to alleviate chronic pain. Using magnetoencephalography (MEG) to study the mechanisms of DBS for pain implicated in painful syndromes. � 2008 Elsevier Ltd. All rights reserved. Keywords: Chronic pain; Phantom that all of these may explain phantom phenomena to some extent. Recently, chronic pain syndromes have been

Thalamocortical dynamics, the millisecond to second changes in activity of thalamocortical circuits, are central to perception, action and cognition. Generated by local circuitry and sculpted by neuromodulatory systems, these dynamics reflect the expression of vigilance states. In sleep, ...

Abnormal brain activity dynamics, in the sense of a thalamocortical dysrhythmia (TCD), has been proposed as the underlying mechanism for a subset of disorders that bridge the traditional delineations of neurology and neuropsychiatry. In order to test this proposal from a psychiatric perspective, a study using magnetoencephalography ...

Cortico-basal ganglia-thalamocortical circuits are severely disrupted by the dopamine depletion of Parkinson's disease (PD), leading to pathologically exaggerated beta oscillations. Abnormal rhythms, found in several circuit nodes are correlated with movement impairments but their neural basis remains unclear. Here, we used dynamic ...

Cortico-basal ganglia-thalamocortical circuits are severely disrupted by the dopamine depletion of Parkinson's disease (PD), leading to pathologically exaggerated beta oscillations. Abnormal rhythms, found in several circuit nodes are correlated with movement impairments but their neural basis remains unclear. Here, we used dynamic ...

The segregated regions of the mammalian cerebral cortex and thalamus form an extensive and complex network, whose structure and function are still only incompletely understood. The present letter describes an application of the concepts of complex networks and random walks that allows the identification of nonrandom, highly structured features of thalamocortical connections ...

The group I metabotropic glutamate receptor 5 (mGluR5) has been implicated in the development of cortical sensory maps. However its precise roles in the synaptic function and plasticity of thalamocortical connections remain unknown. Here we first show that in mGluR5 knockout mice bred onto a C57BL6 background cyto-architectonic differentiation into barrels is missing, but the ...

Serotonergic abnormalities have been reported in both autism and epilepsy. This association may provide insights into underlying mechanisms of these disorders because serotonin plays an important neurotrophic role during brain development--and there is evidence for abnormal cortical development in both autism and some forms of epilepsy. This review ...

The neocortex receives information about the environment and the rest of the brain through pathways from the thalamus. These pathways have frequency-dependent properties that can strongly influence their effect on the neocortex. In 1943 Morison and Dempsey described "augmenting responses," a form of short-term plasticity in some thalamocortical pathways that is triggered by 8- ...

Studies in congenitally blind and bilaterally enucleated individuals show that an early loss of sensory driven activity can lead to massive functional reorganization. However, the anatomical substrate for this functional reorganization is unknown. In the present study, we examined patterns of corticocortical and thalamocortical connections in adult opossums that had been ...

Appetitive motivation and incentive states are essential functions sustained by a common emotional brain process, the SEEKING disposition, which drives explorative and approach behaviors, sustains goal-directed activity, promotes anticipatory cognitions, and evokes feelings of positive excitement which control reward-learning. All such functions are orchestrated by the same "archetypical" neural ...

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 ...

Schizophrenia is associated with a wide range of symptoms. These include auditory hallucinations, delusions, and experiences that one is not in control of one's own thoughts and actions, but that they are inserted by an outside agency. It has been proposed that a disturbance in the sense of self may account for many of these symptoms. This disturbance in turn may be associated with source ...

Higher brain function depends on task-dependent information flow between cortical regions. Converging lines of evidence suggest that interactions between cortical regions and the central thalamus play a key role in establishing the dynamic patterns of functional connectivity that normally support these processes. In patients with chronic disturbances of cognitive function due ...

Recent neurophysiological findings in relation to thalamocortical mechanisms for sensory processing, together with established anatomical and expanding functional evidence, have provided a rational theoretical framework for the interpretation of normal and abnormal EEG rhythmic activities. This perspective is integrated here with earlier animal studies ...

BackgroundThe dorsal thalamus acts as a gateway and modulator for information going to and from the cerebral cortex. This activity requires the formation of reciprocal topographic axon connections between thalamus and cortex. The axons grow along a complex multistep pathway, making sharp turns, crossing expression boundaries, and encountering intermediate targets. However, the cellular and ...

Cocaine affects sensory perception and attention but little is known about the neural substrates underlying these effects in the human brain. We used functional magnetic resonance imaging (fMRI) and a sustained visuospatial attention task to assess if the visual attention network is dysfunctional in cocaine abusers (n=14) compared to age-, gender-, and education-matched controls (n=14). Compared ...

It is argued that a novel control architecture, the Static and Dynamic State (SDS) feedback scheme, which utilizes speed-field tracking, exhibits global stability, and allows on-line tuning by any adaptation mechanism without cancelling stability if certain structural conditions are met, can be viewed as a model of basal ganglia-thalamocortical loops since ...

NrCAM is a neural cell adhesion molecule of the L1 family that has been linked to autism spectrum disorders (ASDs), a disease spectrum in which abnormal thalamocortical connectivity may contribute to visual processing defects. Here we show that NrCAM interaction with Neuropilin-2 (Npn-2) is critical for Semaphorin3F (Sema3F)-induced guidance of ...

The information transfer in the thalamus is blocked dynamically during sleep, in conjunction with the occurrence of spindle waves. In order to describe the dynamic mechanisms which control the sensory transfer of information, it is necessary to have a qualitative model for the response properties of thalamic neurons. As the theoretical understanding of the ...

The information transfer in the thalamus is blocked dynamically during sleep, in conjunction with the occurrence of spindle waves. In order to describe the dynamic mechanisms which control the sensory transfer of information, it is necessary to have a qualitative model for the response properties of thalamic neurons. As the theoretical understanding of the ...

The information transfer in the thalamus is blocked dynamically during sleep, in conjunction with the occurrence of spindle waves. In order to describe the dynamic mechanisms which control the sensory transfer of information, it is necessary to have a qualitative model for the response properties of thalamic neurons. As the theoretical understanding of the ...

The understanding of the structural and dynamic complexity of mammalian brains is greatly facilitated by computer simulations. We present here a detailed large-scale thalamocortical model based on experimental measures in several mammalian species. The model spans three anatomical scales. (i) It is based on global (white-matter) ...

... It is concluded that the hypotension induced by positive acceleration is essential to the changes in thalamo-cortical excitability. (Author). ...

Human and experimental studies indicate that molecular genetic changes in GABA(A) receptors may underlie the expression of spike-and-waves discharges (SWDs) occurring during absence seizures. However, the full spectrum of the genetic defects underlying these seizures has only been partially elucidated, the expression and functional profiles of putative abnormal protein(s) ...

Recent years have witnessed a surge of investigations examining functional brain organization using resting-state functional connectivity MRI (rs-fcMRI). To date, this method has been used to examine systems organization in typical and atypical developing populations. While the majority of these investigations have focused on cortical�cortical interactions, cortical�subcortical interactions ...

[BACKGROUND]: It is reasonable to consider the thalamus a primary candidate for the location of consciousness, given that the thalamus has been referred to as the gateway of nearly all sensory inputs to the corresponding cortical areas. Interestingly, in an early stage of brain development, communicative innervations between the dorsal thalamus and telencephalon must pass through the ventral ...

[Background]It is reasonable to consider the thalamus a primary candidate for the location of consciousness, given that the thalamus has been referred to as the gateway of nearly all sensory inputs to the corresponding cortical areas. Interestingly, in an early stage of brain development, communicative innervations between the dorsal thalamus and telencephalon must pass through the ventral ...

Neural Darwinism (ND) is a large scale selectionist theory of brain development and function that has been hypothesized to relate to consciousness. According to ND, consciousness is entailed by reentrant interactions among neuronal populations in the thalamocortical system (the 'dynamic core'). These interactions, which permit high-order discriminations ...

Resting cortical activity is characterized by a distinct spectral peak in the alpha frequency range. Slowing of this oscillatory peak toward the upper theta-band has been associated with a variety of neurological and neuropsychiatric conditions and has been attributed to altered thalamocortical dynamics. Children born very preterm exhibit altered ...

Throughout the early history of neurology and neuroscience, most theoretical accounts of brain function have emphasized either aspects of localization or distributed properties [1]. Instead, modern views focus extensively on the structure and dynamics of large-scale neuronal networks, especially those of the cerebral cortex and associated thalamocortical

This chapter summarizes a theory of consciousness based on brain structure and dynamics. The theory centers around the notion of reentry--on-going recursive signaling across multiple reciprocally connected brain regions present mainly in the thalamocortical system. It recognized the fundamental beginnings provided by the complementary efforts of Ram�n y ...

The hodotopic framework is a recent revision of Geschwind's disconnection paradigm incorporating advances in functional and white matter imaging. Its intention is to help clinico-pathological correlations across a range of neurological and psychiatric conditions and generate novel research questions. Here I consider hallucinations within this framework. The paper is divided into three parts. The ...

Skeletal growth is a dynamic process. A knowledge of the structure and function of the normal growth plate is essential in order to understand the pathophysiology of abnormal skeletal growth in various diseases. In this well-illustrated article, the authors provide a radiographic classification of abnormal growth plates and discuss ...

Purpose:? Patients with juvenile myoclonic epilepsy (JME) show evidence of microstructural white matter (WM) damage of thalamocortical fiber tracts and changes of blood oxygen level dependent (BOLD) signal in a striatothalamocortical network. The objective of the present study was to investigate microstructural and volumetric alterations of the putamen in patients with JME ...

Mitochondrial dysfunction is a prominent feature of various neurodegenerative diseases. A deeper understanding of the remarkably dynamic nature of mitochondria, characterized by a delicate balance of fission and fusion, has helped to fertilize a recent wave of new studies demonstrating abnormal mitochondrial dynamics in ...

... across the military departments and agencies for Research Development Test and ... On the Nature of Abnormalities in the Dynamics of Viral ...

Purpose: To explore the neural correlates of the thalamus by using resting-state functional magnetic resonance (MR) imaging and to investigate whether thalamic resting-state networks (RSNs) are disrupted in patients with mild traumatic brain injury (MTBI). Materials and Methods: This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained ...

Absence epilepsy (AE) in humans and the genetic AE model in WAG/Rij rats are both associated with abnormalities in sleep architecture that suggest insufficiency of the sleep-promoting mechanisms. In this study we compared the functionality of sleep-active neuronal groups within two well-established sleep-promoting sites, the ventrolateral and median preoptic nuclei (VLPO and ...

The Dynamic Core and Global Workspace hypotheses were independently put forward to provide mechanistic and biologically plausible accounts of how brains generate conscious mental content. The Dynamic Core proposes that reentrant neural activity in the thalamocortical system gives rise to conscious experience. Global Workspace ...

Periventricular leucomalacia has long been investigated as a leading cause of motor and cognitive dysfunction in patients with spastic diplegic cerebral palsy. However, patients with periventricular leucomalacia on conventional magnetic resonance imaging do not always have motor dysfunction and preterm children without neurological abnormalities may have periventricular ...

Purpose: To investigate the effects of 3,4-methylenedioxymethamphetamine (MDMA, commonly known as "ecstasy") on the alterations of brain metabolites and anatomic tissue integrity related to the function of the basal ganglia-thalamocortical circuit by using proton magnetic resonance (MR) spectroscopy and diffusion-tensor MR imaging. Materials and Methods: This study was ...

Activity-dependent dendritic Ca²⁺ signals play a critical role in multiple forms of non-linear cellular output and plasticity. In thalamocortical neurons, despite the well-established spatial separation of sensory and cortical inputs onto proximal and distal dendrites respectively, little is known about the spatio-temporal dynamics ...

BackgroundIn addition to its well-known expression in dorsal telencephalic progenitor cells, where it regulates cell proliferation and identity, the transcription factor Pax6 is expressed in some ventral telencephalic cells, including many postmitotic neurons. Its functions in these cells are unknown.ResultsWe generated a new floxed allele of Pax6 and tested the consequences of a highly specific ...

Injection of NMDAR antagonist into the thalamus can produce delta frequency EEG oscillations in the thalamocortical system. It is surprising that an antagonist of an excitatory neurotransmitter should trigger such activity, and the mechanism is unknown. One hypothesis is that the antagonist blocks excitation of GABAergic cells, thus producing disinhibition. To test this ...

Pregnant female rats were irradiated with 200 r on the 17th, 19th, or 21st day of gestation. Other newborn rats received 200-r head irradiation on the 23rd, 26th, or 29th day after conception. In both groups the effects of irradiation on cortical structure and on the electrical activity of the brain were studied. Structural changes resulting from this treatment ranged from major ...

Up states are a hallmark of striatal physiology. Spontaneous activity in the thalamo-cortical network drives robust plateau depolarizations in the medium spiny projection neurons of the striatum. Medium spiny neuron firing is only possible during up states and is very tightly regulated by dopamine and NMDA receptors. In a rat model of Parkinson's disease the medium spiny ...

This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to ...

Neurons of the central nervous system display a broad spectrum of intrinsic electrophysiological properties that are absent in the traditional �integrate-and-fire� model. A network of neurons with these properties interacting through synaptic receptors with many time scales can produce complex patterns of activity that cannot be intuitively predicted. Computational methods, tightly linked to ...

Mitochondria are dynamic organelles that undergo continuous fission and fusion, which could affect all aspects of mitochondrial function. Mitochondrial dysfunction has been well documented in Alzheimer's disease (AD). In the past few years, emerging evidence indicates that an imbalance of mitochondrial dynamics is involved in the pathogenesis of AD. In ...

Mitochondria are dynamic organelles that undergo continuous fission and fusion, which could affect all aspects of mitochondrial function. Mitochondrial dysfunction has been well documented in Alzheimer�s disease (AD). In the past few years, emerging evidence indicates that an imbalance of mitochondrial dynamics is involved in the pathogenesis of AD. In ...

The range of conduction delays between connected neuronal populations is often modeled as a single discrete delay, assumed to be an effective value averaging over all fiber velocities. This paper shows the effects of distributed delays on signal propagation. A distribution acts as a linear filter, imposing an upper frequency cutoff that is inversely proportional to the delay width. Distributed ...

Central glutamatergic synapses may express AMPA-sensitive glutamate receptors (AMPA-Rs) with distinct gating properties and exhibit different transmission dynamics, which are important for computing various synaptic inputs received at different populations of synapses. However, how glutamatergic synapses acquire AMPA-Rs with distinct kinetics to influence synaptic integration ...

Preterm birth is a leading cause of cognitive impairment in childhood and is associated with cerebral gray and white matter abnormalities. Using multimodal image analysis, we tested the hypothesis that altered thalamic development is an important component of preterm brain injury and is associated with other macro- and microstructural alterations. T(1)- and T(2)-weighted ...

Malformations of cortical development are disorders of altered brain anatomy and architecture that arise from abnormalities in the usual processes of cerebral cortical development. Although they often lead to epilepsy, cognitive delay, and motor impairment, little is known about their effect on sleep. Since malformations may anatomically or functionally disrupt the cerebral ...

Primary dystonia has traditionally been viewed as a basal ganglia disorder, but recent studies suggest that the cerebellum plays a crucial role in the disease. Primary dystonia is associated with several genotypes. Among those, DYT1 and DYT6 are inherited in autosomal dominant fashion with reduced penetrance. Extensive structural and functional imaging studies have been performed on manifesting ...

pathological condition occurred. As a result, they may classify diabetes as an abnormal blood sugar level diabetes as an abnormality in metabolism, and another specialist may classify diabetes as a lifestyle. pathological condition of metabolic disorders is an abnormal state consisting of a metabolic abnormality

to evaluate the wireless network normal and abnormal behaviors and create dynamic normal and abnormal contours metrics, referred to as wireless abnormality distance (WAD), to quantify the network behavior. Wireless wireless abnormality distance KWAD with respect to a feature KF is defined as 2 ...

The thalamocortical pathway, a bundle of myelinated axons that arises from thalamic relay neurons, carries sensory information to the neocortex. Because axon excitation is an obligatory step in the relay of information from the thalamus to the cortex, it represents a potential point of control. We now show that, in adult mice, the activation of nicotinic acetylcholine ...

AIMCerebral palsy (CP) is frequently linked to white matter injury in children born preterm. Diffusion tensor imaging (DTI) is a powerful technique providing precise identification of white matter microstructure. We investigated the relationship between DTI-observed thalamocortical (posterior thalamic radiation) injury, motor (corticospinal tract) injury, and sensorimotor ...

Binding of features and information which are processed at different cortical areas is generally supposed to be achieved by synchrony despite the non-negligible delays between these areas. In this work we study the dynamics and synchronization properties of a simplified model of the thalamocortical circuit where different cortical areas are interconnected ...

Many studies in neuroscience have shown that nonlinear dynamic networks represent a bio-inspired models for information and image processing. Recent studies on the thalamo-cortical system have shown that weakly connected oscillatory networks have the capability of modelling the architecture of a neurocomputer. In particular they have associative properties ...

We studied circuit activities in layer IV of rat somatosensory barrel cortex containing microgyri induced by neonatal freeze lesions. Structural abnormalities in GABAergic interneurons are present in the epileptogenic paramicrogyral area (PMG) and we therefore tested the hypothesis that decreased postsynaptic inhibition within barrel microcircuits occurs in the PMG and ...

Synaptic activity mediated via GABA receptors in thalamic circuits is critically involved in the generation of hypersynchrony associated with absence epilepsy. Neurons of "unspecific" intralaminar thalamic nuclei display characteristic burst patterns during seizure activity, although their synaptic properties remain largely unknown. Here, we used in vitro patch-clamp techniques in neurons of the ...

The transcription factor Pax6 is widely expressed throughout the developing nervous system, including most alar regions of the newly formed murine diencephalon. Later in embryogenesis its diencephalic expression becomes more restricted. It persists in the developing anterior thalamus (conventionally termed "ventral" thalamus) and pretectum but is downregulated in the body of the posterior (dorsal) ...

In twenty unanesthetized, immobilized cats, blocking of thalamocortical recruiting responses was studied according to the way in which the phenomenon was induced. Like EEG desynchronization, blocking of recruiting occurred when arousal was induced central...

The investigations attempted to analyze the effect of activation on thalamocortical systems by means of the blocking of recruiting responses. Experiments were carried out according to the following program: (1) experiments characterizing the effect of ret...

We employed spike-triggered current source-density analysis to examine axonal and postsynaptic currents generated in the visual cortex of awake rabbits by spontaneous spikes of individual Sustained and Transient LGNd neurons. Using these data, we asked if sustained/transient sensory responses are related to short-term synaptic dynamics at the ...

... Accession Number : ADP006084. Title : The Interaction of Thalamo- Cortical Systems in the 40 Hz Following Response,. ...

This article starts with a brief review of the thalamocortical system architecture, which is composed of the projecting thalamic nuclei, the thalamic reticular nucleus, and the neocortex. Then we provide a description of the three states of vigilances followed by a detailed review of major brain rhythms present in the thalamocortical system during ...

... Cats were operantly trained to suppress movement by rewarding a sensori- motor EEG rhythm (the SMR) with positive hypothalamic brain ...

Hypoxic damage to the prefrontal cortex (PFC) has been implicated in the frontal lobe dysfunction found in various neuropsychiatric disorders. The underlying subcortical mechanisms, however, have not been well explored. In this study, we induced a PFC-specific hypoxia-like damage by cobalt-wire implantation to demonstrate that the role of the mediodorsal thalamus (MD) is critical for the ...

Epilepsy is a neurological disorder that affects 1-2% of the population. Despite the available treatments (drug therapy, resective surgery, vagus nerve stimulation), there is a significant subgroup of patients that continues to have disabling seizures. The indications of deep brain stimulation are exponentially growing, and there is a wide experience with deep brain stimulation (DBS) for the ...

This study investigated slow waves (SW; >75?V and <4Hz) characteristics in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). Thirty patients with iRBD and 30 age- and sex-matched healthy subjects underwent one polysomnographic (PSG) nocturnal sleep recording. SW automatic detection was performed on F3, C3, P3, and O1 leads and SW characteristics were derived ...

Polycythaemia vera is a well-known cause of symptomatic chorea, however, the pathophysiology of this correlation remains unclear. We report on a patient with generalized chorea-ballism associated with polycythaemia vera, and we present the findings of 99mTc-hexamethylpropylene amine oxime (HMPAO) SPECT done in both the choreic state and the non-choreic state. The SPECT during both the choreic and ...

Multiple adjacent, roughly mirror-image topographic maps are commonly observed in the sensory neocortex of many species. The cortical regions occupied by these maps are generally believed to be determined initially by genetically controlled chemical markers during development, with thalamocortical afferent activity subsequently exerting a progressively increasing influence ...

Non-rapid eye movement (NREM) sleep has recently garnered support for its role in consolidating hippocampus-based declarative memories in humans. We provide a brief review of the latest research on NREM sleep activity and its association with declarative memory consolidation. Utilizing empirical findings from sleep studies on schizophrenia, Alzheimer's disease, and fibromyalgia, we argue that a ...

Mitochondria play critical roles in neuronal function and almost all aspects of mitochondrial function are altered in Alzheimer neurons. Emerging evidence shows that mitochondria are dynamic organelles that undergo continuous fission and fusion, the balance of which not only controls mitochondrial morphology and number, but also regulates mitochondrial function and ...

Neuronal activity arises from the interplay of membrane and synaptic currents. Although many channel proteins conducting these currents are phylogenetically conserved, channels of the same type in different animals can have different voltage dependencies and dynamics. What does this mean for our ability to derive rules about the role of different types of ion channels in ...

BackgroundEphrinA5 is one of the best-studied members of the Eph-ephrin family of guidance molecules, known to be involved in brain developmental processes. Using in situ hybridization, ephrinA5 mRNA expression has been detected in the retinotectal, the thalamocortical, and the olfactory systems; however, no study focused on the distribution of the protein. Considering that ...

Motor sequence learning is abnormal in presymptomatic Huntington's disease (p-HD). The neural substrates underlying this early manifestation of HD are poorly understood. To study the mechanism of this cognitive abnormality in p-HD, we used positron emission tomography to record brain activity during motor sequence learning in these subjects. Eleven p-HD ...

BACKGROUND AND PURPOSE: Generalized tonic-clonic seizures (GTCS) comprise a common subsyndrome of idiopathic generalized epilepsy (IGE). Previous studies found that patients with GTCS had structural abnormalities in a few specific brain regions. However, the underlying clinical cause leading to these abnormalities remains unclear. The present study aimed ...

node, and the right and left ventricles (RV, LV). In the absence of an abnormal retrograde pathway, ORT extension of that work to the control of fibrillation in intact hearts is impeded currently by the complexity of fibrillation [notwithstanding a recent study that showed interesting dynamical modification

Simultaneous 111In-DPTA and metrizamide CT cisternography correlated closely in the qualitative imaging of cerebrospinal fluid (CSF) dynamics in 9 normal patients and in 11 patients thought to have communicating hydrocephalus. CSF clearance of both tracers was similar; significant absorption occurred in the spinal dural sac. Although delayed elevated serum iodine levels ...

Simultaneous /sup 111/In-DTPA and metrizamide CT cisternography correlated closely in the qualitative imaging of cerebrospinal fluid (CSF) dynamics in 9 normal patients and in 11 patients thought to have communicating hydrocephalus. CSF clearance of both tracers was similar; significant absorption occurred in the spinal dural sac. Although delayed elevated serum iodine levels ...

Metrizamide CT cisternograms were performed on 39 patients with a clinical diagnosis of CSF abnormalities; 20 of these patients underwent radionuclide cisternography as well. Comparison of metrizamide CT and RN cisternography revealed good correlation in the degree, extent, and time sequence of ventricular reflux as well as the extent of cortical staining and cisternal ...

During non-rapid eye movement sleep and certain types of anaesthesia, neurons in the neocortex and thalamus exhibit a distinctive slow (<1?Hz) oscillation that consists of alternating UP and DOWN membrane potential states and which correlates with a pronounced slow (<1?Hz) rhythm in the electroencephalogram. While several studies have claimed that the slow oscillation is generated ...

Action selection is the task of resolving conflicts between multiple sensorimotor systems seeking access to the final common motor path. Recently, 1, 2 we proposed that the basal ganglia may act to provide a biological solution to the problem of selection. To test this notion we have implemented a high level computational model of intrinsic basal ganglia circuitry and its interactions with ...

The low-threshold transient calcium current (I(T)) plays a critical role in modulating the firing behavior of thalamic neurons; however, the role of I(T) in the integration of afferent information within the thalamus is virtually unknown. We have used two-photon laser scanning microscopy coupled with whole-cell recordings to examine calcium dynamics in the neurons of the ...

The low-threshold transient calcium current (I_T) plays a critical role in modulating the firing behavior of thalamic neurons; however, the role of I_T in the integration of afferent information within the thalamus is virtually unknown. We have used two-photon laser scanning microscopy coupled with whole-cell recordings to examine calcium ...

The dorsal pallidal complex is made up of the external and internal segments of the globus pallidus (GPe and GPi respectively). It is part of the main axis of the basal ganglia (BG) that connects the thalamo-cortical networks to the BG input stages (striatum and subthalamic nucleus) and continues directly, and indirectly through the GPe, to the BG output stages (GPi and ...

Subcortical-cortical interactions in the language network were investigated using dynamic causal modeling of magnetoencephalographic data recorded during auditory comprehension. Participants heard sentences that either were correct or contained violations. Sentences containing violations had syntactic or prosodic violations or both. We show that a hidden source, modeling ...

ObjectiveWe propose a theoretical framework for EEG and evoked potential studies based on the single postulate that these data are composed of a combination of waves (as this term is used in the physical sciences) and thalamocortical network activity.MethodsUsing known properties of traveling and standing waves, independent of any neocortical dynamic ...

. Fast aiming movements were measured in a choice reaction paradigm in a healthy control group and in Parkinsonian patients. The patients were tested without ("off") and with l-DOPA medication ("on"). The movement trajectories were used to estimate the parameters of a dynamic linear model. The model is based on the functional structure of the basal ...

Glutamatergic neurotransmission plays important roles in sensory map formation. The absence of the group I metabotropic glutamate receptor 5 (mGluR5) leads to abnormal sensory map formation throughout the mouse somatosensory pathway. To examine the role of cortical mGluR5 expression on barrel map formation, we generated cortex-specific mGluR5 KO mice. Eliminating mGluR5 ...

Abnormally large grains have been observed in Al-Mg alloy AA5182 sheet material after forming at elevated temperature, and the reduced yield strength that results is a practical problem for commercial hot-forming operations. The process by which abnormal grains are produced is investigated through controlled hot tensile testing to reproduce the ...

The epidermis is a dynamic system whose metabolic activity is regulated in large part by the integrity of the permeability barrier. This barrier resides in the stratum corneum and comprises a unique 2-compartment system of structural protein-enriched corneocytes embedded in a lipid-enriched intercellular matrix. Lipid extraction or metabolic imbalances, such as essential fatty ...

Formation of whisker-related barrels in primary somatosensory cortex (S1) requires communication between presynaptic thalamocortical afferents (TCAs) and postsynaptic cortical neurons. GAP-43 is crucially involved in targeting TCAs to postsynaptic S1 neurons but its influence on the interactions between these 2 elements has not been explored. Here, we tested the hypothesis ...

Formation of whisker-related barrels in primary somatosensory cortex (S1) requires communication between presynaptic thalamocortical afferents (TCAs) and postsynaptic cortical neurons. GAP-43 is crucially involved in targeting TCAs to postsynaptic S1 neurons but its influence on the interactions between these 2 elements has not been explored. Here, we tested the hypothesis ...

SummaryPurposeThe thalamus plays an important role in seizure propagation in temporal lobe epilepsy (TLE). This study investigated how structural abnormalities in the focus, ipsilateral thalamus and extrafocal cortical structures relate to each other in TLE with mesiotemporal sclerosis (TLE-MTS) and without hippocampal sclerosis (TLE-no).MethodsT₁ and ...

Congenital anomalies of the central nervous system (CNS) often demonstrate aberrant white matter connections, which may be better characterized with diffusion-tensor imaging (DTI) and fiber tractography (FT) than with conventional magnetic resonance (MR) imaging. DTI-FT demonstrates abnormal hemispheric fiber connections in callosal agenesis or acquired disease of the corpus ...

Complex visual hallucinations may affect some normal individuals on going to sleep and are also seen in pathological states, often in association with a sleep disturbance. The content of these hallucinations is striking and relatively stereotyped, often involving animals and human figures in bright colours and dramatic settings. Conditions causing these hallucinations include narcolepsy-cataplexy ...

We consider a Hodgkin-Huxley-type model of oscillatory activity in neurons of the snail Helix pomatia. This model has a distinctive feature: It demonstrates multistability in oscillatory and silent modes that is typical for the thalamocortical neurons. A single neuron cell can demonstrate a variety of oscillatory activity: Regular and chaotic spiking and bursting behavior. We ...

Demyelination and axonal damage are pathologic hallmarks of multiple sclerosis (MS), leading to loss of neuronal synchronization, functional disconnection amongst brain relays, and clinical sequelae. To investigate these properties, the primary component of the sensorimotor network was analyzed in mildly disabled Relapsing-Remitting MS patients without sensory symptoms at the time of the ...

Thalamic neurons, which play important roles in the genesis of rhythmic activities of the brain, show various bursting behaviors, particularly modulated by complex thalamocortical feedback via cortical neurons. As a first step to explore this complex neural system and focus on the effects of the feedback on the bursting behavior, a simple loop structure delayed in time and ...

Inhibition plays an essential role in shaping and refining the brain's representation of sensory stimulus attributes. In primary auditory cortex (A1), so-called "sideband" inhibition helps to sharpen the tuning of local neuronal responses. Several distinct types of anatomical circuitry could underlie sideband inhibition, including direct thalamocortical (TC) afferents, as well ...

... understand the importance of layer 4 in shaping the development of thalamic ... the ventral basal (vB) region of thalamus of fixed brains obtained at Pi ...

in thalamocortical neurons in vitro. Neu- ron 33:947�958. Huntsman MM, Porcello DM, Homanics GE, DeLorey TM