression analyses supported polynomial relations because medium LR durations were associated with particularly high thorax amplitudes. In Study 2, power changes were computed in the beta and alpha EEG frequency bands of the parietal cortex from before to after exposure to the comedy "Dinner for one" in 56 university students. Highly significant linear relations were calculated between the number of laughs and post-exposure cortical activation (increase of beta, decrease of alpha) due to high activation after frequent laughter. The results from Study 1 supported the hypothesis of a protective brain mechanism that is activated during long LRs to reduce the risk of harm to vital organs in the trunk cavity. The results in Study 2 supported a linear cortical activation and, thus, provided evidence for a biological correlate to the subjective experience of mental refreshment after laughter.

  15. Consequences of Laughter Upon Trunk Compression and Cortical Activation: Linear and Polynomial Relations.

    PubMed

    Svebak, Sven

    2016-08-01

    Results from two studies of biological consequences of laughter are reported. A proposed inhibitory brain mechanism was tested in Study 1. It aims to protect against trunk compression that can cause health hazards during vigorous laughter. Compression may be maximal during moderate durations and, for protective reasons, moderate in enduring vigorous laughs. Twenty-five university students volunteered to see a candid camera film. Laughter responses (LR) and the superimposed ha-responses were operationally assessed by mercury-filled strain gauges strapped around the trunk. On average, the thorax compression amplitudes exceeded those of the abdomen, and greater amplitudes were seen in the males than in the females after correction for resting trunk circumference. Regression analyses supported polynomial relations because medium LR durations were associated with particularly high thorax amplitudes. In Study 2, power changes were computed in the beta and alpha EEG frequency bands of the parietal cortex from before to after exposure to the comedy "Dinner for one" in 56 university students. Highly significant linear relations were calculated between the number of laughs and post-exposure cortical activation (increase of beta, decrease of alpha) due to high activation after frequent laughter. The results from Study 1 supported the hypothesis of a protective brain mechanism that is activated during long LRs to reduce the risk of harm to vital organs in the trunk cavity. The results in Study 2 supported a linear cortical activation and, thus, provided evidence for a biological correlate to the subjective experience of mental refreshment after laughter. PMID:27547260

  16. Reward modulates the effect of visual cortical microstimulation on perceptual decisions

    PubMed Central

    Cicmil, Nela; Cumming, Bruce G; Parker, Andrew J; Krug, Kristine

    2015-01-01

    Effective perceptual decisions rely upon combining sensory information with knowledge of the rewards available for different choices. However, it is not known where reward signals interact with the multiple stages of the perceptual decision-making pathway and by what mechanisms this may occur. We combined electrical microstimulation of functionally specific groups of neurons in visual area V5/MT with performance-contingent reward manipulation, while monkeys performed a visual discrimination task. Microstimulation was less effective in shifting perceptual choices towards the stimulus preferences of the stimulated neurons when available reward was larger. Psychophysical control experiments showed this result was not explained by a selective change in response strategy on microstimulated trials. A bounded accumulation decision model, applied to analyse behavioural performance, revealed that the interaction of expected reward with microstimulation can be explained if expected reward modulates a sensory representation stage of perceptual decision-making, in addition to the better-known effects at the integration stage. DOI: http://dx.doi.org/10.7554/eLife.07832.001 PMID:26402458

  17. Attention modulates cortical processing of pitch feedback errors in voice control.

    PubMed

    Hu, Huijing; Liu, Ying; Guo, Zhiqiang; Li, Weifeng; Liu, Peng; Chen, Shaozhen; Liu, Hanjun

    2015-01-01

    Considerable evidence has shown that unexpected alterations in auditory feedback elicit fast compensatory adjustments in vocal production. Although generally thought to be involuntary in nature, whether these adjustments can be influenced by attention remains unknown. The present event-related potential (ERP) study aimed to examine whether neurobehavioral processing of auditory-vocal integration can be affected by attention. While sustaining a vowel phonation and hearing pitch-shifted feedback, participants were required to either ignore the pitch perturbations, or attend to them with low (counting the number of perturbations) or high attentional load (counting the type of perturbations). Behavioral results revealed no systematic change of vocal response to pitch perturbations irrespective of whether they were attended or not. At the level of cortex, there was an enhancement of P2 response to attended pitch perturbations in the low-load condition as compared to when they were ignored. In the high-load condition, however, P2 response did not differ from that in the ignored condition. These findings provide the first neurophysiological evidence that auditory-motor integration in voice control can be modulated as a function of attention at the level of cortex. Furthermore, this modulatory effect does not lead to a general enhancement but is subject to attentional load.

  18. D-amino acid oxidase is expressed in the ventral tegmental area and modulates cortical dopamine.

    PubMed

    Betts, Jill F; Schweimer, Judith V; Burnham, Katherine E; Burnet, Philip W J; Sharp, Trevor; Harrison, Paul J

    2014-01-01

    D-amino acid oxidase (DAO, DAAO) degrades the NMDA receptor co-agonist D-serine, modulating D-serine levels and thence NMDA receptor function. DAO inhibitors are under development as a therapy for schizophrenia, a disorder involving both NMDA receptor and dopaminergic dysfunction. However, a direct role for DAO in dopamine regulation has not been demonstrated. Here, we address this question in two ways. First, using in situ hybridization and immunohistochemistry, we show that DAO mRNA and immunoreactivity are present in the ventral tegmental area (VTA) of the rat, in tyrosine hydroxylase (TH)-positive and -negative neurons, and in glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes. Second, we show that injection into the VTA of sodium benzoate, a DAO inhibitor, increases frontal cortex extracellular dopamine, as measured by in vivo microdialysis and high performance liquid chromatography. Combining sodium benzoate and D-serine did not enhance this effect, and injection of D-serine alone affected dopamine metabolites but not dopamine. These data show that DAO is expressed in the VTA, and suggest that it impacts on the mesocortical dopamine system. The mechanism by which the observed effects occur, and the implications of these findings for schizophrenia therapy, require further study. PMID:24822045

  19. Neonatal taurine and alanine modulate anxiety-like behavior and decelerate cortical spreading depression in rats previously suckled under different litter sizes.

    PubMed

    Francisco, Elian da Silva; Guedes, Rubem Carlos Araújo

    2015-11-01

    The amino acids taurine and alanine play a role in several physiological processes, including behavior and the electrical activity of the brain. In this study, we investigated the effect of treatment with taurine or alanine on anxiety-like behavior and the excitability-dependent phenomenon known as cortical spreading depression (CSD), using rats suckled in litters with 9 and 15 pups (groups L9 and L15). From postnatal days 7 to 27, the animals received per gavage 300 mg/kg/day of taurine or alanine or both. At 28 days, we tested the animals in the elevated plus maze, and at 33-35 days, we recorded CSD and analyzed its velocity of propagation, amplitude, and duration. Compared with water-treated controls, the L9 groups treated with taurine or alanine displayed anxiolytic behavior (higher number of entries in the open arms; p < 0.05), and reduced CSD velocity (p < 0.001). The effect of both amino acids on CSD was also found in the L15 groups and in five additional L9 groups (naïve, water, taurine, alanine, or both) treated at adulthood (90-110 days). The L15 condition resulted in smaller durations and higher CSD velocities compared with the L9 condition. Besides reinforcing previous evidence of behavioral modulation by taurine and alanine, our data are the first confirmation that treatment with these amino acids decelerates CSD regardless of lactation conditions (normal versus unfavorable lactation) or age at amino acid administration (young versus adult). The results suggest a modulating role for both amino acids on anxiety behavior and neuronal electrical activity.

  20. Clinacanthus nutans Extracts Modulate Epigenetic Link to Cytosolic Phospholipase A2 Expression in SH-SY5Y Cells and Primary Cortical Neurons.

    PubMed

    Tan, Charlene Siew-Hon; Ho, Christabel Fung-Yih; Heng, Swan-Ser; Wu, Jui-Sheng; Tan, Benny Kwong-Huat; Ng, Yee-Kong; Sun, Grace Y; Lin, Teng-Nan; Ong, Wei-Yi

    2016-09-01

    Clinacanthus nutans Lindau (C. nutans), commonly known as Sabah Snake Grass in southeast Asia, is widely used in folk medicine due to its analgesic, antiviral, and anti-inflammatory properties. Our recent study provided evidence for the regulation of cytosolic phospholipase A2 (cPLA2) mRNA expression by epigenetic factors (Tan et al. in Mol Neurobiol. doi: 10.1007/s12035-015-9314-z , 2015). This enzyme catalyzes the release of arachidonic acid from glycerophospholipids, and formation of pro-inflammatory eicosanoids or toxic lipid peroxidation products such as 4-hydroxynonenal. In this study, we examined the effects of C. nutans ethanol leaf extracts on epigenetic regulation of cPLA2 mRNA expression in SH-SY5Y human neuroblastoma cells and mouse primary cortical neurons. C. nutans modulated induction of cPLA2 expression in SH-SY5Y cells by histone deacetylase (HDAC) inhibitors, MS-275, MC-1568, and TSA. C. nutans extracts also inhibited histone acetylase (HAT) activity. Levels of cPLA2 mRNA expression were increased in primary cortical neurons subjected to 0.5-h oxygen-glucose deprivation injury (OGD). This increase was significantly inhibited by C. nutans treatment. Treatment of primary neurons with the HDAC inhibitor MS-275 augmented OGD-induced cPLA2 mRNA expression, and this increase was modulated by C. nutans extracts. OGD-stimulated increase in cPLA2 mRNA expression was also reduced by a Tip60 HAT inhibitor, NU9056. In view of a key role of cPLA2 in the production of pro-inflammatory eicosanoids and free radical damage, and the fact that epigenetic effects on genes are often long-lasting, results suggest a role for C. nutans and phytochemicals to inhibit the production of arachidonic acid-derived pro-inflammatory eicosanoids and chronic inflammation, through epigenetic regulation of cPLA2 expression. PMID:27319010

  1. Cognitively Engaging Activity Is Associated with Greater Cortical and Subcortical Volumes

    PubMed Central

    Seider, Talia R.; Fieo, Robert A.; O’Shea, Andrew; Porges, Eric C.; Woods, Adam J.; Cohen, Ronald A.

    2016-01-01

    As the population ages and dementia becomes a growing healthcare concern, it is increasingly important to identify targets for intervention to delay or attenuate cognitive decline. Research has shown that the most successful interventions aim at altering lifestyle factors. Thus, this study examined how involvement in physical, cognitive, and social activity is related to brain structure in older adults. Sixty-five adults (mean age = 71.4 years, standard deviation = 8.9) received the Community Healthy Activities Model Program for Seniors (CHAMPS), a questionnaire that polls everyday activities in which older adults may be involved, and also underwent structural magnetic resonance imaging. Stepwise regression with backward selection was used to predict weekly time spent in either social, cognitive, light physical, or heavy physical activity from the volume of one of the cortical or subcortical regions of interest (corrected by intracranial volume) as well as age, education, and gender as control variables. Regressions revealed that more time spent in cognitive activity was associated with greater volumes of all brain regions studied: total cortex (β = 0.289, p = 0.014), frontal (β = 0.276, p = 0.019), parietal (β = 0.305, p = 0.009), temporal (β = 0.275, p = 0.020), and occipital (β = 0.256, p = 0.030) lobes, and thalamus (β = 0.310, p = 0.010), caudate (β = 0.233, p = 0.049), hippocampus (β = 0.286, p = 0.017), and amygdala (β = 0.336, p = 0.004). These effects remained even after accounting for the positive association between cognitive activity and education. No other activity variable was associated with brain volumes. Results indicate that time spent in cognitively engaging activity is associated with greater cortical and subcortical brain volume. Findings suggest that interventions aimed at increasing levels of cognitive activity may delay cognitive consequences of aging and decrease the risk of developing dementia. PMID:27199740

  2. Spontaneous cortical DC-potential shifts: modulation stereotypy; relationships to higher EEG-frequencies.

    PubMed

    Etlinger, S C; Guttmann, G; Bauer, H

    1986-07-01

    A description of scalp-recorded, spontaneous, cerebral DC-potential shifts is given independent of other variables (shift stereotypy), in relationship to higher frequencies (theta, alpha 1, alpha 2: 4-13 Hz) and as analyzed pairwise across the median sagittal line (Fz, Cz, Pz) separately according to frequency and condition (relaxation and moderate mental load). Spontaneous DC-shifts are shown to behave unpredictably. Whether measured jointly (up to triads) or as dyad and triad context entropy, the frontal DC-shifts are calculated as being random, whereby their definition as such within the context of the Principle Component Analysis is supported by the analysis of longitudinal registrations. Cross-correlation analysis of the cerebral slow potential's relationship to each of the higher frequencies (theta, alpha 1, alpha 2) reveals it to be highly independent, the highest correlation accounting for merely 11% of the common variance, the average being 9% (R congruent to 0.3). By matching the conjoint activity of the DC-potential between Fz-Cz, Cz-Pz, and Fz-Pz to that of theta, alpha 1, alpha 2 at the same paired sites, the DC-activity is shown to be operating at higher levels of synchronous activity than the higher frequencies, regardless of pairing and/or condition, although the general level of synchronous activity (DC, theta, alpha 1, alpha 2) is remarkably high along the median sagittal line, 75% of the correlation averages of all analysis-pairings being above 0.60.

  3. Neural control of computer cursor velocity by decoding motor cortical spiking activity in humans with tetraplegia*

    PubMed Central

    Kim, Sung-Phil; Simeral, John D; Hochberg, Leigh R; Donoghue, John P; Black, Michael J

    2010-01-01

    Computer-mediated connections between human motor cortical neurons and assistive devices promise to improve or restore lost function in people with paralysis. Recently, a pilot clinical study of an intracortical neural interface system demonstrated that a tetraplegic human was able to obtain continuous two-dimensional control of a computer cursor using neural activity recorded from his motor cortex. This control, however, was not sufficiently accurate for reliable use in many common computer control tasks. Here, we studied several central design choices for such a system including the kinematic representation for cursor movement, the decoding method that translates neuronal ensemble spiking activity into a control signal and the cursor control task used during training for optimizing the parameters of the decoding method. In two tetraplegic participants, we found that controlling a cursor's velocity resulted in more accurate closed-loop control than controlling its position directly and that cursor velocity control was achieved more rapidly than position control. Control quality was further improved over conventional linear filters by using a probabilistic method, the Kalman filter, to decode human motor cortical activity. Performance assessment based on standard metrics used for the evaluation of a wide range of pointing devices demonstrated significantly improved cursor control with velocity rather than position decoding. PMID:19015583

  4. Cortical activation during word processing in late bilinguals: similarities and differences as revealed by functional magnetic resonance imaging.

    PubMed

    Marian, Viorica; Shildkrot, Yevgeniy; Blumenfeld, Henrike K; Kaushanskaya, Margarita; Faroqi-Shah, Yasmeen; Hirsch, Joy

    2007-04-01

    Functional magnetic resonance imaging was used to compare cortical organization of the first (L1, Russian) and second (L2, English) languages. Six fluent Russian-English bilinguals who acquired their second language postpuberty were tested with words and nonwords presented either auditorily or visually. Results showed that both languages activated similar cortical networks, including the inferior frontal, middle frontal, superior temporal, middle temporal, angular, and supramarginal gyri. Within the inferior frontal gyrus (IFG), L2 activated a larger cortical volume than L1 during lexical and phonological processing. For both languages, the left IFG was more active than the right IFG during lexical processing. Within the left IFG, the distance between centers of activation associated with lexical processing of translation equivalents across languages was larger than the distance between centers of activation associated with lexical processing of different words in the same language. Results of phonological processing analyses revealed different centers of activation associated with the first versus the second language in the IFG, but not in the superior temporal gyrus (STG). These findings are discussed within the context of the current literature on cortical organization in bilinguals and suggest variation in bilingual cortical activation associated with lexical, phonological, and orthographic processing.

  5. EEG frequency analysis of cortical brain activities induced by effect of light touch.

    PubMed

    Ishigaki, Tomoya; Ueta, Kozo; Imai, Ryota; Morioka, Shu

    2016-06-01

    In human postural control, touching a fingertip to a stable object with a slight force (<1 N) reduces postural sway independent of mechanical support, which is referred to as the effect of light touch (LT effect). The LT effect is achieved by the spatial orientation according to haptic feedback acquired from an external spatial reference. However, the neural mechanism of the LT effect is incompletely understood. Therefore, the purpose of this study was to employ EEG frequency analysis to investigate the cortical brain activity associated with the LT effect when attentional focus was strictly controlled with the eyes closed during standing (i.e., control, fixed-point touch, sway-referenced touch, and only fingertip attention). We used EEG to measure low-alpha (about 8-10 Hz) and high-alpha rhythm (about 10-12 Hz) task-related power decrease/increase (TRPD/TRPI). The LT effect was apparent only when the subject acquired the stable external spatial reference (i.e., fixed-point touch). Furthermore, the LT-specific effect increased the high-alpha TRPD of two electrodes (C3, P3), which were mainly projected from cortical brain activities of the left primary sensorimotor cortex area and left posterior parietal cortex area. Furthermore, there was a negative correlation between the LT effect and increased TRPD of C3. In contrast, the LT effect correlated positively with increased TRPD of P3. These results suggest that central and parietal high-alpha TRPD of the contralateral hemisphere reflects the sensorimotor information processing and sensory integration for the LT effect. These novel findings reveal a partial contribution of a cortical neural mechanism for the LT effect. PMID:26758719

  6. Influence of slow oscillation on hippocampal activity and ripples through cortico-hippocampal synaptic interactions, analyzed by a cortical-CA3-CA1 network model

    PubMed Central

    Taxidis, Jiannis; Mizuseki, Kenji; Mason, Robert; Owen, Markus R.

    2013-01-01

    Hippocampal sharp wave-ripple complexes (SWRs) involve the synchronous discharge of thousands of cells throughout the CA3-CA1-subiculum-entorhinal cortex axis. Their strong transient output affects cortical targets, rendering SWRs a possible means for memory transfer from the hippocampus to the neocortex for long-term storage. Neurophysiological observations of hippocampal activity modulation by the cortical slow oscillation (SO) during deep sleep and anesthesia, and correlations between ripples and UP states, support the role of SWRs in memory consolidation through a cortico-hippocampal feedback loop. We couple a cortical network exhibiting SO with a hippocampal CA3-CA1 computational network model exhibiting SWRs, in order to model such cortico-hippocampal correlations and uncover important parameters and coupling mechanisms controlling them. The cortical oscillatory output entrains the CA3 network via connections representing the mossy fiber input, and the CA1 network via the temporoammonic pathway (TA). The spiking activity in CA3 and CA1 is shown to depend on the excitation-to-inhibition ratio, induced by combining the two hippocampal inputs, with mossy fiber input controlling the UP-state correlation of CA3 population bursts and corresponding SWRs, whereas the temporoammonic input affects the overall CA1 spiking activity. Ripple characteristics and pyramidal spiking participation to SWRs are shaped by the strength of the Schaffer collateral drive. A set of in vivo recordings from the rat hippocampus confirms a model-predicted segregation of pyramidal cells into subgroups according to the SO state where they preferentially fire and their response to SWRs. These groups can potentially play distinct functional roles in the replay of spike sequences. PMID:23386827

  7. Attentional modulation of informational masking on early cortical representations of speech signals.

    PubMed

    Zhang, Changxin; Arnott, Stephen R; Rabaglia, Cristina; Avivi-Reich, Meital; Qi, James; Wu, Xihong; Li, Liang; Schneider, Bruce A

    2016-01-01

    To recognize speech in a noisy auditory scene, listeners need to perceptually segregate the target talker's voice from other competing sounds (stream segregation). A number of studies have suggested that the attentional demands placed on listeners increase as the acoustic properties and informational content of the competing sounds become more similar to that of the target voice. Hence we would expect attentional demands to be considerably greater when speech is masked by speech than when it is masked by steady-state noise. To investigate the role of attentional mechanisms in the unmasking of speech sounds, event-related potentials (ERPs) were recorded to a syllable masked by noise or competing speech under both active (the participant was asked to respond when the syllable was presented) or passive (no response was required) listening conditions. The results showed that the long-latency auditory response to a syllable (/bi/), presented at different signal-to-masker ratios (SMRs), was similar in both passive and active listening conditions, when the masker was a steady-state noise. In contrast, a switch from the passive listening condition to the active one, when the masker was two-talker speech, significantly enhanced the ERPs to the syllable. These results support the hypothesis that the need to engage attentional mechanisms in aid of scene analysis increases as the similarity (both acoustic and informational) between the target speech and the competing background sounds increases.

  8. Stimulus expectancy modulates inferior frontal gyrus and premotor cortex activity in auditory perception.

    PubMed

    Osnes, Berge; Hugdahl, Kenneth; Hjelmervik, Helene; Specht, Karsten

    2012-04-01

    In studies on auditory speech perception, participants are often asked to perform active tasks, e.g. decide whether the perceived sound is a speech sound or not. However, information about the stimulus, inherent in such tasks, may induce expectations that cause altered activations not only in the auditory cortex, but also in frontal areas such as inferior frontal gyrus (IFG) and motor cortices, even in the absence of an explicit task. To investigate this, we applied spectral mixes of a flute sound and either vowels or specific music instrument sounds (e.g. trumpet) in an fMRI study, in combination with three different instructions. The instructions either revealed no information about stimulus features, or explicit information about either the music instrument or the vowel features. The results demonstrated that, besides an involvement of posterior temporal areas, stimulus expectancy modulated in particular a network comprising IFG and premotor cortices during this passive listening task. PMID:22377261

  9. Cortical Efferents Lacking Mutant huntingtin Improve Striatal Neuronal Activity and Behavior in a Conditional Mouse Model of Huntington's Disease

    PubMed Central

    Estrada-Sánchez, Ana María; Burroughs, Courtney L.; Cavaliere, Stephen; Barton, Scott J.; Chen, Shirley; Yang, X. William

    2015-01-01

    Abnormal electrophysiological activity in the striatum, which receives dense innervation from the cerebral cortex, is believed to set the stage for the behavioral phenotype observed in Huntington's disease (HD), a neurodegenerative condition caused by mutation of the huntingtin (mhtt) protein. However, cortical involvement is far from clear. To determine whether abnormal striatal processing can be explained by mhtt alone (cell-autonomous model) or by mhtt in the corticostriatal projection cell–cell interaction model, we used BACHD/Emx1–Cre (BE) mice, a conditional HD model in which full-length mhtt is genetically reduced in cortical output neurons, including those that project to the striatum. Animals were assessed beginning at 20 weeks of age for at least the next 40 weeks, a range over which presymptomatic BACHD mice become symptomatic. Both open-field and nest-building behavior deteriorated progressively in BACHD mice relative to both BE and wild-type (WT) mice. Neuronal activity patterns in the dorsal striatum, which receives input from the primary motor cortex (M1), followed a similar age progression because BACHD activity changed more rapidly than either BE or WT mice. However, in the M1, BE neuronal activity differed significantly from both WT and BACHD. Although abnormal cortical activity in BE mice likely reflects input from mhtt-expressing afferents, including cortical interneurons, improvements in BE striatal activity and behavior suggest a critical role for mhtt in cortical output neurons in shaping the onset and progression of striatal dysfunction. PMID:25762686

  10. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children.

    PubMed

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-08-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5-8 Hz), alpha (8-12 Hz), sensory motor rhythm (12-16 Hz), and beta (16-25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children.

  11. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children

    PubMed Central

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-01-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5–8 Hz), alpha (8–12 Hz), sensory motor rhythm (12–16 Hz), and beta (16–25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children. PMID:27656629

  12. Brain cortical activation during guitar-induced hand dystonia studied by functional MRI.

    PubMed

    Pujol, J; Roset-Llobet, J; Rosinés-Cubells, D; Deus, J; Narberhaus, B; Valls-Solé, J; Capdevila, A; Pascual-Leone, A

    2000-09-01

    Focal hand dystonia in musicians is a strongly task-related movement disorder. Typically, symptoms become apparent only when players execute specific overpracticed skilled exercises on their instrument. We therefore examined five guitarists with functional MRI during dystonic symptom provocation by means of an adapted guitar inside the magnet. The activation patterns obtained in comparable nondystonic guitarists and in the study patients when performing normal-hand exercise served as references. A 1.5-T system equipped with echo-speed gradients and single-shot echoplanar imaging software was used. Data acquisition was centered on the cortical motor system encompassed in eight contiguous slices. Dystonic musicians compared with both control situations showed a significantly larger activation of the contralateral primary sensorimotor cortex that contrasted with a conspicuous bilateral underactivation of premotor areas. Our results coincide with studies of other dystonia types in that they show an abnormal recruitment of cortical areas involved in the control of voluntary movement. However, they do suggest that the primary sensorimotor cortex, rather than being underactive in idiopathic dystonic patients, may be overactive when tested during full expression of the task-induced movement disorder.

  13. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children

    PubMed Central

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-01-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5–8 Hz), alpha (8–12 Hz), sensory motor rhythm (12–16 Hz), and beta (16–25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children.

  14. Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children.

    PubMed

    Choi, Hyungsoo; Park, Sangjun; Kim, Kyekyoon Kevin; Lee, Kwanghee; Rhyu, Hyun-Seung

    2016-08-01

    Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls). electroencephalographic signals were recorded before and immediately after each movement, and before and after acute exercise under resting conditions, to obtain absolute and relative power estimates for the theta (3.5-8 Hz), alpha (8-12 Hz), sensory motor rhythm (12-16 Hz), and beta (16-25 Hz) bands. After acute HHIM exercise, all children showed significant changes in their relative EEG, mainly in the theta and alpha bands. Individual movements were found to influence relative theta, alpha and beta, and theta-to-beta ratios. He presents aerobic stretching HHIM exercise has demonstrated acute effect on the cortical activity of children. PMID:27656629

  15. Cortical Activity during Perception of Musical Rhythm; Comparing Musicians and Non-musicians

    PubMed Central

    Habibi, Assal; Wirantana, Vinthia; Starr, Arnold

    2014-01-01

    This study investigates the effects of musical training on brain activity to violations of rhythmic expectancies. We recorded behavioral and event-related brain potential (ERP) responses of musicians and non-musicians to discrepancies of rhythm between pairs of unfamiliar melodies based on Western classical rules. Rhythm deviations in the second melody involved prolongation of a note, thus creating a delay in the subsequent note; the duration of the second note was consequently shorter because the offset time was unchanged. In the first melody, on the other hand, the two notes were of equal duration. Musicians detected rhythm deviations significantly better than non-musicians. A negative auditory cortical potential in response to the omitted stimulus was observed at a latency of 150–250 ms from where the note should have been. There were no significant differences of amplitude or latency between musicians and non-musicians. In contrast, the N100 and P200 to the delayed note after the omission were significantly greater in amplitude in musicians compared to non-musicians especially in frontal and frontal-central areas. These findings indicate that long term musical training enhances brain cortical activities involved in processing temporal irregularities of unfamiliar melodies. PMID:25512680

  16. Anhedonia in the psychosis risk syndrome: associations with social impairment and basal orbitofrontal cortical activity

    PubMed Central

    Cressman, Victoria L; Schobel, Scott A; Steinfeld, Sara; Ben-David, Shelly; Thompson, Judy L; Small, Scott A; Moore, Holly; Corcoran, Cheryl M

    2015-01-01

    Background/Objectives: Anhedonia is associated with poor social function in schizophrenia. Here, we examined this association in individuals at clinical high risk (CHR) for schizophrenia and related psychotic disorders, taking into account social anxiety. We then explored correlations between anhedonia and basal metabolic activity in selected forebrain regions implicated in reward processing. Methods: In 62 CHR individuals and 37 healthy controls, we measured social adjustment (Social Adjustment Self-Report Scale), social and physical anhedonia (Chapman Revised Anhedonia Scales), and social anxiety (Social Anxiety Scale for Adolescents) in cross-section. In a subgroup of 25 CHR individuals for whom high-spatial-resolution basal-state functional magnetic resonance imaging data were available, we also assessed correlations of these socio-affective constructs with basal cerebral blood volume in orbitofrontal cortex and related regions involved in reward processing. Results: Relative to controls, CHR individuals reported social impairment, greater social and physical anhedonia, and more social anxiety, exhibiting impairments comparable to schizophrenia. Regression analyses showed that anhedonia predicted social impairment and correlated negatively with basal cerebral blood volume within the orbitofrontal cortex (all P’s<0.05). Conclusions: Anhedonia and social anxiety are prominent in CHR individuals. Trait-like anhedonia may be a core phenotype related to orbitofrontal cortical function that, independent of symptoms, predicts social impairment. These data provide a rationale for interventions that target anhedonia and related activity in orbitofrontal cortical circuits in CHR individuals. PMID:27336033

  17. Cortical activity prior to, and during, observation and execution of sequential finger movements.

    PubMed

    Calmels, Claire; Holmes, Paul; Jarry, Gilbert; Lévèque, Jean-Michel; Hars, Magaly; Stam, Cornelis J

    2006-01-01

    The aim of this study was to provide further evidence for the existence of a mirror neuron system in humans using electroencephalography during the observation and execution of non-object-related movements. Event-related desynchronization and synchronization (ERD/ERS) were used to characterize brain activity prior to, and during, observation and execution of a finger movement in four frequency bands (7-10 Hz, 10-13 Hz, 13-20 Hz, and 20-30 Hz). Electroencephalograms (EEGs) were recorded from 19 electrode sites in eight participants. In all the frequency bands and electrode sites, results revealed that there was no significant differences in EEG cortical activity between the observation condition and the execution conditions. Comparison of the two stages of the movement (i.e., pre-movement and movement) in the observation and execution conditions showed, in most cases, that pre-movement ERD values were less than movement ERD values. Whilst there was not an identical match of EEG cortical indices, this study provides further support for the existence of a mirror neuron system in humans. The incomplete congruence may be explained by the different behaviors, the nature of the task and factors in the observed action coded by the mirror system. PMID:17136468

  18. CD44 deficiency inhibits unloading-induced cortical bone loss through downregulation of osteoclast activity

    PubMed Central

    Li, Yuheng; Zhong, Guohui; Sun, Weijia; Zhao, Chengyang; Zhang, Pengfei; Song, Jinping; Zhao, Dingsheng; Jin, Xiaoyan; Li, Qi; Ling, Shukuan; Li, Yingxian

    2015-01-01

    The CD44 is cellular surface adhesion molecule that is involved in physiological processes such as hematopoiesis, lymphocyte homing and limb development. It plays an important role in a variety of cellular functions including adhesion, migration, invasion and survival. In bone tissue, CD44 is widely expressed in osteoblasts, osteoclasts and osteocytes. However, the mechanisms underlying its role in bone metabolism remain unclear. We found that CD44 expression was upregulated during osteoclastogenesis. CD44 deficiency in vitro significantly inhibited osteoclast activity and function by regulating the NF-κB/NFATc1-mediated pathway. In vivo, CD44 mRNA levels were significantly upregulated in osteoclasts isolated from the hindlimb of tail-suspended mice. CD44 deficiency can reduce osteoclast activity and counteract cortical bone loss in the hindlimb of unloaded mice. These results suggest that therapeutic inhibition of CD44 may protect from unloading induced bone loss by inhibiting osteoclast activity. PMID:26530337

  19. CD44 deficiency inhibits unloading-induced cortical bone loss through downregulation of osteoclast activity.

    PubMed

    Li, Yuheng; Zhong, Guohui; Sun, Weijia; Zhao, Chengyang; Zhang, Pengfei; Song, Jinping; Zhao, Dingsheng; Jin, Xiaoyan; Li, Qi; Ling, Shukuan; Li, Yingxian

    2015-01-01

    The CD44 is cellular surface adhesion molecule that is involved in physiological processes such as hematopoiesis, lymphocyte homing and limb development. It plays an important role in a variety of cellular functions including adhesion, migration, invasion and survival. In bone tissue, CD44 is widely expressed in osteoblasts, osteoclasts and osteocytes. However, the mechanisms underlying its role in bone metabolism remain unclear. We found that CD44 expression was upregulated during osteoclastogenesis. CD44 deficiency in vitro significantly inhibited osteoclast activity and function by regulating the NF-κB/NFATc1-mediated pathway. In vivo, CD44 mRNA levels were significantly upregulated in osteoclasts isolated from the hindlimb of tail-suspended mice. CD44 deficiency can reduce osteoclast activity and counteract cortical bone loss in the hindlimb of unloaded mice. These results suggest that therapeutic inhibition of CD44 may protect from unloading induced bone loss by inhibiting osteoclast activity.

  20. CD44 deficiency inhibits unloading-induced cortical bone loss through downregulation of osteoclast activity.

    PubMed

    Li, Yuheng; Zhong, Guohui; Sun, Weijia; Zhao, Chengyang; Zhang, Pengfei; Song, Jinping; Zhao, Dingsheng; Jin, Xiaoyan; Li, Qi; Ling, Shukuan; Li, Yingxian

    2015-01-01

    The CD44 is cellular surface adhesion molecule that is involved in physiological processes such as hematopoiesis, lymphocyte homing and limb development. It plays an important role in a variety of cellular functions including adhesion, migration, invasion and survival. In bone tissue, CD44 is widely expressed in osteoblasts, osteoclasts and osteocytes. However, the mechanisms underlying its role in bone metabolism remain unclear. We found that CD44 expression was upregulated during osteoclastogenesis. CD44 deficiency in vitro significantly inhibited osteoclast activity and function by regulating the NF-κB/NFATc1-mediated pathway. In vivo, CD44 mRNA levels were significantly upregulated in osteoclasts isolated from the hindlimb of tail-suspended mice. CD44 deficiency can reduce osteoclast activity and counteract cortical bone loss in the hindlimb of unloaded mice. These results suggest that therapeutic inhibition of CD44 may protect from unloading induced bone loss by inhibiting osteoclast activity. PMID:26530337

  1. Preserved Coupling between the Reader's Voice and the Listener's Cortical Activity in Autism Spectrum Disorders

    PubMed Central

    Bourguignon, Mathieu; Wens, Vincent; Op de Beeck, Marc; Marty, Brice; Deconinck, Nicolas; Soncarrieu, Marie-Vincianne; Goldman, Serge; Jousmäki, Veikko; Van Bogaert, Patrick; De Tiège, Xavier

    2014-01-01

    Purpose Investigating the steadiness of the phase-coupling between the time-course of the reader's voice and brain signals of subjects with autism spectrum disorder (ASD) passively listening to connected speech using magnetoencephalography (MEG). In typically developed subjects, such coupling occurs at the right posterior temporal sulcus (pSTS) for frequencies below 1 Hz, and reflects the neural processing of sentence-level rhythmic prosody at the prelexical level. Methods Cortical neuromagnetic signals were recorded with MEG (Elekta Oy, Finland) while seven right-handed and native French-speaking ASD subjects (six males, one female, range: 13–20 years) listened to live (Live) or recorded (Recorded) voices continuously reading a text in French for five minutes. Coherence was computed between the reader's voice time-course and ASD subjects' MEG signals. Coherent neural sources were subsequently reconstructed using a beamformer. Key findings Significant coupling was found at 0.5 Hz in all ASD subjects in Live and in six subjects in Recorded. Coherent sources were located close to the right pSTS in both conditions. No significant difference was found in coherence levels between Live and Recorded, and between ASD subjects and ten typically developed subjects (right-handed, native French-speaking adults, 5 males, 5 females, age range: 21–38 years) included in a previous study. Significance This study discloses a preserved coupling between the reader's voice and ASD subjects' cortical activity at the right pSTS. These findings support the existence of preserved neural processing of sentence-level rhythmic prosody in ASD. The preservation of early cortical processing of prosodic elements in verbal language might be exploited in therapeutic interventions in ASD. PMID:24663673

  2. Fatigue in multiple sclerosis is associated with abnormal cortical activation to voluntary movement--EEG evidence.

    PubMed

    Leocani, L; Colombo, B; Magnani, G; Martinelli-Boneschi, F; Cursi, M; Rossi, P; Martinelli, V; Comi, G

    2001-06-01

    Converging evidence is consistent with the view that fatigue in Multiple Sclerosis is independent from pyramidal tract involvement, suggesting a possible involvement of frontal areas. During voluntary movement, changes of the EEG rhythms can be observed over sensorimotor areas. Event-related desynchronization (ERD) of the 10 and 20 Hz frequency bands occurs during motor planning and execution and is followed after movement termination by event-related synchronization (ERS), expressing cortical idling or inhibition. We evaluated the pattern of cortical activation to voluntary movement in MS patients complaining of fatigue assessed using the Fatigue Severity Scale. Fifteen MS patients complaining of fatigue, 18 MS patients without fatigue, and 14 normal controls were studied. The two patients groups were similar for age, sex, disease duration, and were not disabled (score <1.5 at the Expanded Disability Status Scale). Twenty-nine channel EEG was recorded during about 60 self-paced extensions of the right thumb. The onset latency and amount of the contralateral sensorimotor (C3 electrode) 10 and 18--22 Hz ERD were similar in the three groups. ERD was more widespread anteriorly in the fatigue group compared with normal controls (P < 0.01 over Fz electrode). Postmovement contralateral sensorimotor 18--22 Hz ERS was significantly lower in fatigue MS patients compared with normal subjects (P < 0.005) and with nonfatigue MS patients (P = 0.02). These findings are consistent with a central origin of fatigue in MS and indicate cortical dysfunction even during a simple motor task, resulting in hyperactivity during movement execution and failure of the inhibitory mechanisms intervening after movement termination. PMID:11352624

  3. Cortical activity of skilled performance in a complex sports related motor task.

    PubMed

    Baumeister, Jochen; Reinecke, Kirsten; Liesen, Heinz; Weiss, Michael

    2008-11-01

    A skilled player in goal-directed sports performance has the ability to process internal and external information in an effective manner and decide which pieces of information are important and which are irrelevant. Focused attention and somatosensory information processing play a crucial role in this process. Electroencephalographic (EEG) recordings are able to demonstrate cortical changes in conjunction with this concept and were examined during a golf putting performance in an expert-novice paradigm. The success in putting (score) and performance-related cortical activity were recorded with an EEG during a 5 x 4 min putting series. Subjects were asked to putt balls for four min at their own pace. The EEG data was divided into different frequencies: Theta (4.75-6.75 Hz), Alpha-1 (7-9.5 Hz), Alpha-2 (9.75-12.5 Hz) and Beta-1 (12.75-18.5 Hz) and performance related power values were calculated. Statistical analysis shows significant better performance in the expert golfers (P < 0.001). This was associated with higher fronto-midline Theta power (P < 0.05) and higher parietal Alpha-2 power values (P < 0.05) compared to the novices in golf putting. Frontal Theta and parietal Alpha-2 spectral power in the ongoing EEG demonstrate differences due to skill level. Furthermore the findings suggest that with increasing skill level, golfers have developed task solving strategies including focussed attention and an economy in parietal sensory information processing which lead to more successful performance. In a theoretical framework both cortical parameters may play a role in the concept of the working memory. PMID:18607621

  4. Cortical activation following chronic passive implantation of a wide-field suprachoroidal retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Villalobos, Joel; Fallon, James B.; Nayagam, David A. X.; Shivdasani, Mohit N.; Luu, Chi D.; Allen, Penelope J.; Shepherd, Robert K.; Williams, Chris E.

    2014-08-01

    Objective. The research goal is to develop a wide-field retinal stimulating array for prosthetic vision. This study aimed at evaluating the efficacy of a suprachoroidal electrode array in evoking visual cortex activity after long term implantation. Approach. A planar silicone based electrode array (8 mm × 19 mm) was implanted into the suprachoroidal space in cats (ntotal = 10). It consisted of 20 platinum stimulating electrodes (600 μm diameter) and a trans-scleral cable terminated in a subcutaneous connector. Three months after implantation (nchronic = 6), or immediately after implantation (nacute = 4), an electrophysiological study was performed. Electrode total impedance was measured from voltage transients using 500 μs, 1 mA pulses. Electrically evoked potentials (EEPs) and multi-unit activity were recorded from the visual cortex in response to monopolar retinal stimulation. Dynamic range and cortical activation spread were calculated from the multi-unit recordings. Main results. The mean electrode total impedance in vivo following 3 months was 12.5 ± 0.3 kΩ. EEPs were recorded for 98% of the electrodes. The median evoked potential threshold was 150 nC (charge density 53 μC cm-2). The lowest stimulation thresholds were found proximal to the area centralis. Mean thresholds from multiunit activity were lower for chronic (181 ± 14 nC) compared to acute (322 ± 20 nC) electrodes (P < 0.001), but there was no difference in dynamic range or cortical activation spread. Significance. Suprachoroidal stimulation threshold was lower in chronic than acute implantation and was within safe charge limits for platinum. Electrode-tissue impedance following chronic implantation was higher, indicating the need for sufficient compliance voltage (e.g. 12.8 V for mean impedance, threshold and dynamic range). The wide-field suprachoroidal array reliably activated the retina after chronic implantation.

  5. Characterisation and imaging of cortical impedance changes during interictal and ictal activity in the anaesthetised rat.

    PubMed

    Vongerichten, Anna N; dos Santos, Gustavo Sato; Aristovich, Kirill; Avery, James; McEvoy, Andrew; Walker, Matthew; Holder, David S

    2016-01-01

    Epilepsy affects approximately 50 million people worldwide, and 20-30% of these cases are refractory to antiepileptic drugs. Many patients with intractable epilepsy can benefit from surgical resection of the tissue generating the seizures; however, difficulty in precisely localising seizure foci has limited the number of patients undergoing surgery as well as potentially lowered its effectiveness. Here we demonstrate a novel imaging method for monitoring rapid changes in cerebral tissue impedance occurring during interictal and ictal activity, and show that it can reveal the propagation of pathological activity in the cortex. Cortical impedance was recorded simultaneously to ECoG using a 30-contact electrode mat placed on the exposed cortex of anaesthetised rats, in which interictal spikes (IISs) and seizures were induced by cortical injection of 4-aminopyridine (4-AP), picrotoxin or penicillin. We characterised the tissue impedance responses during IISs and seizures, and imaged these responses in the cortex using Electrical Impedance Tomography (EIT). We found a fast, transient drop in impedance occurring as early as 12ms prior to the IISs, followed by a steep rise in impedance within ~120ms of the IIS. EIT images of these impedance changes showed that they were co-localised and centred at a depth of 1mm in the cortex, and that they closely followed the activity propagation observed in the surface ECoG signals. The fast, pre-IIS impedance drop most likely reflects synchronised depolarisation in a localised network of neurons, and the post-IIS impedance increase reflects the subsequent shrinkage of extracellular space caused by the intense activity. EIT could also be used to picture a steady rise in tissue impedance during seizure activity, which has been previously described. Thus, our results demonstrate that EIT can detect and localise different physiological changes during interictal and ictal activity and, in conjunction with ECoG, may in future improve the

  6. Cortical fMRI activation produced by attentive tracking of moving targets.

    PubMed

    Culham, J C; Brandt, S A; Cavanagh, P; Kanwisher, N G; Dale, A M; Tootell, R B

    1998-11-01

    Attention can be used to keep track of moving items, particularly when there are multiple targets of interest that cannot all be followed with eye movements. Functional magnetic resonance imaging (fMRI) was used to investigate cortical regions involved in attentive tracking. Cortical flattening techniques facilitated within-subject comparisons of activation produced by attentive tracking, visual motion, discrete attention shifts, and eye movements. In the main task, subjects viewed a display of nine green "bouncing balls" and used attention to mentally track a subset of them while fixating. At the start of each attentive-tracking condition, several target balls (e.g., 3/9) turned red for 2 s and then reverted to green. Subjects then used attention to keep track of the previously indicated targets, which were otherwise indistinguishable from the nontargets. Attentive-tracking conditions alternated with passive viewing of the same display when no targets had been indicated. Subjects were pretested with an eye-movement monitor to ensure they could perform the task accurately while fixating. For seven subjects, functional activation was superimposed on each individual's cortically unfolded surface. Comparisons between attentive tracking and passive viewing revealed bilateral activation in parietal cortex (intraparietal sulcus, postcentral sulcus, superior parietal lobule, and precuneus), frontal cortex (frontal eye fields and precentral sulcus), and the MT complex (including motion-selective areas MT and MST). Attentional enhancement was absent in early visual areas and weak in the MT complex. However, in parietal and frontal areas, the signal change produced by the moving stimuli was more than doubled when items were tracked attentively. Comparisons between attentive tracking and attention shifting revealed essentially identical activation patterns that differed only in the magnitude of activation. This suggests that parietal cortex is involved not only in discrete

  7. Impaired gamma-band activity during perceptual organization in adults with autism spectrum disorders: evidence for dysfunctional network activity in frontal-posterior cortices.

    PubMed

    Sun, Limin; Grützner, Christine; Bölte, Sven; Wibral, Michael; Tozman, Tahmine; Schlitt, Sabine; Poustka, Fritz; Singer, Wolf; Freitag, Christine M; Uhlhaas, Peter J

    2012-07-11

    Current theories of the pathophysiology of autism spectrum disorders (ASD) have focused on abnormal temporal coordination of neural activity in cortical circuits as a core impairment of the disorder. In the current study, we examined the possibility that gamma-band activity may be crucially involved in aberrant brain functioning in ASD. Magneto-encephalographic (MEG) data were recorded from 13 adult human participants with ASD and 16 controls during the presentation of Mooney faces. MEG data were analyzed in the 25-150 Hz frequency range and a beamforming approach was used to identify the sources of spectral power. Participants with ASD showed elevated reaction times and reduced detection rates during the perception of upright Mooney faces, while responses to inverted stimuli were in the normal range. Impaired perceptual organization in the ASD group was accompanied by a reduction in both the amplitude and phase locking of gamma-band activity. A beamforming approach identified distinct networks during perceptual organization in controls and participants with ASD. In controls, perceptual organization of Mooney faces involved increased 60-120 Hz activity in a frontoparietal network, while in the ASD group stronger activation was found in visual regions. These findings highlight the contribution of impaired gamma-band activity toward complex visual processing in ASD, suggesting atypical modulation of high-frequency power in frontoposterior networks.

  8. Self-selected conscious strategies do not modulate motor cortical output during action observation

    PubMed Central

    Obhi, Sukhvinder S.

    2015-01-01

    The human motor system is active not only when actions are performed but also when they are observed. Experimenters often manipulate aspects of the action or context to examine factors that influence this “mirror” response. However, little is known about the role of the observer's own top-down intentions and motivation. In this exploratory study, we investigated whether observers are able to exert conscious control over their mirror response, when they are explicitly instructed to either increase or decrease mirroring. Transcranial magnetic stimulation (TMS) was used to elicit motor-evoked potentials (MEPs) in a thumb abductor muscle as participants (n = 13) watched a video of a hand squeezing a rubber ball. The size of these MEPs, relative to the size of MEPs elicited during fixation cross observation, was taken as an index of mirroring. In an initial block of trials, participants were instructed to merely observe the actions presented. After the first block, the concept of mirroring was explained to the participants, and in the second and third blocks participants were instructed to either increase or decrease their mirror response. We did not instruct them about how to achieve this increase or decrease. Our results showed no difference in either facilitation or absolute motor excitability (i.e., nonnormalized MEP size) between the three blocks, indicating that individuals do not seem to be able to exert control over motor excitability during action observation, at least in the absence of a specific and maintained strategy. PMID:26311182

  9. Modulators of androgen and estrogen receptor activity.

    PubMed

    Clarke, Bart L; Khosla, Sundeep

    2010-01-01

    This review focuses on significant recent findings regarding modulators of androgen and estrogen receptor activity. Selective androgen receptor modulators (SARMs) interact with androgen receptors (ARs), and selective estrogen receptor modulators (SERMs) interact with estrogen receptors (ERs), with variable tissue selectivity. SERMs, which interact with both ERб and ERв in a tissue-specific manner to produce diverse outcomes in multiple tissues, continue to generate significant interest for clinical application. Development of SARMs for clinical application has been slower to date because of potential adverse effects, but these diverse compounds continue to be investigated for use in disorders in which modulation of the AR is important. SARMs have been investigated mostly at the basic and preclinical level to date, with few human clinical trials published. These compounds have been evaluated mostly for application in different stages of prostate cancer to date, but they hold promise for multiple other applications. Publication of the large STAR and RUTH clinical trials demonstrated that the SERMs tamoxifen and raloxifene have interesting similarities and differences in tissues that contain ERs. Lasofoxifene, bazedoxifene, and arzoxifene are newer SERMs that have been demonstrated in clinical trials to more potently increase bone mineral density and lower serum cholesterol values than tamoxifen or raloxifene. Both SARMs and SERMs hold great promise for therapeutic use in multiple disorders in which tissue-specific effects are mediated by their respective receptors.

  10. Auditory Cortex Basal Activity Modulates Cochlear Responses in Chinchillas

    PubMed Central

    León, Alex; Elgueda, Diego; Silva, María A.; Hamamé, Carlos M.; Delano, Paul H.

    2012-01-01

    Background The auditory efferent system has unique neuroanatomical pathways that connect the cerebral cortex with sensory receptor cells. Pyramidal neurons located in layers V and VI of the primary auditory cortex constitute descending projections to the thalamus, inferior colliculus, and even directly to the superior olivary complex and to the cochlear nucleus. Efferent pathways are connected to the cochlear receptor by the olivocochlear system, which innervates outer hair cells and auditory nerve fibers. The functional role of the cortico-olivocochlear efferent system remains debated. We hypothesized that auditory cortex basal activity modulates cochlear and auditory-nerve afferent responses through the efferent system. Methodology/Principal Findings Cochlear microphonics (CM), auditory-nerve compound action potentials (CAP) and auditory cortex evoked potentials (ACEP) were recorded in twenty anesthetized chinchillas, before, during and after auditory cortex deactivation by two methods: lidocaine microinjections or cortical cooling with cryoloops. Auditory cortex deactivation induced a transient reduction in ACEP amplitudes in fifteen animals (deactivation experiments) and a permanent reduction in five chinchillas (lesion experiments). We found significant changes in the amplitude of CM in both types of experiments, being the most common effect a CM decrease found in fifteen animals. Concomitantly to CM amplitude changes, we found CAP increases in seven chinchillas and CAP reductions in thirteen animals. Although ACEP amplitudes were completely recovered after ninety minutes in deactivation experiments, only partial recovery was observed in the magnitudes of cochlear responses. Conclusions/Significance These results show that blocking ongoing auditory cortex activity modulates CM and CAP responses, demonstrating that cortico-olivocochlear circuits regulate auditory nerve and cochlear responses through a basal efferent tone. The diversity of the obtained effects

  11. Slow-Frequency Pulsed Transcranial Electrical Stimulation for Modulation of Cortical Plasticity Based on Reciprocity Targeting with Precision Electrical Head Modeling

    PubMed Central

    Luu, Phan; Essaki Arumugam, Easwara Moorthy; Anderson, Erik; Gunn, Amanda; Rech, Dennis; Turovets, Sergei; Tucker, Don M.

    2016-01-01

    In pain management as well as other clinical applications of neuromodulation, it is important to consider the timing parameters influencing activity-dependent plasticity, including pulsed versus sustained currents, as well as the spatial action of electrical currents as they polarize the complex convolutions of the cortical mantle. These factors are of course related; studying temporal factors is not possible when the spatial resolution of current delivery to the cortex is so uncertain to make it unclear whether excitability is increased or decreased with anodal vs. cathodal current flow. In the present study we attempted to improve the targeting of specific cortical locations by applying current through flexible source-sink configurations of 256 electrodes in a geodesic array. We constructed a precision electric head model for 12 healthy individuals. Extraction of the individual’s cortical surface allowed computation of the component of the induced current that is normal to the target cortical surface. In an effort to replicate the long-term depression (LTD) induced with pulsed protocols in invasive animal research and transcranial magnetic stimulation studies, we applied 100 ms pulses at 1.9 s intervals either in cortical-surface-anodal or cortical-surface-cathodal directions, with a placebo (sham) control. The results showed significant LTD of the motor evoked potential as a result of the cortical-surface-cathodal pulses in contrast to the placebo control, with a smaller but similar LTD effect for anodal pulses. The cathodal LTD after-effect was sustained over 90 min following current injection. These results support the feasibility of pulsed protocols with low total charge in non-invasive neuromodulation when the precision of targeting is improved with a dense electrode array and accurate head modeling. PMID:27531976

  12. Slow-Frequency Pulsed Transcranial Electrical Stimulation for Modulation of Cortical Plasticity Based on Reciprocity Targeting with Precision Electrical Head Modeling.

    PubMed

    Luu, Phan; Essaki Arumugam, Easwara Moorthy; Anderson, Erik; Gunn, Amanda; Rech, Dennis; Turovets, Sergei; Tucker, Don M

    2016-01-01

    In pain management as well as other clinical applications of neuromodulation, it is important to consider the timing parameters influencing activity-dependent plasticity, including pulsed versus sustained currents, as well as the spatial action of electrical currents as they polarize the complex convolutions of the cortical mantle. These factors are of course related; studying temporal factors is not possible when the spatial resolution of current delivery to the cortex is so uncertain to make it unclear whether excitability is increased or decreased with anodal vs. cathodal current flow. In the present study we attempted to improve the targeting of specific cortical locations by applying current through flexible source-sink configurations of 256 electrodes in a geodesic array. We constructed a precision electric head model for 12 healthy individuals. Extraction of the individual's cortical surface allowed computation of the component of the induced current that is normal to the target cortical surface. In an effort to replicate the long-term depression (LTD) induced with pulsed protocols in invasive animal research and transcranial magnetic stimulation studies, we applied 100 ms pulses at 1.9 s intervals either in cortical-surface-anodal or cortical-surface-cathodal directions, with a placebo (sham) control. The results showed significant LTD of the motor evoked potential as a result of the cortical-surface-cathodal pulses in contrast to the placebo control, with a smaller but similar LTD effect for anodal pulses. The cathodal LTD after-effect was sustained over 90 min following current injection. These results support the feasibility of pulsed protocols with low total charge in non-invasive neuromodulation when the precision of targeting is improved with a dense electrode array and accurate head modeling. PMID:27531976

  13. Human evoked cortical activity to signal-to-noise ratio and absolute signal level.

    PubMed

    Billings, Curtis J; Tremblay, Kelly L; Stecker, G Christopher; Tolin, Wendy M

    2009-08-01

    The purpose of this study was to determine the effect of signal level and signal-to-noise ratio (SNR) on the latency and amplitude of evoked cortical activity to further our understanding of how the human central auditory system encodes signals in noise. Cortical auditory evoked potentials (CAEPs) were recorded from 15 young normal-hearing adults in response to a 1000 Hz tone presented at two tone levels in quiet and while continuous background noise levels were varied in five equivalent SNR steps. These 12 conditions were used to determine the effects of signal level and SNR level on CAEP components P1, N1, P2, and N2. Based on prior signal-in-noise experiments conducted in animals, we hypothesized that SNR, would be a key contributor to human CAEP characteristics. As hypothesized, amplitude increased and latency decreased with increasing SNR; in addition, there was no main effect of tone level across the two signal levels tested (60 and 75 dB SPL). Morphology of the P1-N1-P2 complex was driven primarily by SNR, highlighting the importance of noise when recording CAEPs. Results are discussed in terms of the current interest in recording CAEPs in hearing aid users.

  14. Cortical voluntary activation of the human knee extensors can be reliably estimated using transcranial magnetic stimulation.

    PubMed

    Sidhu, Simranjit K; Bentley, David J; Carroll, Timothy J

    2009-02-01

    The objective of this study was to determine if a transcranial magnetic stimulation (TMS) method of quantifying the degree to which the motor cortex drives the muscles during voluntary efforts can be reliably applied to the human knee extensors. Although the technique for estimating "cortical" voluntary activation (VA) is valid and reliable for elbow flexors and wrist extensors, evidence that it can be applied to muscles of the lower limb is necessary if twitch interpolation with TMS is to be widely used in research or clinical practice. Eight subjects completed two identical test sessions involving brief isometric knee extensions at forces ranging from rest to maximal voluntary contraction (MVC). Electromyographic (EMG) responses to TMS of the motor cortex and electrical stimulation of the femoral nerve were recorded from the rectus femoris (RF) and biceps femoris (BF) muscles, and knee extension twitch forces evoked by stimulation were measured. The amplitude of TMS-evoked twitch forces decreased linearly between 25% and 100% MVC (r(2) > 0.9), and produced reliable estimations of resting twitch and VA (ICC(2,1) > 0.85). The reliability and size of cortical measures of VA were comparable to those derived from motor nerve stimulation when the resting twitches were estimated on the basis of as few as three TMS trials. Thus, TMS measures of VA may provide a reliable and valid tool in studies investigating central fatigue due to exercise and neurological deficits in neural drive in the lower limbs. PMID:19034956

  15. An EP2 Agonist Facilitates NMDA-Induced Outward Currents and Inhibits Dendritic Beading through Activation of BK Channels in Mouse Cortical Neurons

    PubMed Central

    Hayashi, Yoshinori; Morinaga, Saori; Liu, Xia; Zhang, Jing; Wu, Zhou; Yokoyama, Takeshi; Nakanishi, Hiroshi

    2016-01-01

    Prostaglandin E2 (PGE2), a major metabolite of arachidonic acid produced by cyclooxygenase pathways, exerts its bioactive responses by activating four E-prostanoid receptor subtypes, EP1, EP2, EP3, and EP4. PGE2 enables modulating N-methyl-D-aspartate (NMDA) receptor-mediated responses. However, the effect of E-prostanoid receptor agonists on large-conductance Ca2+-activated K+ (BK) channels, which are functionally coupled with NMDA receptors, remains unclear. Here, we showed that EP2 receptor-mediated signaling pathways increased NMDA-induced outward currents (INMDA-OUT), which are associated with the BK channel activation. Patch-clamp recordings from the acutely dissociated mouse cortical neurons revealed that an EP2 receptor agonist activated INMDA-OUT, whereas an EP3 receptor agonist reduced it. Agonists of EP1 or EP4 receptors showed no significant effects on INMDA-OUT. A direct perfusion of 3,5′-cyclic adenosine monophosphate (cAMP) through the patch pipette facilitated INMDA-OUT, which was abolished by the presence of protein kinase A (PKA) inhibitor. Furthermore, facilitation of INMDA-OUT caused by an EP2 receptor agonist was significantly suppressed by PKA inhibitor. Finally, the activation of BK channels through EP2 receptors facilitated the recovery phase of NMDA-induced dendritic beading in the primary cultured cortical neurons. These results suggest that a direct activation of BK channels by EP2 receptor-mediated signaling pathways plays neuroprotective roles in cortical neurons. PMID:27298516

  16. An EP2 Agonist Facilitates NMDA-Induced Outward Currents and Inhibits Dendritic Beading through Activation of BK Channels in Mouse Cortical Neurons.

    PubMed

    Hayashi, Yoshinori; Morinaga, Saori; Liu, Xia; Zhang, Jing; Wu, Zhou; Yokoyama, Takeshi; Nakanishi, Hiroshi

    2016-01-01

    Prostaglandin E2 (PGE2), a major metabolite of arachidonic acid produced by cyclooxygenase pathways, exerts its bioactive responses by activating four E-prostanoid receptor subtypes, EP1, EP2, EP3, and EP4. PGE2 enables modulating N-methyl-D-aspartate (NMDA) receptor-mediated responses. However, the effect of E-prostanoid receptor agonists on large-conductance Ca(2+)-activated K(+) (BK) channels, which are functionally coupled with NMDA receptors, remains unclear. Here, we showed that EP2 receptor-mediated signaling pathways increased NMDA-induced outward currents (I NMDA-OUT), which are associated with the BK channel activation. Patch-clamp recordings from the acutely dissociated mouse cortical neurons revealed that an EP2 receptor agonist activated I NMDA-OUT, whereas an EP3 receptor agonist reduced it. Agonists of EP1 or EP4 receptors showed no significant effects on I NMDA-OUT. A direct perfusion of 3,5'-cyclic adenosine monophosphate (cAMP) through the patch pipette facilitated I NMDA-OUT, which was abolished by the presence of protein kinase A (PKA) inhibitor. Furthermore, facilitation of I NMDA-OUT caused by an EP2 receptor agonist was significantly suppressed by PKA inhibitor. Finally, the activation of BK channels through EP2 receptors facilitated the recovery phase of NMDA-induced dendritic beading in the primary cultured cortical neurons. These results suggest that a direct activation of BK channels by EP2 receptor-mediated signaling pathways plays neuroprotective roles in cortical neurons. PMID:27298516

  17. Consequences of Laughter Upon Trunk Compression and Cortical Activation: Linear and Polynomial Relations

    PubMed Central

    Svebak, Sven

    2016-01-01

    Results from two studies of biological consequences of laughter are reported. A proposed inhibitory brain mechanism was tested in Study 1. It aims to protect against trunk compression that can cause health hazards during vigorous laughter. Compression may be maximal during moderate durations and, for protective reasons, moderate in enduring vigorous laughs. Twenty-five university students volunteered to see a candid camera film. Laughter responses (LR) and the superimposed ha-responses were operationally assessed by mercury-filled strain gauges strapped around the trunk. On average, the thorax compression amplitudes exceeded those of the abdomen, and greater amplitudes were seen in the males than in the females after correction for resting trunk circumference. Regression analyses supported polynomial relations because medium LR durations were associated with particularly high thorax amplitudes. In Study 2, power changes were computed in the beta and alpha EEG frequency bands of the parietal cortex from before to after exposure to the comedy “Dinner for one” in 56 university students. Highly significant linear relations were calculated between the number of laughs and post-exposure cortical activation (increase of beta, decrease of alpha) due to high activation after frequent laughter. The results from Study 1 supported the hypothesis of a protective brain mechanism that is activated during long LRs to reduce the risk of harm to vital organs in the trunk cavity. The results in Study 2 supported a linear cortical activation and, thus, provided evidence for a biological correlate to the subjective experience of mental refreshment after laughter. PMID:27547260

  18. Variation in the topography of the speech production cortex verified by cortical stimulation and high gamma activity.

    PubMed

    Babajani-Feremi, Abbas; Rezaie, Roozbeh; Narayana, Shalini; Choudhri, Asim F; Fulton, Stephen P; Boop, Frederick A; Wheless, James W; Papanicolaou, Andrew C

    2014-12-17

    In this study, we have addressed the question of functional brain reorganization for language in the presence and absence of anatomical lesions in two patients with epilepsy using cortical stimulation mapping and high gamma (HG) activity in subdural grid recordings. In both, the expressive language cortex was defined as the cortical patch below the electrode(s) that when stimulated resulted in speech arrest, and during speech expression tasks generated HG activity. This patch fell within the borders of Broca's area, as defined anatomically, in the case of the patient with a lesion, but outside that area in the other, lesion-free patient. Such results highlight the necessity for presurgical language mapping in all cases of surgery involving the language-dominant hemisphere and suggest that HG activity during expressive language tasks can be informative and helpful in conjunction with cortical stimulation mapping for expressive language mapping.

  19. Variation in the topography of the speech production cortex verified by cortical stimulation and high gamma activity

    PubMed Central

    Rezaie, Roozbeh; Narayana, Shalini; Choudhri, Asim F.; Fulton, Stephen P.; Boop, Frederick A.; Wheless, James W.; Papanicolaou, Andrew C.

    2014-01-01

    In this study, we have addressed the question of functional brain reorganization for language in the presence and absence of anatomical lesions in two patients with epilepsy using cortical stimulation mapping and high gamma (HG) activity in subdural grid recordings. In both, the expressive language cortex was defined as the cortical patch below the electrode(s) that when stimulated resulted in speech arrest, and during speech expression tasks generated HG activity. This patch fell within the borders of Broca’s area, as defined anatomically, in the case of the patient with a lesion, but outside that area in the other, lesion-free patient. Such results highlight the necessity for presurgical language mapping in all cases of surgery involving the language-dominant hemisphere and suggest that HG activity during expressive language tasks can be informative and helpful in conjunction with cortical stimulation mapping for expressive language mapping. PMID:25371284

  20. Processing abstract language modulates motor system activity.

    PubMed

    Glenberg, Arthur M; Sato, Marc; Cattaneo, Luigi; Riggio, Lucia; Palumbo, Daniele; Buccino, Giovanni

    2008-06-01

    Embodiment theory proposes that neural systems for perception and action are also engaged during language comprehension. Previous neuroimaging and neurophysiological studies have only been able to demonstrate modulation of action systems during comprehension of concrete language. We provide neurophysiological evidence for modulation of motor system activity during the comprehension of both concrete and abstract language. In Experiment 1, when the described direction of object transfer or information transfer (e.g., away from the reader to another) matched the literal direction of a hand movement used to make a response, speed of responding was faster than when the two directions mismatched (an action-sentence compatibility effect). In Experiment 2, we used single-pulse transcranial magnetic stimulation to study changes in the corticospinal motor pathways to hand muscles while reading the same sentences. Relative to sentences that do not describe transfer, there is greater modulation of activity in the hand muscles when reading sentences describing transfer of both concrete objects and abstract information. These findings are discussed in relation to the human mirror neuron system. PMID:18470821

  1. Investigating the effects of a sensorimotor rhythm-based BCI training on the cortical activity elicited by mental imagery

    NASA Astrophysics Data System (ADS)

    Toppi, J.; Risetti, M.; Quitadamo, L. R.; Petti, M.; Bianchi, L.; Salinari, S.; Babiloni, F.; Cincotti, F.; Mattia, D.; Astolfi, L.

    2014-06-01

    Objective. It is well known that to acquire sensorimotor (SMR)-based brain-computer interface (BCI) control requires a training period before users can achieve their best possible performances. Nevertheless, the effect of this training procedure on the cortical activity related to the mental imagery ability still requires investigation to be fully elucidated. The aim of this study was to gain insights into the effects of SMR-based BCI training on the cortical spectral activity associated with the performance of different mental imagery tasks. Approach. Linear cortical estimation and statistical brain mapping techniques were applied on high-density EEG data acquired from 18 healthy participants performing three different mental imagery tasks. Subjects were divided in two groups, one of BCI trained subjects, according to their previous exposure (at least six months before this study) to motor imagery-based BCI training, and one of subjects who were naive to any BCI paradigms. Main results. Cortical activation maps obtained for trained and naive subjects indicated different spectral and spatial activity patterns in response to the mental imagery tasks. Long-term effects of the previous SMR-based BCI training were observed on the motor cortical spectral activity specific to the BCI trained motor imagery task (simple hand movements) and partially generalized to more complex motor imagery task (playing tennis). Differently, mental imagery with spatial attention and memory content could elicit recognizable cortical spectral activity even in subjects completely naive to (BCI) training. Significance. The present findings contribute to our understanding of BCI technology usage and might be of relevance in those clinical conditions when training to master a BCI application is challenging or even not possible.

  2. Coherent Activity in Bilateral Parieto-Occipital Cortices during P300-BCI Operation.

    PubMed

    Takano, Kouji; Ora, Hiroki; Sekihara, Kensuke; Iwaki, Sunao; Kansaku, Kenji

    2014-01-01

    The visual P300 brain-computer interface (BCI), a popular system for electroencephalography (EEG)-based BCI, uses the P300 event-related potential to select an icon arranged in a flicker matrix. In earlier studies, we used green/blue (GB) luminance and chromatic changes in the P300-BCI system and reported that this luminance and chromatic flicker matrix was associated with better performance and greater subject comfort compared with the conventional white/gray (WG) luminance flicker matrix. To highlight areas involved in improved P300-BCI performance, we used simultaneous EEG-fMRI recordings and showed enhanced activities in bilateral and right lateralized parieto-occipital areas. Here, to capture coherent activities of the areas during P300-BCI, we collected whole-head 306-channel magnetoencephalography data. When comparing functional connectivity between the right and left parieto-occipital channels, significantly greater functional connectivity in the alpha band was observed under the GB flicker matrix condition than under the WG flicker matrix condition. Current sources were estimated with a narrow-band adaptive spatial filter, and mean imaginary coherence was computed in the alpha band. Significantly greater coherence was observed in the right posterior parietal cortex under the GB than under the WG condition. Re-analysis of previous EEG-based P300-BCI data showed significant correlations between the power of the coherence of the bilateral parieto-occipital cortices and their performance accuracy. These results suggest that coherent activity in the bilateral parieto-occipital cortices plays a significant role in effectively driving the P300-BCI.

  3. Increased brain cortical activity during parabolic flights has no influence on a motor tracking task.

    PubMed

    Schneider, Stefan; Brümmer, Vera; Mierau, Andreas; Carnahan, Heather; Dubrowski, Adam; Strüder, Heiko K

    2008-03-01

    Previous studies showed that changing forces of gravity as they typically occur during parabolic flights might be responsible for adaptional processes of the CNS. However, until now it has not been differentiated between primary influences of weightlessness and secondary influences due to psycho-physiological factors (e.g., physical or mental strain). With the aim of detecting parabolic flight related changes in central cortical activity, a resting EEG was deduced in 16 subjects before, during and after parabolic flights. After subdividing EEG into alpha-, beta-,delta- and theta-wave bands, an increase in beta-power was noticeable inflight, whereas alpha(1)-power was increased postflight. No changes could be observed for the control group. To control possible effects of cortical activation, a manual tracking task with mirror inversion was performed during either the phase of weightlessness or during the normal gravity phase of a parabolic flight. No differences in performance nor in adaptation could be observed between both groups. A third group, performing under normal and stress-free conditions in a lab showed similar tracking values. We assume that the specific increase in brain activity is a sign of an increase in arousal inflight. This does support previous assumptions of non-specific stressors during parabolic flights and has to be considered as a relevant factor for experiments on central nerve adaptation. Although no influences of stress and/or weightlessness on motor performance and adaptation could be observed, we suggest that an "inflight" control group seems to be more adequate than a laboratory control group to investigate gravity-dependent changes in motor control.

  4. Variations in Disrupted-in-Schizophrenia 1 gene modulate long-term longitudinal differences in cortical thickness in patients with a first-episode of psychosis.

    PubMed

    Vázquez-Bourgon, Javier; Roiz-Santiañez, Roberto; Papiol, Sergi; Ferro, Adele; Varela-Gómez, Noemí; Fañanás, Lourdes; Crespo-Facorro, Benedicto

    2016-09-01

    Schizophrenia patients typically present a widespread bilateral cortical thinning from the early stages of the illness. However, there is controversy whether this reduction in cortical thickness (CT) is static or progressive over the evolution of the disorder. Disrupted-in-Schizophrenia 1 (DISC1) is one of the main candidates genes for schizophrenia, as it has been found associated to the illness, and to several endophenotypes of the disorder including structural brain differences. This gene is known to be involved in neurodevelopment and brain maturation processes. We therefore hypothesized that variations in this gene modulate different progressions of CT in psychosis. Seventy-nine Caucasian drug-naive patients experiencing a first episode of non-affective psychosis were genotyped for rs6675281 (Leu607Phe) and rs821616 (Ser704Cys) SNPs of the DISC1 gene. Brain MRIs were carried out at baseline and 3 years after initiating the treatment. Other clinical and socio-demographic variables were recorded to rule out possible confounding effects. Patients homozygous for the Leu allele of the rs6675281 SNP had a significant (p < 0.05) descend in CT over the 3-years period, while those carrying the Phe allele presented an increase in CT. When combining the two SNPs we found a synergic effect on CT progression, presenting those patients homozygous for Leu607 +Ser704 a more pronounced cortical thinning. In conclusion, DISC1 gene variations may modulate the longitudinal changes in cortical thickness in patients suffering from a first episode of non-affective psychosis. PMID:26209938

  5. High-calcium diet modulates effects of long-term prolactin exposure on the cortical bone calcium content in ovariectomized rats.

    PubMed

    Charoenphandhu, Narattaphol; Tudpor, Kukiat; Thongchote, Kanogwun; Saengamnart, Wasana; Puntheeranurak, Supaporn; Krishnamra, Nateetip

    2007-02-01

    High physiological prolactin induced positive calcium balance by stimulating intestinal calcium absorption, reducing renal calcium excretion, and increasing bone calcium deposition in female rats. Although prolactin-induced increase in trabecular bone calcium deposition was absent after ovariectomy, its effects on cortical bones were still controversial. The present investigation, therefore, aimed to study the effect of in vivo long-term high physiological prolactin induced by either anterior pituitary (AP) transplantation or 2.5 mg/kg prolactin injection on cortical bones in ovariectomized rats. Since the presence of prolactin receptors (PRLR) in different bones of normal adult rats has not been reported, we first determined mRNA expression of both short- and long-form PRLRs at the cortical sites (tibia and femur) and trabecular sites (calvaria and vertebrae) by using the RT-PCR. Our results showed the mRNA expression of both PRLR isoforms with predominant long form at all sites. However, high prolactin levels induced by AP transplantation in normal rats did not have any effect on the femoral bone mineral density or bone mineral content. By using (45)Ca kinetic study, 2.5 mg/kg prolactin did not alter bone formation, bone resorption, calcium deposition, and total calcium content in tibia and femur of adult ovariectomized rats. AP transplantation also had no effect on the cortical total calcium content in adult ovariectomized rats. Because previous work showed that the effects of prolactin were age dependent and could be modulated by high-calcium diet, interactions between prolactin and these two parameters were investigated. The results demonstrated that 2.0% wt/wt high-calcium diet significantly increased the tibial total calcium content in 9-wk-old young AP-grafted ovariectomized rats but decreased the tibial total calcium content in 22-wk-old adult rats. As for the vertebrae, the total calcium contents in both young and adult rats were not changed by high

  6. TASK DIFFICULTY MODULATES ACTIVITY OF SPECIFIC NEURONAL POPULATIONS IN PRIMARY VISUAL CORTEX

    PubMed Central

    Chen, Yao; Martinez-Conde, Susana; Macknik, Stephen L.; Bereshpolova, Yulia; Swadlow, Harvey A.; Alonso, Jose-Manuel

    2008-01-01

    Spatial attention enhances our ability to detect stimuli at restricted regions of the visual field. This enhancement is thought to depend on the difficulty of the task being performed, but the underlying neuronal mechanisms for this dependency remain largely unknown. Here we demonstrate that task difficulty modulates neuronal firing rate at the earliest stages of cortical visual processing (area V1) in the macaque monkey. These modulations are spatially specific: increasing task difficulty enhances V1 neuronal firing rate at the focus of attention and suppresses it in regions surrounding the focus. Moreover, we show that response enhancement and suppression are mediated by distinct populations of neurons that differ in direction selectivity, spike width, interspike interval distribution and contrast sensitivity. Our results provide strong support for center-surround models of spatial attention and suggest that task difficulty modulates the activity of specific populations of neurons in the primary visual cortex. PMID:18604204

  7. Lempel-Ziv complexity of cortical activity during sleep and waking in rats

    PubMed Central

    Abásolo, Daniel; Simons, Samantha; Morgado da Silva, Rita; Tononi, Giulio

    2015-01-01

    Understanding the dynamics of brain activity manifested in the EEG, local field potentials (LFP), and neuronal spiking is essential for explaining their underlying mechanisms and physiological significance. Much has been learned about sleep regulation using conventional EEG power spectrum, coherence, and period-amplitude analyses, which focus primarily on frequency and amplitude characteristics of the signals and on their spatio-temporal synchronicity. However, little is known about the effects of ongoing brain state or preceding sleep-wake history on the nonlinear dynamics of brain activity. Recent advances in developing novel mathematical approaches for investigating temporal structure of brain activity based on such measures, as Lempel-Ziv complexity (LZC) can provide insights that go beyond those obtained with conventional techniques of signal analysis. Here, we used extensive data sets obtained in spontaneously awake and sleeping adult male laboratory rats, as well as during and after sleep deprivation, to perform a detailed analysis of cortical LFP and neuronal activity with LZC approach. We found that activated brain states—waking and rapid eye movement (REM) sleep are characterized by higher LZC compared with non-rapid eye movement (NREM) sleep. Notably, LZC values derived from the LFP were especially low during early NREM sleep after sleep deprivation and toward the middle of individual NREM sleep episodes. We conclude that LZC is an important and yet largely unexplored measure with a high potential for investigating neurophysiological mechanisms of brain activity in health and disease. PMID:25717159

  8. An ECG-based Algorithm for the Automatic Identification of Autonomic Activations Associated with Cortical Arousal

    PubMed Central

    Basner, Mathias; Griefahn, Barbara; Müller, Uwe; Plath, Gernot; Samel, Alexander

    2007-01-01

    Objectives: EEG arousals are associated with autonomic activations. Visual EEG arousal scoring is time consuming and suffers from low interobserver agreement. We hypothesized that information on changes in heart rate alone suffice to predict the occurrence of cortical arousal. Methods: Two visual AASM EEG arousal scorings of 56 healthy subject nights (mean age 37.0 ± 12.8 years, 26 male) were obtained. For each of 5 heartbeats following the onset of 3581 consensus EEG arousals and of an equal number of control conditions, differences to a moving median were calculated and used to estimate likelihood ratios (LRs) for 10 categories of heartbeat differences. Comparable to 5 consecutive diagnostic tests, these LRs were used to calculate the probability of heart rate responses being associated with cortical arousals. Results: EEG and ECG arousal indexes agreed well across a wide range of decision thresholds, resulting in a receiver operating characteristic (ROC) with an area under the curve of 0.91. For the decision threshold chosen for the final analyses, a sensitivity of 68.1% and a specificity of 95.2% were obtained. ECG and EEG arousal indexes were poorly correlated (r = 0.19, P <0.001, ICC = 0.186), which could in part be attributed to 3 outliers. The Bland-Altman plot showed an unbiased estimation of EEG arousal indexes by ECG arousal indexes with a standard deviation of ± 7.9 arousals per hour sleep. In about two-thirds of all cases, ECG arousal scoring was matched by at least one (22.2%) or by both (42.5%) of the visual scorings. Sensitivity of the algorithm increased with increasing duration of EEG arousals. The ECG algorithm was also successfully validated with 30 different nights of 10 subjects (mean age 35.3 ▯ 13.6 years, 5 male). Conclusions: In its current version, the ECG algorithm cannot replace visual EEG arousal scoring. Sensitivity for detecting <10-s EEG arousals needs to be improved. However, in a nonclinical population, it may be valuable to

  9. Multichannel time domain fNIRS mapping of cortical activation and superficial systemic responses during neuromuscular electrical stimulation

    NASA Astrophysics Data System (ADS)

    Re, R.; Muthalib, M.; Zucchelli, L.; Perrey, S.; Contini, D.; Caffini, M.; Spinelli, L.; Kerr, G.; Torricelli, A.

    2013-06-01

    We recorded maps of cortical and systemic hemodynamic responses (oxy-hemoglobin, O2Hb and deoxy-hemoglobin, HHb) during incremental neuromuscular electrical stimulation (NMES) of the right forearm in nine subjects by a 32- channel time domain fNIRS (TD-fNIRS) instrument. Statistical parametric maps (SPM) relative to the different current stimulations (under and over the maximal tolerated intensity-MTI) versus the 10%MTI were generated. Exploiting the temporal information contained in the TD-fNIRS signal it was possible to create different maps referring to the deeper (cortical activations) and the more superficial (systemic changes) head layers. The increasing of the stimulation current on the right forearm muscle produced a significantly larger bilateral sensorimotor and prefrontal cortical activations (i.e. increase in the O2Hb and decrease in HHb) than the systemic changes. Physiological parameters (heart rate, breathing rate and skin conductance) were also monitored.

  10. Differential involvement of amygdala and cortical NMDA receptors activation upon encoding in odor fear memory.

    PubMed

    Hegoburu, Chloé; Parrot, Sandrine; Ferreira, Guillaume; Mouly, Anne-Marie

    2014-12-01

    Although the basolateral amygdala (BLA) plays a crucial role for the acquisition of fear memories, sensory cortices are involved in their long-term storage in rats. However, the time course of their respective involvement has received little investigation. Here we assessed the role of the glutamatergic N-methyl-d-aspartate (NMDA) receptors in the BLA and olfactory cortex at discrete moments of an odor fear conditioning session. We showed that NMDA receptors in BLA are critically involved in odor fear acquisition during the first association but not during the next ones. In the cortex, NMDA receptor activation at encoding is not necessary for recent odor fear memory while its role in remote memory storage needs further investigation.

  11. Differential involvement of amygdala and cortical NMDA receptors activation upon encoding in odor fear memory.

    PubMed

    Hegoburu, Chloé; Parrot, Sandrine; Ferreira, Guillaume; Mouly, Anne-Marie

    2014-12-01

    Although the basolateral amygdala (BLA) plays a crucial role for the acquisition of fear memories, sensory cortices are involved in their long-term storage in rats. However, the time course of their respective involvement has received little investigation. Here we assessed the role of the glutamatergic N-methyl-d-aspartate (NMDA) receptors in the BLA and olfactory cortex at discrete moments of an odor fear conditioning session. We showed that NMDA receptors in BLA are critically involved in odor fear acquisition during the first association but not during the next ones. In the cortex, NMDA receptor activation at encoding is not necessary for recent odor fear memory while its role in remote memory storage needs further investigation. PMID:25403452

  12. Differential involvement of amygdala and cortical NMDA receptors activation upon encoding in odor fear memory

    PubMed Central

    Hegoburu, Chloé; Parrot, Sandrine; Ferreira, Guillaume

    2014-01-01

    Although the basolateral amygdala (BLA) plays a crucial role for the acquisition of fear memories, sensory cortices are involved in their long-term storage in rats. However, the time course of their respective involvement has received little investigation. Here we assessed the role of the glutamatergic N-methyl-d-aspartate (NMDA) receptors in the BLA and olfactory cortex at discrete moments of an odor fear conditioning session. We showed that NMDA receptors in BLA are critically involved in odor fear acquisition during the first association but not during the next ones. In the cortex, NMDA receptor activation at encoding is not necessary for recent odor fear memory while its role in remote memory storage needs further investigation. PMID:25403452

  13. Maintaining Gait Performance by Cortical Activation during Dual-Task Interference: A Functional Near-Infrared Spectroscopy Study.

    PubMed

    Lu, Chia-Feng; Liu, Yan-Ci; Yang, Yea-Ru; Wu, Yu-Te; Wang, Ray-Yau

    2015-01-01

    In daily life, mobility requires walking while performing a cognitive or upper-extremity motor task. Although previous studies have evaluated the effects of dual tasks on gait performance, few studies have evaluated cortical activation and its association with gait disturbance during dual tasks. In this study, we simultaneously assessed gait performance and cerebral oxygenation in the bilateral prefrontal cortices (PFC), premotor cortices (PMC), and supplemental motor areas (SMA), using functional near-infrared spectroscopy, in 17 young adults performing dual tasks. Each participant was evaluated while performing normal-pace walking (NW), walking while performing a cognitive task (WCT), and walking while performing a motor task (WMT). Our results indicated that the left PFC exhibited the strongest and most sustained activation during WCT, and that NW and WMT were associated with minor increases in oxygenation levels during their initial phases. We observed increased activation in channels in the SMA and PMC during WCT and WMT. Gait data indicated that WCT and WMT both caused reductions in walking speed, but these reductions resulted from differing alterations in gait properties. WCT was associated with significant changes in cadence, stride time, and stride length, whereas WMT was associated with reductions in stride length only. During dual-task activities, increased activation of the PMC and SMA correlated with declines in gait performance, indicating a control mechanism for maintaining gait performance during dual tasks. Thus, the regulatory effects of cortical activation on gait behavior enable a second task to be performed while walking.

  14. EGFR mediates astragaloside IV-induced Nrf2 activation to protect cortical neurons against in vitro ischemia/reperfusion damages.

    PubMed

    Gu, Da-Min; Lu, Pei-Hua; Zhang, Ke; Wang, Xiang; Sun, Min; Chen, Guo-Qian; Wang, Qiong

    2015-02-13

    In this study, we tested the potential role of astragaloside IV (AS-IV) against oxygen and glucose deprivation/re-oxygenation (OGD/R)-induced damages in murine cortical neurons, and studied the associated signaling mechanisms. AS-IV exerted significant neuroprotective effects against OGD/R by reducing reactive oxygen species (ROS) accumulation, thereby attenuating oxidative stress and neuronal cell death. We found that AS-IV treatment in cortical neurons resulted in NF-E2-related factor 2 (Nrf2) signaling activation, evidenced by Nrf2 Ser-40 phosphorylation, and its nuclear localization, as well as transcription of antioxidant-responsive element (ARE)-regulated genes: heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1) and sulphiredoxin 1 (SRXN-1). Knockdown of Nrf2 through lentiviral shRNAs prevented AS-IV-induced ARE genes transcription, and abolished its anti-oxidant and neuroprotective activities. Further, we discovered that AS-IV stimulated heparin-binding-epidermal growth factor (HB-EGF) release to trans-activate epidermal growth factor receptor (EGFR) in cortical neurons. Blockage or silencing EGFR prevented Nrf2 activation by AS-IV, thus inhibiting AS-IV-mediated anti-oxidant and neuroprotective activities against OGD/R. In summary, AS-IV protects cortical neurons against OGD/R damages through activating of EGFR-Nrf2 signaling. PMID:25582778

  15. Maintaining Gait Performance by Cortical Activation during Dual-Task Interference: A Functional Near-Infrared Spectroscopy Study

    PubMed Central

    Yang, Yea-Ru; Wu, Yu-Te; Wang, Ray-Yau

    2015-01-01

    In daily life, mobility requires walking while performing a cognitive or upper-extremity motor task. Although previous studies have evaluated the effects of dual tasks on gait performance, few studies have evaluated cortical activation and its association with gait disturbance during dual tasks. In this study, we simultaneously assessed gait performance and cerebral oxygenation in the bilateral prefrontal cortices (PFC), premotor cortices (PMC), and supplemental motor areas (SMA), using functional near-infrared spectroscopy, in 17 young adults performing dual tasks. Each participant was evaluated while performing normal-pace walking (NW), walking while performing a cognitive task (WCT), and walking while performing a motor task (WMT). Our results indicated that the left PFC exhibited the strongest and most sustained activation during WCT, and that NW and WMT were associated with minor increases in oxygenation levels during their initial phases. We observed increased activation in channels in the SMA and PMC during WCT and WMT. Gait data indicated that WCT and WMT both caused reductions in walking speed, but these reductions resulted from differing alterations in gait properties. WCT was associated with significant changes in cadence, stride time, and stride length, whereas WMT was associated with reductions in stride length only. During dual-task activities, increased activation of the PMC and SMA correlated with declines in gait performance, indicating a control mechanism for maintaining gait performance during dual tasks. Thus, the regulatory effects of cortical activation on gait behavior enable a second task to be performed while walking. PMID:26079605

  16. Disease activity and severity in early inflammatory arthritis predict hand cortical bone loss

    PubMed Central

    Pye, Stephen R.; Adams, Judith E.; Ward, Kate A.; Bunn, Diane K.; Symmons, Deborah P. M.

    2010-01-01

    Objectives. To determine the influence of disease-related variables on hand cortical bone loss in women with early inflammatory arthritis (IA), and whether hand cortical bone mass predicts subsequent joint damage. Method. Adults aged ≥16 years with recent onset of IA were recruited to the Norfolk Arthritis Register between 1990 and 1998, and followed prospectively. At baseline, patients had their joints examined for swelling and tenderness and had CRP and disease activity 28-joint assessment score (DAS-28) measured. Radiographs of the hands were performed in a subgroup of patients at Year 1 and at follow-up, which were assessed using digital X-ray radiogrammetry (DXR). They were also evaluated for the presence of erosions using Larsen’s method. Linear mixed models were used to investigate whether disease-related factors predicted change in DXR–areal bone mineral density (BMDa). We also evaluated whether DXR–BMDa predicted the subsequent occurrence of erosive disease. Results. Two hundred and four women, mean (s.d.) age 55.1 (14.0) years, were included. Median follow-up between radiographs was 4 years. The mean within-subject change in BMDa was 0.024 g/cm2 equivalent to 1% decline per year. After adjustment for age, height and weight, compared with those within the lower tertile for CRP, those in the upper tertile had greater subsequent loss of bone. This was true also for DAS-28 and Larsen score. Among those without erosions on the initial radiograph (121), DXR–BMDa at baseline did not predict the new occurrence of erosions. Conclusion. Increased disease activity and severity are associated with accelerated bone loss. However, lower BMDa did not predict the new occurrence of erosive disease. PMID:20573690

  17. Localizing evoked cortical activity associated with balance reactions: does the anterior cingulate play a role?

    PubMed

    Marlin, Amanda; Mochizuki, George; Staines, William R; McIlroy, William E

    2014-06-15

    The ability to correct balance disturbances is essential for the maintenance of upright stability. Although information about how the central nervous system controls balance reactions in humans remains limited, recent literature highlights a potentially important role for the cerebral cortex. The objective of this study was to determine the neural source of the well-reported balance-evoked N1 response. It was hypothesized that the N1 is associated with an "error-detection" event in response to the induced perturbation and therefore may be associated with activity within the anterior cingulate cortex (ACC). The localized source of the N1 evoked by perturbations to standing balance was compared, within each participant, to the location of an error-related negativity (ERN) known to occur within the ACC while performing a flanker task. In contrast to the main hypotheses, the results revealed that the location of the N1 was not within the ACC. The mean Talairach coordinates for the ERN were (6.47, -4.41, 41.17) mm, corresponding to the cingulate gyrus [Brodmann area (BA) 24], as expected. However, coordinates for the N1 dipole were (5.74, -11.81, 53.73) mm, corresponding to the medial frontal gyrus (BA 6), specifically the supplementary motor area. This may suggest the N1 is linked to the planning and execution of elements of the evoked balance reactions rather than being associated with error or event detection. Alternatively, it is possible that the N1 is associated with variation in the cortical representation due to task-specific differences in the activation of a distributed network of error-related processing. Subsequent work should focus on disentangling these two possible explanations as they relate to the cortical processing linked to reactive balance control.

  18. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation—A Computational Study

    NASA Astrophysics Data System (ADS)

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-06-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort.

  19. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation-A Computational Study.

    PubMed

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-01-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort. PMID:27273817

  20. Effect of Anatomically Realistic Full-Head Model on Activation of Cortical Neurons in Subdural Cortical Stimulation—A Computational Study

    PubMed Central

    Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan

    2016-01-01

    Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort. PMID:27273817

  1. Influence of motor imagination on cortical activation during functional electrical stimulation

    PubMed Central

    Reynolds, Clare; Osuagwu, Bethel A.; Vuckovic, Aleksandra

    2015-01-01

    Objective Motor imagination (MI) and functional electrical stimulation (FES) can activate the sensory-motor cortex through efferent and afferent pathways respectively. Motor imagination can be used as a control strategy to activate FES through a brain–computer interface as the part of a rehabilitation therapy. It is believed that precise timing between the onset of MI and FES is important for strengthening the cortico-spinal pathways but it is not known whether prolonged MI during FES influences cortical response. Methods Electroencephalogram was measured in ten able-bodied participants using MI strategy to control FES through a BCI system. Event related synchronisation/desynchronisation (ERS/ERD) over the sensory-motor cortex was analysed and compared in three paradigms: MI before FES, MI before and during FES and FES alone activated automatically. Results MI practiced both before and during FES produced strongest ERD. When MI only preceded FES it resulted in a weaker beta ERD during FES than when FES was activated automatically. Following termination of FES, beta ERD returns to the baseline level within 0.5 s while alpha ERD took longer than 1 s. Conclusions When MI and FES are combined for rehabilitation purposes it is recommended that MI is practiced throughout FES activation period. Significance The study is relevant for neurorehabilitation of movement. PMID:25454278

  2. Spectroscopic measurement of cortical nitric oxide release induced by ascending activation.

    PubMed

    Espinosa, N; Cudeiro, J; Mariño, J

    2015-01-29

    The transition from sleep to the awake state is regulated by the activation of subcortical nuclei of the brainstem (BS) and basal forebrain (BF), releasing acetylcholine and glutamate throughout the cortex and inducing a tonic state of neural activity. It has been suggested that such activation is also mediated by the massive and diffuse cortical release of nitric oxide (NO). In this work we have combined the spectroscopic measurement of NO levels in the somatosensory cortex of the cat through its marker methemoglobin, as well as two other hemodynamic markers (oxyhemoglobin--oxyHb--and deoxyhemoglobin--deoxyHb), together with the electrical stimulation of BS and BF--to induce an experimental transition from a sleep-like state to an awake-like mode. The results show an increase of NO levels either after BS or BF activation. The response induced by BS stimulation was biphasic in the three studied markers, and lasted for up to 30s. The changes induced by BF were monophasic lasting for up to 20s. The systemic blockade of NO production abolished the observed responses to BS whereas responses to BF stimulation were much less affected. These results indicate a crucial role for NO in the neuronal activation induced by the ascending systems. PMID:25463513

  3. Gender specific changes in cortical activation patterns during exposure to artificial gravity

    NASA Astrophysics Data System (ADS)

    Schneider, Stefan; Robinson, Ryan; Smith, Craig; von der Wiesche, Melanie; Goswami, Nandu

    2014-11-01

    Keeping astronauts healthy during long duration spaceflight remains a challenge. Artificial gravity (AG) generated by a short arm human centrifuges (SAHC) is proposed as the next generation of integrated countermeasure devices that will allow human beings to safely spend extended durations in space, although comparatively little is known about any psychological side effects of AG on brain function. 16 participants (8 male and 8 female, GENDER) were exposed to 10 min at a baseline gravitational load (G-Load) of +.03 Gz, then 10 min at +.6 Gz for females and +.8 Gz for males, before being exposed to increasing levels of AG in a stepped manner by increasing the acceleration by +.1 Gz every 3 min until showing signs of pre-syncope. EEG recordings were taken of brain activity during 2 min time periods at each AG level. Analysing the results of the mixed total population of participants by two way ANOVA, a significant effect of centrifugation on alpha and beta activity was found (p<.01). Furthermore results revealed a significant interaction between G-LOAD and GENDER alpha-activity (p<.01), but not for beta-activity. Although the increase in alpha and beta activity with G-LOAD does not reflect a general model of cortical arousal and therefore cannot support previous findings reporting that AG may be a cognitively arousing environment, the gender specific responses identified in this study may have wider implications for EEG and AG research.

  4. The Cell-Type Specific Cortical Microcircuit: Relating Structure and Activity in a Full-Scale Spiking Network Model

    PubMed Central

    Potjans, Tobias C.; Diesmann, Markus

    2014-01-01

    In the past decade, the cell-type specific connectivity and activity of local cortical networks have been characterized experimentally to some detail. In parallel, modeling has been established as a tool to relate network structure to activity dynamics. While available comprehensive connectivity maps ( Thomson, West, et al. 2002; Binzegger et al. 2004) have been used in various computational studies, prominent features of the simulated activity such as the spontaneous firing rates do not match the experimental findings. Here, we analyze the properties of these maps to compile an integrated connectivity map, which additionally incorporates insights on the specific selection of target types. Based on this integrated map, we build a full-scale spiking network model of the local cortical microcircuit. The simulated spontaneous activity is asynchronous irregular and cell-type specific firing rates are in agreement with in vivo recordings in awake animals, including the low rate of layer 2/3 excitatory cells. The interplay of excitation and inhibition captures the flow of activity through cortical layers after transient thalamic stimulation. In conclusion, the integration of a large body of the available connectivity data enables us to expose the dynamical consequences of the cortical microcircuitry. PMID:23203991

  5. Nanomolar Bifenthrin Alters Synchronous Ca2+ Oscillations and Cortical Neuron Development Independent of Sodium Channel Activity

    PubMed Central

    Cao, Zhengyu; Cui, Yanjun; Nguyen, Hai M.; Jenkins, David Paul; Wulff, Heike

    2014-01-01

    Bifenthrin, a relatively stable type I pyrethroid that causes tremors and impairs motor activity in rodents, is broadly used. We investigated whether nanomolar bifenthrin alters synchronous Ca2+ oscillations (SCOs) necessary for activity-dependent dendritic development. Primary mouse cortical neurons were cultured 8 or 9 days in vitro (DIV), loaded with the Ca2+ indicator Fluo-4, and imaged using a Fluorescence Imaging Plate Reader Tetra. Acute exposure to bifenthrin rapidly increased the frequency of SCOs by 2.7-fold (EC50 = 58 nM) and decreased SCO amplitude by 36%. Changes in SCO properties were independent of modifications in voltage-gated sodium channels since 100 nM bifenthrin had no effect on the whole-cell Na+ current, nor did it influence neuronal resting membrane potential. The L-type Ca2+ channel blocker nifedipine failed to ameliorate bifenthrin-triggered SCO activity. By contrast, the metabotropic glutamate receptor (mGluR)5 antagonist MPEP [2-methyl-6-(phenylethynyl)pyridine] normalized bifenthrin-triggered increase in SCO frequency without altering baseline SCO activity, indicating that bifenthrin amplifies mGluR5 signaling independent of Na+ channel modification. Competitive [AP-5; (−)-2-amino-5-phosphonopentanoic acid] and noncompetitive (dizocilpine, or MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate]) N-methyl-d-aspartate antagonists partially decreased both basal and bifenthrin-triggered SCO frequency increase. Bifenthrin-modified SCO rapidly enhanced the phosphorylation of cAMP response element–binding protein (CREB). Subacute (48 hours) exposure to bifenthrin commencing 2 DIV–enhanced neurite outgrowth and persistently increased SCO frequency and reduced SCO amplitude. Bifenthrin-stimulated neurite outgrowth and CREB phosphorylation were dependent on mGluR5 activity since MPEP normalized both responses. Collectively these data identify a new mechanism by which bifenthrin potently alters Ca2

  6. Dampened neural activity and abolition of epileptic-like activity in cortical slices by active ingredients of spices.

    PubMed

    Pezzoli, Maurizio; Elhamdani, Abdeladim; Camacho, Susana; Meystre, Julie; González, Stephanie Michlig; le Coutre, Johannes; Markram, Henry

    2014-10-31

    Active ingredients of spices (AIS) modulate neural response in the peripheral nervous system, mainly through interaction with TRP channel/receptors. The present study explores how different AIS modulate neural response in layer 5 pyramidal neurons of S1 neocortex. The AIS tested are agonists of TRPV1/3, TRPM8 or TRPA1. Our results demonstrate that capsaicin, eugenol, menthol, icilin and cinnamaldehyde, but not AITC dampen the generation of APs in a voltage- and time-dependent manner. This effect was further tested for the TRPM8 ligands in the presence of a TRPM8 blocker (BCTC) and on TRPM8 KO mice. The observable effect was still present. Finally, the influence of the selected AIS was tested on in vitro gabazine-induced seizures. Results coincide with the above observations: except for cinnamaldehyde, the same AIS were able to reduce the number, duration of the AP bursts and increase the concentration of gabazine needed to elicit them. In conclusion, our data suggests that some of these AIS can modulate glutamatergic neurons in the brain through a TRP-independent pathway, regardless of whether the neurons are stimulated intracellularly or by hyperactive microcircuitry.

  7. A topological study of repetitive co-activation networks in in vitro cortical assemblies.

    PubMed

    Pirino, Virginia; Riccomagno, Eva; Martinoia, Sergio; Massobrio, Paolo

    2015-02-01

    To address the issue of extracting useful information from large data-set of large scale networks of neurons, we propose an algorithm that involves both algebraic-statistical and topological tools. We investigate the electrical behavior of in vitro cortical assemblies both during spontaneous and stimulus-evoked activity coupled to Micro-Electrode Arrays (MEAs). Our goal is to identify core sub-networks of repetitive and synchronous patterns of activity and to characterize them. The analysis is performed at different resolution levels using a clustering algorithm that reduces the network dimensionality. To better visualize the results, we provide a graphical representation of the detected sub-networks and characterize them with a topological invariant, i.e. the sequence of Betti numbers computed on the associated simplicial complexes. The results show that the extracted sub-populations of neurons have a more heterogeneous firing rate with respect to the entire network. Furthermore, the comparison of spontaneous and stimulus-evoked behavior reveals similarities in the identified clusters of neurons, indicating that in both conditions similar activation patterns drive the global network activity. PMID:25559130

  8. Sequential evolution of cortical activity and effective connectivity of swallowing using fMRI.

    PubMed

    Mihai, Paul Glad; Otto, Mareile; Platz, Thomas; Eickhoff, Simon B; Lotze, Martin

    2014-12-01

    Swallowing consists of a hierarchical sequence of primary motor and somatosensory processes. The temporal interplay of different phases is complex and clinical disturbances frequent. Of interest was the temporal interaction of the swallowing network. Time resolution optimized functional magnetic resonance imaging was used to describe the temporal sequence of representation sites of swallowing and their functional connectivity. Sixteen young healthy volunteers were investigated who swallowed 2 ml of water 20 times per run with a repetition time for functional imaging of 514 ms. After applying the general linear model approach to identify activation magnitude in preselected regions of interest repeated measures analysis of variance (rmANOVA) was used to detect relevant effects on lateralization, time, and onset. Furthermore, dynamic causal modeling (DCM) was applied to uncover where the input enters the model and the way in which the cortical regions are connected. The temporal analysis revealed a successive activation starting at the premotor cortex, supplementary motor area (SMA), and bilateral thalamus, followed by the primary sensorimotor cortex, the posterior insula, and cerebellum and culminating with activation in the pons shortly before subsiding. The rmANOVA revealed that activation was lateralized initially to the left hemisphere and gradually moved to the right hemisphere over time. The group random effects DCM analysis resulted in a most likely model that consisted of inputs to SMA and M1S1, bidirectionally connected, and a one-way connection from M1S1 to the posterior insula.

  9. Mapping of cortical activity in the first two decades of life: a high-density sleep electroencephalogram study.

    PubMed

    Kurth, Salomé; Ringli, Maya; Geiger, Anja; LeBourgeois, Monique; Jenni, Oskar G; Huber, Reto

    2010-10-01

    Evidence that electroencephalography (EEG) slow-wave activity (SWA) (EEG spectral power in the 1-4.5 Hz band) during non-rapid eye movement sleep (NREM) reflects plastic changes is increasing (Tononi and Cirelli, 2006). Regional assessment of gray matter development from neuroimaging studies reveals a posteroanterior trajectory of cortical maturation in the first three decades of life (Shaw et al., 2008). Our aim was to test whether this regional cortical maturation is reflected in regional changes of sleep SWA. We evaluated all-night high-density EEG (128 channels) in 55 healthy human subjects (2.4-19.4 years) and assessed age-related changes in NREM sleep topography. As in adults, we observed frequency-specific topographical distributions of sleep EEG power in all subjects. However, from early childhood to late adolescence, the location on the scalp showing maximal SWA underwent a shift from posterior to anterior regions. This shift along the posteroanterior axis was only present in the SWA frequency range and remained stable across the night. Changes in the topography of SWA during sleep parallel neuroimaging study findings indicating cortical maturation starts early in posterior areas and spreads rostrally over the frontal cortex. Thus, SWA might reflect the underlying processes of cortical maturation. In the future, sleep SWA assessments may be used as a clinical tool to detect aberrations in cortical maturation.

  10. Complementary Functional Organization of Neuronal Activity Patterns in the Perirhinal, Lateral Entorhinal, and Medial Entorhinal Cortices

    PubMed Central

    Keene, Christopher S.; Bladon, John; McKenzie, Sam; Liu, Cindy D.; O'Keefe, Joseph

    2016-01-01

    It is commonly conceived that the cortical areas of the hippocampal region are functionally divided into the perirhinal cortex (PRC) and the lateral entorhinal cortex (LEC), which selectively process object information; and the medial entorhinal cortex (MEC), which selectively processes spatial information. Contrary to this notion, in rats performing a task that demands both object and spatial information processing, single neurons in PRC, LEC, and MEC, including those in both superficial and deep cortical areas and in grid, border, and head direction cells of MEC, have a highly similar range of selectivity to object and spatial dimensions of the task. By contrast, representational similarity analysis of population activity reveals a key distinction in the organization of information in these areas, such that PRC and LEC populations prioritize object over location information, whereas MEC populations prioritize location over object information. These findings bring to the hippocampal system a growing emphasis on population analyses as a powerful tool for characterizing neural representations supporting cognition and memory. SIGNIFICANCE STATEMENT Contrary to the common view that brain regions in the “what” and “where” streams distinctly process object and spatial cues, respectively, we found that both streams encode both object and spatial information but distinctly organize memories for objects and space. Specifically, perirhinal cortex and lateral entorhinal cortex represent objects and, within the object-specific representations, the locations where they occur. Conversely, medial entorhinal cortex represents relevant locations and, within those spatial representations, the objects that occupy them. Furthermore, these findings reach beyond simple notions of perirhinal cortex and lateral entorhinal cortex neurons as object detectors and MEC neurons as position detectors, and point to a more complex organization of memory representations within the medial

  11. Calcium-mediated release of glucanase activity from cortical granules of sea urchin eggs.

    PubMed

    Moy, G W; Kopf, G S; Gache, C; Vacquier, V D

    1983-12-01

    Confluent monolayers of sea urchin eggs were bonded to culture dishes coated with protamine sulfate. The cytoplasm was then sheared away by a jet of isosmotic buffer. About 326,000 circular fragments of individual egg cortices (430 micrograms protein) remained bound to each dish. The fragments are composed of cortical granules (CG), plasma membrane, and vitelline layer. A single dish contains 7.7 X 10(8) CG and is referred to as a CG lawn (CGL). Ca2+-EGTA buffers of estimated free-Ca2+ concentrations (0.06-25.7 microM) were applied to CGL and samples removed and assayed for the CG marker enzyme exo-beta (1 leads to 3)-glucanohydrolase (glucanase). Estimated free-Ca2+ concentrations above 2.75 microM caused the total release of the glucanase to the supernatant within 4 min. The half-maximal rate of appearance of glucanase occurred in 2.5 microM Ca2+. At all Ca2+ concentrations tested, the appearance of enzyme activity exhibited sigmoidal kinetics. The visual disappearance of CG correlated with the appearance of glucanase in the Ca2+ buffer. In response to Ca2+ the CG probably lyse, fuse with adjacent CG, or fuse with the underlying plasma membrane. The calmodulin antagonist trifluoperazine inhibited Ca2+-mediated glucanase release from CGL (I50 8 microM). The sensitivity of the CGL to Ca2+ in the 1-10 microM range is rapidly lost during incubation of CGL in the isolation buffer. ATP and low temperature retard the rate of loss of Ca2+ sensitivity. These secretory granules are a model for studying the mechanism of Ca2+-induced secretion. In addition, they contain structural proteins and enzymes which function in the fertilization process. CGL preparations should be useful in studies dealing with the processing of CG components after their release in response to micromolar concentrations of Ca2+.

  12. Objective Phonological and Subjective Perceptual Characteristics of Syllables Modulate Spatiotemporal Patterns of Superior Temporal Gyrus Activity

    PubMed Central

    Frye, Richard E.; Fisher, Janet McGraw; Witzel, Thomas; Ahlfors, Seppo P.; Swank, Paul; Liederman, Jacqueline; Halgren, Eric

    2008-01-01

    Natural consonant vowel syllables are reliably classified by most listeners as voiced or voiceless. However, our previous research (Liederman et al., 2005) suggests that among synthetic stimuli varying systematically in voice onset time (VOT), syllables that are classified reliably as voiceless are nonetheless perceived differently within and between listeners. This perceptual ambiguity was measured by variation in the accuracy of matching two identical stimuli presented in rapid succession. In the current experiment, we used magnetoencephalography (MEG) to examine the differential contribution of objective (i.e., VOT) and subjective (i.e., perceptual ambiguity) acoustic features on speech processing. Distributed source models estimated cortical activation within two regions of interest in the superior temporal gyrus (STG) and one in the inferior frontal gyrus. These regions were differentially modulated by VOT and perceptual ambiguity. Ambiguity strongly influenced lateralization of activation; however, the influence on lateralization was different in the anterior and middle/posterior portions of the STG. The influence of ambiguity on the relative amplitude of activity in the right and left anterior STG activity depended on VOT, whereas that of middle/posterior portions of the STG did not. These data support the idea that early cortical responses are bilaterally distributed whereas late processes are lateralized to the dominant hemisphere and support a “how/what” dual-stream auditory model. This study helps to clarify the role of the anterior STG, especially in the right hemisphere, in syllable perception. Moreover, our results demonstrate that both objective phonological and subjective perceptual characteristics of syllables independently modulate spatiotemporal patterns of cortical activation. PMID:18356082

  13. Time in Cortical Circuits

    PubMed Central

    Shadlen, Michael N.; Jazayeri, Mehrdad; Nobre, Anna C.; Buonomano, Dean V.

    2015-01-01

    Time is central to cognition. However, the neural basis for time-dependent cognition remains poorly understood. We explore how the temporal features of neural activity in cortical circuits and their capacity for plasticity can contribute to time-dependent cognition over short time scales. This neural activity is linked to cognition that operates in the present or anticipates events or stimuli in the near future. We focus on deliberation and planning in the context of decision making as a cognitive process that integrates information across time. We progress to consider how temporal expectations of the future modulate perception. We propose that understanding the neural basis for how the brain tells time and operates in time will be necessary to develop general models of cognition. SIGNIFICANCE STATEMENT Time is central to cognition. However, the neural basis for time-dependent cognition remains poorly understood. We explore how the temporal features of neural activity in cortical circuits and their capacity for plasticity can contribute to time-dependent cognition over short time scales. We propose that understanding the neural basis for how the brain tells time and operates in time will be necessary to develop general models of cognition. PMID:26468192

  14. Cortical Activation Patterns during Long-Term Memory Retrieval of Visually or Haptically Encoded Objects and Locations

    ERIC Educational Resources Information Center

    Stock, Oliver; Roder, Brigitte; Burke, Michael; Bien, Siegfried; Rosler, Frank

    2009-01-01

    The present study used functional magnetic resonance imaging to delineate cortical networks that are activated when objects or spatial locations encoded either visually (visual encoding group, n = 10) or haptically (haptic encoding group, n = 10) had to be retrieved from long-term memory. Participants learned associations between auditorily…

  15. Achievement, Underachievement and Cortical Activation: A Comparative EEG Study of Adolescents of Average and Above-Average Intelligence

    ERIC Educational Resources Information Center

    Staudt, Beate; Neubauer, Aljoscha C.

    2006-01-01

    In this study the "neural efficiency" phenomenon (more efficient brain function in brighter as compared to less intelligent individuals) was investigated regarding differences in intelligence (average vs. above-average intelligence) and scholastic achievement (achievers vs. underachievers). The cortical activation (assessed by event-related…

  16. Cortical Regions Recruited for Complex Active-Learning Strategies and Action Planning Exhibit Rapid Reactivation during Memory Retrieval

    ERIC Educational Resources Information Center

    Voss, Joel L.; Galvan, Ashley; Gonsalves, Brian D.

    2011-01-01

    Memory retrieval can involve activity in the same sensory cortical regions involved in perception of the original event, and this neural "reactivation" has been suggested as an important mechanism of memory retrieval. However, it is still unclear if fragments of experience other than sensory information are retained and later reactivated during…

  17. The relationship between brain cortical activity and brain oxygenation in the prefrontal cortex during hypergravity exposure.

    PubMed

    Smith, Craig; Goswami, Nandu; Robinson, Ryan; von der Wiesche, Melanie; Schneider, Stefan

    2013-04-01

    Artificial gravity has been proposed as a method to counteract the physiological deconditioning of long-duration spaceflight; however, the effects of hypergravity on the central nervous system has had little study. The study aims to investigate whether there is a relationship between prefrontal cortex brain activity and prefrontal cortex oxygenation during exposure to hypergravity. Twelve healthy participants were selected to undergo hypergravity exposure aboard a short-arm human centrifuge. Participants were exposed to hypergravity in the +Gz axis, starting from 0.6 +Gz for women, and 0.8 +Gz for men, and gradually increasing by 0.1 +Gz until the participant showed signs of syncope. Brain cortical activity was measured using electroencephalography (EEG) and localized to the prefrontal cortex using standard low-resolution brain electromagnetic tomography (LORETA). Prefrontal cortex oxygenation was measured using near-infrared spectroscopy (NIRS). A significant increase in prefrontal cortex activity (P < 0.05) was observed during hypergravity exposure compared with baseline. Prefrontal cortex oxygenation was significantly decreased during hypergravity exposure, with a decrease in oxyhemoglobin levels (P < 0.05) compared with baseline and an increase in deoxyhemoglobin levels (P < 0.05) with increasing +Gz level. No significant correlation was found between prefrontal cortex activity and oxy-/deoxyhemoglobin. It is concluded that the increase in prefrontal cortex activity observed during hypergravity was most likely not the result of increased +Gz values resulting in a decreased oxygenation produced through hypergravity exposure. No significant relationship between prefrontal cortex activity and oxygenation measured by NIRS concludes that brain activity during exposure to hypergravity may be difficult to measure using NIRS. Instead, the increase in prefrontal cortex activity might be attributable to psychological stress, which could pose a problem for the use of a

  18. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    PubMed

    Muthalib, Makii; Re, Rebecca; Zucchelli, Lucia; Perrey, Stephane; Contini, Davide; Caffini, Matteo; Spinelli, Lorenzo; Kerr, Graham; Quaresima, Valentina; Ferrari, Marco; Torricelli, Alessandro

    2015-01-01

    Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions.

  19. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study.

    PubMed

    Muthalib, Makii; Re, Rebecca; Zucchelli, Lucia; Perrey, Stephane; Contini, Davide; Caffini, Matteo; Spinelli, Lorenzo; Kerr, Graham; Quaresima, Valentina; Ferrari, Marco; Torricelli, Alessandro

    2015-01-01

    Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions. PMID:26158464

  20. Effects of Increasing Neuromuscular Electrical Stimulation Current Intensity on Cortical Sensorimotor Network Activation: A Time Domain fNIRS Study

    PubMed Central

    Zucchelli, Lucia; Perrey, Stephane; Contini, Davide; Caffini, Matteo; Spinelli, Lorenzo; Kerr, Graham; Quaresima, Valentina; Ferrari, Marco; Torricelli, Alessandro

    2015-01-01

    Neuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions. PMID:26158464

  1. Erythropoietin Modulates Cerebral and Serum Degradation Products from Excess Calpain Activation following Prenatal Hypoxia-Ischemia.

    PubMed

    Jantzie, Lauren L; Winer, Jesse L; Corbett, Christopher J; Robinson, Shenandoah

    2016-01-01

    Preterm infants suffer central nervous system (CNS) injury from hypoxia-ischemia and inflammation - termed encephalopathy of prematurity. Mature CNS injury activates caspase and calpain proteases. Erythropoietin (EPO) limits apoptosis mediated by activated caspases, but its role in modulating calpain activation has not yet been investigated extensively following injury to the developing CNS. We hypothesized that excess calpain activation degrades developmentally regulated molecules essential for CNS circuit formation, myelination and axon integrity, including neuronal potassium-chloride co-transporter (KCC2), myelin basic protein (MBP) and phosphorylated neurofilament (pNF), respectively. Further, we predicted that post-injury EPO treatment could mitigate CNS calpain-mediated degradation. Using prenatal transient systemic hypoxia-ischemia (TSHI) in rats to mimic CNS injury from extreme preterm birth, and postnatal EPO treatment with a clinically relevant dosing regimen, we found sustained postnatal excess cortical calpain activation following prenatal TSHI, as shown by the cleavage of alpha II-spectrin (αII-spectrin) into 145-kDa αII-spectrin degradation products (αII-SDPs) and p35 into p25. Postnatal expression of the endogenous calpain inhibitor calpastatin was also reduced following prenatal TSHI. Calpain substrate expression following TSHI, including cortical KCC2, MBP and NF, was modulated by postnatal EPO treatment. Calpain activation was reflected in serum levels of αII-SDPs and KCC2 fragments, and notably, EPO treatment also modulated KCC2 fragment levels. Together, these data indicate that excess calpain activity contributes to the pathogenesis of encephalopathy of prematurity. Serum biomarkers of calpain activation may detect ongoing cerebral injury and responsiveness to EPO or similar neuroprotective strategies. PMID:26551007

  2. Axonal elongation and dendritic branching is enhanced by adenosine A2A receptors activation in cerebral cortical neurons.

    PubMed

    Ribeiro, Filipa F; Neves-Tomé, Raquel; Assaife-Lopes, Natália; Santos, Telma E; Silva, Rui F M; Brites, Dora; Ribeiro, Joaquim A; Sousa, Mónica M; Sebastião, Ana M

    2016-06-01

    Axon growth and dendrite development are key processes for the establishment of a functional neuronal network. Adenosine, which is released by neurons and glia, is a known modulator of synaptic transmission but its influence over neuronal growth has been much less investigated. We now explored the action of adenosine A2A receptors (A2AR) upon neurite outgrowth, discriminating actions over the axon or dendrites, and the mechanisms involved. Morphometric analysis of primary cultures of cortical neurons from E18 Sprague-Dawley rats demonstrated that an A2AR agonist, CGS 21680, enhances axonal elongation and dendritic branching, being the former prevented by inhibitors of phosphoinositide 3-kinase, mitogen-activated protein kinase and phospholipase C, but not of protein kinase A. By testing the influence of a scavenger of BDNF (brain-derived neurotrophic factor) over the action of the A2AR agonist and the action of a selective A2AR antagonist over the action of BDNF, we could conclude that while the action of A2ARs upon dendritic branching is dependent on the presence of endogenous BDNF, the influence of A2ARs upon axonal elongation is independent of endogenous BDNF. In consonance with the action over axonal elongation, A2AR activation promoted a decrease in microtubule stability and an increase in microtubule growth speed in axonal growth cones. In conclusion, we disclose a facilitatory action of A2ARs upon axonal elongation and microtubule dynamics, providing new insights for A2ARs regulation of neuronal differentiation and axonal regeneration.

  3. Positive affect modulates activity in the visual cortex to images of high calorie foods.

    PubMed

    Killgore, William D S; Yurgelun-Todd, Deborah A

    2007-05-01

    Activity within the visual cortex can be influenced by the emotional salience of a stimulus, but it is not clear whether such cortical activity is modulated by the affective status of the individual. This study used functional magnetic resonance imaging (fMRI) to examine the relationship between affect ratings on the Positive and Negative Affect Schedule and activity within the occipital cortex of 13 normal-weight women while viewing images of high calorie and low calorie foods. Regression analyses revealed that when participants viewed high calorie foods, Positive Affect correlated significantly with activity within the lingual gyrus and calcarine cortex, whereas Negative Affect was unrelated to visual cortex activity. In contrast, during presentations of low calorie foods, affect ratings, regardless of valence, were unrelated to occipital cortex activity. These findings suggest a mechanism whereby positive affective state may affect the early stages of sensory processing, possibly influencing subsequent perceptual experience of a stimulus. PMID:17464782

  4. Social touch modulates endogenous μ-opioid system activity in humans.

    PubMed

    Nummenmaa, Lauri; Tuominen, Lauri; Dunbar, Robin; Hirvonen, Jussi; Manninen, Sandra; Arponen, Eveliina; Machin, Anna; Hari, Riitta; Jääskeläinen, Iiro P; Sams, Mikko

    2016-09-01

    In non-human primates, opioid-receptor blockade increases social grooming, and the endogenous opioid system has therefore been hypothesized to support maintenance of long-term relationships in humans as well. Here we tested whether social touch modulates opioidergic activation in humans using in vivo positron emission tomography (PET). Eighteen male participants underwent two PET scans with [11C]carfentanil, a ligand specific to μ-opioid receptors (MOR). During the social touch scan, the participants lay in the scanner while their partners caressed their bodies in a non-sexual fashion. In the baseline scan, participants lay alone in the scanner. Social touch triggered pleasurable sensations and increased MOR availability in the thalamus, striatum, and frontal, cingulate, and insular cortices. Modulation of activity of the opioid system by social touching might provide a neurochemical mechanism reinforcing social bonds between humans.

  5. A biased activation theory of the cognitive and attentional modulation of emotion.

    PubMed

    Rolls, Edmund T

    2013-01-01

    Cognition can influence emotion by biasing neural activity in the first cortical region in which the reward value and subjective pleasantness of stimuli is made explicit in the representation, the orbitofrontal cortex (OFC). The same effect occurs in a second cortical tier for emotion, the anterior cingulate cortex (ACC). Similar effects are found for selective attention, to for example the pleasantness vs. the intensity of stimuli, which modulates representations of reward value and affect in the orbitofrontal and anterior cingulate cortices. The mechanisms for the effects of cognition and attention on emotion are top-down biased competition and top-down biased activation. Affective and mood states can in turn influence memory and perception, by backprojected biasing influences. Emotion-related decision systems operate to choose between gene-specified rewards such as taste, touch, and beauty. Reasoning processes capable of planning ahead with multiple steps held in working memory in the explicit system can allow the gene-specified rewards not to be selected, or to be deferred. The stochastic, noisy, dynamics of decision-making systems in the brain may influence whether decisions are made by the selfish-gene-specified reward emotion system, or by the cognitive reasoning system that explicitly calculates reward values that are in the interests of the individual, the phenotype.

  6. Activation of Aurora-A is essential for neuronal migration via modulation of microtubule organization.

    PubMed

    Takitoh, Takako; Kumamoto, Kanako; Wang, Chen-Chi; Sato, Makoto; Toba, Shiori; Wynshaw-Boris, Anthony; Hirotsune, Shinji

    2012-08-01

    Neuronal migration is a critical feature to ensure proper location and wiring of neurons during cortical development. Postmitotic neurons migrate from the ventricular zone into the cortical plate to establish neuronal lamina in an "inside-out" gradient of maturation. Here, we report that the mitotic kinase Aurora-A is critical for the regulation of microtubule organization during neuronal migration via an Aurora-A-NDEL1 pathway in the mouse. Suppression of Aurora-A activity by inhibitors or siRNA resulted in severe impairment of neuronal migration of granular neurons. In addition, in utero injection of the Aurora-A kinase-dead mutant provoked defective migration of cortical neurons. Furthermore, we demonstrated that suppression of Aurora-A impaired microtubule modulation in migrating neurons. Interestingly, suppression of CDK5 by an inhibitor or siRNA reduced Aurora-A activity and NDEL1 phosphorylation by Aurora-A, which led to defective neuronal migration. We found that CDK5RAP2 is a key molecule that mediates functional interaction and is essential for centrosomal targeting of Aurora-A. Our observations demonstrated novel and surprising cross talk between Aurora-A and CDK5 during neuronal migration. PMID:22875938

  7. It’s All in the Eyes: Subcortical and Cortical Activation during Grotesqueness Perception in Autism

    PubMed Central

    Zürcher, Nicole R.; Donnelly, Nick; Rogier, Ophélie; Russo, Britt; Hippolyte, Loyse; Hadwin, Julie; Lemonnier, Eric; Hadjikhani, Nouchine

    2013-01-01

    Atypical face processing plays a key role in social interaction difficulties encountered by individuals with autism. In the current fMRI study, the Thatcher illusion was used to investigate several aspects of face processing in 20 young adults with high-functioning autism spectrum disorder (ASD) and 20 matched neurotypical controls. “Thatcherized” stimuli were modified at either the eyes or the mouth and participants discriminated between pairs of faces while cued to attend to either of these features in upright and inverted orientation. Behavioral data confirmed sensitivity to the illusion and intact configural processing in ASD. Directing attention towards the eyes vs. the mouth in upright faces in ASD led to (1) improved discrimination accuracy; (2) increased activation in areas involved in social and emotional processing; (3) increased activation in subcortical face-processing areas. Our findings show that when explicitly cued to attend to the eyes, activation of cortical areas involved in face processing, including its social and emotional aspects, can be enhanced in autism. This suggests that impairments in face processing in autism may be caused by a deficit in social attention, and that giving specific cues to attend to the eye-region when performing behavioral therapies aimed at improving social skills may result in a better outcome. PMID:23342130

  8. Dissociated wake-like and sleep-like electro-cortical activity during sleep.

    PubMed

    Nobili, Lino; Ferrara, Michele; Moroni, Fabio; De Gennaro, Luigi; Russo, Giorgio Lo; Campus, Claudio; Cardinale, Francesco; De Carli, Fabrizio

    2011-09-15

    Sleep is traditionally considered a global process involving the whole brain. However, recent studies have shown that sleep depth is not evenly distributed within the brain. Sleep disorders, such as sleepwalking, also suggest that EEG features of sleep and wakefulness might be simultaneously present in different cerebral regions. In order to probe the coexistence of dissociated (wake-like and sleep-like) electrophysiological behaviors within the sleeping brain, we analyzed intracerebral electroencephalographic activity drawn from sleep recordings of five patients with pharmacoresistant focal epilepsy without sleep disturbances, who underwent pre-surgical intracerebral electroencephalographic investigation. We applied spectral and wavelet transform analysis techniques to electroencephalographic data recorded from scalp and intracerebral electrodes localized within the Motor cortex (Mc) and the dorso-lateral Prefrontal cortex (dlPFc). The Mc showed frequent Local Activations (lasting from 5 to more than 60s) characterized by an abrupt interruption of the sleep electroencephalographic slow waves pattern and by the appearance of a wake-like electroencephalographic high frequency pattern (alpha and/or beta rhythm). Local activations in the Mc were paralleled by a deepening of sleep in other regions, as expressed by the concomitant increase of slow waves in the dlPFc and scalp electroencephalographic recordings. These results suggest that human sleep can be characterized by the coexistence of wake-like and sleep-like electroencephalographic patterns in different cortical areas, supporting the hypothesis that unusual phenomena, such as NREM parasomnias, could result from an imbalance of these two states. PMID:21718789

  9. It's all in the eyes: subcortical and cortical activation during grotesqueness perception in autism.

    PubMed

    Zürcher, Nicole R; Donnelly, Nick; Rogier, Ophélie; Russo, Britt; Hippolyte, Loyse; Hadwin, Julie; Lemonnier, Eric; Hadjikhani, Nouchine

    2013-01-01

    Atypical face processing plays a key role in social interaction difficulties encountered by individuals with autism. In the current fMRI study, the Thatcher illusion was used to investigate several aspects of face processing in 20 young adults with high-functioning autism spectrum disorder (ASD) and 20 matched neurotypical controls. "Thatcherized" stimuli were modified at either the eyes or the mouth and participants discriminated between pairs of faces while cued to attend to either of these features in upright and inverted orientation. Behavioral data confirmed sensitivity to the illusion and intact configural processing in ASD. Directing attention towards the eyes vs. the mouth in upright faces in ASD led to (1) improved discrimination accuracy; (2) increased activation in areas involved in social and emotional processing; (3) increased activation in subcortical face-processing areas. Our findings show that when explicitly cued to attend to the eyes, activation of cortical areas involved in face processing, including its social and emotional aspects, can be enhanced in autism. This suggests that impairments in face processing in autism may be caused by a deficit in social attention, and that giving specific cues to attend to the eye-region when performing behavioral therapies aimed at improving social skills may result in a better outcome.

  10. Regulation of Extrasynaptic GABAA α4 Receptors by Ethanol-Induced Protein Kinase A, but Not Protein Kinase C Activation in Cultured Rat Cerebral Cortical Neurons.

    PubMed

    Carlson, Stephen L; Bohnsack, J Peyton; Patel, Vraj; Morrow, A Leslie

    2016-01-01

    Ethanol produces changes in GABAA receptor trafficking and function that contribute to ethanol dependence symptomatology. Extrasynaptic γ-aminobutyric acid A receptors (GABAA-R) mediate inhibitory tonic current and are of particular interest because they are potentiated by physiologically relevant doses of ethanol. Here, we isolate GABAA α4δ receptors by western blotting in subsynaptic fractions to investigate protein kinase A (PKA) and protein kinase C (PKC) modulation of ethanol-induced receptor trafficking, while extrasynaptic receptor function is determined by measurement of tonic inhibition and responses evoked by 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP). Rat cerebral cortical neurons were grown for 18 days in vitro and exposed to ethanol and/or PKA/PKC modulators. Ethanol exposure (1 hour) did not alter GABAA α4 receptor abundance, but it increased tonic current amplitude, an effect that was prevented by inhibiting PKA, but not PKC. Direct activation of PKA, but not PKC, increased the abundance and tonic current of extrasynaptic α4δ receptors. In contrast, prolonged ethanol exposure (4 hours) reduced α4δ receptor abundance as well as tonic current, and this effect was also PKA dependent. Finally, PKC activation by ethanol or phorbol-12,13-dibutyrate (PdBu) had no effect on extrasynaptic α4δ subunit abundance or activity. We conclude that ethanol alters extrasynaptic α4δ receptor function and expression in cortical neurons in a PKA-dependent manner, but ethanol activation of PKC does not influence these receptors. These results could have clinical relevance for therapeutic strategies to restore normal GABAergic functioning for the treatment of alcohol use disorders.

  11. Cortical Control of Affective Networks

    PubMed Central

    Kumar, Sunil; Black, Sherilynn J.; Hultman, Rainbo; Szabo, Steven T.; DeMaio, Kristine D.; Du, Jeanette; Katz, Brittany M.; Feng, Guoping; Covington, Herbert E.; Dzirasa, Kafui

    2013-01-01

    Transcranial magnetic stimulation and deep brain stimulation have emerged as therapeutic modalities for treatment refractory depression; however, little remains known regarding the circuitry that mediates the therapeutic effect of these approaches. Here we show that direct optogenetic stimulation of prefrontal cortex (PFC) descending projection neurons in mice engineered to express Chr2 in layer V pyramidal neurons (Thy1–Chr2 mice) models an antidepressant-like effect in mice subjected to a forced-swim test. Furthermore, we show that this PFC stimulation induces a long-lasting suppression of anxiety-like behavior (but not conditioned social avoidance) in socially stressed Thy1–Chr2 mice: an effect that is observed >10 d after the last stimulation. Finally, we use optogenetic stimulation and multicircuit recording techniques concurrently in Thy1–Chr2 mice to demonstrate that activation of cortical projection neurons entrains neural oscillatory activity and drives synchrony across limbic brain areas that regulate affect. Importantly, these neural oscillatory changes directly correlate with the temporally precise activation and suppression of limbic unit activity. Together, our findings show that the direct activation of cortical projection systems is sufficient to modulate activity across networks underlying affective regulation. They also suggest that optogenetic stimulation of cortical projection systems may serve as a viable therapeutic strategy for treating affective disorders. PMID:23325249

  12. Abnormal activation of the motor cortical network in idiopathic scoliosis demonstrated by functional MRI.

    PubMed

    Domenech, Julio; García-Martí, G; Martí-Bonmatí, L; Barrios, C; Tormos, J M; Pascual-Leone, A

    2011-07-01

    The aetiology of idiopathic scoliosis (IS) remains unknown, but there is growing support for the possibility of an underlying neurological disorder. Functional magnetic resonance imaging (fMRI) can characterize the abnormal activation of the sensorimotor brain network in movement disorders and could provide further insights into the neuropathogenesis of IS. Twenty subjects were included in the study; 10 adolescents with IS (mean age of 15.2, 8 girls and 2 boys) and 10 age-matched healthy controls. The average Cobb angle of the primary curve in the IS patients was 35° (range 27°-55°). All participants underwent a block-design fMRI experiment in a 1.5-Tesla MRI scanner to explore cortical activation following a simple motor task. Rest periods alternated with activation periods during which participants were required to open and close their hand at an internally paced rate of approximately 1 Hz. Data were analyzed with Statistical Parametric Mapping (SPM5) including age, sex and laterality as nuisance variables to minimise the presence of bias in the results. Compared to controls, IS patients showed significant increases in blood oxygenation level dependent (BOLD) activity in contralateral supplementary motor area when performing the motor task with either hand. No significant differences were observed when testing between groups in the functional activation in the primary motor cortex, premotor cortex and somatosensory cortex. Additionally, the IS group showed a greater interhemispheric asymmetry index than the control group (0.30 vs. 0.13, p < 0.001). This study demonstrates an abnormal pattern of brain activation in secondary motor areas during movement execution in patients with IS. These findings support the hypothesis that a sensorimotor integration disorder underlies the pathogenesis of IS.

  13. Dynamics of Elongation Factor 2 Kinase Regulation in Cortical Neurons in Response to Synaptic Activity

    PubMed Central

    Kenney, Justin W.; Sorokina, Oksana; Genheden, Maja; Sorokin, Anatoly

    2015-01-01

    The rapid regulation of cell signaling in response to calcium in neurons is essential for real-time processing of large amounts of information in the brain. A vital regulatory component, and one of the most energy-intensive biochemical processes in cells, is the elongation phase of mRNA translation, which is controlled by the Ca2+/CaM-dependent elongation factor 2 kinase (eEF2K). However, little is known about the dynamics of eEF2K regulation in neurons despite its established role in learning and synaptic plasticity. To explore eEF2K dynamics in depth, we stimulated synaptic activity in mouse primary cortical neurons. We find that synaptic activity results in a rapid, but transient, increase in eEF2K activity that is regulated by a combination of AMPA and NMDA-type glutamate receptors and the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin complex 1 (mTORC1) pathways. We then used computational modeling to test the hypothesis that considering Ca2+-coordinated MEK/ERK, mTORC1, and eEF2k activation is sufficient to describe the observed eEF2K dynamics. Although such a model could partially fit the empirical findings, it also suggested that a crucial positive regulator of eEF2K was also necessary. Through additional modeling and empirical evidence, we demonstrate that AMP kinase (AMPK) is also an important regulator of synaptic activity-driven eEF2K dynamics in neurons. Our combined modeling and experimental findings provide the first evidence that it is necessary to consider the combined interactions of Ca2+ with MEK/ERK, mTORC1, and AMPK to adequately explain eEF2K regulation in neurons. PMID:25698741

  14. Effects of location and timing of co-activated neurons in the auditory midbrain on cortical activity: implications for a new central auditory prosthesis

    NASA Astrophysics Data System (ADS)

    Straka, Małgorzata M.; McMahon, Melissa; Markovitz, Craig D.; Lim, Hubert H.

    2014-08-01

    Objective. An increasing number of deaf individuals are being implanted with central auditory prostheses, but their performance has generally been poorer than for cochlear implant users. The goal of this study is to investigate stimulation strategies for improving hearing performance with a new auditory midbrain implant (AMI). Previous studies have shown that repeated electrical stimulation of a single site in each isofrequency lamina of the central nucleus of the inferior colliculus (ICC) causes strong suppressive effects in elicited responses within the primary auditory cortex (A1). Here we investigate if improved cortical activity can be achieved by co-activating neurons with different timing and locations across an ICC lamina and if this cortical activity varies across A1. Approach. We electrically stimulated two sites at different locations across an isofrequency ICC lamina using varying delays in ketamine-anesthetized guinea pigs. We recorded and analyzed spike activity and local field potentials across different layers and locations of A1. Results. Co-activating two sites within an isofrequency lamina with short inter-pulse intervals (<5 ms) could elicit cortical activity that is enhanced beyond a linear summation of activity elicited by the individual sites. A significantly greater extent of normalized cortical activity was observed for stimulation of the rostral-lateral region of an ICC lamina compared to the caudal-medial region. We did not identify any location trends across A1, but the most cortical enhancement was observed in supragranular layers, suggesting further integration of the stimuli through the cortical layers. Significance. The topographic organization identified by this study provides further evidence for the presence of functional zones across an ICC lamina with locations consistent with those identified by previous studies. Clinically, these results suggest that co-activating different neural populations in the rostral-lateral ICC rather

  15. Cortical activation to object shape and speed of motion during the first year

    PubMed Central

    Wilcox, Teresa; Hawkins, Laura B.; Hirskkowitz, Amy; Boas, David A.

    2014-01-01

    A great deal is known about the functional organization of cortical networks that mediate visual object processing in the adult. The current research is part of a growing effort to identify the functional maturation of these pathways in the developing brain. The current research used near-infrared spectroscopy to investigate functional activation of the infant cortex during the processing of featural information (shape) and spatiotemporal information (speed of motion) during the first year of life. Our investigation focused on two areas that were implicated in previous studies: anterior temporal cortex and posterior parietal cortex. Neuroimaging data were collected with 207 infants across three age groups: 3 to 6 months (Experiment 1), 7 to 8 months (Experiment 2), and 10 to 12 months (Experiments 3 and 4). The neuroimaging data revealed age-related changes in patterns of activation to shape and speed information, mostly involving posterior parietal areas, some of which were predicted and others that were not. We suggest that these changes reflect age-related differences in the perceptual and/or cognitive processes engaged during the task. PMID:24821531

  16. Pairing broadband noise with cortical stimulation induces extensive suppression of ascending sensory activity

    PubMed Central

    Markovitz, Craig D.; Hogan, Patrick S.; Wesen, Kyle A.; Lim, Hubert H.

    2015-01-01

    Objective The corticofugal system can alter coding along the ascending sensory pathway. Within the auditory system, electrical stimulation of the auditory cortex (AC) paired with a pure tone can cause egocentric shifts in the tuning of auditory neurons, making them more sensitive to the pure tone frequency. Since tinnitus has been linked with hyperactivity across auditory neurons, we sought to develop a new neuromodulation approach that could suppress a wide range of neurons rather than enhance specific frequency-tuned neurons. Approach We performed experiments in the guinea pig to assess the effects of cortical stimulation paired with broadband noise (PN-Stim) on ascending auditory activity within the central nucleus of the inferior colliculus (CNIC), a widely studied region for AC stimulation paradigms. Main results All eight stimulated AC regions induced extensive suppression of activity across the CNIC that was not possible with noise stimulation alone. This suppression built up over time and remained after the PN-Stim paradigm. Significance We propose that the corticofugal system is designed to decrease the brain’s input gain to irrelevant stimuli and PN-Stim is able to artificially amplify this effect to suppress neural firing across the auditory system. The PN-Stim concept may have potential for treating tinnitus and other neurological disorders. PMID:25686163

  17. Neural speech recognition: continuous phoneme decoding using spatiotemporal representations of human cortical activity

    NASA Astrophysics Data System (ADS)

    Moses, David A.; Mesgarani, Nima; Leonard, Matthew K.; Chang, Edward F.

    2016-10-01

    Objective. The superior temporal gyrus (STG) and neighboring brain regions play a key role in human language processing. Previous studies have attempted to reconstruct speech information from brain activity in the STG, but few of them incorporate the probabilistic framework and engineering methodology used in modern speech recognition systems. In this work, we describe the initial efforts toward the design of a neural speech recognition (NSR) system that performs continuous phoneme recognition on English stimuli with arbitrary vocabulary sizes using the high gamma band power of local field potentials in the STG and neighboring cortical areas obtained via electrocorticography. Approach. The system implements a Viterbi decoder that incorporates phoneme likelihood estimates from a linear discriminant analysis model and transition probabilities from an n-gram phonemic language model. Grid searches were used in an attempt to determine optimal parameterizations of the feature vectors and Viterbi decoder. Main results. The performance of the system was significantly improved by using spatiotemporal representations of the neural activity (as opposed to purely spatial representations) and by including language modeling and Viterbi decoding in the NSR system. Significance. These results emphasize the importance of modeling the temporal dynamics of neural responses when analyzing their variations with respect to varying stimuli and demonstrate that speech recognition techniques can be successfully leveraged when decoding speech from neural signals. Guided by the results detailed in this work, further development of the NSR system could have applications in the fields of automatic speech recognition and neural prosthetics.

  18. Pairing broadband noise with cortical stimulation induces extensive suppression of ascending sensory activity

    NASA Astrophysics Data System (ADS)

    Markovitz, Craig D.; Hogan, Patrick S.; Wesen, Kyle A.; Lim, Hubert H.

    2015-04-01

    Objective. The corticofugal system can alter coding along the ascending sensory pathway. Within the auditory system, electrical stimulation of the auditory cortex (AC) paired with a pure tone can cause egocentric shifts in the tuning of auditory neurons, making them more sensitive to the pure tone frequency. Since tinnitus has been linked with hyperactivity across auditory neurons, we sought to develop a new neuromodulation approach that could suppress a wide range of neurons rather than enhance specific frequency-tuned neurons. Approach. We performed experiments in the guinea pig to assess the effects of cortical stimulation paired with broadband noise (PN-Stim) on ascending auditory activity within the central nucleus of the inferior colliculus (CNIC), a widely studied region for AC stimulation paradigms. Main results. All eight stimulated AC subregions induced extensive suppression of activity across the CNIC that was not possible with noise stimulation alone. This suppression built up over time and remained after the PN-Stim paradigm. Significance. We propose that the corticofugal system is designed to decrease the brain’s input gain to irrelevant stimuli and PN-Stim is able to artificially amplify this effect to suppress neural firing across the auditory system. The PN-Stim concept may have potential for treating tinnitus and other neurological disorders.

  19. Tracking the will to attend: Cortical activity indexes self-generated, voluntary shifts of attention.

    PubMed

    Gmeindl, Leon; Chiu, Yu-Chin; Esterman, Michael S; Greenberg, Adam S; Courtney, Susan M; Yantis, Steven

    2016-10-01

    The neural substrates of volition have long tantalized philosophers and scientists. Over the past few decades, researchers have employed increasingly sophisticated technology to investigate this issue, but many studies have been limited considerably by their reliance on intrusive experimental procedures (e.g., abrupt instructional cues), measures of brain activity contaminated by overt behavior, or introspective self-report techniques of questionable validity. Here, we used multivoxel pattern time-course analysis of functional magnetic resonance imaging data to index voluntary, covert perceptual acts-shifts of visuospatial attention-in the absence of instructional cues, overt behavioral indices, and self-report. We found that these self-generated, voluntary attention shifts were time-locked to activity in the medial superior parietal lobule, supporting the hypothesis that this brain region is engaged in voluntary attentional reconfiguration. Self-generated attention shifts were also time-locked to activity in the basal ganglia, a novel finding that motivates further research into the role of the basal ganglia in acts of volition. Remarkably, prior to self-generated shifts of attention, we observed early and selective increases in the activation of medial frontal (dorsal anterior cingulate) and lateral prefrontal (right middle frontal gyrus) cortex-activity that likely reflects processing related to the intention or preparation to reorient attention. These findings, which extend recent evidence on freely chosen motor movements, suggest that dorsal anterior cingulate and lateral prefrontal cortices play key roles in both overt and covert acts of volition, and may constitute core components of a brain network underlying the will to attend. PMID:27301353

  20. Ignition's glow: Ultra-fast spread of global cortical activity accompanying local "ignitions" in visual cortex during conscious visual perception.

    PubMed

    Noy, N; Bickel, S; Zion-Golumbic, E; Harel, M; Golan, T; Davidesco, I; Schevon, C A; McKhann, G M; Goodman, R R; Schroeder, C E; Mehta, A D; Malach, R

    2015-09-01

    Despite extensive research, the spatiotemporal span of neuronal activations associated with the emergence of a conscious percept is still debated. The debate can be formulated in the context of local vs. global models, emphasizing local activity in visual cortex vs. a global fronto-parietal "workspace" as the key mechanisms of conscious visual perception. These alternative models lead to differential predictions with regard to the precise magnitude, timing and anatomical spread of neuronal activity during conscious perception. Here we aimed to test a specific aspect of these predictions in which local and global models appear to differ - namely the extent to which fronto-parietal regions modulate their activity during task performance under similar perceptual states. So far the main experimental results relevant to this debate have been obtained from non-invasive methods and led to conflicting interpretations. Here we examined these alternative predictions through large-scale intracranial measurements (Electrocorticogram - ECoG) in 43 patients and 4445 recording sites. Both ERP and broadband high frequency (50-150 Hz - BHF) responses were examined through the entire cortex during a simple 1-back visual recognition memory task. Our results reveal short latency intense visual responses, localized first in early visual cortex followed (at ∼200 ms) by higher order visual areas, but failed to show significant delayed (300 ms) visual activations. By contrast, oddball image repeat events, linked to overt motor responses, were associated with a significant increase in a delayed (300 ms) peak of BHF power in fronto-parietal cortex. Comparing BHF responses with ERP revealed an additional peak in the ERP response - having a similar latency to the well-studied P3 scalp EEG response. Posterior and temporal regions demonstrated robust visual category selectivity. An unexpected observation was that high-order visual cortex responses were essentially concurrent (at ∼200 ms

  1. Can the activities of the large scale cortical network be expressed by neural energy? A brief review.

    PubMed

    Wang, Rubin; Zhu, Yating

    2016-02-01

    This paper mainly discusses and summarize that the changes of biological energy in the brain can be expressed by the biophysical energy we constructed. Different from the electrochemical energy, the biophysical energy proposed in the paper not only can be used to simulate the activity of neurons but also be used to simulate the neural activity of large scale cortical networks, so that the scientific nature of the neural energy coding was discussed.

  2. Spiking in auditory cortex following thalamic stimulation is dominated by cortical network activity

    PubMed Central

    Krause, Bryan M.; Raz, Aeyal; Uhlrich, Daniel J.; Smith, Philip H.; Banks, Matthew I.

    2014-01-01

    The state of the sensory cortical network can have a profound impact on neural responses and perception. In rodent auditory cortex, sensory responses are reported to occur in the context of network events, similar to brief UP states, that produce “packets” of spikes and are associated with synchronized synaptic input (Bathellier et al., 2012; Hromadka et al., 2013; Luczak et al., 2013). However, traditional models based on data from visual and somatosensory cortex predict that ascending sensory thalamocortical (TC) pathways sequentially activate cells in layers 4 (L4), L2/3, and L5. The relationship between these two spatio-temporal activity patterns is unclear. Here, we used calcium imaging and electrophysiological recordings in murine auditory TC brain slices to investigate the laminar response pattern to stimulation of TC afferents. We show that although monosynaptically driven spiking in response to TC afferents occurs, the vast majority of spikes fired following TC stimulation occurs during brief UP states and outside the context of the L4>L2/3>L5 activation sequence. Specifically, monosynaptic subthreshold TC responses with similar latencies were observed throughout layers 2–6, presumably via synapses onto dendritic processes located in L3 and L4. However, monosynaptic spiking was rare, and occurred primarily in L4 and L5 non-pyramidal cells. By contrast, during brief, TC-induced UP states, spiking was dense and occurred primarily in pyramidal cells. These network events always involved infragranular layers, whereas involvement of supragranular layers was variable. During UP states, spike latencies were comparable between infragranular and supragranular cells. These data are consistent with a model in which activation of auditory cortex, especially supragranular layers, depends on internally generated network events that represent a non-linear amplification process, are initiated by infragranular cells and tightly regulated by feed-forward inhibitory

  3. Human motor cortical activity is selectively phase-entrained on underlying rhythms.

    PubMed

    Miller, Kai J; Hermes, Dora; Honey, Christopher J; Hebb, Adam O; Ramsey, Nick F; Knight, Robert T; Ojemann, Jeffrey G; Fetz, Eberhard E

    2012-01-01

    The functional significance of electrical rhythms in the mammalian brain remains uncertain. In the motor cortex, the 12-20 Hz beta rhythm is known to transiently decrease in amplitude during movement, and to be altered in many motor diseases. Here we show that the activity of neuronal populations is phase-coupled with the beta rhythm on rapid timescales, and describe how the strength of this relation changes with movement. To investigate the relationship of the beta rhythm to neuronal dynamics, we measured local cortical activity using arrays of subdural electrocorticographic (ECoG) electrodes in human patients performing simple movement tasks. In addition to rhythmic brain processes, ECoG potentials also reveal a spectrally broadband motif that reflects the aggregate neural population activity beneath each electrode. During movement, the amplitude of this broadband motif follows the dynamics of individual fingers, with somatotopically specific responses for different fingers at different sites on the pre-central gyrus. The 12-20 Hz beta rhythm, in contrast, is widespread as well as spatially coherent within sulcal boundaries and decreases in amplitude across the pre- and post-central gyri in a diffuse manner that is not finger-specific. We find that the amplitude of this broadband motif is entrained on the phase of the beta rhythm, as well as rhythms at other frequencies, in peri-central cortex during fixation. During finger movement, the beta phase-entrainment is diminished or eliminated. We suggest that the beta rhythm may be more than a resting rhythm, and that this entrainment may reflect a suppressive mechanism for actively gating motor function. PMID:22969416

  4. Cortical activation associated with determination of depth order during transparent motion perception: A normalized integrative fMRI-MEG study.

    PubMed

    Natsukawa, Hiroaki; Kobayashi, Tetsuo

    2015-10-01

    When visual patterns drifting in different directions and/or at different speeds are superimposed on the same plane, observers perceive transparent surfaces on planes of different depths. This phenomenon is known as transparent motion perception. In this study, cortical activities were measured using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) to reveal the cortical dynamics associated with determination of depth order during transparent motion perception. In addition, offline eye movement measurements were performed to determine the latencies of the start of both pursuit eye movements and depth attention that are important in determination of the depth order. MEG and fMRI data were analyzed by a normalized integrative fMRI-MEG method that enables reconstruction of time-varying dipole moments of activated regions from MEG signals. Statistical analysis of fMRI data was performed to identify activated regions. The activated regions were used as spatial constraints for the reconstruction using the integrative fMRI-MEG method. We focused on the period between latencies (216-405 ms) determined by eye movement experiment, which are related to determination of the depth order. The results of integrative analysis revealed that significant neural activities were observed in the visual association area, the human middle temporal area, the intraparietal sulcus, the lateral occipital cortex, and the anterior cingulate cortex between 216 and 405 ms. These results suggest that initial eye movement and accompanying cortical activations during focused duration play an important role in determining the depth order during transparent motion perception.

  5. Neural correlates of executive dysfunction in schizophrenia: failure to modulate brain activity with task demands.

    PubMed

    Dirnberger, Georg; Fuller, Rebecca; Frith, Chris; Jahanshahi, Marjan

    2014-11-12

    In schizophrenia, executive functions are impaired and are associated with altered activation of prefrontal areas. We used H2[15]O PET to examine patients with schizophrenia and matched controls on a random number generation (RNG) task and a control counting (COUNT) task. To assess the effects of increasing task demand, both tasks were performed at three different rates (intervals 1, 2 or 3 s). Both groups showed a significant increase in the nonrandomness of responses at faster rates of RNG. Despite similar performances, patients but not controls showed higher activation of the right dorsolateral prefrontal cortex (DLPFC) and atypically reduced activation of the right anterior cingulate gyrus and the right medial frontal gyrus in RNG compared with COUNT, whereas only for controls, activation of the left DLPFC was increased and activation of the right superior temporal gyrus and the right superior frontal gyrus was reduced in the same comparison. Whereas for the controls several cortical areas including the bilateral superior temporal gyrus and the bilateral DLPFC, together with the right cerebellum, showed significant changes in regional cerebral blood flow with faster or slower rates, patients with schizophrenia showed rate-dependent changes only in the left cerebellum. In conclusion, the patients' failure to modulate cortical activation with changing demands of rate, particularly in prefrontal areas and in the cerebellum, and even when performance is similar to that in healthy controls, is a characteristic of their abnormal pattern of executive processing. PMID:25275638

  6. Ginkgo biloba Extract (EGb 761®) Inhibits Glutamate-induced Up-regulation of Tissue Plasminogen Activator Through Inhibition of c-Fos Translocation in Rat Primary Cortical Neurons.

    PubMed

    Cho, Kyu Suk; Lee, Ian Myungwon; Sim, Seobo; Lee, Eun Joo; Gonzales, Edson Luck; Ryu, Jong Hoon; Cheong, Jae Hoon; Shin, Chan Young; Kwon, Kyoung Ja; Han, Seol-Heui

    2016-01-01

    EGb 761(®) , a standardized extract of Ginkgo biloba leaves, has antioxidant and antiinflammatory properties in experimental models of neurodegenerative disorders such as stroke and Alzheimer's disease. Tissue plasminogen activator (tPA) acts a neuromodulator and plays a crucial role in the manifestation of neurotoxicity leading to exaggerated neuronal cell death in neurological insult conditions. In this study, we investigated the effects of EGb 761 on the basal and glutamate-induced activity and expression of tPA in rat primary cortical neurons. Under basal condition, EGb 761 inhibited both secreted and cellular tPA activities, without altering tPA mRNA level, as modulated by the activation of p38. Compared with basal condition, EGb 761 inhibited the glutamate-induced up-regulation of tPA mRNA resulting in the normalization of overt tPA activity and expression. c-Fos is a component of AP-1, which plays a critical role in the modulation of tPA expression. Interestingly, EGb 761 inhibited c-Fos nuclear translocation without affecting c-Fos expression in glutamate-induced rat primary cortical neurons. These results demonstrated that EGb 761 can modulate tPA activity under basal and glutamate-stimulated conditions by both translational and transcriptional mechanisms. Thus, EGb 761 could be a potential and effective therapeutic strategy in tPA-excessive neurotoxic conditions.

  7. Cortical midline structures and autobiographical-self processes: an activation-likelihood estimation meta-analysis.

    PubMed

    Araujo, Helder F; Kaplan, Jonas; Damasio, Antonio

    2013-09-04

    The autobiographical-self refers to a mental state derived from the retrieval and assembly of memories regarding one's biography. The process of retrieval and assembly, which can focus on biographical facts or personality traits or some combination thereof, is likely to vary according to the domain chosen for an experiment. To date, the investigation of the neural basis of this process has largely focused on the domain of personality traits using paradigms that contrasted the evaluation of one's traits (self-traits) with those of another person's (other-traits). This has led to the suggestion that cortical midline structures (CMSs) are specifically related to self states. Here, with the goal of testing this suggestion, we conducted activation-likelihood estimation (ALE) meta-analyses based on data from 28 neuroimaging studies. The ALE results show that both self-traits and other-traits engage CMSs; however, the engagement of medial prefrontal cortex is greater for self-traits than for other-traits, while the posteromedial cortex is more engaged for other-traits than for self-traits. These findings suggest that the involvement CMSs is not specific to the evaluation of one's own traits, but also occurs during the evaluation of another person's traits.

  8. Nonlinear analysis and modeling of cortical activation and deactivation patterns in the immature fetal electrocorticogram

    NASA Astrophysics Data System (ADS)

    Schwab, Karin; Groh, Tobias; Schwab, Matthias; Witte, Herbert

    2009-03-01

    An approach combining time-continuous nonlinear stability analysis and a parametric bispectral method was introduced to better describe cortical activation and deactivation patterns in the immature fetal electroencephalogram (EEG). Signal models and data-driven investigations were performed to find optimal parameters of the nonlinear methods and to confirm the occurrence of nonlinear sections in the fetal EEG. The resulting measures were applied to the in utero electrocorticogram (ECoG) of fetal sheep at 0.7 gestation when organized sleep states were not developed and compared to previous results at 0.9 gestation. Cycling of the nonlinear stability of the fetal ECoG occurred already at this early gestational age, suggesting the presence of premature sleep states. This was accompanied by cycling of the time-variant biamplitude which reflected ECoG synchronization effects during premature sleep states associated with nonrapid eye movement sleep later in gestation. Thus, the combined nonlinear and time-variant approach was able to provide important insights into the properties of the immature fetal ECoG.

  9. Cortical Midline Structures and Autobiographical-Self Processes: An Activation-Likelihood Estimation Meta-Analysis

    PubMed Central

    Araujo, Helder F.; Kaplan, Jonas; Damasio, Antonio

    2013-01-01

    The autobiographical-self refers to a mental state derived from the retrieval and assembly of memories regarding one’s biography. The process of retrieval and assembly, which can focus on biographical facts or personality traits or some combination thereof, is likely to vary according to the domain chosen for an experiment. To date, the investigation of the neural basis of this process has largely focused on the domain of personality traits using paradigms that contrasted the evaluation of one’s traits (self-traits) with those of another person’s (other-traits). This has led to the suggestion that cortical midline structures (CMSs) are specifically related to self states. Here, with the goal of testing this suggestion, we conducted activation-likelihood estimation (ALE) meta-analyses based on data from 28 neuroimaging studies. The ALE results show that both self-traits and other-traits engage CMSs; however, the engagement of medial prefrontal cortex is greater for self-traits than for other-traits, while the posteromedial cortex is more engaged for other-traits than for self-traits. These findings suggest that the involvement CMSs is not specific to the evaluation of one’s own traits, but also occurs during the evaluation of another person’s traits. PMID:24027520

  10. Electrical neuroimaging reveals intensity-dependent activation of human cortical gustatory and somatosensory areas by electric taste.

    PubMed

    Ohla, Kathrin; Toepel, Ulrike; le Coutre, Johannes; Hudry, Julie

    2010-12-01

    To analyze the neural basis of electric taste we performed electrical neuroimaging analyses of event-related potentials (ERPs) recorded while participants received electrical pulses to the tongue. Pulses were presented at individual taste threshold to excite gustatory fibers selectively without concomitant excitation of trigeminal fibers and at high intensity evoking a prickling and, thus, activating trigeminal fibers. Sour, salty and metallic tastes were reported at both intensities while clear prickling was reported at high intensity only. ERPs exhibited augmented amplitudes and shorter latencies for high intensity. First activations of gustatory areas (bilateral anterior insula, medial orbitofrontal cortex) were observed at 70-80ms. Common somatosensory regions were more strongly, but not exclusively, activated at high intensity. Our data provide a comprehensive view on the dynamics of cortical processing of the gustatory and trigeminal portions of electric taste and suggest that gustatory and trigeminal afferents project to overlapping cortical areas. PMID:20858525

  11. Revision of the DELFIC Particle Activity Module

    SciTech Connect

    Hooper, David A; Jodoin, Vincent J

    2010-09-01

    The Defense Land Fallout Interpretive Code (DELFIC) was originally released in 1968 as a tool for modeling fallout patterns and for predicting exposure rates. Despite the continual advancement of knowledge of fission yields, decay behavior of fission products, and biological dosimetry, the decay data and logic of DELFIC have remained mostly unchanged since inception. Additionally, previous code revisions caused a loss of conservation of radioactive nuclides. In this report, a new revision of the decay database and the Particle Activity Module is introduced and explained. The database upgrades discussed are replacement of the fission yields with ENDF/B-VII data as formatted in the Oak Ridge Isotope Generation (ORIGEN) code, revised decay constants, revised exposure rate multipliers, revised decay modes and branching ratios, and revised boiling point data. Included decay logic upgrades represent a correction of a flaw in the treatment of the fission yields, extension of the logic to include more complex decay modes, conservation of nuclides (including stable nuclides) at all times, and conversion of key variables to double precision for nuclide conservation. Finally, recommended future work is discussed with an emphasis on completion of the overall radiation physics upgrade, particularly for dosimetry, induced activity, decay of the actinides, and fractionation.

  12. Distinct cortical networks activated by auditory attention and working memory load.

    PubMed

    Huang, Samantha; Seidman, Larry J; Rossi, Stephanie; Ahveninen, Jyrki

    2013-12-01

    Auditory attention and working memory (WM) allow for selection and maintenance of relevant sound information in our minds, respectively, thus underlying goal-directed functioning in everyday acoustic environments. It is still unclear whether these two closely coupled functions are based on a common neural circuit, or whether they involve genuinely distinct subfunctions with separate neuronal substrates. In a full factorial functional MRI (fMRI) design, we independently manipulated the levels of auditory-verbal WM load and attentional interference using modified Auditory Continuous Performance Tests. Although many frontoparietal regions were jointly activated by increases of WM load and interference, there was a double dissociation between prefrontal cortex (PFC) subareas associated selectively with either auditory attention or WM. Specifically, anterior dorsolateral PFC (DLPFC) and the right anterior insula were selectively activated by increasing WM load, whereas subregions of middle lateral PFC and inferior frontal cortex (IFC) were associated with interference only. Meanwhile, a superadditive interaction between interference and load was detected in left medial superior frontal cortex, suggesting that in this area, activations are not only overlapping, but reflect a common resource pool recruited by increased attentional and WM demands. Indices of WM-specific suppression of anterolateral non-primary auditory cortices (AC) and attention-specific suppression of primary AC were also found, possibly reflecting suppression/interruption of sound-object processing of irrelevant stimuli during continuous task performance. Our results suggest a double dissociation between auditory attention and working memory in subregions of anterior DLPFC vs. middle lateral PFC/IFC in humans, respectively, in the context of substantially overlapping circuits.

  13. On the other hand: Increased cortical activation to human versus mechanical hands in infants.

    PubMed

    Biondi, Marisa; Boas, David A; Wilcox, Teresa

    2016-11-01

    There is a large body of work demonstrating that infants are sensitive to the distinction between human and mechanical entities from the early months of life, and have different expectations for the way these entities move and interact. The current work investigates the extent to which the functional organization of the immature brain reflects these early emerging sensitivities. Infants aged 8months watched two kinds of hands (human or mechanical) engage in two kinds of events (one with a functional outcome and one without). Using functional near-infrared spectroscopy (fNIRS), we assessed hemodynamic activation in the left and right temporal and temporal-occipital cortex in response to these events. The neuroimaging data revealed a significantly greater increase in activation in the right middle-posterior temporal cortex to events executed by the human than the mechanical hand; the event in which the hand engaged (function or non-function) did not significantly influence hemodynamic responses. In comparison, the left middle-temporal cortex showed significantly greater activation to events executed by the human than mechanical hand, but only when the events were functionally relevant. That is, the left middle-posterior temporal cortex responded selectively to human (as compared to mechanical) agents, but only in the context of functionally relevant actions on objects. These results reveal that the immature brain is functionally specialized to support infants' processing of human and non-human agents as distinct entities. These results also shed light on the cognitive and cortical mechanisms that guide infants' learning about agentive action and object function.

  14. Distinct cortical networks activated by auditory attention and working memory load

    PubMed Central

    Huang, Samantha; Seidman, Larry J.; Rossi, Stephanie; Ahveninen, Jyrki

    2013-01-01

    Auditory attention and working memory (WM) allow for selection and maintenance of relevant sound information in our minds, respectively, thus underlying goal-directed functioning in everyday acoustic environments. It is still unclear whether these two closely coupled functions are based on a common neural circuit, or whether they involve genuinely distinct subfunctions with separate neuronal substrates. In a full factorial functional MRI (fMRI) design, we independently manipulated the levels of auditory-verbal WM load and attentional interference using modified Auditory Continuous Performance Tests. Although many frontoparietal regions were jointly activated by increases of WM load and interference, there was a double dissociation between prefrontal cortex (PFC) subareas associated selectively with either auditory attention or WM. Specifically, anterior dorsolateral PFC (DLPFC) and the right anterior insula were selectively activated by increasing WM load, whereas subregions of middle lateral PFC and inferior frontal cortex (IFC) were associated with interference only. Meanwhile, a superadditive interaction between interference and load was detected in left medial superior frontal cortex, suggesting that in this area, activations are not only overlapping, but reflect a common resource pool recruited by increased attentional and WM demands. Indices of WM-specific suppression of anterolateral non-primary auditory cortices (AC) and attention-specific suppression of primary AC were also found, possibly reflecting suppression/interruption of sound-object processing of irrelevant stimuli during continuous task performance. Our results suggest a double dissociation between auditory attention and working memory in subregions of anterior DLPFC vs. middle lateral PFC/IFC in humans, respectively, in the context of substantially overlapping circuits. PMID:23921102

  15. On the other hand: Increased cortical activation to human versus mechanical hands in infants.

    PubMed

    Biondi, Marisa; Boas, David A; Wilcox, Teresa

    2016-11-01

    There is a large body of work demonstrating that infants are sensitive to the distinction between human and mechanical entities from the early months of life, and have different expectations for the way these entities move and interact. The current work investigates the extent to which the functional organization of the immature brain reflects these early emerging sensitivities. Infants aged 8months watched two kinds of hands (human or mechanical) engage in two kinds of events (one with a functional outcome and one without). Using functional near-infrared spectroscopy (fNIRS), we assessed hemodynamic activation in the left and right temporal and temporal-occipital cortex in response to these events. The neuroimaging data revealed a significantly greater increase in activation in the right middle-posterior temporal cortex to events executed by the human than the mechanical hand; the event in which the hand engaged (function or non-function) did not significantly influence hemodynamic responses. In comparison, the left middle-temporal cortex showed significantly greater activation to events executed by the human than mechanical hand, but only when the events were functionally relevant. That is, the left middle-posterior temporal cortex responded selectively to human (as compared to mechanical) agents, but only in the context of functionally relevant actions on objects. These results reveal that the immature brain is functionally specialized to support infants' processing of human and non-human agents as distinct entities. These results also shed light on the cognitive and cortical mechanisms that guide infants' learning about agentive action and object function. PMID:27417344

  16. Cortical network reorganization guided by sensory input features.

    PubMed

    Kilgard, Michael P; Pandya, Pritesh K; Engineer, Navzer D; Moucha, Raluca

    2002-12-01

    Sensory experience alters the functional organization of cortical networks. Previous studies using behavioral training motivated by aversive or rewarding stimuli have demonstrated that cortical plasticity is specific to salient inputs in the sensory environment. Sensory experience associated with electrical activation of the basal forebrain (BasF) generates similar input specific plasticity. By directly engaging plasticity mechanisms and avoiding extensive behavioral training, BasF stimulation makes it possible to efficiently explore how specific sensory features contribute to cortical plasticity. This review summarizes our observations that cortical networks employ a variety of strategies to improve the representation of the sensory environment. Different combinations of receptive-field, temporal, and spectrotemporal plasticity were generated in primary auditory cortex neurons depending on the pitch, modulation rate, and order of sounds paired with BasF stimulation. Simple tones led to map expansion, while modulated tones altered the maximum cortical following rate. Exposure to complex acoustic sequences led to the development of combination-sensitive responses. This remodeling of cortical response characteristics may reflect changes in intrinsic cellular mechanisms, synaptic efficacy, and local neuronal connectivity. The intricate relationship between the pattern of sensory activation and cortical plasticity suggests that network-level rules alter the functional organization of the cortex to generate the most behaviorally useful representation of the sensory environment.

  17. Difference in cortical activation during use of volar and dorsal hand splints: a functional magnetic resonance imaging study

    PubMed Central

    Jang, Sung Ho; Jang, Woo Hyuk

    2016-01-01

    There have been no studies reported on the difference in cortical activation during use of volar and dorsal hand splints. We attempted to investigate the difference in cortical activation in the somatosensory cortical area during use of volar and dorsal hand splints by functional magnetic resonance imaging (fMRI). We recruited eight healthy volunteers. fMRI was performed while subjects who were fitted with volar or dorsal hand splints performed grasp-release movements. Regions of interest were placed on the primary motor cortex (M1), primary somatosensory cortex (S1), posterior parietal cortex (PPC), and secondary somatosensory cortex (S2). Results of group analysis of fMRI data showed that the total numbers of activated voxels in all ROIs were significantly higher during use of volar hand splint (3,376) compared with that (1,416) during use of dorsal hand splint. In each ROI, use of volar hand splint induced greater activation in all ROIs (M1: 1,748, S1: 1,455, PPC: 23, and S2: 150) compared with use of dorsal hand splint (M1: 783, S1: 625, PPC: 0, and S2: 8). The peak activated value was also higher during use of volar hand splint (t-value: 17.29) compared with that during use of dorsal hand splint (t-value: 13.11). Taken together, use of volar hand splint induced greater cortical activation relevant to somatosensory function than use of dorsal hand splint. This result would be important for the physiatrist and therapist to apply appropriate somatosensory input in patients with brain injury.

  18. Difference in cortical activation during use of volar and dorsal hand splints: a functional magnetic resonance imaging study

    PubMed Central

    Jang, Sung Ho; Jang, Woo Hyuk

    2016-01-01

    There have been no studies reported on the difference in cortical activation during use of volar and dorsal hand splints. We attempted to investigate the difference in cortical activation in the somatosensory cortical area during use of volar and dorsal hand splints by functional magnetic resonance imaging (fMRI). We recruited eight healthy volunteers. fMRI was performed while subjects who were fitted with volar or dorsal hand splints performed grasp-release movements. Regions of interest were placed on the primary motor cortex (M1), primary somatosensory cortex (S1), posterior parietal cortex (PPC), and secondary somatosensory cortex (S2). Results of group analysis of fMRI data showed that the total numbers of activated voxels in all ROIs were significantly higher during use of volar hand splint (3,376) compared with that (1,416) during use of dorsal hand splint. In each ROI, use of volar hand splint induced greater activation in all ROIs (M1: 1,748, S1: 1,455, PPC: 23, and S2: 150) compared with use of dorsal hand splint (M1: 783, S1: 625, PPC: 0, and S2: 8). The peak activated value was also higher during use of volar hand splint (t-value: 17.29) compared with that during use of dorsal hand splint (t-value: 13.11). Taken together, use of volar hand splint induced greater cortical activation relevant to somatosensory function than use of dorsal hand splint. This result would be important for the physiatrist and therapist to apply appropriate somatosensory input in patients with brain injury. PMID:27651775

  19. Difference in cortical activation during use of volar and dorsal hand splints: a functional magnetic resonance imaging study.

    PubMed

    Jang, Sung Ho; Jang, Woo Hyuk

    2016-08-01

    There have been no studies reported on the difference in cortical activation during use of volar and dorsal hand splints. We attempted to investigate the difference in cortical activation in the somatosensory cortical area during use of volar and dorsal hand splints by functional magnetic resonance imaging (fMRI). We recruited eight healthy volunteers. fMRI was performed while subjects who were fitted with volar or dorsal hand splints performed grasp-release movements. Regions of interest were placed on the primary motor cortex (M1), primary somatosensory cortex (S1), posterior parietal cortex (PPC), and secondary somatosensory cortex (S2). Results of group analysis of fMRI data showed that the total numbers of activated voxels in all ROIs were significantly higher during use of volar hand splint (3,376) compared with that (1,416) during use of dorsal hand splint. In each ROI, use of volar hand splint induced greater activation in all ROIs (M1: 1,748, S1: 1,455, PPC: 23, and S2: 150) compared with use of dorsal hand splint (M1: 783, S1: 625, PPC: 0, and S2: 8). The peak activated value was also higher during use of volar hand splint (t-value: 17.29) compared with that during use of dorsal hand splint (t-value: 13.11). Taken together, use of volar hand splint induced greater cortical activation relevant to somatosensory function than use of dorsal hand splint. This result would be important for the physiatrist and therapist to apply appropriate somatosensory input in patients with brain injury. PMID:27651775

  20. Modulation of neural activity during observational learning of actions and their sequential orders.

    PubMed

    Frey, Scott H; Gerry, Valerie E

    2006-12-20

    How does the brain transform perceptual representations of others' actions into motor representations that can be used to guide behavior? Here we used functional magnetic resonance imaging to record human brain activity while subjects watched others construct multipart objects under varied task demands. We find that relative to resting baseline, passive action observation increases activity within inferior frontal and parietal cortices implicated in action encoding (mirror system) and throughout a distributed network of areas involved in motor representation, including dorsal premotor cortex, pre-supplementary motor area, cerebellum, and basal ganglia (experiments 1 and 2). Relative to passive observation, these same areas show increased activity when subjects observe with the intention to subsequently reproduce component actions using the demonstrated sequential procedures (experiment 1). Observing the same actions with the intention of reproducing component actions, but without the requirement to use the demonstrated sequential procedure, increases activity in the same regions, although to a lesser degree (experiment 2). These findings demonstrate that when attempting to learn behaviors through observation, the observers' intentions modulate responses in a widely distributed network of cortical and subcortical regions implicated previously in action encoding and/or motor representation. Among these regions, only activity within the right intraparietal sulcus predicts the accuracy with which observed procedures are subsequently performed. Successful formation of motor representations of sequential procedures through observational learning is dependent on computations implemented within this parietal region. PMID:17182769

  1. Somatostatin-Expressing Inhibitory Interneurons in Cortical Circuits

    PubMed Central

    Yavorska, Iryna; Wehr, Michael

    2016-01-01

    Cortical inhibitory neurons exhibit remarkable diversity in their morphology, connectivity, and synaptic properties. Here, we review the function of somatostatin-expressing (SOM) inhibitory interneurons, focusing largely on sensory cortex. SOM neurons also comprise a number of subpopulations that can be distinguished by their morphology, input and output connectivity, laminar location, firing properties, and expression of molecular markers. Several of these classes of SOM neurons show unique dynamics and characteristics, such as facilitating synapses, specific axonal projections, intralaminar input, and top-down modulation, which suggest possible computational roles. SOM cells can be differentially modulated by behavioral state depending on their class, sensory system, and behavioral paradigm. The functional effects of such modulation have been studied with optogenetic manipulation of SOM cells, which produces effects on learning and memory, task performance, and the integration of cortical activity. Different classes of SOM cells participate in distinct disinhibitory circuits with different inhibitory partners and in different cortical layers. Through these disinhibitory circuits, SOM cells help encode the behavioral relevance of sensory stimuli by regulating the activity of cortical neurons based on subcortical and intracortical modulatory input. Associative learning leads to long-term changes in the strength of connectivity of SOM cells with other neurons, often influencing the strength of inhibitory input they receive. Thus despite their heterogeneity and variability across cortical areas, current evidence shows that SOM neurons perform unique neural computations, forming not only distinct molecular but also functional subclasses of cortical inhibitory interneurons. PMID:27746722

  2. Telmisartan Modulates Glial Activation: In Vitro and In Vivo Studies

    PubMed Central

    Torika, Nofar; Asraf, Keren; Danon, Abraham; Apte, Ron N.; Fleisher-Berkovich, Sigal

    2016-01-01

    The circulating renin-angiotensin system (RAS), including the biologically active angiotensin II, is a fundamental regulatory mechanism of blood pressure conserved through evolution. Angiotensin II components of the RAS have also been identified in the brain. In addition to pro-inflammatory cytokines, neuromodulators, such as angiotensin II can induce (through angiotensin type 1 receptor (AT1R)) some of the inflammatory actions of brain glial cells and influence brain inflammation. Moreover, in Alzheimer’s disease (AD) models, where neuroinflammation occurs, increased levels of cortical AT1Rs have been shown. Still, the precise role of RAS in neuroinflammation is not completely clear. The overall aim of the present study was to elucidate the role of RAS in the modulation of glial functions and AD pathology. To reach this goal, the specific aims of the present study were a. to investigate the long term effect of telmisartan (AT1R blocker) on tumor necrosis factor-α (TNF-α), interleukin 1-β (IL1-β) and nitric oxide (NO) release from glial cells. b. to examine the effect of intranasally administered telmisartan on amyloid burden and microglial activation in 5X familial AD (5XFAD) mice. Telmisartan effects in vivo were compared to those of perindopril (angiotensin converting enzyme inhibitor). Long-term-exposure of BV2 microglia to telmisartan significantly decreased lipopolysaccharide (LPS) -induced NO, inducible NO synthase, TNF-α and IL1-β synthesis. The effect of Telmisartan on NO production in BV2 cells was confirmed also in primary neonatal rat glial cells. Intranasal administration of telmisartan (1 mg/kg/day) for up to two months significantly reduced amyloid burden and CD11b expression (a marker for microglia) both in the cortex and hipoccampus of 5XFAD. Based on the current view of RAS and our data, showing reduced amyloid burden and glial activation in the brains of 5XFAD transgenic mice, one may envision potential intervention with the progression

  3. Telmisartan Modulates Glial Activation: In Vitro and In Vivo Studies.

    PubMed

    Torika, Nofar; Asraf, Keren; Danon, Abraham; Apte, Ron N; Fleisher-Berkovich, Sigal

    2016-01-01

    The circulating renin-angiotensin system (RAS), including the biologically active angiotensin II, is a fundamental regulatory mechanism of blood pressure conserved through evolution. Angiotensin II components of the RAS have also been identified in the brain. In addition to pro-inflammatory cytokines, neuromodulators, such as angiotensin II can induce (through angiotensin type 1 receptor (AT1R)) some of the inflammatory actions of brain glial cells and influence brain inflammation. Moreover, in Alzheimer's disease (AD) models, where neuroinflammation occurs, increased levels of cortical AT1Rs have been shown. Still, the precise role of RAS in neuroinflammation is not completely clear. The overall aim of the present study was to elucidate the role of RAS in the modulation of glial functions and AD pathology. To reach this goal, the specific aims of the present study were a. to investigate the long term effect of telmisartan (AT1R blocker) on tumor necrosis factor-α (TNF-α), interleukin 1-β (IL1-β) and nitric oxide (NO) release from glial cells. b. to examine the effect of intranasally administered telmisartan on amyloid burden and microglial activation in 5X familial AD (5XFAD) mice. Telmisartan effects in vivo were compared to those of perindopril (angiotensin converting enzyme inhibitor). Long-term-exposure of BV2 microglia to telmisartan significantly decreased lipopolysaccharide (LPS) -induced NO, inducible NO synthase, TNF-α and IL1-β synthesis. The effect of Telmisartan on NO production in BV2 cells was confirmed also in primary neonatal rat glial cells. Intranasal administration of telmisartan (1 mg/kg/day) for up to two months significantly reduced amyloid burden and CD11b expression (a marker for microglia) both in the cortex and hipoccampus of 5XFAD. Based on the current view of RAS and our data, showing reduced amyloid burden and glial activation in the brains of 5XFAD transgenic mice, one may envision potential intervention with the progression of

  4. Changes in cortical activity associated with adaptive behavior during repeated balance perturbation of unpredictable timing

    PubMed Central

    Mierau, Andreas; Hülsdünker, Thorben; Strüder, Heiko K.

    2015-01-01

    The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control. PMID:26528154

  5. Cortical activity is more stable when sensory stimuli are consciously perceived

    PubMed Central

    Schurger, Aaron; Sarigiannidis, Ioannis; Naccache, Lionel; Sitt, Jacobo D.; Dehaene, Stanislas

    2015-01-01

    According to recent evidence, stimulus-tuned neurons in the cerebral cortex exhibit reduced variability in firing rate across trials, after the onset of a stimulus. However, in order for a reduction in variability to be directly relevant to perception and behavior, it must be realized within trial—the pattern of activity must be relatively stable. Stability is characteristic of decision states in recurrent attractor networks, and its possible relevance to conscious perception has been suggested by theorists. However, it is difficult to measure on the within-trial time scales and broadly distributed spatial scales relevant to perception. We recorded simultaneous magneto- and electroencephalography (MEG and EEG) data while subjects observed threshold-level visual stimuli. Pattern-similarity analyses applied to the data from MEG gradiometers uncovered a pronounced decrease in variability across trials after stimulus onset, consistent with previous single-unit data. This was followed by a significant divergence in variability depending upon subjective report (seen/unseen), with seen trials exhibiting less variability. Applying the same analysis across time, within trial, we found that the latter effect coincided in time with a difference in the stability of the pattern of activity. Stability alone could be used to classify data from individual trials as “seen” or “unseen.” The same metric applied to EEG data from patients with disorders of consciousness exposed to auditory stimuli diverged parametrically according to clinically diagnosed level of consciousness. Differences in signal strength could not account for these results. Conscious perception may involve the transient stabilization of distributed cortical networks, corresponding to a global brain-scale decision. PMID:25847997

  6. Functional Genetic Variation in Dopamine Signaling Moderates Prefrontal Cortical Activity During Risky Decision Making.

    PubMed

    Kohno, Milky; Nurmi, Erika L; Laughlin, Christopher P; Morales, Angelica M; Gail, Emma H; Hellemann, Gerhard S; London, Edythe D

    2016-02-01

    Brain imaging has revealed links between prefrontal activity during risky decision-making and striatal dopamine receptors. Specifically, striatal dopamine D2-like receptor availability is correlated with risk-taking behavior and sensitivity of prefrontal activation to risk in the Balloon Analogue Risk Task (BART). The extent to which these associations, involving a single neurochemical measure, reflect more general effects of dopaminergic functioning on risky decision making, however, is unknown. Here, 65 healthy participants provided genotypes and performed the BART during functional magnetic resonance imaging. For each participant, dopamine function was assessed using a gene composite score combining known functional variation across five genes involved in dopaminergic signaling: DRD2, DRD3, DRD4, DAT1, and COMT. The gene composite score was negatively related to dorsolateral prefrontal cortical function during risky decision making, and nonlinearly related to earnings on the task. Iterative permutations of all possible allelic variations (7777 allelic combinations) was tested on brain function in an independently defined region of the prefrontal cortex and confirmed empirical validity of the composite score, which yielded stronger association than 95% of all other possible combinations. The gene composite score also accounted for a greater proportion of variability in neural and behavioral measures than the independent effects of each gene variant, indicating that the combined effects of functional dopamine pathway genes can provide a robust assessment, presumably reflecting the cumulative and potentially interactive effects on brain function. Our findings support the view that the links between dopaminergic signaling, prefrontal function, and decision making vary as a function of dopamine signaling capacity. PMID:26119471

  7. Cortical activities of heat-sensitization responses in suspended moxibustion: an EEG source analysis with sLORETA.

    PubMed

    Wang, Juan; Yi, Ming; Zhang, Chan; Bian, Zhijie; Wan, You; Chen, Rixin; Li, Xiaoli

    2015-12-01

    Moxibustion is under active research as a complementary and alternative treatment for various diseases such as pain. "Heat-sensitization" responses have been reported during suspended moxibustion, whose occurrence is associated with significantly better therapeutic effects. The present study aimed to investigate the cortical activities of this interesting phenomenon by a standardized low-resolution brain electromagnetic tomography. We performed electroencephalography recording in a group of patients with chronic low back pain before, during, and after moxibustion treatment at Yaoyangguan (DU3) areas. 11 out of 21 subjects experienced strong heat-sensitization during moxibustion, which were accompanied with significant decreases of current densities in the beta frequency bands in prefrontal, primary and second somatosensory, and cingulate cortices, as well as increased current densities in the alpha2 band in the left insula. No changes were detected in patients without sensitization responses, or in the post-moxibustion phase of either group. These data indicated widespread activity changes across different frequency bands during heat-sensitization. Cortical oscillatory activities could be used to evaluate the "heat-sensitization" responses during suspended moxibustion.

  8. A topological hypothesis for the functional connections of the cortex. A principle of the cortical graphs' based on the neuroimaging.

    PubMed

    Gomez, J F; Lopera, F J

    1999-09-01

    Combined EEG and PET techniques show three activation levels of the cortex: deep sleep, relaxed state and alert. We propose, correspondingly, that a cortical module can be in one of three equivalent states: inactivated, pre-activated, and activated. Neuroimaging techniques can show activated cortical regions in detail. However, the functional connections (FCs) among them are not shown in the image. They can be found by EEG-coherence functions. This can be seen as a 'three-level- cortical graph'. A cortical graph is a mathematical representation where the cortical units (modules or regions) are represented by points (nodes) and the FCs are represented by lines between these points. At the upper level, activated modules can establish FCs implying high electrical coherence (they are the winners of a competitive process between preactivated modules at the middle level). We propose that, during alert state, the activated nodes and the dynamic switching among them always form connected graphs. It means that, for any possible configuration, there always exists a path (direct or indirect) between any couple of nodes. We base our view on (1) analysis of simple tasks by PET; (2) the existence of coordinated behavior in normal subjects; (3) cortical topologies previously proposed; and (4) computer simulations of cortico-cortical connections. We also suggest that disengaged (nonconnected) cortical graphs, produce 'functional disconnection syndromes' which cause some symptoms in schizophrenia, and Alzheimer disease.

  9. Dynamics of Electrocorticographic (ECoG) Activity in Human Temporal and Frontal Cortical Areas During Music Listening

    PubMed Central

    Potes, Cristhian; Gunduz, Aysegul; Brunner, Peter; Schalk, Gerwin

    2012-01-01

    Previous studies demonstrated that brain signals encode information about specific features of simple auditory stimuli or of general aspects of natural auditory stimuli. How brain signals represent the time course of specific features in natural auditory stimuli is not well understood. In this study, we show in eight human subjects that signals recorded from the surface of the brain (electrocorticography (ECoG)) encode information about the sound intensity of music. ECoG activity in the high gamma band recorded from the posterior part of the superior temporal gyrus as well as from an isolated area in the precentral gyrus were observed to be highly correlated with the sound intensity of music. These results not only confirm the role of auditory cortices in auditory processing but also point to an important role of premotor and motor cortices. They also encourage the use of ECoG activity to study more complex acoustic features of simple or natural auditory stimuli. PMID:22537600

  10. Neuronal avalanches are diverse and precise activity patterns that are stable for many hours in cortical slice cultures.

    PubMed