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Sample records for bilateral continuous theta

  1. Network mechanisms of responsiveness to continuous theta-burst stimulation.

    PubMed

    Rizk, Sviatlana; Ptak, Radek; Nyffeler, Thomas; Schnider, Armin; Guggisberg, Adrian G

    2013-10-01

    Continuous theta-burst stimulation (cTBS) can modify behavior, but effects are inconsistent and their mechanisms insufficiently understood. As coherence in resting-state networks influences human behavior, we hypothesized that cTBS may act via modulation of neural oscillation coherence. This study used electroencephalography (EEG) to investigate whether behavioral effects of cTBS on visuospatial attention are associated with coherence changes in the attention network. In healthy human subjects, cTBS of the right posterior parietal cortex (PPC) and the right frontal eye field was compared with sham stimulation. Effects on visuospatial attention were quantified with a visual exploration task, and network effects were assessed from surface EEG with inverse solutions and source coherence analyses. Before stimulation, left visual exploration was linearly correlated with alpha-band coherence between the right temporo-parietal cortex and the rest of the brain. Posterior parietal cortex stimulation induced neglect-like visual exploration behavior in the majority, but not all, subjects. It reduced alpha-band coherence between the stimulation site and the rest of the brain but also enhanced it between the contralateral left parietal cortex and the rest of the brain. The contralateral increase correlated with the induced reduction in left visual attention. The behavioral response of individual participants to cTBS could be predicted by coherence in the right temporo-parietal junction before stimulation. Behavioral effects of cTBS therefore depend on network states before stimulation and are linearly associated with changes in network interactions. In particular, cTBS modulates an interhemispheric competition in alpha-band coherence. EEG network imaging might help to optimize therapeutic cTBS in the future. PMID:23941616

  2. Continuous theta burst stimulation of angular gyrus reduces subjective recollection.

    PubMed

    Yazar, Yasemin; Bergström, Zara M; Simons, Jon S

    2014-01-01

    The contribution of lateral parietal regions such as the angular gyrus to human episodic memory has been the subject of much debate following widespread observations of left parietal activity in healthy volunteers during functional neuroimaging studies of memory retrieval. Patients with lateral parietal lesions are not amnesic, but recent evidence indicates that their memory abilities may not be entirely preserved. Whereas recollection appears intact when objective measures such as source accuracy are used, patients often exhibit reduced subjective confidence in their accurate recollections. When asked to recall autobiographical memories, they may produce spontaneous narratives that lack richness and specificity, but can remember specific details when prompted. Two distinct theoretical accounts have been proposed to explain these results: that the patients have a deficit in the bottom-up capturing of attention by retrieval output, or that they have an impairment in the subjective experience of recollection. The present study aimed to differentiate between these accounts using continuous theta burst stimulation (cTBS) in healthy participants to disrupt function of specific left parietal subregions, including angular gyrus. Inconsistent with predictions of the attentional theory, angular gyrus cTBS did not result in greater impairment of free recall than cued recall. Supporting predictions of the subjective recollection account, temporary disruption of angular gyrus was associated with highly accurate source recollection accuracy but a selective reduction in participants' rated source confidence. The findings are consistent with a role for angular gyrus in the integration of memory features into a conscious representation that enables the subjective experience of remembering. PMID:25333985

  3. Modulation of Visual Cortex Excitability by Continuous Theta Burst Stimulation Depends on Coil Type

    PubMed Central

    Brückner, Sabrina; Kammer, Thomas

    2016-01-01

    Subthreshold continuous theta burst stimulation of the visual cortex has been reported to cause inhibitory effects on phosphene threshold. In contrast, we observed no inhibition in a former study applying higher stimulation intensities. The main discrepancies between our experiments and the former studies were stimulation intensity and coil type. We aimed at investigating the role of these factors on the modulatory effects of continuous theta burst stimulation applied to the visual cortex. In a between-group-design, we used either a figure-of-eight-coil or a round coil, respectively. We measured phosphene thresholds prior and after continuous theta burst stimulation applied at 80% of individual phosphene threshold. With the figure-of-eight-coil, phosphene thresholds significantly decreased following stimulation. This is in line with the results of our former study but contrary to the increase observed in the other two studies. Using a round coil, no significant effect was observed. A correlation analysis revealed an inhibitory effect in subjects with higher phosphene thresholds only. Furthermore, the slope of the baseline phosphene threshold seems to predict the direction of modulation, independent from coil type. Thus, modulatory effects of continuous theta burst stimulation seem to depend on coil type and psychophysics parameters, probably due to different cortex volumes stimulated. Stochastic resonance phenomena might account for the differences observed. PMID:27459108

  4. Enhancing treatment effects by combining continuous theta burst stimulation with smooth pursuit training.

    PubMed

    Hopfner, Simone; Cazzoli, Dario; Müri, René M; Nef, Tobias; Mosimann, Urs P; Bohlhalter, Stephan; Vanbellingen, Tim; Nyffeler, Thomas

    2015-07-01

    Continuous theta burst stimulation (cTBS) represents a promising approach in the treatment of neglect syndrome. However, it is not known whether cTBS in conjunction with another technique may enhance the therapeutic effects. In the present sham-controlled study, we aimed to combine cTBS with smooth pursuit training (SPT), another method known to effectively improve neglect symptoms, and to evaluate whether this combination would result in a stronger effect than SPT alone. Eighteen patients with left spatial neglect after right-hemispheric stroke were included in the study and performed a cancellation task on a large 54.6″ touchscreen monitor. A sequential application of cTBS and SPT induced a significantly greater improvement of neglect than SPT alone. After the combined application of these two methods, patients detected significantly more targets and their cancellation behaviour presented a significantly greater shift towards the contralesional hemispace. We suggest that a combined, sequential application of cTBS and SPT is a promising new approach to treat neglect. PMID:25455568

  5. Continuous theta-burst stimulation demonstrates a causal role of premotor homunculus in action understanding.

    PubMed

    Michael, John; Sandberg, Kristian; Skewes, Joshua; Wolf, Thomas; Blicher, Jakob; Overgaard, Morten; Frith, Chris D

    2014-04-01

    Although it is well established that regions of premotor cortex (PMC) are active during action observation, it remains controversial whether they play a causal role in action understanding. In the experiment reported here, we used off-line continuous theta-burst stimulation (cTBS) to investigate this question. Participants received cTBS over the hand and lip areas of left PMC, in separate sessions, before completing a pantomime-recognition task in which half of the trials contained pantomimed hand actions, and half contained pantomimed mouth actions. The results reveal a double dissociation: Participants were less accurate in recognizing pantomimed hand actions after receiving cTBS over the hand area than over the lip area and less accurate in recognizing pantomimed mouth actions after receiving cTBS over the lip area than over the hand area. This finding constrains theories of action understanding by showing that somatotopically organized regions of PMC contribute causally to action understanding and, thus, that the mechanisms underpinning action understanding and action performance overlap. PMID:24549297

  6. Combined transcranial alternating current stimulation and continuous theta burst stimulation: a novel approach for neuroplasticity induction.

    PubMed

    Goldsworthy, Mitchell R; Vallence, Ann-Maree; Yang, Ruiting; Pitcher, Julia B; Ridding, Michael C

    2016-02-01

    Non-invasive brain stimulation can induce functionally relevant plasticity in the human cortex, making it potentially useful as a therapeutic tool. However, the induced changes are highly variable between individuals, potentially limiting research and clinical utility. One factor that might contribute to this variability is the level of cortical inhibition at the time of stimulation. The alpha rhythm (~ 8-13 Hz) recorded with electroencephalography (EEG) is thought to reflect pulsatile cortical inhibition; therefore, targeting non-invasive brain stimulation to particular phases of the alpha rhythm may provide an approach to enhance plasticity induction. Transcranial alternating current stimulation (tACS) has been shown to entrain cortical oscillations in a frequency-specific manner. We investigated whether the neuroplastic response to continuous theta burst stimulation (cTBS) was enhanced by timing bursts of stimuli to the peak or the trough of a tACS-imposed alpha rhythm. While motor evoked potentials (MEPs) were unaffected when cTBS was applied in-phase with the peak of the tACS-imposed oscillation, MEP depression was enhanced when cTBS was applied in-phase with the trough. This enhanced MEP depression was dependent on the individual peak frequency of the endogenous alpha rhythm recorded with EEG prior to stimulation, and was strongest in those participants classified as non-responders to standard cTBS. These findings suggest that tACS may be used in combination with cTBS to enhance the plasticity response. Furthermore, the peak frequency of endogenous alpha, as measured with EEG, may be used as a simple marker to pre-select those individuals likely to benefit from this approach. PMID:26663460

  7. Variation in left posterior parietal-motor cortex interhemispheric facilitation following right parietal continuous theta-burst stimulation in healthy adults.

    PubMed

    Killington, Christopher; Barr, Christopher; Loetscher, Tobias; Bradnam, Lynley V

    2016-08-25

    Spatial neglect is modeled on an imbalance of interhemispheric inhibition (IHI); however evidence is emerging that it may not explain neglect in all cases. The aim of this study was to investigate the IHI imbalance model of visual neglect in healthy adults, using paired pulse transcranial magnetic stimulation to probe excitability of projections from posterior parietal cortex (PPC) to contralateral primary motor cortex (M1) bilaterally. Motor-evoked potentials (MEPs) were recorded from the first dorsal interossei and facilitation was determined as ratio of conditioned to non-conditioned MEP amplitude. A laterality index reflecting the balance of excitability between the two hemispheres was calculated. A temporal order judgment task (TOJ) assessed visual attention. Continuous theta-burst stimulation was used to transiently suppress right parietal cortex activity and the effect on laterality and judgment task measured, along with associations between baseline and post stimulation measures. Stimulation had conflicting results on laterality, with most participants demonstrating an effect in the negative direction with no decrement in the TOJ task. Correlation analysis suggests a strong association between laterality direction and degree of facilitation of left PPC-to right M1 following stimulation (r=.902), with larger MEP facilitation at baseline demonstrating greater reduction (r=-.908). Findings indicate there was relative balance between the cortices at baseline but right PPC suppression did not evoke left PPC facilitation in most participants, contrary to the IHI imbalance model. Left M1 facilitation prior to stimulation may predict an individual's response to continuous theta-burst stimulation of right PPC. PMID:27267243

  8. [Perioperative Pain Management of Minimally Invasive Esophagectomy with Bilateral Continuous Thoracic Paravertebral Block].

    PubMed

    Hida, Kumiko; Murata, Hiroaki; Sakai, Akiko; Ogami, Keiko; Maekawa, Takuji; Hara, Tetsuya

    2016-02-01

    Minimally invasive esophagectomy has become popular as a surgical procedure for esophageal cancer. We describe bilateral continuous thoracic paravertebral blocks for perioperative pain management in 3 patients who underwent minimally invasive esophagectomy. After anesthesia induction, bilateral thoracic paravertebral catheters were placed under ultrasound guidance with the patients in left lateral decubitus position at the sixth or seventh right intercostal space and eighth or ninth left intercostal space, respectively. Multiple ports for thoracoscopic procedures were located between the right third and ninth intercostal spaces. Laparoscopy-assisted gastric tube reconstruction was performed with skin incisions at bilateral T7-10 dermatomes. Intraoperative intermittent bolus injections of ropivacaine through the thoracic paravertebral catheters were used in combination with sevoflurane-remifentanil anesthesia, followed by continuous thoracic paravertebral infusion of ropivacaine for postoperative analgesia with continuous intravenous fentanyl infusion and periodical intravenous acetaminophen administration. Numerical rating scales of postoperative pain at rest and when coughing were 4 or less for 48 hr after surgery. No complications related to thoracic paravertebral catheterization were observed. Bilateral continuous thoracic paravertebral blocks at different intercostal levels can provide good perioperative analgesia for minimally invasive esophagectomy. PMID:27017762

  9. Continuous Theta Burst Stimulation (cTBS) on Left Cerebellar Hemisphere Affects Mental Rotation Tasks during Music Listening

    PubMed Central

    Picazio, Silvia; Oliveri, Massimiliano; Koch, Giacomo; Caltagirone, Carlo; Petrosini, Laura

    2013-01-01

    Converging evidence suggests an association between spatial and music domains. A cerebellar role in music-related information processing as well as in spatial-temporal tasks has been documented. Here, we investigated the cerebellar role in the association between spatial and musical domains, by testing performances in embodied (EMR) or abstract (AMR) mental rotation tasks of subjects listening Mozart Sonata K.448, which is reported to improve spatial-temporal reasoning, in the presence or in the absence of continuous theta burst stimulation (cTBS) of the left cerebellar hemisphere. In the absence of cerebellar cTBS, music listening did not influence either MR task, thus not revealing a “Mozart Effect”. Cerebellar cTBS applied before musical listening made subjects faster (P = 0.005) and less accurate (P = 0.005) in performing the EMR but not the AMR task. Thus, cerebellar inhibition by TBS unmasked the effect of musical listening on motor imagery. These data support a coupling between music listening and sensory-motor integration in cerebellar networks for embodied representations. PMID:23724071

  10. Asymmetry in the dorsolateral prefrontal cortex and aggressive behavior: a continuous theta-burst magnetic stimulation study.

    PubMed

    Perach-Barzilay, N; Tauber, A; Klein, E; Chistyakov, A; Ne'eman, R; Shamay-Tsoory, S G

    2013-01-01

    Aggressive behavior is aimed at causing damage or pain to another individual. Aggression has been associated with structural and functional deficits in numerous brain areas, including the dorsolateral region of the prefrontal cortex (DLPFC), typically related to inhibition and impulse control. In this study, we used inhibitory continuous theta-burst magnetic stimulation (cTBS) to explore the role of the right and left DLPFC in aggression. Sixteen healthy right-handed volunteers underwent two sessions involving random, real and sham, right and left DLPFC stimulations. These sessions were followed by the Social Orientation Paradigm (SOP), a monetary task that was specially designed to assess participants' aggressive tendencies by measuring the patterns of their reactive aggression (a response to a perceived provocation) and proactive aggression (an aggressive act with goal-oriented purposes). Results indicate that using cTBS to target the left DLPFC was associated with a greater increase in aggressive responses than right DLPFC stimulation. This pattern of results was found for both reactive and proactive types of aggressive reactions. It is concluded that DLPFC asymmetry is involved in modulating reactive and proactive aggression. Our results are in line with recent studies suggesting that the left DLPFC plays a major role in aggressive behavior. PMID:22963204

  11. Behavioral effects and neural changes induced by continuous and not continuous treadmill training, post bilateral cerebral ischemia in gerbils.

    PubMed

    Kitabatake, Takae Tamy; Marini, Luana de Castro; Gonçalves, Renata Batagini; Bertolino, Guilherme; de Souza, Hugo Celso Dutra; de Araujo, João Eduardo

    2015-09-15

    This study aims to investigate the effects of treadmill training and the possible influences of the start, regularity, and duration after experimental ischemic stroke. We performed bilateral occlusion of both the carotid arteries for 5 min in Mongolian gerbils. The training groups were: continuous training for 5 consecutive days or not continuous training for 3 non-consecutive days. The groups remained in the treadmill for 15 min, and the training started 12 or 24h after the stroke. In the activity cage (AC), behaviors of crossing and distance traveled were registered. The forced motor behavior was analyzed by a Rota Rod test. After the experiments, the brains were perfused, and coronal sections of the striatum, motor cortex M1, and CA1 area of the hippocampus were cut and stained with hematoxylin and eosin. Behavioral and morphological data analysis was performed by an ANOVA and MANCOVA. Results showed an increased density of neurons in the CA1 area of the hippocampus, motor cortex M1, and the striatum in ischemic training groups compared to the not training ischemic groups. Animals subjected to continuous training that started 24h after ischemia showed a satisfactory behavior in the AC and a higher number of striatal neurons when compared to ischemic animals. The animals in the not continuous training started 12h after the stroke showed an unsatisfactory performance in the AC and Rota Rod. These findings suggest that early training and not continuous training are inadequate for motor behavior improvement after stroke. PMID:25975174

  12. Lead isotopes reveal bilateral asymmetry and vertical continuity in the Hawaiian mantle plume.

    PubMed

    Abouchami, W; Hofmann, A W; Galer, S J G; Frey, F A; Eisele, J; Feigenson, M

    2005-04-14

    The two parallel chains of Hawaiian volcanoes ('Loa' and 'Kea') are known to have statistically different but overlapping radiogenic isotope characteristics. This has been explained by a model of a concentrically zoned mantle plume, where the Kea chain preferentially samples a more peripheral portion of the plume. Using high-precision lead isotope data for both centrally and peripherally located volcanoes, we show here that the two trends have very little compositional overlap and instead reveal bilateral, non-concentric plume zones, probably derived from the plume source in the mantle. On a smaller scale, along the Kea chain, there are isotopic differences between the youngest lavas from the Mauna Kea and Kilauea volcanoes, but the 550-thousand-year-old Mauna Kea lavas are isotopically identical to Kilauea lavas, consistent with Mauna Kea's position relative to the plume, which was then similar to that of present-day Kilauea. We therefore conclude that narrow (less than 50 kilometres wide) compositional streaks, as well as the larger-scale bilateral zonation, are vertically continuous over tens to hundreds of kilometres within the plume. PMID:15829954

  13. U.S.-CHINA RADIOLOGICAL SOURCE SECURITY PROJECT: CONTINUING AND EXPANDING BILATERAL COOPERATION

    SciTech Connect

    Zhu, Zhixuan; Zhou, Qifu; Yang, Yaoyun; Huang, Chaoyun; Lloyd, James; Williams, Adam; Feldman, Alexander; Streeper, Charles; Pope, Noah G.; Hawk, Mark; Rawl, Rick; Howell, Randy A.; Kennedy, Catherine

    2009-10-07

    The successful radiological security cooperation between the U.S. and China to secure at-risk sites near venues of the 2008 Beijing Summer Olympics has led to an expanded bilateral nonproliferation cooperation scope. The U.S. Department of Energy’s National Nuclear Security Administration, the Chinese Atomic Energy Authority and the China Ministry of Environmental Protection are continuing joint efforts to secure radiological sources throughout China under the U.S.-China Peaceful Uses of Nuclear Technology (PUNT) Agreement. Joint cooperation activities include physical security upgrades of sites with International Atomic Energy Agency (IAEA) Category 1 radiological sources, packaging, recovery, and storage of high activity transuranic and beta gamma sources, and secure transportation practices for the movement of recovered sources. Expansion of cooperation into numerous provinces within China includes the use of integrated training workshops that will demonstrate methodologies and best practices between U.S. and Chinese radiological source security and recovery experts. The fiscal year 2009 expanded scope of cooperation will be conducted similar to the 2008 Olympic cooperation with the Global Threat Reduction Initiative taking the lead for the U.S., PUNT being the umbrella agreement, and Los Alamos, Sandia, and Oak Ridge National Laboratories operating as technical working groups. This paper outlines the accomplishments of the joint implementation and training efforts to date and discusses the possible impact on future U.S./China cooperation.

  14. Surgical Considerations and Challenges for Bilateral Continuous-Flow Durable Device Implantation.

    PubMed

    Maltais, Simon; Womack, Sara; Davis, Mary E; Danter, Matthew R; Kushwaha, Sudhir S; Stulak, John M; Haglund, Nicholas

    2016-01-01

    The concept of biventricular support with durable centrifugal pumps is evolving, and the surgical strategy and best practice guidelines for implantation of right-sided devices are still unknown. We present optimal strategy for bilateral HeartWare continuous-flow ventricular assist device (HVAD) implantation in a series of four patients. Patients were implanted with the HVAD pumps simultaneously or sequentially. This report offers a perspective on surgical considerations such as right ventricular positioning, implications related to potential risks of obstruction from the tricuspid apparatus, the role if any of downsizing the outflow anastomosis, and considerations for speed adjustments. In this series, one patient died on support and three patients experienced pump thrombosis requiring device revision. All other patients survived until orthotopic heart transplantation, although one of these patients died from perioperative complications, 2 days posttransplantation. Surgical management of patients with medically refractory biventricular heart failure remains challenging and associated with a high incidence of pump thrombosis. Best practice guidelines from experts' consensus are still needed to address this challenging population. PMID:26479465

  15. Continuous nicotinamide administration improves behavioral recovery and reduces lesion size following bilateral frontal controlled cortical impact injury.

    PubMed

    Vonder Haar, Cole; Anderson, Gail D; Hoane, Michael R

    2011-10-31

    Previous research has demonstrated considerable preclinical efficacy of nicotinamide (NAM; vitamin B(3)) in animal models of TBI with systemic dosing at 50 and 500 mg/kg yielding improvements on sensory, motor, cognitive and histological measures. The current study aimed to utilize a more specific dosing paradigm in a clinically relevant delivery mechanism: continuously secreting subcutaneous pumps. A bilateral frontal controlled cortical impact (CCI) or sham surgery was performed and rats were treated with NAM (150 mg/kg day) or saline (1 ml/kg) pumps 30 min after CCI, continuing until seven days post-CCI. Rats were given a loading dose of NAM (50mg/kg) or saline (1 ml/kg) following pump implant. Rats received behavioral testing (bilateral tactile adhesive removal, locomotor placing task and Morris water maze) starting on day two post-CCI and were sacrificed at 31 days post-CCI and brains were stained to examine lesion size. NAM-treated rats had reductions in sensory, motor and cognitive behavioral deficits compared to vehicle-treated rats. Specifically, NAM-treated rats significantly improved on the bilateral tactile adhesive removal task, locomotor placing task and the reference memory paradigm of the Morris water maze. Lesion size was also significantly reduced in the NAM-treated group. The results from this study indicate that at the current dose, NAM produces beneficial effects on recovery from a bilateral frontal brain injury and that it may be a relevant compound to be explored in human studies. PMID:21704653

  16. Multiple blocks of intermittent and continuous theta-burst stimulation applied via transcranial magnetic stimulation differently affect sensory responses in rat barrel cortex

    PubMed Central

    Thimm, Andreas; Funke, Klaus

    2015-01-01

    Cortical sensory processing varies with cortical state and the balance of inhibition to excitation. Repetitive transcranial magnetic stimulation (rTMS) has been shown to modulate human cortical excitability. In a rat model, we recently showed that intermittent theta-burst stimulation (iTBS) applied to the corpus callosum, to activate primarily supragranular cortical pyramidal cells but fewer subcortical neurons, strongly reduced the cortical expression of parvalbumin (PV), indicating reduced activity of fast-spiking interneurons. Here, we used the well-studied rodent barrel cortex system to test how iTBS and continuous TBS (cTBS) modulate sensory responses evoked by either single or double stimuli applied to the principal (PW) and/or adjacent whisker (AW) in urethane-anaesthetized rats. Compared to sham stimulation, iTBS but not cTBS particularly enhanced late (>18 ms) response components of multi-unit spiking and local field potential responses in layer 4 but not the very early response (<18 ms). Similarly, only iTBS diminished the suppression of the second response evoked by paired PW or AW–PW stimulation at 20 ms intervals. The effects increased with each of the five iTBS blocks applied. With cTBS a mild effect similar to that of iTBS was first evident after 4–5 stimulation blocks. Enhanced cortical c-Fos and zif268 expression but reduced PV and GAD67 expression was found only after iTBS, indicating increased cortical activity due to lowered inhibition. We conclude that iTBS but less cTBS may primarily weaken a late recurrent-type cortical inhibition mediated via a subset of PV+ interneurons, enabling stronger late response components believed to contribute to the perception of sensory events. PMID:25504571

  17. Differential effects of continuous theta burst stimulation over left premotor cortex and right prefrontal cortex on modulating upper limb somatosensory input.

    PubMed

    Brown, Matt J N; Staines, W Richard

    2016-02-15

    Somatosensory evoked potentials (SEPs) represent somatosensory processing in non-primary motor areas (i.e. frontal N30 and N60) and somatosensory cortices (i.e. parietal P50). It is well-known that the premotor cortex (PMC) and prefrontal cortex (PFC) are involved in the preparation and planning of upper limb movements but it is currently unclear how they modulate somatosensory processing for upper limb motor control. In the current study, two experiments examined SEP modulations after continuous theta burst stimulation (cTBS) was used to transiently disrupt the left PMC (Experiment 1) and right PFC (Experiment 2). Both Experiment 1 (n=15) and Experiment 2 (n=16) used pre-post experimental designs. In both experiments participants performed a task requiring detection of varying amplitudes of attended vibrotactile (VibT) stimuli to the left index finger (D2) and execution of a pre-matched finger sequence with the right (contralateral) hand to specific VibT targets. During the task, SEPs were measured to median nerve (MN) stimulations time-locked during pre-stimulus (250 ms before VibT), early response selection (250 ms after VibT), late preparatory (750 ms after VibT) and execution (1250 ms VibT) phases. The key findings of Experiment 1 revealed significant decreases in N30 and N60 peak amplitudes after cTBS to PMC. In contrast, the results of Experiment 2, also found significant decreased N60 peak amplitudes as well as trends for increased N30 and P50 peak amplitudes. A direct comparison of Experiment 1 and Experiment 2 confirmed differential modulation of N30 peak amplitudes after PMC (gated) compared to PFC (enhanced) cTBS. Collectively, these results support that both the left PMC and right PFC have modulatory roles on early somatosensory input into non-primary motor areas, such as PMC and supplementary motor area (SMA), represented by frontal N30 and N60 SEPs. These results confirm that PMC and PFC are both part of a network that regulates somatosensory input

  18. Continuous bilateral infusion of vigabatrin into the subthalamic nucleus: Effects on seizure threshold and GABA metabolism in two rat models.

    PubMed

    Gey, Laura; Gernert, Manuela; Löscher, Wolfgang

    2016-07-01

    The subthalamic nucleus (STN) plays a crucial role as a regulator of basal ganglia outflow but also influences the activity of cortical and limbic structures, so that it is widely used as a therapeutic target in different brain diseases, including epilepsy. In addition to electrical stimulation of the STN, targeted delivery of anti-seizure drugs to the STN may constitute an alternative treatment approach in patients with pharmacoresistant epilepsy. In the present experimental study, we investigated the anti-seizure and adverse effects of chronic infusion of vigabatrin into the STN of rats. Vigabatrin is a clinically approved anti-seizure drug, which acts by increasing brain GABA levels by irreversibly inhibiting GABA-aminotransferase (GABA-T). Based on functional and neurochemical effects of acute STN microinjection, doses for continuous infusion were calculated and administered, using an innovative drug infusion technology. Bilateral infusion of only 10μg/day vigabatrin over 3weeks into the STN resulted in an almost complete inhibition of GABA-T and 4-fold increase in GABA in the target region, which was associated with a significant increase in seizure threshold, determined once weekly by i.v. infusion of pentylenetetrazole (PTZ). Lower doses or unilateral infusion were less effective, both on PTZ seizures and on kindled seizures. Bilateral infusion into substantia nigra pars reticulata was less effective and more toxic than STN infusion. In part of the rats, tolerance to the anti-seizure effect developed. The data demonstrate that chronic administration of very low, nontoxic doses of vigabatrin into STN is an effective means of increasing local GABA concentrations and seizure threshold. PMID:26976738

  19. [Safe and Effective Analgesia with Bilateral Continuous TAP Block for a Patient with Marfan Syndrome after Open Abdominal Aortic Aneurysm Repair].

    PubMed

    Katakura, Yumi; Sakurai, Asako; Endo, Masaru; Hamada, Takako; Nomoto, Mayuko; Yamada, Hiroshi; Takeda, Koji

    2016-06-01

    A patient with Marfan syndrome underwent emergency open abdominal aortic aneurysm repair. She was referred to our department for postoperative analgesia. Taking the risk of possible dural ectasia into consideration, we avoided epidural block. Alternatively, we performed bilateral continuous transversus abdominis plane (TAP) block with sufficient analgesia. Lumbosacral dural ectasia is frequently observed in patients with Marfan syndrome. A few reports described that their fragile dura may contribute to an increased risk of dural puncture and postdural puncture headache (PDPH). Thus, in planning neuraxial block for a patient with Marfan syndrome, the possible consequences of lumbosacral dural ectasia should be considered. A case we herein present shows bilateral continuous TAP block could be a safe and effective alternative to epidural block. PMID:27483660

  20. Resting state theta band source distribution and functional connectivity in remitted schizophrenia.

    PubMed

    Shreekantiah Umesh, D; Tikka, Sai Krishna; Goyal, Nishant; Nizamie, S Haque; Sinha, Vinod Kumar

    2016-09-01

    Increased resting theta activity is one consistent observation occurring during all the phases of schizophrenia. However, the resting theta oscillations during the remission phase are yet unclear. We studied resting theta current source density and functional connectivity in remitted schizophrenia and compared with healthy controls. Significantly increased current source density was found in the dominant anterior cingulate cortex. Increased connectivity between the inferior parietal lobe bilaterally and between the left inferior parietal lobe and right middle frontal gyrus was also found. It may be concluded that schizophrenia patients have aberrant regional theta band current source density and functional connectivity even during remission. PMID:27484634

  1. Understanding the theta aurora

    NASA Astrophysics Data System (ADS)

    Fear, Robert; Milan, Steve; Carter, Jennifer; Maggiolo, Romain; Fazakerley, Andrew; Dandouras, Iannis; Mende, Stephen

    2015-04-01

    The theta aurora, first observed by Dynamics Explorer in the 1980s, is a configuration of the Earth's aurora in which auroral emissions extend into and across the polar cap in the form of a transpolar arc. It is well established that the theta aurora occurs predominantly when the interplanetary magnetic field has a northward component, but over the last thirty years various mechanisms have been put forward to explain this intriguing phenomenon. In the last couple of years, a range of evidence has accumulated which strongly suggests that the transpolar arc is formed as proposed by Milan et al. (2005): magnetotail reconnection occurs during intervals of northward IMF, which results in a local "wedge" of closed magnetospheric flux that remains trapped in the magnetotail. Precipitation on these closed field lines results in the transpolar arc analogously to the formation of the aurora in the main oval. Evidence for magnetotail reconnection as the cause of the theta aurora includes the timescales necessary to influence the location at which the transpolar arc forms, and the presence of characteristic ionospheric flows which are excited by magnetotail reconnection and which are statistically associated with transpolar arcs (Fear & Milan, 2012a,b). Most recently, direct observation has been made of a localised wedge of closed magnetic flux, "trapped" in the lobe, which was observed to move back and forth in a manner which (to our knowledge) can only be explained by the magnetotail reconnection mechanism (Fear et al., 2014). In this talk, we summarise the evidence for the formation of the theta aurora by magnetotail reconnection, and discuss the remaining challenges in obtaining a comprehensive understanding of this spectacular phenomenon.

  2. Ramanujan's mock theta functions.

    PubMed

    Griffin, Michael; Ono, Ken; Rolen, Larry

    2013-04-01

    In his famous deathbed letter, Ramanujan introduced the notion of a mock theta function, and he offered some alleged examples. Recent work by Zwegers [Zwegers S (2001) Contemp Math 291:268-277 and Zwegers S (2002) PhD thesis (Univ of Utrecht, Utrecht, The Netherlands)] has elucidated the theory encompassing these examples. They are holomorphic parts of special harmonic weak Maass forms. Despite this understanding, little attention has been given to Ramanujan's original definition. Here, we prove that Ramanujan's examples do indeed satisfy his original definition. PMID:23536292

  3. Peak frequency in the theta and alpha bands correlates with human working memory capacity.

    PubMed

    Moran, Rosalyn J; Campo, Pablo; Maestu, Fernando; Reilly, Richard B; Dolan, Raymond J; Strange, Bryan A

    2010-01-01

    Theta oscillations in the local field potential of neural ensembles are considered key mediators of human working memory. Theoretical accounts arising from animal hippocampal recordings propose that the phase of theta oscillations serves to instantiate sequential neuronal firing to form discrete representations of items held online. Human evidence of phase relationships in visual working memory has enhanced this theory, implicating long theta cycles in supporting greater memory capacity. Here we use human magnetoencephalographic recordings to examine a novel, alternative principle of theta functionality. The principle we hypothesize is derived from information theory and predicts that rather than long (low frequency) theta cycles, short (high frequency) theta cycles are best suited to support high information capacity. From oscillatory activity recorded during the maintenance period of a visual working memory task we show that a network of brain regions displays an increase in peak 4-12 Hz frequency with increasing memory load. Source localization techniques reveal that this network comprises bilateral prefrontal and right parietal cortices. Further, the peak of oscillation along this theta-alpha frequency axis is significantly higher in high capacity individuals compared to low capacity individuals. Importantly while we observe the adherence of cortical neuronal oscillations to our novel principle of theta functioning, we also observe the traditional inverse effect of low frequency theta maintaining high loads, where critically this was located in medial temporal regions suggesting parallel, dissociable hippocampal-centric, and prefrontal-centric theta mechanisms. PMID:21206531

  4. The theta aurora

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Craven, J. D.; Gurnett, D. A.; Shawhan, S. D.; Burch, J. L.; Winningham, J. D.; Chappell, C. R.; Waite, J. H.; Maynard, N. C.; Sugiura, M.

    1986-01-01

    A comprehensive review is presented of the characteristics of theta aurora as revealed from four imaging efforts with the DE 1 and 2 satellites. The theta aurora consists of an auroral oval with a sun-aligned arc extending from the dayside to the nightside sectors of the oval. The DE 1 spacecraft provided high altitude simultaneous measurements of the electric and magnetic fields and plasma and the DE 2 collected equivalent low altitude data on the four events. The plasma was found to convect sunward when the transpolar arc appeared, while the convection was antisunward in other regions over the polar cap. The arc plasmas featured field-aligned electron acceleration into the polar atmosphere and field-aligned current sheets, both of which were sparse over the rest of the polar cap. The ions originated in the ionosphere and the solar wind; ions over the rest of the polar cap mainly arrived from the magnetosphere. Further discussions are provided of the dominant electrons and ions and the associated flow directions into and out of the various regions of the pole, similarities between the transpolar arc and the auroral oval, and interactions between the ionosphere and the auroral phenomena.

  5. Theta vocabulary II. Multidimensional case

    NASA Astrophysics Data System (ADS)

    Kharchev, S.; Zabrodin, A.

    2016-06-01

    It is shown that the Jacobi and Riemann identities of degree four for the multidimensional theta functions as well as the Weierstrass identities emerge as algebraic consequences of the fundamental multidimensional binary identities connecting the theta functions with Riemann matrices τ and 2 τ.

  6. Feasibility and Safety of Continuous and Chronic Bilateral Deep Brain Stimulation of the Medial Forebrain Bundle in the Naïve Sprague-Dawley Rat

    PubMed Central

    Furlanetti, Luciano L.; Döbrössy, Máté D.; Aranda, Iñigo A.; Coenen, Volker A.

    2015-01-01

    Objective. Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (MFB) has provided rapid and dramatic reduction of depressive symptoms in a clinical trial. Early intracranial self-stimulation experiments of the MFB suggested detrimental side effects on the animals' health; therefore, the current study looked at the viability of chronic and continuous MFB-DBS in rodents, with particular attention given to welfare issues and identification of stimulated pathways. Methods. Sprague-Dawley female rats were submitted to stereotactic microelectrode implantation into the MFB. Chronic continuous DBS was applied for 3–6 weeks. Welfare monitoring and behavior changes were assessed. Postmortem histological analysis of c-fos protein expression was carried out. Results. MFB-DBS resulted in mild and temporary weight loss in the animals, which was regained even with continuing stimulation. MFB-DBS led to increased and long-lasting c-fos expression in target regions of the mesolimbic/mesocortical system. Conclusions. Bilateral continuous chronic MFB-DBS is feasible, safe, and without impact on the rodent's health. MFB-DBS results in temporary increase in exploration, which could explain the initial weight loss, and does not produce any apparent behavioral abnormalities. This platform represents a powerful tool for further preclinical investigation of the MFB stimulation in the treatment of depression. PMID:25960609

  7. Successful treatment of Raynaud’s syndrome in a lupus patient with continuous bilateral popliteal sciatic nerve blocks: a case report

    PubMed Central

    Dao, Thuan; Amaro-Driedger, David; Mehta, Jaideep

    2016-01-01

    Raynaud’s syndrome has been treated medically and invasively, sometimes with regional anesthesia leading up to sympathectomy. We demonstrate that regional anesthesia was in this case a useful technique that can allow some patients to find temporary but significant relief from symptoms of Raynaud’s syndrome exacerbation. We present a 43-year-old woman with Raynaud’s syndrome secondary to lupus who was treated with bilateral popliteal nerve block catheters for ischemic pain and necrosis of her feet; this led to almost immediate resolution of her pain and return of color and function of her feet. While medical management should continue to be a front-line treatment for Raynaud’s syndrome, regional anesthesia can be useful in providing rapid dissipation of symptoms and may thus serve as a viable option for short-term management of this syndrome. PMID:27366104

  8. Resonances, and mechanisms of Theta-production

    SciTech Connect

    Ya.I. Azimov; I.I. Strakovsky

    2004-09-01

    After explaining necessity of exotic hadrons, we discuss mechanisms which could determine production of the exotic Theta-baryon. A possible important role of resonances (producing the Theta in real or virtual decays) is emphasized for various processes. Several experimental directions for studies of such resonances, and the Theta itself, are suggested. We briefly discuss also recent negative results on the Theta-baryon.

  9. Bilateral cellulitis.

    PubMed

    Batra, Vivek; Baras, Alexander

    2015-01-01

    We present a case of bilateral lesions in a 50-year-old man, which were on first impression mistaken for and initially treated as bilateral cellulitis. We propose that bilateral cellulitis, as opposed to unilateral, is rare and that other aetiologies should be considered in evaluating a patient with bilateral lesions. The differential diagnosis includes stasis-dermatitis, lipodermatosclerosis, lymphoedema and vascular lesions such as Kaposi sarcoma, as was identified in this case. Early consultation with dermatology and biopsy in unclear cases mitigates the unnecessary use of prolonged antibiotics, antibiotic resistance and Clostridium difficile infections. HIV testing is an essential screening test in all adults who present with non-specific viral symptoms and rash. PMID:26392449

  10. Theta EEG neurofeedback benefits early consolidation of motor sequence learning.

    PubMed

    Rozengurt, Roman; Barnea, Anat; Uchida, Sunao; Levy, Daniel A

    2016-07-01

    Procedural learning is subject to consolidation processes believed to depend on the modulation of functional connections involved in representing the acquired skill. While sleep provides the most commonly studied framework for such consolidation processes, posttraining modulation of oscillatory brain activity may also impact on plasticity processes. Under the hypothesis that consolidation of motor learning is associated with theta band activity, we used EEG neurofeedback (NFB) to enable participants to selectively increase either theta or beta power in their EEG spectra following the acquisition phase of motor sequence learning. We tested performance on a motor task before and after training, right after the NFB session to assess immediate NFB effects, 1 day after NFB to assess interaction between NFB effects and overnight sleep-dependent stabilization, and 1 week after the initial session, to assess the effects of NFB on long-term stabilization of motor training. We also explored the extent of the influence of single-electrode NFB on EEG recorded across the scalp. Results revealed a significantly greater improvement in performance immediately after NFB in the theta group than in the beta group. This effect continued for testing up to 1 week following training. Across participants, post-NFB improvement correlated positively with theta/beta ratio change achieved during NFB. Additionally, NFB was found to cause widespread band-power modulation beyond the electrode used for feedback. Thus, upregulating postlearning theta power may yield contributions to the immediate performance and subsequent consolidation of an acquired motor skill. PMID:27080752

  11. On Ramanujan's definition of mock theta function.

    PubMed

    Rhoades, Robert C

    2013-05-01

    In his famous "deathbed" letter, Ramanujan "defined" the notion of a mock theta function and offered some examples of functions he believed satisfied his definition. Very recently, Griffin et al. established for the first time that Ramanujan's mock theta functions actually satisfy his own definition. On the other hand, Zwegers' 2002 doctoral thesis [Zwegers S (2002) Mock theta functions. PhD thesis (Univ Utrecht, Utrecht, The Netherlands)] showed that all of Ramanujan's examples are holomorphic parts of harmonic Maass forms. This has led to an alternate definition of a mock theta function. This paper shows that Ramanujan's definition of mock theta function is not equivalent to the modern definition. PMID:23625007

  12. Theta oscillations during the processing of monetary loss and gain: A perspective on gender and impulsivity

    PubMed Central

    Kamarajan, Chella; Rangaswamy, Madhavi; Chorlian, David B.; Manz, Niklas; Tang, Yongqiang; Pandey, Ashwini K.; Roopesh, Bangalore N.; Stimus, Arthur T.; Porjesz, Bernice

    2008-01-01

    Event-related oscillations (EROs) have proved to be very useful in the understanding of a variety of neurocognitive processes including reward/outcome processing. In the present study, theta power (4.0–7.0 Hz) following outcome stimuli in the time window of the N2-P3 complex (200–500 ms) was analyzed in healthy normals (20 males and 20 females) while performing a gambling task that involved monetary loss and gain. The main aim was to analyze outcome processing in terms of event-related theta power in the context of valence, amount, gender, and impulsivity. The S-transform was used for the signal processing of the ERO data in terms of time-frequency-power. Results from filtered waveforms showed a partially consistent phase-alignment of the increased theta activity corresponding to N2 and P3 components following the outcome stimuli. Gain conditions produced more theta power than loss conditions. While there was anterior involvement in both gain and loss, posterior activation was stronger during gain conditions than during loss conditions. Females exhibited posterior maxima during gain conditions while males had an anterior maxima during both loss and gain conditions. The current source density of theta activity in females involved larger areas of the scalp including a bilateral frontal activity while males predominantly had a frontal midline activity. Theta power was significantly higher in females than males across all conditions. Low theta (4.0–5.5 Hz) predominantly contributed to the posterior activity during gain conditions. High theta (5.5–7.0 Hz) was more associated with impulsivity measures than low theta activity. These findings may offer valuable clues to understand outcome processing, impulsivity, and gender differences. PMID:18616934

  13. Ketamine disrupts theta modulation of gamma in a computer model of hippocampus

    PubMed Central

    Neymotin, Samuel A.; Lazarewicz, Maciej T.; Sherif, Mohamed; Contreras, Diego; Finkel, Leif H.; Lytton, William W.

    2011-01-01

    Abnormalities in oscillations have been suggested to play a role in schizophrenia. We studied theta-modulated gamma oscillations in a computer model of hippocampal CA3 in vivo with and without simulated application of ketamine, an NMDA receptor antagonist and psychotomimetic. Networks of 1200 multi-compartment neurons (pyramidal, basket and oriens-lacunosum moleculare, OLM, cells) generated theta and gamma oscillations from intrinsic network dynamics: basket cells primarily generated gamma and amplified theta, while OLM cells strongly contributed to theta. Extrinsic medial septal inputs paced theta and amplified both theta and gamma oscillations. Exploration of NMDA receptor reduction across all location combinations demonstrated that the experimentally-observed ketamine effect occurred only with isolated reduction of NMDA receptors on OLMs. In the ketamine simulations, lower OLM activity reduced theta power and disinhibited pyramidal cells, resulting in increased basket cell activation and gamma power. Our simulations predict: ketamine increases firing rates;oscillations can be generated by intrinsic hippocampal circuits;medial septum inputs pace and augment oscillations;pyramidal cells lead basket cells at the gamma peak but lag at trough;basket cells amplify theta rhythms;ketamine alters oscillations due to primary blockade at OLM NMDA receptors;ketamine alters phase relationships of cell firing;ketamine reduces network responsivity to the environmentketamine effect could be reversed by providing a continuous inward current to OLM cells. We suggest that this last prediction has implications for a possible novel treatment for cognitive deficits of schizophrenia by targeting OLM cells. PMID:21832203

  14. Bilateral Sagittal Split Osteotomy

    PubMed Central

    Monson, Laura A.

    2013-01-01

    The bilateral sagittal split osteotomy is an indispensable tool in the correction of dentofacial abnormalities. The technique has been in practice since the late 1800s, but did not reach widespread acceptance and use until several modifications were described in the 1960s and 1970s. Those modifications came from a desire to make the procedure safer, more reliable, and more predictable with less relapse. Those goals continue to stimulate innovation in the field today and have helped the procedure evolve to be a very dependable, consistent method of correction of many types of malocclusion. The operative surgeon should be well versed in the history, anatomy, technical aspects, and complications of the bilateral sagittal split osteotomy to fully understand the procedure and to counsel the patient. PMID:24872760

  15. Traveling Theta Waves in the Human Hippocampus.

    PubMed

    Zhang, Honghui; Jacobs, Joshua

    2015-09-01

    The hippocampal theta oscillation is strongly correlated with behaviors such as memory and spatial navigation, but we do not understand its specific functional role. One hint of theta's function came from the discovery in rodents that theta oscillations are traveling waves that allow parts of the hippocampus to simultaneously exhibit separate oscillatory phases. Because hippocampal theta oscillations in humans have different properties compared with rodents, we examined these signals directly using multielectrode recordings from neurosurgical patients. Our findings confirm that human hippocampal theta oscillations are traveling waves, but also show that these oscillations appear at a broader range of frequencies compared with rodents. Human traveling waves showed a distinctive pattern of spatial propagation such that there is a consistent phase spread across the hippocampus regardless of the oscillations' frequency. This suggests that traveling theta oscillations are important functionally in humans because they coordinate phase coding throughout the hippocampus in a consistent manner. Significance statement: We show for the first time in humans that hippocampal theta oscillations are traveling waves, moving along the length of the hippocampus in a posterior-anterior direction. The existence of these traveling theta waves is important for understanding hippocampal neural coding because they cause neurons at separate positions in the hippocampus to experience different theta phases simultaneously. The theta phase that a neuron measures is a key factor in how that cell represents behavioral information. Therefore, the existence of traveling theta waves indicates that, to fully understand how a hippocampal neuron represents information, it is vital to also account for that cell's location in addition to conventional measures of neural activity. PMID:26354915

  16. Numerical experiments on the theta pinch

    NASA Technical Reports Server (NTRS)

    Volosevich, P. P.; Zukakishyili, G. G.

    1979-01-01

    Numerical calculation of theta pinch problems are presented. Physical processes in theta pinch systems are considered in a one dimensional, two temperature magnetohydrodynamic, approximation with allowance for end losses by longitudinal heat conductivity. The numerical calculations are compared with results of earlier experiments.

  17. Event-related delta and theta synchronization during explicit and implicit emotion processing.

    PubMed

    Knyazev, G G; Slobodskoj-Plusnin, J Y; Bocharov, A V

    2009-12-29

    Emotion information processing may occur in two modes which are differently represented in conscious awareness. Fast online processing involves coarse-grained analysis of salient features, and is not represented in conscious awareness; offline processing takes hundreds of milliseconds to generate fine-grained analysis, and is represented in conscious awareness. These processing modes may be studied using event-related electroencephalogram theta and delta synchronization as a marker of emotion processing. Two experiments were conducted, which differed on the mode of emotional information presentation. In the explicit mode subjects were explicitly instructed to evaluate the emotional content of presented stimuli; in the implicit mode they performed a gender discrimination task. Firstly, we show that in both experiments theta and delta synchronization is stronger upon presentation of "emotional" than "neutral" stimuli, and in subjects who are more sensitive, or experience higher emotional involvement than in less sensitive or detached subjects. Secondly, we show that in the implicit mode theta and delta synchronization is more pronounced in an early (before 250 ms post-stimulus) processing stage, whereas in the explicit mode it is more pronounced in a later processing stage. Source localization analysis showed that implicit processing of angry and happy (relative to neutral) faces is associated with higher early (before 250 ms) theta synchronization in the right parietal cortex and the right insula, respectively. Explicit processing of angry and happy faces is associated with higher late (after 250 ms) theta synchronization in the left temporal lobe and bilateral prefrontal cortex, respectively. PMID:19796666

  18. Coherent theta-band EEG activity predicts item-context binding during encoding.

    PubMed

    Summerfield, Christopher; Mangels, Jennifer A

    2005-02-01

    Episodic memories consist of semantic information coupled with a rich array of contextual detail. Here, we investigate the neural processes by which information about the sensory context of a learning event is "bound" to the semantic representation of the to-be-encoded item. We present evidence that item-context binding during encoding is mediated by frontoposterior electroencephalographic (EEG) phase locking within and between hemispheres in the theta (4-8 Hz) band. During a task in which subjects encoded words in different font colors, later memory for the word was associated with sustained frontal theta activity and frontoposterior theta-band coherence, primarily within the left hemisphere. When the word-color association was later successfully retrieved, however, neurons synchronized their theta-band responses bilaterally in a more sustained fashion, particularly during the latter part of the stimulus epoch (>800 ms). Our results confirm the importance of functional coupling between frontal and posterior regions for successful encoding. One interpretation of these data is hemispheric contributions to item and context encoding may be asymmetric, with left hemisphere coherence facilitating semantic processing of an item and right hemisphere coherence facilitating processing of sensory context. Theta-band coherence may be an important mechanism by which brain networks exchange information during learning. PMID:15652304

  19. Developmental change in EEG theta activity in the medial prefrontal cortex during response control.

    PubMed

    Liu, Zhong-Xu; Woltering, Steven; Lewis, Marc D

    2014-01-15

    Cognitive control functions continue to improve from infancy until early adulthood, allowing flexible adaptation to a complex environment. However, it remains controversial how this development in cognitive capabilities is mediated by changes in cortical activity: both age-related increases and decreases of mediofrontal neural activity have been observed and interpreted as neural underpinnings of this functional development. To better understand this developmental process, we examined EEG theta activity in the mediofrontal region using a Go/No-go response control task. We found that both pre-stimulus baseline theta-power and theta-power during the response control task, without baseline-correction, decreased with age. Conversely, when task-related theta-power was baseline corrected (using a ratio method), it exhibited a positive developmental trajectory. The age-related theta-power increase was source-localized to the anterior cingulate cortex. This increase in theta activity also partially mediated age-related improvements in response control and was greatest in a condition that demanded greater effort. Theta activity in older children also showed greater temporal reliability across trials as measured by inter-trial phase-coherence. Interestingly, directly subtracting baseline activity from task-related activity did not yield significant developmental effects, which highlights the necessity of separating and contrasting the pre-stimulus baseline with task-related processing in the understanding of neurodevelopmental changes. PMID:24007804

  20. Emotional conflict processing induce boosted theta oscillation.

    PubMed

    Ma, Jianling; Liu, Chang; Chen, Xu

    2015-05-19

    Although previous studies have reported the neural correlates and dynamics of emotional conflict processing, the neural oscillatory features of such processing remain unclear. The present study uses time-frequency analysis to determine the event-related spectral perturbation (ERSP) characteristics underlying emotional conflict processing. Our behavioral results replicate previous findings of shorter response times and fewer response errors under the congruent condition relative to the incongruent condition, indicating a robust interference effect. Theta oscillatory activity was larger for the incongruent than for the congruent condition over frontal and frontal-central midline areas, reflecting a greater need for control under conditions of conflict. Moreover, the theta power difference was negatively associated with the RT difference, indicating that greater theta power leads to better behavioral performance. The present findings provide evidence that the theta oscillation is necessary for the control of emotional conflict. PMID:25863173

  1. Note on trigonometric expansions of theta functions

    NASA Astrophysics Data System (ADS)

    Chouikha, A. Raouf

    2003-04-01

    We are interested in properties of coefficients of certain expansions of the classical theta functions. We show that they are solutions of a differential system derived from the heat equation. We plan to explicitly give expressions of these coefficients.

  2. Human hippocampal theta activity during virtual navigation.

    PubMed

    Ekstrom, Arne D; Caplan, Jeremy B; Ho, Emily; Shattuck, Kirk; Fried, Itzhak; Kahana, Michael J

    2005-01-01

    This study examines whether 4-8-Hz theta oscillations can be seen in the human hippocampus, and whether these oscillations increase during virtual movement and searching, as they do in rodents. Recordings from both hippocampal and neocortical depth electrodes were analyzed while six epileptic patients played a virtual taxi-driver game. During the game, the patients alternated between searching for passengers, whose locations were random, and delivering them to stores, whose locations remained constant. In both hippocampus and neocortex, theta increased during virtual movement in all phases of the game. Hippocampal and neocortical theta activity were also significantly correlated with each other, but this correlation did not differ between neocortex and hippocampus and within disparate neocortical electrodes. Our findings demonstrate the existence of movement-related theta oscillations in human hippocampus, and suggest that both cortical and hippocampal oscillations play a role in attention and sensorimotor integration. PMID:16114040

  3. Adaptive [theta]-methods for pricing American options

    NASA Astrophysics Data System (ADS)

    Khaliq, Abdul Q. M.; Voss, David A.; Kazmi, Kamran

    2008-12-01

    We develop adaptive [theta]-methods for solving the Black-Scholes PDE for American options. By adding a small, continuous term, the Black-Scholes PDE becomes an advection-diffusion-reaction equation on a fixed spatial domain. Standard implementation of [theta]-methods would require a Newton-type iterative procedure at each time step thereby increasing the computational complexity of the methods. Our linearly implicit approach avoids such complications. We establish a general framework under which [theta]-methods satisfy a discrete version of the positivity constraint characteristic of American options, and numerically demonstrate the sensitivity of the constraint. The positivity results are established for the single-asset and independent two-asset models. In addition, we have incorporated and analyzed an adaptive time-step control strategy to increase the computational efficiency. Numerical experiments are presented for one- and two-asset American options, using adaptive exponential splitting for two-asset problems. The approach is compared with an iterative solution of the two-asset problem in terms of computational efficiency.

  4. Speech encoding by coupled cortical theta and gamma oscillations.

    PubMed

    Hyafil, Alexandre; Fontolan, Lorenzo; Kabdebon, Claire; Gutkin, Boris; Giraud, Anne-Lise

    2015-01-01

    Many environmental stimuli present a quasi-rhythmic structure at different timescales that the brain needs to decompose and integrate. Cortical oscillations have been proposed as instruments of sensory de-multiplexing, i.e., the parallel processing of different frequency streams in sensory signals. Yet their causal role in such a process has never been demonstrated. Here, we used a neural microcircuit model to address whether coupled theta-gamma oscillations, as observed in human auditory cortex, could underpin the multiscale sensory analysis of speech. We show that, in continuous speech, theta oscillations can flexibly track the syllabic rhythm and temporally organize the phoneme-level response of gamma neurons into a code that enables syllable identification. The tracking of slow speech fluctuations by theta oscillations, and its coupling to gamma-spiking activity both appeared as critical features for accurate speech encoding. These results demonstrate that cortical oscillations can be a key instrument of speech de-multiplexing, parsing, and encoding. PMID:26023831

  5. Distinct representations and theta dynamics in dorsal and ventral hippocampus

    PubMed Central

    Royer, Sébastien; Sirota, Anton; Patel, Jagdish; Buzsáki, György

    2010-01-01

    Although anatomical, lesion and imaging studies of the hippocampus indicate qualitatively different information processing along its septo-temporal axis, physiological mechanisms supporting such distinction are missing. We found fundamental differences between the dorsal (dCA3) and the ventral-most parts (vCA3) of the hippocampus in both environmental representation and temporal dynamics. Discrete place fields of dCA3 neurons evenly covered all parts of the testing environments. In contrast, vCA3 neurons i) rarely showed continuous two-dimensional place fields, ii) differentiated open and closed arms of a radial maze, and iii) discharged similar firing patterns with respect to the goals, both on multiple arms of a radial maze and during opposite journeys in a zig-zag maze. In addition, theta power and the fraction of theta-rhythmic neurons were substantially reduced in the ventral as compared to dorsal hippocampus. We hypothesize that the spatial representation in the septo-temporal axis of the hippocampus is progressively decreased. This change is paralleled with a reduction of theta rhythm and an increased representation of non-spatial information. PMID:20130187

  6. Subthalamic nucleus local field potential activity during the Eriksen flanker task reveals a novel role for theta phase during conflict monitoring.

    PubMed

    Zavala, Baltazar; Brittain, John-Stuart; Jenkinson, Ned; Ashkan, Keyoumars; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Green, Alexander L; Aziz, Tipu; Zaghloul, Kareem; Brown, Peter

    2013-09-11

    The subthalamic nucleus (STN) is thought to play a central role in modulating responses during conflict. Computational models have suggested that the location of the STN in the basal ganglia, as well as its numerous connections to conflict-related cortical structures, allows it to be ideally situated to act as a global inhibitor during conflict. Additionally, recent behavioral experiments have shown that deep brain stimulation to the STN results in impulsivity during high-conflict situations. However, the precise mechanisms that mediate the "hold-your-horses" function of the STN remain unclear. We recorded from deep brain stimulation electrodes implanted bilaterally in the STN of 13 human subjects with Parkinson's disease while they performed a flanker task. The incongruent trials with the shortest reaction times showed no behavioral or electrophysiological differences from congruent trials, suggesting that the distracter stimuli were successfully ignored. In these trials, cue-locked STN theta band activity demonstrated phase alignment across trials and was followed by a periresponse increase in theta power. In contrast, incongruent trials with longer reaction times demonstrated a relative reduction in theta phase alignment followed by higher theta power. Theta phase alignment negatively correlated with subject reaction time, and theta power positively correlated with trial reaction time. Thus, when conflicting stimuli are not properly ignored, disruption of STN theta phase alignment may help operationalize the hold-your-horses role of the nucleus, whereas later increases in the amplitude of theta oscillations may help overcome this function. PMID:24027276

  7. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze.

    PubMed

    Hernández-Pérez, J Jesús; Gutiérrez-Guzmán, Blanca E; López-Vázquez, Miguel Á; Olvera-Cortés, María E

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  8. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze

    PubMed Central

    Hernández-Pérez, J. Jesús; Gutiérrez-Guzmán, Blanca E.; López-Vázquez, Miguel Á.; Olvera-Cortés, María E.

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  9. Frequency-Specific Synchronization in the Bilateral Subthalamic Nuclei Depending on Voluntary Muscle Contraction and Relaxation in Patients with Parkinson’s Disease

    PubMed Central

    Kato, Kenji; Yokochi, Fusako; Iwamuro, Hirokazu; Kawasaki, Takashi; Hamada, Kohichi; Isoo, Ayako; Kimura, Katsuo; Okiyama, Ryoichi; Taniguchi, Makoto; Ushiba, Junichi

    2016-01-01

    The volitional control of muscle contraction and relaxation is a fundamental component of human motor activity, but how the processing of the subcortical networks, including the subthalamic nucleus (STN), is involved in voluntary muscle contraction (VMC) and voluntary muscle relaxation (VMR) remains unclear. In this study, local field potentials (LFPs) of bilateral STNs were recorded in patients with Parkinson’s disease (PD) while performing externally paced VMC and VMR tasks of the unilateral wrist extensor muscle. The VMC- or VMR-related oscillatory activities and their functional couplings were investigated over the theta (4–7 Hz), alpha (8–13 Hz), beta (14–35 Hz), and gamma (40–100 Hz) frequency bands. Alpha and beta desynchronizations were observed in bilateral STNs at the onset of both VMC and VMR tasks. On the other hand, theta and gamma synchronizations were prominent in bilateral STNs specifically at the onset of the VMC task. In particular, just after VMC, theta functional coupling between the bilateral STNs increased, and the theta phase became coupled to the gamma amplitude within the contralateral STN in a phase-amplitude cross-frequency coupled manner. On the other hand, the prominent beta-gamma cross-frequency couplings observed in the bilateral STNs at rest were reduced by the VMC and VMR tasks. These results suggest that STNs are bilaterally involved in the different performances of muscle contraction and relaxation through the theta-gamma and beta-gamma networks between bilateral STNs in patients with PD. PMID:27064969

  10. Analysis of matrix cracking and local delamination in (O/theta/-theta)sub s graphite epoxy laminates under tension load

    NASA Technical Reports Server (NTRS)

    Salpekar, S. A.; O'Brien, T. K.

    1991-01-01

    Several 3D finite element analyses of (O/theta/-theta)sub s graphite epoxy laminates, where theta = 15, 20, 25, 30, and 45 deg, subjected to axial tension load were performed. The interlaminar stresses in the theta/-theta interface were calculated with and without a matrix crack in the central -theta plies. The interlaminar normal stress changes from a small compressive stress when no matrix crack is present to a high tensile stress at the intersection of the matrix crack and free edge. The analysis of local delamination from the -theta matrix crack indicates a high strain energy release rate and a localized mode I component near the free edge, within one ply distance from the matrix crack. In order to examine the stress state causing the matrix cracking the maximum principal normal stress in a plane perpendicular to the fiber direction in the -theta ply was calculated in an uncracked laminate. The corresponding shear stress parallel to the fiber was also calculated. The principal normal stress at the laminate edge increases through the ply thickness and reached a very high tensile value at the theta/-theta interface indicating that the crack in the -theta ply may initiate at the theta/-theta interface. Crack profiles on the laminate edge in the -theta ply were constructed from the principal stress directions. The cracks were found to be more curved for layups with smaller theta angles, which is consistent with experimental observations in the literature.

  11. Analysis of matrix cracking and local delamination in (0/theta/-theta)sub s graphite epoxy laminates under tension load

    NASA Technical Reports Server (NTRS)

    Salpekar, S. A.; Obrien, T. K.

    1991-01-01

    Several 3D finite element analyses of (0/theta/-theta)sub s graphite epoxy laminates, where theta=15, 20, 25, 30, and 45 deg, subjected to axial tension load were performed. The interlaminar stresses in the theta/-theta interface were calculated with and without a matrix crack in the central -theta plies. The interlaminar normal stress changes from a small compressive stress when no matrix crack is present to a high tensile stress at the intersection of the matrix crack and free edge. The analysis of local delamination from the -theta matrix crack indicates a high strain energy release rate and a localized mode I component near the free edge, within one ply distance from the matrix crack. In order to examine the stress state causing the matrix cracking the maximum principal normal stress in a plane perpendicular to the fiber direction in the -theta ply was calculated in an uncracked laminate. The corresponding shear stress parallel to the fiber was also calculated. The principal normal stress at the laminate edge increases through the ply thickness and reached a very high tensile value at the theta/-theta interface indicating that the crack in the -theta ply may initiate at the theta/-theta interface. Crack profiles on the laminate edge in the -theta ply were constructed from the principal stress directions. The cracks were found to be more curved for layups with smaller theta angles, which is consistent with experimental observations in the literature.

  12. Measuring Theta_13 at Daya Bay

    SciTech Connect

    Lau, Kwong

    2014-03-14

    We measured the neutrino mixing angle, theta13, presumably related to the preponderance of matter over antimatter in our universe with high precision. We determined theta13 by measuring the disappearance of neutrinos from a group of six nuclear reactors. The target, located inside a mountain at about 2 km from the reactors, is 80 tons of liquid scintillator doped with trace amount of Gadolinium to increase its neutron detection efficiency. The neutrino flux is measured by the inverse beta-decay reaction where the final-state particles are detected by the liquid scintillator. The measured value of theta13, based on data collected over 3 years, is large, around 8 degrees, rendering the measurement of the parameter related to matter-antimatter asymmetry in future long baseline neutrino experiments easier.

  13. Frontal-posterior theta oscillations reflect memory retrieval during sentence comprehension.

    PubMed

    Meyer, Lars; Grigutsch, Maren; Schmuck, Noura; Gaston, Phoebe; Friederici, Angela D

    2015-10-01

    Successful working-memory retrieval requires that items be retained as distinct units. At the neural level, it has been shown that theta-band oscillatory power increases with the number of to-be-distinguished items during working-memory retrieval. Here we hypothesized that during sentence comprehension, verbal-working-memory retrieval demands lead to increased theta power over frontal cortex, supposedly supporting the distinction amongst stored items during verbal-working-memory retrieval. Also, synchronicity may increase between the frontal cortex and the posterior cortex, with the latter supposedly supporting item retention. We operationalized retrieval by using pronouns, which refer to and trigger the retrieval of antecedent nouns from a preceding sentence part. Retrieval demand was systematically varied by changing the pronoun antecedent: Either, it was non-embedded in the preceding main clause, and thus easy-to-retrieve across a single clause boundary, or embedded in the preceding subordinate clause, and thus hard-to-retrieve across a double clause boundary. We combined electroencephalography (EEG), scalp-level time-frequency analysis, source localization, and source-level coherence analysis, observing a frontal-midline and broad left-hemispheric theta-power increase for embedded-antecedent compared to non-embedded-antecedent retrieval. Sources were localized to left-frontal, left-parietal, and bilateral-inferior-temporal cortices. Coherence analyses suggested synchronicity between left-frontal and left-parietal and between left-frontal and right-inferior-temporal cortices. Activity of an array of left-frontal, left-parietal, and bilateral-inferior-temporal cortices may thus assist retrieval during sentence comprehension, potentially indexing the orchestration of item distinction, verbal working memory, and long-term memory. Our results extend prior findings by mapping prior knowledge on the functional role of theta oscillations onto processes genuine to human

  14. Analysis of matrix cracking and local delamination in (0/theta/-theta)s graphite epoxy laminates under tensile load

    NASA Technical Reports Server (NTRS)

    Salpekar, S. A.; O'Brien, T. K.

    1993-01-01

    Three-dimensional element analyses of (0/theta/-theta)s graphite epoxy laminates, where theta = 15, 20, 25, 30, and 45 deg, subjected to axial tensile load, were performed. The interlaminar stresses in the theta/-theta interface were calculated with and without a matrix crack in the central -theta plies. The interlaminar normal stress changes from a small compressive stress when no matrix crack is present to a high tensile stress at the intersection of the matrix crack and the free edge. The analysis of local delamination from the -theta matrix crack indicates a high strain energy release rate and a localized Mode I component near the free edge, within one-ply distance from the matrix crack. To examine the stress state causing the matrix cracking, the maximum principal normal stress in a plane perpendicular to the fiber direction in the -theta ply was calculated in an uncracked laminate. The corresponding shear stress parallel to the fiber was also calculated. The principal normal stress at the laminate edge increased through the ply thickness and reached a very high tensile value at the theta/-theta interface indicating that the crack in the -theta ply may initiate at the theta/-theta interface.

  15. Hippocampal theta, gamma, and theta-gamma coupling: effects of aging, environmental change, and cholinergic activation

    PubMed Central

    Jacobson, Tara K.; Howe, Matthew D.; Schmidt, Brandy; Hinman, James R.; Escabí, Monty A.

    2013-01-01

    Hippocampal theta and gamma oscillations coordinate the timing of multiple inputs to hippocampal neurons and have been linked to information processing and the dynamics of encoding and retrieval. One major influence on hippocampal rhythmicity is from cholinergic afferents. In both humans and rodents, aging is linked to impairments in hippocampus-dependent function along with degradation of cholinergic function. Cholinomimetics can reverse some age-related memory impairments and modulate oscillations in the hippocampus. Therefore, one would expect corresponding changes in these oscillations and possible rescue with the cholinomimetic physostigmine. Hippocampal activity was recorded while animals explored a familiar or a novel maze configuration. Reexposure to a familiar situation resulted in minimal aging effects or changes in theta or gamma oscillations. In contrast, exploration of a novel maze configuration increased theta power; this was greater in adult than old animals, although the deficit was reversed with physostigmine. In contrast to the theta results, the effects of novelty, age, and/or physostigmine on gamma were relatively weak. Unrelated to the behavioral situation were an age-related decrease in the degree of theta-gamma coupling and the fact that physostigmine lowered the frequency of theta in both adult and old animals. The results indicate that age-related changes in gamma and theta modulation of gamma, while reflecting aging changes in hippocampal circuitry, seem less related to aging changes in information processing. In contrast, the data support a role for theta and the cholinergic system in encoding and that hippocampal aging is related to impaired encoding of new information. PMID:23303862

  16. Human Hippocampal Theta Oscillations during Movement without Visual Cues.

    PubMed

    Qasim, Salman E; Jacobs, Joshua

    2016-03-16

    The hippocampus exhibits theta oscillations when animals navigate. Vass et al. (2016) discovered that theta oscillations are also present when humans are moved through a virtual environment without sensory feedback, indicating that theta oscillations have a general role in spatial cognition beyond sensorimotor processing. PMID:26985718

  17. Further study of the theta component of the interplanetary magnetic field.

    NASA Technical Reports Server (NTRS)

    Rosenberg, R. L.; Coleman, P. J., Jr.; Ness, N. F.

    1973-01-01

    Measurements of the interplanetary magnetic field taken with Imp 3, Pioneer 6, and Explorer 34 constitute a large portion of the data available at low and moderate solar activity and provide nearly continuous coverage from mid-1965 through 1966 without radial effects. Study of these observations provides further evidence for the following B sub theta effect initially discovered with Mariners 2, 4, and 5. At low or moderate solar activity, the mean value of B sub theta is negative (approximately northward in the observations) above the solar equatorial plane and positive below it for an interplanetary field directed outward from the sun, and vice versa for an inward field. Thus, for an outward field, the r-theta component of a line of magnetic force above or below the equatorial plane was skewed relative to the average value of r in the direction away from the equatorial plane. Comparisons between different spacecraft are discussed.

  18. Electromagnetic theta gun and tubular projectiles

    SciTech Connect

    Burgess, T.J.; Cnare, E.C.; Oberkampf, W.L.; Beard, S.G.; Cowan, M.

    1980-12-01

    Unlike the better known rail gun, the theta gun applies the propelling force along the length of its projectile. This is shown to allow much greater acceleration of high fineness ratio projectiles for a given barrel pressure, allowing much shorter barrels for military applications. A computer code which simulates performance of the theta gun is described and experimental results from a few simple, low energy experiments show close agreement with code predictions. Trajectories and aerodynamic heating for three candidate military projectiles are calculated for vertical and horizontal atmospheric launches where initial velocity is as high as 3 km/s. The calculations indicate that in some cases a thin layer of heatshield (ablator) will be required to control projectile heating.

  19. Speech encoding by coupled cortical theta and gamma oscillations

    PubMed Central

    Hyafil, Alexandre; Fontolan, Lorenzo; Kabdebon, Claire; Gutkin, Boris; Giraud, Anne-Lise

    2015-01-01

    Many environmental stimuli present a quasi-rhythmic structure at different timescales that the brain needs to decompose and integrate. Cortical oscillations have been proposed as instruments of sensory de-multiplexing, i.e., the parallel processing of different frequency streams in sensory signals. Yet their causal role in such a process has never been demonstrated. Here, we used a neural microcircuit model to address whether coupled theta–gamma oscillations, as observed in human auditory cortex, could underpin the multiscale sensory analysis of speech. We show that, in continuous speech, theta oscillations can flexibly track the syllabic rhythm and temporally organize the phoneme-level response of gamma neurons into a code that enables syllable identification. The tracking of slow speech fluctuations by theta oscillations, and its coupling to gamma-spiking activity both appeared as critical features for accurate speech encoding. These results demonstrate that cortical oscillations can be a key instrument of speech de-multiplexing, parsing, and encoding. DOI: http://dx.doi.org/10.7554/eLife.06213.001 PMID:26023831

  20. [Bilateral operculum syndrome].

    PubMed

    Lerman-Sagie, T; Porat-Alkabetz, E; Meir, J J; Harel, S

    1996-09-01

    The bilateral operculum syndrome, is a unique developmental syndrome. It is characterized by spastic paralysis of the muscles of the face, pharynx, and of mastication, as well as by epilepsy and mental retardation. Imaging studies show bilateral, structural abnormalities in the frontal, perisylvian region consistent with polymicrogyria. These children are usually diagnosed as suffering from cerebral palsy, but in the bilateral operculum syndrome, intelligence is relatively preserved despite the severe motor involvement. Misdiagnosis may lead to improper estimation of rehabilitation potential preventing appropriate therapy, especially in the field of alternative communication. We present a 3-year-old boy, apparently the first case of this syndrome to be described in Israel. PMID:8940497

  1. Progressive Fracture of [0/90/ + or - Theta]s Composite Structure Under Uniform Pressure Load

    NASA Technical Reports Server (NTRS)

    Gotsis, Pascalis K.; Chamis, Christos C.; Gotsis, Christos K.; Mouratidis, Ericos

    2007-01-01

    S-Glass/epoxy [0/90/plus or minus theta]s for theta =45 deg., 60 deg., and 75 deg. laminated fiber-reinforced composite stiffened plate was simulated to investigated for damage and fracture progression under uniform pressure. An integrated computer code was augmented for the simulation of the damage initiation, growth, accumulation, and propagation to fracture and to structural collapse. Results show in detail the damage progression sequence and structural fracture resistance during different degradation stages. Damage through the thickness of the laminate initiated first at [0/90/plus or minus 45]s at 15.168 MPa (2200 psi), followed by [0/90/plus or minus 60]s at 16.96 MPa (2460 psi) and finally by [0/90/plus or minus 75]s at 19.3 MPa (2800 psi). After damage initiation happened the cracks propagate rapidly to structural fracture.

  2. [Bilateral segmental neurofibromatosis].

    PubMed

    Rose, I; Vakilzadeh, F

    1991-12-01

    Segmental neurofibromatosis is a rare type of neurofibromatosis. We report a case of bilateral manifestation, review the literature on this extremely uncommon variant, and discuss the possible causative mechanisms and the genetic risk of segmental neurofibromatosis. PMID:1765491

  3. Alpha and theta brain oscillations index dissociable processes in spoken word recognition.

    PubMed

    Strauß, Antje; Kotz, Sonja A; Scharinger, Mathias; Obleser, Jonas

    2014-08-15

    Slow neural oscillations (~1-15 Hz) are thought to orchestrate the neural processes of spoken language comprehension. However, functional subdivisions within this broad range of frequencies are disputed, with most studies hypothesizing only about single frequency bands. The present study utilizes an established paradigm of spoken word recognition (lexical decision) to test the hypothesis that within the slow neural oscillatory frequency range, distinct functional signatures and cortical networks can be identified at least for theta- (~3-7 Hz) and alpha-frequencies (~8-12 Hz). Listeners performed an auditory lexical decision task on a set of items that formed a word-pseudoword continuum: ranging from (1) real words over (2) ambiguous pseudowords (deviating from real words only in one vowel; comparable to natural mispronunciations in speech) to (3) pseudowords (clearly deviating from real words by randomized syllables). By means of time-frequency analysis and spatial filtering, we observed a dissociation into distinct but simultaneous patterns of alpha power suppression and theta power enhancement. Alpha exhibited a parametric suppression as items increasingly matched real words, in line with lowered functional inhibition in a left-dominant lexical processing network for more word-like input. Simultaneously, theta power in a bilateral fronto-temporal network was selectively enhanced for ambiguous pseudowords only. Thus, enhanced alpha power can neurally 'gate' lexical integration, while enhanced theta power might index functionally more specific ambiguity-resolution processes. To this end, a joint analysis of both frequency bands provides neural evidence for parallel processes in achieving spoken word recognition. PMID:24747736

  4. Echinoderms Have Bilateral Tendencies

    PubMed Central

    Zhao, Wenchan; Wang, Sishuo; Lv, Jianhao

    2012-01-01

    Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present. PMID:22247765

  5. Successful Reconstruction of Asymptomatic Bilateral External Carotid Artery Aneurysms.

    PubMed

    Loja, Melissa N; Pevec, William C

    2016-04-01

    True aneurysms of the external carotid artery (ECA) are extremely rare with an unknown incidence and natural history. We present the successful operative management of an asymptomatic 65-year-old man found to have bilateral internal carotid artery stenosis and bilateral ECA aneurysms. His bilateral carotid arteries were reconstructed with bifurcated interposition grafts in a staged fashion. The patient recovered without sequelae and continues to be asymptomatic 1 year after reconstruction. We present the operative management of this rare case. PMID:26802292

  6. Theta oscillations accompanying concurrent auditory stream segregation.

    PubMed

    Tóth, Brigitta; Kocsis, Zsuzsanna; Urbán, Gábor; Winkler, István

    2016-08-01

    The ability to isolate a single sound source among concurrent sources is crucial for veridical auditory perception. The present study investigated the event-related oscillations evoked by complex tones, which could be perceived as a single sound and tonal complexes with cues promoting the perception of two concurrent sounds by inharmonicity, onset asynchrony, and/or perceived source location difference of the components tones. In separate task conditions, participants performed a visual change detection task (visual control), watched a silent movie (passive listening) or reported for each tone whether they perceived one or two concurrent sounds (active listening). In two time windows, the amplitude of theta oscillation was modulated by the presence vs. absence of the cues: 60-350ms/6-8Hz (early) and 350-450ms/4-8Hz (late). The early response appeared both in the passive and the active listening conditions; it did not closely match the task performance; and it had a fronto-central scalp distribution. The late response was only elicited in the active listening condition; it closely matched the task performance; and it had a centro-parietal scalp distribution. The neural processes reflected by these responses are probably involved in the processing of concurrent sound segregation cues, in sound categorization, and response preparation and monitoring. The current results are compatible with the notion that theta oscillations mediate some of the processes involved in concurrent sound segregation. PMID:27170058

  7. Bilateral popliteal arterial dissection.

    PubMed

    Chen, Po-Liang; Ko, Shih-Yu; Tan, Ken-Hing

    2012-01-01

    A clinical feature of bilateral popliteal arterial dissection without involving the descending aorta, bilateral iliac, as well as femoral arteries has never been reported in the past literature. We report a 56-year-old man with hypertension and coronary artery disease who presented to our emergency department with complaints of bilateral knee pain after long-distance walking. Physical examination was notable for elevated blood pressure, but there was no palpable pulsation over dorsalis pedis arteries on his feet. Laboratory evaluation revealed a d-dimer level of 35.2 mg/L (FEU) on the day of the test and 1.2 mg/L one and a half months ago (normal level, <0.55). These findings were suggestive of a recent-onset peripheral arterial occlusive disorder. Computed tomography of the aorta showed bilateral popliteal arterial dissection with arterial intimal flap. Abdominal aorta, bilateral iliac, and femoral arteries remained intact with only arteriosclerotic change. Minimally invasive endovascular stent grafting was then performed. The patient had an uneventful recovery. PMID:21106320

  8. [Bilateral caudate head infarcts].

    PubMed

    Kuriyama, N; Yamamoto, Y; Akiguchi, I; Oiwa, K; Nakajima, K

    1997-11-01

    We reported a 67-year-old woman with bilateral caudate head infarcts. She developed sudden mutism followed by abulia. She was admitted to our hospital 2 months after ictus for further examination. She showed prominent abulia and was inactive, slow and apathetic. Spontaneous activity and speech, immediate response to queries, spontaneous word recall and attention and persistence to complex programs were disturbed. Apparent motor disturbance, gait disturbance, motor aphasia, apraxia and remote memory disturbance were not identified. She seemed to be depressed but not sad. Brain CT and MRI revealed bilateral caudate head hemorrhagic infarcts including bilateral anterior internal capsules, in which the left lesion was more extensive than right one and involved the part of the left putamen. These infarct locations were thought to be supplied by the area around the medial striate artery including Heubner's arteries and the A1 perforator. Digital subtraction angiography showed asymptomatic right internal carotid artery occlusion. She bad had hypertension, diabetes mellitus and atrial fibrillation and also had a left atrium with a large diameter. The infarcts were thought to be caused by cardioembolic occlusion to the distal portion of the left internal carotid artery. Although some variations of vasculature at the anterior communicating artery might contribute to bilateral medial striate artery infarcts, we could not demonstrate such abnormalities by angiography. Bilateral caudate head infarcts involving the anterior internal capsule may cause prominent abulia. The patient did not improve by drug and rehabilitation therapy and died suddenly a year after discharge. PMID:9503974

  9. Bilateral inferior turbinate osteoma.

    PubMed

    Sahemey, R; Warfield, A T; Ahmed, S

    2016-01-01

    Osteomas are the most common benign osteoclastic tumours of the paranasal sinuses. However, nasal cavity and turbinate osteomas are extremely rare. Only nine middle turbinate, three inferior turbinate and one inferior turbinate osteoma cases have been reported to date. The present case report describes the management and follow-up of symptomatic bilateral inferior turbinate osteoma.A 60-year-old female presented with symptoms of bilateral nasal obstruction and right-sided epiphora. Radiological investigation found hypertrophic bony changes involving both inferior turbinates. The patient was managed successfully by endoscopic inferior turbinectomies in order to achieve a patent airway, with no further recurrence of tumour after 3 months postoperatively.To the best of our knowledge, this is the first reported case of bilateral inferior turbinate osteoma. We describe a safe and minimally invasive method of tumour resection, which has a better cosmetic outcome compared with other approaches. PMID:27534890

  10. Efficacy of bilateral pallidotomy.

    PubMed

    Kim, R; Alterman, R; Kelly, P J; Fazzini, E; Eidelberg, D; Beric, A; Sterio, D

    1997-03-15

    Unilateral pallidotomy is a safe and effective treatment for medically refractory bradykinetic Parkinson's disease, especially in those patients with levodopa-induced dyskinesia and severe on-off fluctuations. The efficacy of bilateral pallidotomy is less certain. The authors completed 11 of 12 attempted bilateral pallidotomies among 150 patients undergoing pallidotomy at New York University. In all but one patient, the pallidotomies were separated by at least 9 months. Patients were selected for bilateral pallidotomy if they exhibited bilateral rigidity, bradykinesia, or levodopa-induced dyskinesia prior to treatment or if they exhibited disease progression contralateral to their previously treated side. The Unified Parkinson's Disease Rating Scale (UPDRS) and timed upper-extremity tasks of the Core Assessment Protocol for Intracerebral Transplantation (CAPIT) were administered to all 12 patients in the "off" state (12 hours without receiving medications) preoperatively and again at 6 and 12 months after each procedure. The median UPDRS and contralateral CAPIT scores improved 60% following the initial procedure (p = 0.008, Wilcoxon rank sums test). The second pallidotomy generated only an additional 10% improvement in the UPDRS and CAPIT scores ipsilateral to the original procedure (p = 0.05). Worsened speech was observed in two cases. In the 12th case, total speech arrest was noted during test stimulation. Speech returned within minutes after stimulation was halted. Lesioning was not performed. These results indicate that bilateral pallidotomy has a narrow therapeutic window. Motor improvement ipsilateral to the first lesion leaves little room for further improvement from the second lesion and the risk of speech deficit is greatly enhanced. Chronic pallidal stimulation contralateral to a previously successful pallidotomy may prove to be a safer alternative for the subset of patients who require bilateral procedures. PMID:15096015

  11. Bilateral ovarian Burkitt's lymphoma.

    PubMed

    Gutiérrez-García, L; Medina Ramos, N; García Rodríguez, R; Barber, M A; Arias, M D; García, J A

    2009-01-01

    Primary ovarian lymphoma is a rare entity. We submit a case of a 34-year-old black patient presenting with a bilateral adnexal tumor. She underwent hysterectomy with double salpingo-oophorectomy followed by polychemotherapy treatment. Histology confirmed Epstein-Barr virus-positive bilateral Burkitt's lymphoma. The patient died from septic shock after a month of treatment. Endemic Burkitt's lymphoma has a predilection for the female genital tract, manifesting itself clinically as a pelvic mass and less frequently as a menstrual disorder. It is a rare entity in our environment but should be kept in mind when treating patients of African origin. PMID:19480266

  12. Hippocampo-cerebellar theta band phase synchrony in rabbits.

    PubMed

    Wikgren, J; Nokia, M S; Penttonen, M

    2010-02-17

    Hippocampal functioning, in the form of theta band oscillation, has been shown to modulate and predict cerebellar learning of which rabbit eyeblink conditioning is perhaps the most well-known example. The contribution of hippocampal neural activity to cerebellar learning is only possible if there is a functional connection between the two structures. Here, in the context of trace eyeblink conditioning, we show (1) that, in addition to the hippocampus, prominent theta oscillation also occurs in the cerebellum, and (2) that cerebellar theta oscillation is synchronized with that in the hippocampus. Further, the degree of phase synchrony (PS) increased both as a response to the conditioning stimuli and as a function of the relative power of hippocampal theta oscillation. However, the degree of PS did not change as a function of either training or learning nor did it predict learning rate as the hippocampal theta ratio did. Nevertheless, theta band synchronization might reflect the formation of transient neural assemblies between the hippocampus and the cerebellum. These findings help us understand how hippocampal function can affect eyeblink conditioning, during which the critical plasticity occurs in the cerebellum. Future studies should examine cerebellar unit activity in relation to hippocampal theta oscillations in order to discover the detailed mechanisms of theta-paced neural activity. PMID:19945512

  13. Bilateral pisotriquetral loose bodies

    PubMed Central

    Williams, GR; Holland, P; Beazley, J; Hyder, N

    2012-01-01

    Case reports detailing diagnosis and effective treatment of pisotriquetral loose bodies are scarce. This article describes an even rarer case of bilateral pisotriquetral joint loose bodies, explores the relative diagnostic roles of magnetic resonance imaging versus computed tomography, and outlines effective strategies used for the management of this condition drawn from the literature and our own experience. PMID:22507708

  14. Bilateral periorbital ecthyma gangrenosum.

    PubMed

    Ghosheh, Faris R; Kathuria, Sajeev S

    2006-01-01

    We describe a case of bilateral periorbital ecthyma gangrenosum in a diabetic patient with renal failure. Ecthyma gangrenosum is a cutaneous manifestation of Pseudomonas sepsis. We briefly review the pathogenesis of ecthyma gangrenosum and discuss previous reports of periocular involvement. In our patient, conservative measures and supportive care of the periorbital tissue resulted in a good outcome. PMID:17117116

  15. Theta Phase Synchrony and Conscious Target Perception

    PubMed Central

    Slagter, Heleen A.; Lutz, Antoine; Greischar, Lawrence L.; Nieuwenhuis, Sander; Davidson, Richard J.

    2008-01-01

    The information processing capacity of the human mind is limited, as is evidenced by the attentional blink—a deficit in identifying the second of two targets (T1 and T2) presented in close succession. This deficit is thought to result from an overinvestment of limited resources in T1 processing. We previously reported that intensive mental training in a style of meditation aimed at reducing elaborate object processing, reduced brain resource allocation to T1, and improved T2 accuracy [Slagter, H. A., Lutz, A., Greisschar, L. L., Frances, A. D., Nieuwenhuis, S., Davis, J., et al. Mental training affects distribution of limited brain resources. PloS Biology, 5, e138, 2007]. Here we report EEG spectral analyses to examine the possibility that this reduction in elaborate T1 processing rendered the system more available to process new target information, as indexed by T2-locked phase variability. Intensive mental training was associated with decreased cross-trial variability in the phase of oscillatory theta activity after successfully detected T2s, in particular, for those individuals who showed the greatest reduction in brain resource allocation to T1. These data implicate theta phase locking in conscious target perception, and suggest that after mental training the cognitive system is more rapidly available to process new target information. Mental training was not associated with changes in the amplitude of T2-induced responses or oscillatory activity before task onset. In combination, these findings illustrate the usefulness of systematic mental training in the study of the human mind by revealing the neural mechanisms that enable the brain to successfully represent target information. PMID:18823234

  16. Neural circuits underlying the generation of theta oscillations.

    PubMed

    Pignatelli, Michele; Beyeler, Anna; Leinekugel, Xavier

    2012-01-01

    Theta oscillations represent the neural network configuration underlying active awake behavior and paradoxical sleep. This major EEG pattern has been extensively studied, from physiological to anatomical levels, for more than half a century. Nevertheless the cellular and network mechanisms accountable for the theta generation are still not fully understood. This review synthesizes the current knowledge on the circuitry involved in the generation of theta oscillations, from the hippocampus to extra hippocampal structures such as septal complex, entorhinal cortex and pedunculopontine tegmentum, a main trigger of theta state through direct and indirect projections to the septal complex. We conclude with a short overview of the perspectives offered by technical advances for deciphering more precisely the different neural components underlying the emergence of theta oscillations. PMID:21964249

  17. Learning to learn: theta oscillations predict new learning, which enhances related learning and neurogenesis.

    PubMed

    Nokia, Miriam S; Sisti, Helene M; Choksi, Monica R; Shors, Tracey J

    2012-01-01

    Animals in the natural world continuously encounter learning experiences of varying degrees of novelty. New neurons in the hippocampus are especially responsive to learning associations between novel events and more cells survive if a novel and challenging task is learned. One might wonder whether new neurons would be rescued from death upon each new learning experience or whether there is an internal control system that limits the number of cells that are retained as a function of learning. In this experiment, it was hypothesized that learning a task that was similar in content to one already learned previously would not increase cell survival. We further hypothesized that in situations in which the cells are rescued hippocampal theta oscillations (3-12 Hz) would be involved and perhaps necessary for increasing cell survival. Both hypotheses were disproved. Adult male Sprague-Dawley rats were trained on two similar hippocampus-dependent tasks, trace and very-long delay eyeblink conditioning, while recording hippocampal local-field potentials. Cells that were generated after training on the first task were labeled with bromodeoxyuridine and quantified after training on both tasks had ceased. Spontaneous theta activity predicted performance on the first task and the conditioned stimulus induced a theta-band response early in learning the first task. As expected, performance on the first task correlated with performance on the second task. However, theta activity did not increase during training on the second task, even though more cells were present in animals that had learned. Therefore, as long as learning occurs, relatively small changes in the environment are sufficient to increase the number of surviving neurons in the adult hippocampus and they can do so in the absence of an increase in theta activity. In conclusion, these data argue against an upper limit on the number of neurons that can be rescued from death by learning. PMID:22348078

  18. Theta, beta and gamma rate modulations in the developing auditory system.

    PubMed

    Vanvooren, Sophie; Hofmann, Michael; Poelmans, Hanne; Ghesquière, Pol; Wouters, Jan

    2015-09-01

    In the brain, the temporal analysis of many important auditory features relies on the synchronized firing of neurons to the auditory input rhythm. These so-called neural oscillations play a crucial role in sensory and cognitive processing and deviances in oscillatory activity have shown to be associated with neurodevelopmental disorders. Given the importance of neural auditory oscillations in normal and impaired sensory and cognitive functioning, there has been growing interest in their developmental trajectory from early childhood on. In the present study, neural auditory processing was investigated in typically developing young children (n = 40) and adults (n = 27). In all participants, auditory evoked theta, beta and gamma responses were recorded. The results of this study show maturational differences between children and adults in neural auditory processing at cortical as well as at brainstem level. Neural background noise at cortical level was shown to be higher in children compared to adults. In addition, higher theta response amplitudes were measured in children compared to adults. For beta and gamma rate modulations, different processing asymmetry patterns were observed between both age groups. The mean response phase was also shown to differ significantly between children and adults for all rates. Results suggest that cortical auditory processing of beta develops from a general processing pattern into a more specialized asymmetric processing preference over age. Moreover, the results indicate an enhancement of bilateral representation of monaural sound input at brainstem with age. A dissimilar efficiency of auditory signal transmission from brainstem to cortex along the auditory pathway between children and adults is suggested. These developmental differences might be due to both functional experience-dependent as well as anatomical changes. The findings of the present study offer important information about maturational differences between children

  19. Theta Oscillation Reveals the Temporal Involvement of Different Attentional Networks in Contingent Reorienting

    PubMed Central

    Chang, Chi-Fu; Liang, Wei-Kuang; Lai, Chiou-Lian; Hung, Daisy L.; Juan, Chi-Hung

    2016-01-01

    In the visual world, rapidly reorienting to relevant objects outside the focus of attention is vital for survival. This ability from the interaction between goal-directed and stimulus-driven attentional control is termed contingent reorienting. Neuroimaging studies have demonstrated activations of the ventral and dorsal attentional networks (DANs) which exhibit right hemisphere dominance, but the temporal dynamics of the attentional networks still remain unclear. The present study used event-related potential (ERP) to index the locus of spatial attention and Hilbert-Huang transform (HHT) to acquire the time-frequency information during contingent reorienting. The ERP results showed contingent reorienting induced significant N2pc on both hemispheres. In contrast, our time-frequency analysis found further that, unlike the N2pc, theta oscillation during contingent reorienting differed between hemispheres and experimental sessions. The inter-trial coherence (ITC) of the theta oscillation demonstrated that the two sides of the attentional networks became phase-locked to contingent reorienting at different stages. The left attentional networks were associated with contingent reorienting in the first experimental session whereas the bilateral attentional networks play a more important role in this process in the subsequent session. This phase-locked information suggests a dynamic temporal evolution of the involvement of different attentional networks in contingent reorienting and a potential role of the left ventral network in the first session. PMID:27375459

  20. Bilateral renal calculi

    PubMed Central

    Sreenevasan, G

    1974-01-01

    Bilateral renal calculi were present in 114 (10.7%) of 1,070 cases of proved urinary calculus admitted to the Urological Department of the General Hospital, Kuala Lumpur, during the period November 1968—May 1973. The management of bilateral renal calculi is discussed with reference to the first 100 cases in this series. The introduction of renography has greatly facilitated the decision as to which kidney should be operated on first. The management of patients with and without uraemia is discussed and the use of the modified V and V—Y incisions for the removal of staghorn calculi is described. Complications and results are briefly reviewed. ImagesFig. 1Fig. 4Fig. 6Fig. 7 PMID:4845653

  1. Bilateral Presumed Tuberculous Choroiditis

    PubMed Central

    Mohammadi, Naseh; Ghassemi, Fariba; Shojaei, Esfandiar; Moradnejad, Pardis

    2016-01-01

    Purpose: To describe a case of bilateral presumed tuberculous choroiditis which resolved promptly with a short course of antituberculous therapy. Case Report: A 44-year-old lady presented with bilateral visual loss of 8 months’duration. Considering the presence of pan-uveitis, severe macular edema, multifocal leakage on fluorescein angiography, positive tuberculin skin test, and after excluding other diseases, she underwent anti-tuberculous therapy (ATT) for disseminated choroiditis due to presumed ocular tuberculosis. She improved promptly and completely. There were no signs of relapse 18 months after completion of the treatment course. In a young patient with disseminated choroiditis and relatively short duration of symptoms, a course of ATT for 6 months may effectively treat the disease preventing relapse for a considerable period of time. Conclusion: In Presumed Tuberculous chroiditis early diagnosis is crucial for prompt and complete improvement. PMID:27413507

  2. Bilateral Mandibular Paramolars

    PubMed Central

    Dhull, Rachita Singh; Panda, Swagatika; Acharya, Sonu; Yadav, Shweta; Mohanty, Gatha

    2014-01-01

    ABSTRACT Supernumerary tooth is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. They can cause a variety of complications in the develo­ping dentition. Supernumerary teeth can present in various forms and in any region of the mandible or maxilla, but have a predisposition for the anterior maxilla. Here is the presentation of a case of unusual location of supernumerary teeth located in between mandibular first and second molar region bilaterally. How to cite this article: Dhull KS, Dhull RS, Panda S, Acharya S, Yadav S, Mohanty G. Bilateral Mandibular Paramolars. Int J Clin Pediatr Dent 2014;7(1):40-42. PMID:25206236

  3. Theta synchronizes the activity of medial prefrontal neurons during learning.

    PubMed

    Paz, Rony; Bauer, Elizabeth P; Paré, Denis

    2008-07-01

    Memory consolidation is thought to involve the gradual transfer of transient hippocampal-dependent traces to distributed neocortical sites via the rhinal cortices. Recently, medial prefrontal (mPFC) neurons were shown to facilitate this process when their activity becomes synchronized. However, the mechanisms underlying this enhanced synchrony remain unclear. Because the hippocampus projects to the mPFC, we tested whether theta oscillations contribute to synchronize mPFC neurons during learning. Thus, we obtained field (LFP) and unit recordings from multiple mPFC sites during the acquisition of a trace-conditioning task, where a visual conditioned stimulus (CS) predicted reward delivery. In quiet waking, the activity of mPFC neurons was modulated by theta oscillations. During conditioning, CS presentation caused an increase in mPFC theta power that augmented as the CS gained predictive value for reward delivery. This increased theta power coincided with a transient theta phase locking at distributed mPFC sites, an effect that was also manifest in the timing of mPFC unit activity. Overall, these results show that theta oscillations contribute to synchronize neuronal activity at distributed mPFC sites, suggesting that the hippocampus, by generating a stronger theta source during learning, can synchronize mPFC activity, in turn facilitating rhinal transfer of its activity to the neocortex. PMID:18612069

  4. Bilateral Nipple Leiomyoma

    PubMed Central

    Kapakli, Mahmut Sertan; Altintoprak, Fatih; Cayırcı, Mine; Manukyan, Manuk Norayk; Kebudi, Abut

    2013-01-01

    Cutaneous leiomyomas are benign smooth muscle neoplasms of the skin. They arise from vascular, arrector pili, genital, and areolar smooth muscles. The most common localizations of cutaneous leiomyomas are the extensor surfaces of the extremities and the trunk. To our knowledge, only few cases of one-sided nipple leiomyomas have been reported, but two-sided nipple leiomyomas have not been presented. For the first time, here, we report a bilateral nipple leiomyoma. PMID:23762734

  5. Compressive Bilateral Filtering.

    PubMed

    Sugimoto, Kenjiro; Kamata, Sei-Ichiro

    2015-11-01

    This paper presents an efficient constant-time bilateral filter that produces a near-optimal performance tradeoff between approximate accuracy and computational complexity without any complicated parameter adjustment, called a compressive bilateral filter (CBLF). The constant-time means that the computational complexity is independent of its filter window size. Although many existing constant-time bilateral filters have been proposed step-by-step to pursue a more efficient performance tradeoff, they have less focused on the optimal tradeoff for their own frameworks. It is important to discuss this question, because it can reveal whether or not a constant-time algorithm still has plenty room for improvements of performance tradeoff. This paper tackles the question from a viewpoint of compressibility and highlights the fact that state-of-the-art algorithms have not yet touched the optimal tradeoff. The CBLF achieves a near-optimal performance tradeoff by two key ideas: 1) an approximate Gaussian range kernel through Fourier analysis and 2) a period length optimization. Experiments demonstrate that the CBLF significantly outperforms state-of-the-art algorithms in terms of approximate accuracy, computational complexity, and usability. PMID:26068315

  6. Analysis of the energetic parameters of a theta pinch

    SciTech Connect

    Cavalcanti, G. H.; Farias, E. E.

    2009-12-15

    This work is devoted to study experimentally the performance of a theta pinch when the number of capacitors and turns of magnetic coil and the diameter of the glass tube are changed. To model the theta pinch a simple RLC circuit is used and the measurement of energy transmission from the bank of capacitors to the plasma is made using few experimental resources. In this work it was analyzed more than 2500 curves with a nonlinear procedure. Our results show that it is possible to design an optimized theta pinch making the appropriated choice of energetic parameters and therefore to reduce the stress of the system.

  7. Effects of theta burst stimulation on referred phantom sensations in patients with spinal cord injury.

    PubMed

    Nardone, Raffaele; De Blasi, Pierpaolo; Höller, Yvonne; Taylor, Alexandra C; Brigo, Francesco; Trinka, Eugen

    2016-03-01

    To further explore the mechanisms underlying cortical reorganization in patients with phantom sensations after deafferentation, a repetitive transcranial magnetic stimulation study was carried out in two patients with referred phantom sensations (RPS) after incomplete spinal cord injury at the thoracic level. We delivered continuous (inhibitory), intermittent (excitatory), and placebo theta burst stimulation to the contralateral primary motor cortex (M1), primary somatosensory cortex (S1), and secondary somatosensory cortex (S2). Perception of RPS was significantly and transiently disrupted by inhibitory theta burst stimulation applied over S1 and, to a lesser extent, S2. This study supports the hypothesis that RPS depend on remapping in the somatosensory cortex and provides further electrophysiological evidence in vivo that cortical reorganizational processes are critically modulated by GABAergic mechanisms. Enhancement of GABAergic activity may block cortical reorganization, leading to RPS in spinal cord injury patients. PMID:26626415

  8. Intrinsic Cornu Ammonis Area 1 Theta-Nested Gamma Oscillations Induced by Optogenetic Theta Frequency Stimulation

    PubMed Central

    Butler, James L.; Mendonça, Philipe R. F.; Robinson, Hugh P. C.

    2016-01-01

    Gamma oscillations (30–120 Hz) are thought to be important for various cognitive functions, including perception and working memory, and disruption of these oscillations has been implicated in brain disorders, such as schizophrenia and Alzheimer's disease. The cornu ammonis area 1 (CA1) of the hippocampus receives gamma frequency inputs from upstream regions (cornu ammonis area 3 and medial entorhinal cortex) and generates itself a faster gamma oscillation. The exact nature and origin of the intrinsic CA1 gamma oscillation is still under debate. Here, we expressed channelrhodopsin-2 under the CaMKIIα promoter in mice and prepared hippocampal slices to produce a model of intrinsic CA1 gamma oscillations. Sinusoidal optical stimulation of CA1 at theta frequency was found to induce robust theta-nested gamma oscillations with a temporal and spatial profile similar to CA1 gamma in vivo. The results suggest the presence of a single gamma rhythm generator with a frequency range of 65–75 Hz at 32°C. Pharmacological analysis found that the oscillations depended on both AMPA and GABAA receptors. Cell-attached and whole-cell recordings revealed that excitatory neuron firing slightly preceded interneuron firing within each gamma cycle, suggesting that this intrinsic CA1 gamma oscillation is generated with a pyramidal–interneuron circuit mechanism. SIGNIFICANCE STATEMENT This study demonstrates that the cornu ammonis area 1 (CA1) is capable of generating intrinsic gamma oscillations in response to theta input. This gamma generator is independent of activity in the upstream regions, highlighting that CA1 can produce its own gamma oscillation in addition to inheriting activity from the upstream regions. This supports the theory that gamma oscillations predominantly function to achieve local synchrony, and that a local gamma generated in each area conducts the signal to the downstream region. PMID:27076416

  9. Reversed theta sequences of hippocampal cell assemblies during backward travel.

    PubMed

    Cei, Anne; Girardeau, Gabrielle; Drieu, Céline; Kanbi, Karim El; Zugaro, Michaël

    2014-05-01

    Hippocampal cell assemblies coding for past, present and future events form theta-timescale (~100 ms) sequences that represent spatio-temporal episodes. However, the underlying mechanisms remain largely unknown. We recorded hippocampal and entorhinal cortical activity as rats experienced backward travel on a model train. Although the firing fields of place cells remained stable, the order in which they were activated in the theta sequence was reversed during backward travel. Thus, hippocampal cell assemblies coordinated their relative timing to correctly predict the sequential traversal of place fields in reverse order. At the single-cell level, theta phase represented distance traveled through the field, even though the head of the rat was oriented opposite to travel direction and entorhinal head-direction cells maintained their preferred firing direction. Our results challenge most theoretical models of theta sequence generation in the hippocampus. PMID:24667574

  10. Simultaneous observations of a theta aurora and associated magnetotail plasmas

    SciTech Connect

    Huang, C.Y.; Craven, J.D.; Frank, L.A.

    1989-08-01

    Observations of a transpolar arc and simultaneous measurements of associated plasmas in the magnetotail lobe on March 25, 1982, are presented. The auroral imager on board Dynamics Explorer 1 observes a theta aurora in the northern polar cap for more than 2 hours, between 0502 and 0720 UT. ISEE 1 is located in the southern lobe of the geomagnetic tail at a distance of 22.2 RE during this time. The plasma and particle detectors measure intermittent bursts of particle fluxes between 0530 and 0705 UT. The observations suggest that these particle fluxes represent the high-altitude signature of a theta aurora in the southern polar cap. The relatively dense and energetic plasmas are organized into several filamentary structures. Magnetic mapping between the two polar regions indicates that the theta aurora in the southern hemisphere is a mirror reflection about the noon-midnight meridional plane of the theta aurora in the northern hemisphere.

  11. Hippocampal-Prefrontal Theta Oscillations Support Memory Integration.

    PubMed

    Backus, Alexander R; Schoffelen, Jan-Mathijs; Szebényi, Szabolcs; Hanslmayr, Simon; Doeller, Christian F

    2016-02-22

    Integration of separate memories forms the basis of inferential reasoning--an essential cognitive process that enables complex behavior. Considerable evidence suggests that both hippocampus and medial prefrontal cortex (mPFC) play a crucial role in memory integration. Although previous studies indicate that theta oscillations facilitate memory processes, the electrophysiological mechanisms underlying memory integration remain elusive. To bridge this gap, we recorded magnetoencephalography data while participants performed an inference task and employed novel source reconstruction techniques to estimate oscillatory signals from the hippocampus. We found that hippocampal theta power during encoding predicts subsequent memory integration. Moreover, we observed increased theta coherence between hippocampus and mPFC. Our results suggest that integrated memory representations arise through hippocampal theta oscillations, possibly reflecting dynamic switching between encoding and retrieval states, and facilitating communication with mPFC. These findings have important implications for our understanding of memory-based decision making and knowledge acquisition. PMID:26832442

  12. The cos-theta coil re-re-visited

    NASA Astrophysics Data System (ADS)

    Crawford, Christopher

    2013-10-01

    Precision measurement of symmetry violating effects such the electric dipole moment (EDM) of fundamental particles requires extremely uniform fields. The cos-theta coil is the standard workhorse for generating uniform transverse magnetic fields in these experiments. Limitations in field uniformity include fringe effects (finite length), discretization (finite number of wires), and construction tolerance (finite resources). The field can be isolated from its environment by superposition of two coaxial cos-theta coils of different radii and opposite magnetic moment (double-cos-theta coil), or by shielding the coil inside a permeable or superconducting cylinder. I will discuss methods for optimizing the field uniformity of a compact cos-theta coil, and compare the ultimate limit on errors due to each source described above. Within the context of the scalar potential, I will show a straightforward generalization to non-circular coils with z- or ϕ-symmetry. Supported in part by DOE contract DE-SC0008107.

  13. Simultaneous observations of a theta aurora and associated magnetotail plasmas

    NASA Technical Reports Server (NTRS)

    Huang, C. Y.; Craven, J. D.; Frank, L. A.

    1989-01-01

    Observations of a transpolar arc and simultaneous measurements of associated plasmas in the magnetotail lobe on March 25, 1982, are presented. The auroral imager on board Dynamics Explorer 1 observes a theta aurora in the northern polar cap for more than two hours, between 0502 and 0720 UT. ISEE 1 is located in the southern lobe of the geomagnetic tail at a distance of 22.2 R(E) during this time. The plasma and particle detectors measure intermittent bursts of particle fluxes between 0530 and 0705 UT. The observations suggest that these particle fluxes represent the high-altitude signature of a theta aurora in the southern polar cap. The relatively dense and energetic plasmas are organized into several filamentary structures. Magnetic mapping between the two polar regions indicates that the theta aurora in the Southern Hemisphere is a mirror reflection about the noon-midnight meridional plane of the theta aurora in the Northern Hemisphere.

  14. Neutrino mass hierarchy determination for theta{sub 13} = 0

    SciTech Connect

    Gandhi, Raj; Ghoshal, Pomita; Goswami, Srubabati; Sankar, S. Uma

    2010-03-30

    We examine the possibility of determining the neutrino mass hierarchy in the limit theta{sub 13} = 0 using atmospheric neutrinos as the source. In this limit, theta{sub 13} driven matter effects are absent so independent measurements of DELTA{sub 31} and DELTA{sub 32} can, in principle, lead to hierarchy determination. Since their difference is DELTA{sub 21}, one needs an experimental arrangement where DELTA{sub 21}L/E > or approx. 1 can be achieved. This can be satisfied by atmospheric neutrinos which have a large range of L and E. Still, we find that hierarchy determination in the theta{sub 13} = 0 limit with atmospheric neutrinos is not a realistic possibility, even in conjunction with a beam experiment like T2K or NOnuA. We discuss why, and also reiterate the general conditions for hierarchy determination if theta{sub 13} = 0.

  15. Probing {theta}{sub 23} in neutrino telescopes

    SciTech Connect

    Choubey, Sandhya; Niro, Viviana; Rodejohann, Werner

    2008-06-01

    Among all neutrino mixing parameters, the atmospheric neutrino mixing angle {theta}{sub 23} introduces the strongest variation on the flux ratios of ultrahigh-energy neutrinos. We investigate the potential of these flux ratio measurements at neutrino telescopes to constrain {theta}{sub 23}. We consider astrophysical neutrinos originating from pion, muon-damped, and neutron sources and make a comparative study of their sensitivity reach to {theta}{sub 23}. It is found that neutron sources are most favorable for testing deviations from maximal {theta}{sub 23}. Using a {chi}{sup 2} analysis, we show, in particular, the power of combining (i) different flux ratios from the same type of source, and also (ii) combining flux ratios from different astrophysical sources. We include in our analysis 'impure' sources, i.e., deviations from the usually assumed initial (1 ratio 2 ratio 0), (0 ratio 1 ratio 0), or (1 ratio 0 ratio 0) flux compositions.

  16. Modulation of EEG Theta Band Signal Complexity by Music Therapy

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Joydeep; Lee, Eun-Jeong

    The primary goal of this study was to investigate the impact of monochord (MC) sounds, a type of archaic sounds used in music therapy, on the neural complexity of EEG signals obtained from patients undergoing chemotherapy. The secondary goal was to compare the EEG signal complexity values for monochords with those for progressive muscle relaxation (PMR), an alternative therapy for relaxation. Forty cancer patients were randomly allocated to one of the two relaxation groups, MC and PMR, over a period of six months; continuous EEG signals were recorded during the first and last sessions. EEG signals were analyzed by applying signal mode complexity, a measure of complexity of neuronal oscillations. Across sessions, both groups showed a modulation of complexity of beta-2 band (20-29Hz) at midfrontal regions, but only MC group showed a modulation of complexity of theta band (3.5-7.5Hz) at posterior regions. Therefore, the neuronal complexity patterns showed different changes in EEG frequency band specific complexity resulting in two different types of interventions. Moreover, the different neural responses to listening to monochords and PMR were observed after regular relaxation interventions over a short time span.

  17. Osteomyelitis of Bilateral Femoral Heads After Childbirth: A Case Report

    PubMed Central

    Lee, Kyung Soo; Kong, Sangwon; Kim, Junho; Kim, Taikon; Choi, Chan Beom; Kim, Yee-Suk

    2015-01-01

    Hip and pelvic pain during pregnancy or after delivery is a common problem in young females, and in most cases this problem has a self-limiting course. The patient described in this case suffered from severe hip pain after childbirth. MR imaging study was performed and it showed arthritis of bilateral hip joints and osteomyelitis of femoral heads with an abscess in the surrounding muscle. Infection, such as septic arthritis or osteomyelitis, is an extremely rare cause of peripartum joint pain. The patient's clinical symptoms and laboratory findings improved with antibiotic therapy. However, limitation of motion of the bilateral hip joints persisted although the patient continued rehabilitative therapy for 15 months, and the patient had to undergo bilateral total hip replacement. Hereby, we present a case of severe osteomyelitis and pyogenic arthritis of bilateral femoral heads and hip joints after delivery, which eventually required bilateral total hip replacement. PMID:26161359

  18. Synchronous Bilateral Breast Cancers

    PubMed Central

    Subramanyan, Annapurneswari; Radhakrishna, Selvi

    2015-01-01

    Background Bilateral breast cancer (BBC) is not an uncommon entity in contemporary breast clinics. Improved life expectancy after breast cancer treatment and routine use of contra-lateral breast mammography has led to increased incidence of BBC. Our study objective was to define the epidemiological and tumour characteristics of BBC in India. Materials and Methods A total of 1251 breast cancer patients were treated during the period January 2007 to March 2015 and 30 patients were found to have BBC who constituted the study population (60 tumour samples). Synchronous bilateral breast cancers (SBC) was defined as two tumours diagnosed within an interval of 6 months and a second cancer diagnosed after 6 months was labelled as metachronous breast cancer (MBC). Analyses of patient and tumour characteristics were done in this prospective data base of BBC patients. Results Median patient age was 66 years (range 39-85). Majority of the patients had SBC (n=28) and in 12 patients the second tumour was clinically occult and detected only by mammography of the contra-lateral breast. The second tumour was found at lower tumour size compared to the first in 73% of cases and was negative for axillary metastasis in 80% of cases (24/30). Infiltrating ductal carcinoma was the commonest histological type (n=51) and majority of the tumours were ER/PR positive (50/60). Her2 was overexpressed in 13 tumours (21%). Over 70% (22/30) of patients had similar histology in both breasts and amongst them grade concordance was present in about 69% (15/22) of patients. Concordance rates of ER, PR and Her2 statuses were 83%, 80% and 90% respectively. Bilateral mastectomy was the commonest surgery performed in 80% of the patients followed by bilateral breast conservation in 13%. At the end of study period, 26 patients were alive and disease free. Median survival was 29 months (range 3-86 months). Conclusion In most patients with BBC, the second tumour is identified at an early stage than index

  19. Medial prefrontal theta phase coupling during spatial memory retrieval.

    PubMed

    Kaplan, Raphael; Bush, Daniel; Bonnefond, Mathilde; Bandettini, Peter A; Barnes, Gareth R; Doeller, Christian F; Burgess, Neil

    2014-06-01

    Memory retrieval is believed to involve a disparate network of areas, including medial prefrontal and medial temporal cortices, but the mechanisms underlying their coordination remain elusive. One suggestion is that oscillatory coherence mediates inter-regional communication, implicating theta phase and theta-gamma phase-amplitude coupling in mnemonic function across species. To examine this hypothesis, we used non-invasive whole-head magnetoencephalography (MEG) as participants retrieved the location of objects encountered within a virtual environment. We demonstrate that, when participants are cued with the image of an object whose location they must subsequently navigate to, there is a significant increase in 4-8 Hz theta power in medial prefrontal cortex (mPFC), and the phase of this oscillation is coupled both with ongoing theta phase in the medial temporal lobe (MTL) and perceptually induced 65-85 Hz gamma amplitude in medial parietal cortex. These results suggest that theta phase coupling between mPFC and MTL and theta-gamma phase-amplitude coupling between mPFC and neocortical regions may play a role in human spatial memory retrieval. PMID:24497013

  20. Analytical Insights on Theta-Gamma Coupled Neural Oscillators

    PubMed Central

    2013-01-01

    In this paper, we study the dynamics of a quadratic integrate-and-fire neuron, spiking in the gamma (30–100 Hz) range, coupled to a delta/theta frequency (1–8 Hz) neural oscillator. Using analytical and semianalytical methods, we were able to derive characteristic spiking times for the system in two distinct regimes (depending on parameter values): one regime where the gamma neuron is intrinsically oscillating in the absence of theta input, and a second one in which gamma spiking is directly gated by theta input, i.e., windows of gamma activity alternate with silence periods depending on the underlying theta phase. In the former case, we transform the equations such that the system becomes analogous to the Mathieu differential equation. By solving this equation, we can compute numerically the time to the first gamma spike, and then use singular perturbation theory to find successive spike times. On the other hand, in the excitable condition, we make direct use of singular perturbation theory to obtain an approximation of the time to first gamma spike, and then extend the result to calculate ensuing gamma spikes in a recursive fashion. We thereby give explicit formulas for the onset and offset of gamma spike burst during a theta cycle, and provide an estimation of the total number of spikes per theta cycle both for excitable and oscillator regimes. PMID:23945442

  1. Bilateral posterior sternoclavicular dislocation.

    PubMed

    Baumann, Matthias; Vogel, Tobias; Weise, Kuno; Muratore, Tim; Trobisch, Per

    2010-07-01

    Posterior sternoclavicular dislocations are a rare injury, representing <5% of all sternoclavicular dislocations and 1 in 1600 shoulder girdle injuries. Proper imaging with computed tomography and prompt diagnosis are essential steps in preventing potentially lethal complications observed in approximately 3% of all posterior sternoclavicular dislocations. Surgical treatment is necessary if closed reduction fails. With the medial clavicular epiphysis being the last to close (between ages 22 and 25), children and adolescents typically present with epiphyseal fractures rather than joint dislocations. If closed reduction fails, open reduction and internal fixation (ORIF) should be considered in fractures, whereas complex reconstructions with tendon graft procedures have been recommended for joint dislocations. This article presents a case of a traumatic bilateral posterior sternoclavicular dislocation due to an epiphyseal fracture in a 15-year-old boy. To our knowledge, this is the first reported case of a bilateral posterior sternoclavicular dislocation. Attempted closed reduction failed with redislocation after 2 days. The patient subsequently required ORIF. This article describes our technique with anterior retraction of the medial clavicle, closure of the posterior periosteum, and ORIF using nonabsorbable sutures. Postoperative shoulder mobilization was started on day 1. At final follow-up, the patient was completely asymptomatic. PMID:20608625

  2. Bilateral cochlear implantation: current concepts, indications, and results.

    PubMed

    Basura, Gregory J; Eapen, Rose; Buchman, Craig A

    2009-12-01

    The optimal treatment for bilateral hearing loss continues to evolve as cochlear implant (CI) and hearing aid technologies advance, as does our understanding of the central auditory system. Ongoing discussions continue on the validity and feasibility of bilateral CI in terms of performance, justification of need, medical/surgical safety concerns, and economics. The purpose of this review article is to provide an update on the advantages and disadvantages of bilateral CI and to provide a discussion on timing (simultaneous vs. sequential), technology (bimodal vs. binaural) and feasibility. Binaural advantages are found in both adult and pediatric bilateral CI recipients, the greatest being the head shadow effect and improvements in localization and loudness summation. This theoretically offers an advantage over their unilateral implanted counterparts in terms of improved sound localization and enhanced speech perception under noisy conditions. Most investigators agree that bilateral stimulation during critical periods of development is paramount for optimizing auditory functioning in children. Currently, bilateral CI is widely accepted as a safe and effective means of bilateral auditory stimulation. PMID:19894280

  3. Cooled radiofrequency ablation for bilateral greater occipital neuralgia.

    PubMed

    Vu, Tiffany; Chhatre, Akhil

    2014-01-01

    This report describes a case of bilateral greater occipital neuralgia treated with cooled radiofrequency ablation. The case is considered in relation to a review of greater occipital neuralgia, continuous thermal and pulsed radiofrequency ablation, and current medical literature on cooled radiofrequency ablation. In this case, a 35-year-old female with a 2.5-year history of chronic suboccipital bilateral headaches, described as constant, burning, and pulsating pain that started at the suboccipital region and radiated into her vertex. She was diagnosed with bilateral greater occipital neuralgia. She underwent cooled radiofrequency ablation of bilateral greater occipital nerves with minimal side effects and 75% pain reduction. Cooled radiofrequency ablation of the greater occipital nerve in challenging cases is an alternative to pulsed and continuous RFA to alleviate pain with less side effects and potential for long-term efficacy. PMID:24716017

  4. Quantum modular forms, mock modular forms, and partial theta functions

    NASA Astrophysics Data System (ADS)

    Kimport, Susanna

    Defined by Zagier in 2010, quantum modular forms have been the subject of an explosion of recent research. Many of these results are aimed at discovering examples of these functions, which are defined on the rational numbers and have "nice" modularity properties. Though the subject is in its early stages, numerous results (including Zagier's original examples) show these objects naturally arising from many areas of mathematics as limits of other modular-like functions. One such family of examples is due to Folsom, Ono, and Rhoades, who connected these new objects to partial theta functions (introduced by Rogers in 1917) and mock modular forms (about which there is a rich theory, whose origins date back to Ramanujan in 1920). In this thesis, we build off of the work of Folsom, Ono, and Rhoades by providing an infinite family of quantum modular forms of arbitrary positive half-integral weight. Further, this family of quantum modular forms "glues" mock modular forms to partial theta functions and is constructed from a so-called "universal" mock theta function by extending a method of Eichler and Zagier (originally defined for holomorphic Jacobi forms) into a non-holomorphic setting. In addition to the infinite family, we explore the weight 1/2 and 3/2 functions in more depth. For both of these weights, we are able to explicitly write down the quantum modular form, as well as the corresponding "errors to modularity," which can be shown to be Mordell integrals of specific theta functions and, as a consequence, are real-analytic functions. Finally, we turn our attention to the partial theta functions associated with these low weight examples. Berndt and Kim provide asymptotic expansions for a certain class of partial theta functions as q approaches 1 radially within the unit disk. Here, we extend this work to not only obtain asymptotic expansions for this class of functions as q approaches any root of unity, but also for a certain class of derivatives of these functions

  5. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning.

    PubMed

    Hoffmann, Loren C; Cicchese, Joseph J; Berry, Stephen D

    2015-01-01

    Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3-12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3-7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning. PMID:25918501

  6. Harnessing the power of theta: natural manipulations of cognitive performance during hippocampal theta-contingent eyeblink conditioning

    PubMed Central

    Hoffmann, Loren C.; Cicchese, Joseph J.; Berry, Stephen D.

    2015-01-01

    Neurobiological oscillations are regarded as essential to normal information processing, including coordination and timing of cells and assemblies within structures as well as in long feedback loops of distributed neural systems. The hippocampal theta rhythm is a 3–12 Hz oscillatory potential observed during cognitive processes ranging from spatial navigation to associative learning. The lower range, 3–7 Hz, can occur during immobility and depends upon the integrity of cholinergic forebrain systems. Several studies have shown that the amount of pre-training theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning. Our lab has used a brain-computer interface (BCI) that delivers eyeblink conditioning trials contingent upon the explicit presence or absence of hippocampal theta. A behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to four-fold increase in learning speed. This behavioral effect is accompanied by enhanced amplitude and synchrony of hippocampal local field potential (LFP)s, multi-unit excitation, and single-unit response patterns that depend on theta state. Additionally, training in the presence of hippocampal theta has led to increases in the salience of tone-induced unit firing patterns in the medial prefrontal cortex, followed by persistent multi-unit activity during the trace interval. In cerebellum, rhythmicity and precise synchrony of stimulus time-locked LFPs with those of hippocampus occur preferentially under the theta condition. Here we review these findings, integrate them into current models of hippocampal-dependent learning and suggest how improvement in our understanding of neurobiological oscillations is critical for theories of medial temporal lobe processes underlying intact and pathological learning. PMID:25918501

  7. Theta oscillations and human navigation: a magnetoencephalography study.

    PubMed

    de Araújo, Dráulio B; Baffa, Oswaldo; Wakai, Ronald T

    2002-01-01

    Magnetoencephalography (MEG) was used to study alpha and theta activity while subjects navigated through a computer-generated virtual reality town. The subjects were first allowed to explore the environment freely. They then had to navigate from a starting point to a destination, knowing that an obstruction would appear at one of several possible locations along the main route and force them to take a detour. Spatiotemporal analysis of the theta and alpha bands were performed (1) prior to the start of navigation, (2) from the start of navigation until the obstruction was encountered, (3) during the time subjects were contemplating a detour and were not navigating, and (4) from the resumption of navigation until the destination was reached. In all subjects, theta power was strongest during the two periods of navigation. The peak frequency of the oscillations was approximately 3.7 Hz. Control studies consisted of a motor task similar to that required for navigation, passive viewing of a tour through the same virtual reality town, and a mental concentration task. No consistent increases in theta power were seen in the MEG during any of the control tasks. The results suggest an association between theta rhythm and the performance of navigational tasks in humans. PMID:11798388

  8. Theta oscillations regulate the speed of locomotion via a hippocampus to lateral septum pathway

    PubMed Central

    Bender, Franziska; Gorbati, Maria; Cadavieco, Marta Carus; Denisova, Natalia; Gao, Xiaojie; Holman, Constance; Korotkova, Tatiana; Ponomarenko, Alexey

    2015-01-01

    Hippocampal theta oscillations support encoding of an animal's position during spatial navigation, yet longstanding questions about their impact on locomotion remain unanswered. Combining optogenetic control of hippocampal theta oscillations with electrophysiological recordings in mice, we show that hippocampal theta oscillations regulate locomotion. In particular, we demonstrate that their regularity underlies more stable and slower running speeds during exploration. More regular theta oscillations are accompanied by more regular theta-rhythmic spiking output of pyramidal cells. Theta oscillations are coordinated between the hippocampus and its main subcortical output, the lateral septum (LS). Chemo- or optogenetic inhibition of this pathway reveals its necessity for the hippocampal regulation of running speed. Moreover, theta-rhythmic stimulation of LS projections to the lateral hypothalamus replicates the reduction of running speed induced by more regular hippocampal theta oscillations. These results suggest that changes in hippocampal theta synchronization are translated into rapid adjustment of running speed via the LS. PMID:26455912

  9. Theta oscillations regulate the speed of locomotion via a hippocampus to lateral septum pathway.

    PubMed

    Bender, Franziska; Gorbati, Maria; Cadavieco, Marta Carus; Denisova, Natalia; Gao, Xiaojie; Holman, Constance; Korotkova, Tatiana; Ponomarenko, Alexey

    2015-01-01

    Hippocampal theta oscillations support encoding of an animal's position during spatial navigation, yet longstanding questions about their impact on locomotion remain unanswered. Combining optogenetic control of hippocampal theta oscillations with electrophysiological recordings in mice, we show that hippocampal theta oscillations regulate locomotion. In particular, we demonstrate that their regularity underlies more stable and slower running speeds during exploration. More regular theta oscillations are accompanied by more regular theta-rhythmic spiking output of pyramidal cells. Theta oscillations are coordinated between the hippocampus and its main subcortical output, the lateral septum (LS). Chemo- or optogenetic inhibition of this pathway reveals its necessity for the hippocampal regulation of running speed. Moreover, theta-rhythmic stimulation of LS projections to the lateral hypothalamus replicates the reduction of running speed induced by more regular hippocampal theta oscillations. These results suggest that changes in hippocampal theta synchronization are translated into rapid adjustment of running speed via the LS. PMID:26455912

  10. Segmented flow sampling with push-pull theta pipettes.

    PubMed

    Saha-Shah, Anumita; Green, Curtis M; Abraham, David H; Baker, Lane A

    2016-03-21

    We report development of a mobile and easy-to-fabricate theta pipette microfluidic device for segmented flow sampling. The theta pipettes were also used as electrospray emitters for analysis of sub-nanoliter segments, which resulted in delivery of analyte to the vacuum inlet of the mass spectrometer without multiple transfer steps. Theta pipette probes enable sample collection with high spatial resolution due to micron or smaller sized probe inlets and can be used to manipulate aqueous segments in the range of 200 pL to tens of nanoliters. Optimized conditions can enable sampling with high spatial and temporal resolution, suitable for chemical monitoring in biological samples and studies of sample heterogeneity. Intercellular heterogeneity among Allium cepa cells was studied by collecting cytoplasm from multiple cells using a single probe. Extracted cytoplasm was analyzed in a fast and high throughput manner by direct electrospray mass spectrometry of segmented sample from the probe tip. PMID:26907673

  11. Geometrical model for non-zero {theta}{sub 13}

    SciTech Connect

    Chen Junmou; Wang Bin; Li Xueqian

    2011-10-01

    Based on Friedberg and Lee's geometric picture by which the tribimaximal Pontecorvo-Maki-Nakawaga-Sakata leptonic mixing matrix is constructed, namely, corresponding mixing angles correspond to the geometric angles among the sides of a cube. We suggest that the three realistic mixing angles, which slightly deviate from the values determined for the cube, are due to a viable deformation from the perfectly cubic shape. Taking the best-fitted results of {theta}{sub 12} and {theta}{sub 23} as inputs, we determine the central value of sin{sup 2}2{theta}{sub 13} should be 0.0238, with a relatively large error tolerance; this value lies in the range of measurement precision of the Daya Bay experiment and is consistent with recent results from the T2K Collaboration.

  12. Frontal theta as a mechanism for cognitive control

    PubMed Central

    Cavanagh, James F.; Frank, Michael J.

    2014-01-01

    Recent advancements in cognitive neuroscience have afforded a description of neural responses in terms of latent algorithmic operations. However, the adoption of this approach to human scalp EEG has been more limited, despite the ability of this methodology to quantify canonical neuronal processes. Here we provide evidence that theta band activities over the mid-frontal cortex appear to reflect a common computation used for realizing the need for cognitive control. Moreover, by virtue of inherent properties of field oscillations, these theta band processes may be used to communicate this need and subsequently implement such control across disparate brain regions. Frontal theta is thus a compelling candidate mechanism by which emergent processes such as ‘cognitive control’ may be biophysically realized. PMID:24835663

  13. Pre-stimulus thalamic theta power predicts human memory formation.

    PubMed

    Sweeney-Reed, Catherine M; Zaehle, Tino; Voges, Jürgen; Schmitt, Friedhelm C; Buentjen, Lars; Kopitzki, Klaus; Richardson-Klavehn, Alan; Hinrichs, Hermann; Heinze, Hans-Jochen; Knight, Robert T; Rugg, Michael D

    2016-09-01

    Pre-stimulus theta (4-8Hz) power in the hippocampus and neocortex predicts whether a memory for a subsequent event will be formed. Anatomical studies reveal thalamus-hippocampal connectivity, and lesion, neuroimaging, and electrophysiological studies show that memory processing involves the dorsomedial (DMTN) and anterior thalamic nuclei (ATN). The small size and deep location of these nuclei have limited real-time study of their activity, however, and it is unknown whether pre-stimulus theta power predictive of successful memory formation is also found in these subcortical structures. We recorded human electrophysiological data from the DMTN and ATN of 7 patients receiving deep brain stimulation for refractory epilepsy. We found that greater pre-stimulus theta power in the right DMTN was associated with successful memory encoding, predicting both behavioral outcome and post-stimulus correlates of successful memory formation. In particular, significant correlations were observed between right DMTN theta power and both frontal theta and right ATN gamma (32-50Hz) phase alignment, and frontal-ATN theta-gamma cross-frequency coupling. We draw the following primary conclusions. Our results provide direct electrophysiological evidence in humans of a role for the DMTN as well as the ATN in memory formation. Furthermore, prediction of subsequent memory performance by pre-stimulus thalamic oscillations provides evidence that post-stimulus differences in thalamic activity that index successful and unsuccessful encoding reflect brain processes specifically underpinning memory formation. Finally, the findings broaden the understanding of brain states that facilitate memory encoding to include subcortical as well as cortical structures. PMID:27208861

  14. Differential geometry of the Fermat quartic and theta functions

    NASA Astrophysics Data System (ADS)

    Hadnot, Jason

    2012-02-01

    The universal curve over a finite cover of the moduli space of elliptic curves with level four structure is embedded in C as the Fermat quartic and is parametrized via the four Jacobi theta functions. Constructions from completely integrable systems have shown the importance of looking at the curvature of certain spaces and here we compute sectional curvatures. For our computations, we choose the ambient Fubini-Study metric of C. We also derive several theta identities which arise from the quartic's holomorphic two-form.

  15. Simultaneous bilateral spontaneous pneumothorax.

    PubMed

    Graf-Deuel, E; Knoblauch, A

    1994-04-01

    We describe 12 patients with simultaneous bilateral spontaneous pneumothorax (SBSP). They represent 4 percent of patients with spontaneous pneumothorax seen at our hospital from 1971 to 1990. Five of the 12 had no underlying lung disease. In the seven remaining patients, SBSP was secondary to histiocytosis X, lymphangioleiomyomatosis, osteogenic sarcoma with pleural and pulmonary metastases, Hodgkin's disease, mesothelioma, cystic fibrosis, or miliary tuberculosis. Nineteen of the 56 patients with SBSP (34 percent) described in the literature (this series included) had pulmonary disease related to disorders of cells of mesenchymal origin. Emphysema and bullous lung disease were not associated with SBSP. Long-term prognosis was a function of pulmonary status. Four of the patients described herein died during the period reviewed. All suffered from severe underlying disease. In no case was SBSP the main cause of death. With timely treatment, the short-term prognosis is benign even for patients with underlying lung disease. Surgical pleurectomy should be attempted early, especially in SBSP secondary to underlying lung disease. PMID:8162740

  16. Acute silicosis with bilateral pneumothorax

    PubMed Central

    Srivastava, G N; Prasad, Rajniti; Meena, Manoj; Hussain, Moosa

    2014-01-01

    We present a case of acute silicosis with bilateral pneumothorax of a 28-year-old man working at a stone crusher factory for 1 year. He presented to the emergency department with cough, respiratory distress and diffuse chest pain. The patient was managed with bilateral intercostal tube drainage under water seal, oxygen inhalation and conservative therapy. On follow-up he showed improvement of resting dyspnoea and was doing well. This case is being reported because of the rare complications of acute silicosis as bilateral pneumothorax. PMID:24862410

  17. Acute silicosis with bilateral pneumothorax.

    PubMed

    Srivastava, G N; Prasad, Rajniti; Meena, Manoj; Hussain, Moosa

    2014-01-01

    We present a case of acute silicosis with bilateral pneumothorax of a 28-year-old man working at a stone crusher factory for 1 year. He presented to the emergency department with cough, respiratory distress and diffuse chest pain. The patient was managed with bilateral intercostal tube drainage under water seal, oxygen inhalation and conservative therapy. On follow-up he showed improvement of resting dyspnoea and was doing well. This case is being reported because of the rare complications of acute silicosis as bilateral pneumothorax. PMID:24862410

  18. Bilateral internal laryngoceles mimicking asthma.

    PubMed

    Aksoy, Elif A; Elsürer, Cağdaş; Serin, Gediz M; Unal, O Faruk

    2013-05-01

    Laryngocele is an air-filled, abnormal dilation of the laryngeal saccule that extends upward within the false vocal fold, in communication with the laryngeal lumen. A case of 43-year-old male with bilateral internal laryngoceles, who has been treated as asthma for 4 years, is presented. The patient had dyspnea, cough, and excessive phlegm for a month and a late onset stridor. Flexible nasopharyngolaryngoscopy showed bilateral cystic enlargements of the false vocal folds and true vocal folds could not be visualized. Laryngeal CT without contrast enhancement showed bilateral internal laryngoceles. Submucosal total excision of bilateral cystic masses including parts of false vocal folds was performed. The symptoms resolved immediately after surgery. Although the incidence of internal laryngocele is rare, it should be remembered in the differential diagnosis of upper airway problems and diagnostic flexible nasopharnygolaryngoscopy is routinely indicated for airway evaluation in at-risk patients. PMID:24174956

  19. Holomorphic projections and Ramanujan’s mock theta functions

    PubMed Central

    Imamoğlu, Özlem; Raum, Martin; Richter, Olav K.

    2014-01-01

    We use spectral methods of automorphic forms to establish a holomorphic projection operator for tensor products of vector-valued harmonic weak Maass forms and vector-valued modular forms. We apply this operator to discover simple recursions for Fourier series coefficients of Ramanujan’s mock theta functions. PMID:24591582

  20. A Low energy neutrino factory for large theta(13)

    SciTech Connect

    Geer, Steve; Mena, Olga; Pascoli, Silvia; /Durham U., IPPP

    2007-01-01

    If the value of {theta}{sub 13} is within the reach of the upcoming generation of long-baseline experiments, T2K and NOvA, they show that a low-energy neutrino factory, with peak energy in the few GeV range, would provide a sensitive tool to explore CP-violation and the neutrino mass hierarchy. They consider baselines with typical length 1000-1500 km. The unique performance of the low energy neutrino factory is due to the rich neutrino oscillation pattern at energies between 1 and 4 GeV at baselines {Omicron}(1000) km. They perform both a semi-analytical study of the sensitivities and a numerical analysis to explore how well this setup can measure {theta}{sub 13}, CP-violation, and determine the type of mass hierarchy and the {theta}{sub 23} quadrant. A low energy neutrino factory provides a powerful tool to resolve ambiguities and make precise parameter determinations, for both large and fairly small values of the mixing parameter {theta}{sub 13}.

  1. Presence of state transitions in the cryptophyte alga Guillardia theta

    PubMed Central

    Cheregi, Otilia; Kotabová, Eva; Prášil, Ondřej; Schröder, Wolfgang P.; Kaňa, Radek; Funk, Christiane

    2015-01-01

    Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO2 assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions. PMID:26254328

  2. Presence of state transitions in the cryptophyte alga Guillardia theta.

    PubMed

    Cheregi, Otilia; Kotabová, Eva; Prášil, Ondřej; Schröder, Wolfgang P; Kaňa, Radek; Funk, Christiane

    2015-10-01

    Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO2 assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions. PMID:26254328

  3. Interindividual Differences in Alpha and Theta Power Reflect Memory Performance.

    ERIC Educational Resources Information Center

    Klimesch, W.; Vogt, F.; Doppelmayr, M.

    1999-01-01

    Tested whether tonic EEG power is related to memory performance by analyzing ongoing EEG for 60 subjects in 5 experimental conditions. Subjects with good memory performance had significantly larger upper alpha power, but less theta and lower alpha power. Also discusses findings for subjects good at calculation. (SLD)

  4. Isolated Bilateral Lacrimal Gland Agenesis.

    PubMed

    Al-Ryalat, Nosaiba T; Ezzat, Jumana W; Ababneh, Osama H; AlRyalat, Saif Aldeen S; Al-Hadidy, Azmy M

    2016-01-01

    A 5-year-old boy presented to the ophthalmology department complaining of absent tearing while crying. Slit-lamp examination showed decreased tear margin film with normal punctae. Orbit magnetic resonance imaging was done and showed bilateral absent lacrimal glands. This is the third case of isolated bilateral lacrimal gland agenesis in the literature. [J Pediatr Ophthalmol Strabismus. 2016;53:e35-e38.]. PMID:27486892

  5. Violations of parity and charge conjugation in the {theta} vacuum with imaginary chemical potential

    SciTech Connect

    Kouno, Hiroaki; Sakai, Yuji; Sasaki, Takahiro; Kashiwa, Kouji; Yahiro, Masanobu

    2011-04-01

    Charge conjugation (C) and parity (P) are exact symmetries at {theta}={pi} and {Theta}{identical_to}{mu}/(iT)={pi}, where {theta} is the parameter of the so-called {theta} vacuum, {mu} is the imaginary quark-number chemical potential and T is the temperature. Spontaneous breakings of these discrete symmetries are investigated by the Polyakov-loop extended Nambu-Jona-Lasinio model. At zero T, P symmetry is spontaneously broken while C symmetry is conserved. As T increases, P symmetry is restored just after C symmetry is spontaneously broken, so that either P or C symmetry or both the symmetries are spontaneously broken for any T. The chiral-symmetry restoration and the deconfinement transition at {theta}={Theta}=0 are remnants of the P restoration and the C breaking at {theta}={Theta}={pi}, respectively.

  6. Simultaneous Bilateral Ophthalmic Artery Chemosurgery for Bilateral Retinoblastoma (Tandem Therapy)

    PubMed Central

    Abramson, David H.; Marr, Brian P.; Francis, Jasmine H.; Dunkel, Ira J.; Fabius, Armida W. M.; Brodie, Scott E.; Mondesire-Crump, Ijah; Gobin, Y. Pierre

    2016-01-01

    Objective Report on the 7-year experience with bilateral ophthalmic artery chemosurgery (OAC-Tandem therapy) for bilateral retinoblastoma. Design Retrospective, single institution study. Subjects 120 eyes of 60 children with bilateral retinoblastoma treated since March 2008. Methods Retrospective review of all children treated at Memorial Sloan Kettering with bilateral ophthalmic artery chemosurgery (Melphalan, Carboplatin, Topotecan, Methotrexate) delivered in the same initial session to both naïve and previously treated eyes. Main Outcome Measures Ocular survival, metastatic disease, patient survival from metastases, second cancers, systemic adverse effects, need for transfusion of blood products, electroretinogram before and after treatment. Results 116 eyes were salvaged (4 eyes were enucleated: 3 because of progressive disease, 1 family choice). Kaplan Meier ocular survival was 99.2% at one year, 96.9% at 2 and 3 years and 94.9% for years 4 through 7. There were no cases of metastatic disease or metastatic deaths with a mean follow-up of 3.01 years. Two children developed second cancers (both pineoblastoma) and one of them died. Transfusion of blood products was required in 3 cases (4 transfusions), 1.9%. Two children developed fever/neutropenia requiring hospitalization (0.95%). ERGs were improved in 21.6% and unchanged after treatment in 52.5% of cases (increase or decrease of less than 25μV). Conclusions Bilateral ophthalmic artery chemosurgery is a safe and effective technique for managing bilateral retinoblastoma-even when eyes are advanced bilaterally, and if both eyes have progressed after systemic chemotherapy. Ocular survival was excellent (94.9% at 8 years), there were no cases of of metastatic disease and no deaths from metastatic disease, but children remain at risk for second cancers. In 21.6% of cases ERG function improved. Despite using chemotherapy in both eyes in the same session, systemic toxicity was low. PMID:27258771

  7. Theta and alpha EEG frequency interplay in subjects with mild cognitive impairment: evidence from EEG, MRI, and SPECT brain modifications

    PubMed Central

    Moretti, Davide V.

    2015-01-01

    Background: Temporo-parietal and medial temporal cortex atrophy are associated with mild cognitive impairment (MCI) due to Alzheimer disease (AD) as well as the reduction of regional cerebral blood perfusion in hippocampus. Moreover, the increase of EEG alpha3/alpha2 power ratio has been associated with MCI due to AD and with an increase in theta frequency power in a group of subjects with impaired cerebral perfusion in hippocampus. Methods: Seventy four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording and high resolution 3D magnetic resonance imaging (MRI). Among the patients, a subset of 27 subjects underwent also perfusion single-photon emission computed tomography and hippocampal atrophy evaluation. Alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. Three MCI groups were detected according to increasing tertile values of alpha3/alpha2 power ratio and difference of cortical thickness among the groups estimated. Results: Higher alpha3/alpha2 power ratio group had wider cortical thinning than other groups, mapped to the Supramarginal and Precuneus bilaterally. Subjects with higher alpha3/alpha2 frequency power ratio showed a constant trend to a lower perfusion than lower alpha3/alpha2 group. Moreover, this group correlates with both a bigger hippocampal atrophy and an increase of theta frequency power. Conclusion: Higher EEG alpha3/alpha2 power ratio was associated with temporo-parietal cortical thinning, hippocampal atrophy and reduction of regional cerebral perfusion in medial temporal cortex. In this group an increase of theta frequency power was detected inMCI subjects. The combination of higher EEG alpha3/alpha2 power ratio, cortical thickness measure and regional cerebral perfusion reveals a complex interplay between EEG cerebral rhythms, structural and functional brain modifications. PMID:25926789

  8. Modulation of Hippocampal Theta Oscillations and Spatial Memory by Relaxin-3 Neurons of the Nucleus Incertus

    ERIC Educational Resources Information Center

    Ma, Sherie; Olucha-Bordonau, Francisco E.; Hossain, M. Akhter; Lin, Feng; Kuei, Chester; Liu, Changlu; Wade, John D.; Sutton, Steven W.; Nunez, Angel; Gundlach, Andrew L.

    2009-01-01

    Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that "pacemaker" neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the…

  9. Learner Acquisition of Dialect Variation in a Study Abroad Context: The Case of the Spanish [Theta

    ERIC Educational Resources Information Center

    Ringer-Hilfinger, Kathryn

    2012-01-01

    The present study aims at analyzing the acquisition of dialect variation by native English-speaking university students who study Spanish for a semester in Spain. The selected variable is the phoneme /[theta]/ (theta). The goal is to assess learner awareness, opinion, and use of [theta]. Data were elicited through a set of oral and written tasks…

  10. Tensor analyzing powers T/sub 20/(theta) and T/sub 22/(theta) in the /sup 2/H(darrow,. gamma. ) /sup 4/He reaction

    SciTech Connect

    Seyler, R.G.; Weller, H.R.

    1985-05-01

    Reaction theory expressions are used to prove that the tensor analyzing powers T/sub 20/(theta) and T/sub 22/(theta) for the /sup 2/H(darrow,..gamma..) /sup 4/He reaction are isotropic if the reaction is pure E2 and terms quadratic in channel-spin-2 matrix elements are neglected. Experimental departures from isotropy can be expected near theta-0/sup 0/, 90/sup 0/, and 189/sup 0/.

  11. Event-related desynchronization of frontal-midline theta rhythm during preconscious auditory oddball processing.

    PubMed

    Kawamata, Masaru; Kirino, Eiji; Inoue, Reiichi; Arai, Heii

    2007-10-01

    The goal of this study was to explore the frontal-midline theta rhythm (Fm theta) generation mechanism employing event-related desynchronization/synchronization (ERD/ERS) analysis in relation to task-irrelevant external stimuli. A dual paradigm was employed: a videogame and the simultaneous presentation of passive auditory oddball stimuli. We analyzed the data concerning ERD/ERS using both Fast Fourier Transformation (FFT) and wavelet transform (WT). In the FFT data, during the periods with appearance of Fm theta, apparent ERD of the theta band was observed at Fz and Cz. ERD when Fm theta was present was much more prominent than when Fm theta was absent. In the WT data, as in the FFT data, ERD was seen again, but in this case the ERD was preceded by ERS during both the periods with and without Fm theta. Furthermore, the WT analysis indicated that ERD was followed by ERS during the periods without Fm theta. However, during Fm theta, no apparent ERS following ERD was seen. In our study, Fm theta was desynchronized by the auditory stimuli that were independent of the video game task used to evoke the Fm theta. The ERD of Fm theta might be reflecting the mechanism of "positive suppression" to process external auditory stimuli automatically and preventing attentional resources from being unnecessarily allocated to those stimuli. Another possibility is that Fm theta induced by our dual paradigm may reflect information processing modeled by multi-item working memory requirements for playing the videogame and the simultaneous auditory processing using a memory trace. ERS in the WT data without Fm theta might indicate further processing of the auditory information free from "positive suppression" control reflected by Fm theta. PMID:17993201

  12. A model code for the radiative theta pinch

    SciTech Connect

    Lee, S.; Saw, S. H.; Lee, P. C. K.; Akel, M.; Damideh, V.; Khattak, N. A. D.; Mongkolnavin, R.; Paosawatyanyong, B.

    2014-07-15

    A model for the theta pinch is presented with three modelled phases of radial inward shock phase, reflected shock phase, and a final pinch phase. The governing equations for the phases are derived incorporating thermodynamics and radiation and radiation-coupled dynamics in the pinch phase. A code is written incorporating correction for the effects of transit delay of small disturbing speeds and the effects of plasma self-absorption on the radiation. Two model parameters are incorporated into the model, the coupling coefficient f between the primary loop current and the induced plasma current and the mass swept up factor f{sub m}. These values are taken from experiments carried out in the Chulalongkorn theta pinch.

  13. Simplified scaling model for the THETA-pinch

    SciTech Connect

    Ewing, K. J.; Thomson, D. B.

    1982-02-01

    A simple ID scaling model for the fast THETA-pinch was developed and written as a code that would be flexible, inexpensive in computer time, and readily available for use with the Los Alamos explosive-driven high-magnetic-field program. The simplified model uses three successive separate stages: (1) a snowplow-like radial implosion, (2) an idealized resistive annihilation of reverse bias field, and (3) an adiabatic compression stage of a BETA = 1 plasma for which ideal pressure balance is assumed to hold. The code uses one adjustable fitting constant whose value was first determined by comparison with results from the Los Alamos Scylla III, Scyllacita, and Scylla IA THETA-pinches.

  14. The role of REM sleep theta activity in emotional memory.

    PubMed

    Hutchison, Isabel C; Rathore, Shailendra

    2015-01-01

    While non-REM (NREM) sleep has been strongly implicated in the reactivation and consolidation of memory traces, the role of rapid-eye movement (REM) sleep remains unclear. A growing body of research on humans and animals provide behavioral evidence for a role of REM sleep in the strengthening and modulation of emotional memories. Theta activity-which describes low frequency oscillations in the local field potential within the hippocampus, amygdala and neocortex-is a prominent feature of both wake and REM sleep in humans and rodents. Theta coherence between the hippocampus and amygdala drives large-scale pontine-geniculo-occipital (PGO) waves, the density of which predicts increases in plasticity-related gene expression. This could potentially facilitate the processing of emotional memory traces within the hippocampus during REM sleep. Further, the timing of hippocampal activity in relation to theta phase is vital in determining subsequent potentiation of neuronal activity. This could allow the emotionally modulated strengthening of novel and gradual weakening of consolidated hippocampal memory traces during REM sleep. Hippocampal theta activity is also correlated with REM sleep levels of achetylcholine - which is thought to reduce hippocampal inputs in the neocortex. The additional low levels of noradrenaline during REM sleep, which facilitate feedback within the neocortex, could allow the integration of novel memory traces previously consolidated during NREM sleep. We therefore propose that REM sleep mediates the prioritized processing of emotional memories within the hippocampus, the integration of previously consolidated memory traces within the neocortex, as well as the disengagement of consolidated neocortical memory traces from the hippocampus. PMID:26483709

  15. The role of REM sleep theta activity in emotional memory

    PubMed Central

    Hutchison, Isabel C.; Rathore, Shailendra

    2015-01-01

    While non-REM (NREM) sleep has been strongly implicated in the reactivation and consolidation of memory traces, the role of rapid-eye movement (REM) sleep remains unclear. A growing body of research on humans and animals provide behavioral evidence for a role of REM sleep in the strengthening and modulation of emotional memories. Theta activity—which describes low frequency oscillations in the local field potential within the hippocampus, amygdala and neocortex—is a prominent feature of both wake and REM sleep in humans and rodents. Theta coherence between the hippocampus and amygdala drives large-scale pontine-geniculo-occipital (PGO) waves, the density of which predicts increases in plasticity-related gene expression. This could potentially facilitate the processing of emotional memory traces within the hippocampus during REM sleep. Further, the timing of hippocampal activity in relation to theta phase is vital in determining subsequent potentiation of neuronal activity. This could allow the emotionally modulated strengthening of novel and gradual weakening of consolidated hippocampal memory traces during REM sleep. Hippocampal theta activity is also correlated with REM sleep levels of achetylcholine - which is thought to reduce hippocampal inputs in the neocortex. The additional low levels of noradrenaline during REM sleep, which facilitate feedback within the neocortex, could allow the integration of novel memory traces previously consolidated during NREM sleep. We therefore propose that REM sleep mediates the prioritized processing of emotional memories within the hippocampus, the integration of previously consolidated memory traces within the neocortex, as well as the disengagement of consolidated neocortical memory traces from the hippocampus. PMID:26483709

  16. Correlation of hippocampal theta rhythm with changes in cutaneous temperature

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Saleh, M. A.; Karem, R. D.

    1974-01-01

    Investigation of the possibility that the hippocampus performs the function of alerting an animal to changes in cutaneous temperature, using unanesthetized, loosely restrained rabbits. The results indicate that the hippocampal theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hyppocampal neuron which is, in turn, connected with other areas of the brain involved in temperature regulation.

  17. Cold iron cos THETA magnet option for the SSC

    SciTech Connect

    Reardon, P.

    1985-01-01

    We review first the evolution over the past several years of a cold iron, high field cos THETA magnet design option for the SSC. We note the collaborative approach pursued by BNL and LBL on the 2-in-1 option, and the culmination of this effort in the tests of the BNL 4.5 m model magnets. Next, we discuss the subsequent 1-in-1 option being pursued jointly by BNL, Fermilab and LBL.

  18. Grid cells and theta as oscillatory interference: theory and predictions.

    PubMed

    Burgess, Neil

    2008-01-01

    The oscillatory interference model [Burgess et al. (2007) Hippocampus 17:801-802] of grid cell firing is reviewed as an algorithmic level description of path integration and as an implementation level description of grid cells and their inputs. New analyses concern the relationships between the variables in the model and the theta rhythm, running speed, and the intrinsic firing frequencies of grid cells. New simulations concern the implementation of velocity-controlled oscillators (VCOs) with different preferred directions in different neurons. To summarize the model, the distance traveled along a specific direction is encoded by the phase of a VCO relative to a baseline frequency. Each VCO is an intrinsic membrane potential oscillation whose frequency increases from baseline as a result of depolarization by synaptic input from speed modulated head-direction cells. Grid cell firing is driven by the VCOs whose preferred directions match the current direction of motion. VCOs are phase-reset by location-specific input from place cells to prevent accumulation of error. The baseline frequency is identified with the local average of VCO frequencies, while EEG theta frequency is identified with the global average VCO frequency and comprises two components: the frequency at zero speed and a linear response to running speed. Quantitative predictions are given for the inter-relationships between a grid cell's intrinsic firing frequency and grid scale, the two components of theta frequency, and the running speed of the animal. Qualitative predictions are given for the properties of the VCOs, and the relationship between environmental novelty, the two components of theta, grid scale and place cell remapping. PMID:19021256

  19. Rapid memory stabilization by transient theta coherence in the human medial temporal lobe.

    PubMed

    Thézé, Raphaël; Guggisberg, Adrian G; Nahum, Louis; Schnider, Armin

    2016-04-01

    Presenting stimuli again after presentation of intervening stimuli improves their retention, an effect known as the spacing effect. However, using event-related potentials (ERPs), we had observed that immediate, in comparison to spaced, repetition of pictures induced a positive frontal potential at 200-300 ms. This potential appeared to emanate from the left medial temporal lobe (MTL), a structure critical for memory consolidation. In this study, we tested the behavioral relevance of this signal and explored functional connectivity changes during picture repetition. We obtained high-density electroencephalographic recordings from 14 healthy subjects performing a continuous recognition task where pictures were either repeated immediately or after 9 intervening items. Conventional ERP analysis replicated the positive frontal potential emanating from the left MTL at 250-350 ms in response to immediately repeated stimuli. Connectivity analysis showed that this ERP was associated with increased coherence in the MTL region-left more that right-in the theta-band (3.5-7 Hz) 200-400 ms following immediate, but not spaced, repetition. This increase was stronger in subjects who better recognized immediately repeated stimuli after 30 min. These findings indicate that transient theta-band synchronization between the MTL and the rest of the brain at 200-400 ms reflects a memory stabilizing signal. © 2015 Wiley Periodicals, Inc. PMID:26386180

  20. Cell discharge correlates of posterior hypothalamic theta rhythm. Recipe for success in recording stable field potential.

    PubMed

    Bocian, Renata; Kłos-Wojtczak, Paulina; Konopacki, Jan

    2016-09-01

    The theta rhythm discovered in the posterior hypothalamus area (PHa) differs from theta observed in the hippocampal formation. In comparison to hippocampal spontaneous theta, the theta recorded in the PHa is rarely registered, has lower amplitude, often disappears, and sometimes returns after a few minutes. These features indicate that spontaneous theta recorded in the PHa is not an appropriate experimental model to search for the correlation between PHa cell discharges and local field potential. In this paper we present standard experimental conditions necessary to record theta-related cells in the PHa in anesthetized rats. Three pharmacological agents were used in the experiments to induce PHa theta rhythm in urethanized rats: carbachol (CCH), carbenoxolone and kainic acid, which are potent enough to induce well-synchronized PHa theta. However, CCH was found to be the best pharmacological tool to induce PHa theta oscillations, due to its longest duration of action and lack of preliminary epileptogenic effects. It seems that CCH-induced theta can be the most suitable pharmacological model for experiments with the use of protocol of long-lasting recordings of PHa theta-related cell discharges. PMID:27353451

  1. A Modified Theta Projection Model for Creep Behavior of Metals and Alloys

    NASA Astrophysics Data System (ADS)

    Kumar, Manish; Singh, I. V.; Mishra, B. K.; Ahmad, S.; Venugopal Rao, A.; Kumar, Vikas

    2016-06-01

    In this work, a modified theta projection model is proposed for the constitutive modeling of creep behavior of metals and alloys. In the conventional theta projection model, strain hardening exponent is a function of time and theta, whereas in the modified theta projection model, the exponent is taken as a function of time, theta, and applied stress. The results obtained by the modified theta projection model for Al 2124 T851 alloy at constant uniaxial tensile stress are compared with the experimental results and with the predictions of the conventional theta projection method. The creep behavior of Al 7075 T651 alloy is also predicted using modified and conventional theta projection model and compared with the available experimental data. It is observed that the modified theta projection model captures the creep behavior more accurately as compared to the conventional theta projection model. The modified theta projection model can be used to predict the creep strain of pure metals and class M alloys (similar creep behavior to pure metals) for intermediate range of stress and temperature.

  2. The Experiences of Deaf Young People with Sequential Bilateral Cochlear Implants

    ERIC Educational Resources Information Center

    Mather, Julie; Gregory, Sue; Archbold, Sue

    2011-01-01

    Fifteen young people who had received sequential bilateral cochlear implants were interviewed about their experiences. The majority had become full-time users, and all found improvements in listening with the second implant, including those who did not continue to wear it. All would recommend sequential bilateral implantation to their peers. For…

  3. Bilateral carotid and bilateral vertebral artery dissection following facial massage.

    PubMed

    Chakrapani, Andrea L; Zink, Walter; Zimmerman, Robert; Riina, Howard; Benitez, Ronald

    A 50-year-old woman underwent facial massage. After 13 days, she experienced left retro-orbital pain, ptosis, and miosis. Magnetic resonance imaging (MRI) showed stenotic dissection of bilateral cervical internal carotid and vertebral arteries. The intracranial vasculature was intact. She was treated conservatively with long-term oral anticoagulation and remains asymptomatic 18 months later. PMID:18388028

  4. Theta Series, Wall-Crossing and Quantum Dilogarithm Identities

    NASA Astrophysics Data System (ADS)

    Alexandrov, Sergei; Pioline, Boris

    2016-05-01

    Motivated by mathematical structures which arise in string vacua and gauge theories with {{{N}=2}} supersymmetry, we study the properties of certain generalized theta series which appear as Fourier coefficients of functions on a twisted torus. In Calabi-Yau string vacua, such theta series encode instanton corrections from k Neveu-Schwarz five-branes. The theta series are determined by vector-valued wave-functions, and in this work we obtain the transformation of these wave-functions induced by Kontsevich-Soibelman symplectomorphisms. This effectively provides a quantum version of these transformations, where the quantization parameter is inversely proportional to the five-brane charge k. Consistency with wall-crossing implies a new five-term relation for Faddeev's quantum dilogarithm {Φ_b} at b = 1, which we prove. By allowing the torus to be non-commutative, we obtain a more general five-term relation valid for arbitrary b and k, which may be relevant for the physics of five-branes at finite chemical potential for angular momentum.

  5. Impaired theta-gamma coupling in APP-deficient mice

    PubMed Central

    Zhang, Xiaomin; Zhong, Wewei; Brankačk, Jurij; Weyer, Sascha W.; Müller, Ulrike C.; Tort, Adriano B. L.; Draguhn, Andreas

    2016-01-01

    Amyloid precursor protein (APP) is critically involved in the pathophysiology of Alzheimer’s disease, but its physiological functions remain elusive. Importantly, APP knockout (APP-KO) mice exhibit cognitive deficits, suggesting that APP plays a role at the neuronal network level. To investigate this possibility, we recorded local field potentials (LFPs) from the posterior parietal cortex, dorsal hippocampus and lateral prefrontal cortex of freely moving APP-KO mice. Spectral analyses showed that network oscillations within the theta- and gamma-frequency bands were not different between APP-KO and wild-type mice. Surprisingly, however, while gamma amplitude coupled to theta phase in all recorded regions of wild-type animals, in APP-KO mice theta-gamma coupling was strongly diminished in recordings from the parietal cortex and hippocampus, but not in LFPs recorded from the prefrontal cortex. Thus, lack of APP reduces oscillatory coupling in LFP recordings from specific brain regions, despite not affecting the amplitude of the oscillations. Together, our findings reveal reduced cross-frequency coupling as a functional marker of APP deficiency at the network level. PMID:26905287

  6. Theta Series, Wall-Crossing and Quantum Dilogarithm Identities

    NASA Astrophysics Data System (ADS)

    Alexandrov, Sergei; Pioline, Boris

    2016-08-01

    Motivated by mathematical structures which arise in string vacua and gauge theories with N=2 supersymmetry, we study the properties of certain generalized theta series which appear as Fourier coefficients of functions on a twisted torus. In Calabi-Yau string vacua, such theta series encode instanton corrections from k Neveu-Schwarz five-branes. The theta series are determined by vector-valued wave-functions, and in this work we obtain the transformation of these wave-functions induced by Kontsevich-Soibelman symplectomorphisms. This effectively provides a quantum version of these transformations, where the quantization parameter is inversely proportional to the five-brane charge k. Consistency with wall-crossing implies a new five-term relation for Faddeev's quantum dilogarithm {Φ_b} at b = 1, which we prove. By allowing the torus to be non-commutative, we obtain a more general five-term relation valid for arbitrary b and k, which may be relevant for the physics of five-branes at finite chemical potential for angular momentum.

  7. Comparison of numerical techniques for the evaluation of the Doppler broadening functions psi(x,theta) and chi(x,theta)

    NASA Technical Reports Server (NTRS)

    Canright, R. B., Jr.; Semler, T. T.

    1972-01-01

    Several approximations to the Doppler broadening functions psi(x, theta) and chi(x, theta) are compared with respect to accuracy and speed of evaluation. A technique, due to A. M. Turning (1943), is shown to be at least as accurate as direct numerical quadrature and somewhat faster than Gaussian quadrature. FORTRAN 4 listings are included.

  8. Continuous, Full-Circle Arctangent Circuit

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C.; Howard, David E.; Smith, Dennis A.

    2005-01-01

    A circuit generates an analog voltage proportional to an angle, in response to two sinusoidal input voltages having magnitudes proportional to the sine and cosine of the angle, respectively. That is to say, given input voltages proportional to sin(Omega(t))sin(Theta) and sin(Omega(t))cos(Theta) [where Theta denotes the angle, mega denotes 2(pi) x a carrier frequency, and t denotes time], the circuit generates a steady voltage proportional to Theta. The output voltage varies continuously from its minimum to its maximum value as Theta varies from -180deg to 180deg. While the circuit could accept input modulated sine and cosine signals from any source, it must be noted that such signals are typical of the outputs of shaft-angle resolvers in electromagnetic actuators used to measure and control shaft angles for diverse purposes like aiming scientific instruments and adjusting valve openings. In effect, the circuit is an analog computer that calculates the arctangent of the ratio between the sine and cosine signals. The full-circle angular range of this arctangent circuit stands in contrast to the range of prior analog arctangent circuits, which is from slightly greater than -90deg to slightly less than +90deg. Moreover, for applications in which continuous variation of output is preferred to discrete increments of output, this circuit offers a clear advantage over resolver- to-digital integrated circuits.

  9. Sex differences in human EEG theta oscillations during spatial navigation in virtual reality.

    PubMed

    Kober, Silvia Erika; Neuper, Christa

    2011-03-01

    The present study examines theta oscillations (electroencephalographic (EEG) activity with a frequency of 4-8 Hz) in male and female young adults during spatial navigation in virtual environments. Twenty-seven participants (13 males and 14 females) performed a spatial navigation task in a virtual maze where they had to find the shortest ways between landmarks. Absolute theta band power and event-related desynchronisation/synchronisation (ERD/ERS) in the theta frequency band was used to analyze the EEG data. Processing of spatial cues or landmarks induced cortical theta activity compared to a baseline condition, confirming the hypothesis that theta oscillations reflect sensorimotor integration. The sensorimotor integration hypothesis proposes that theta oscillations coordinate sensory information with a motor plan to direct wayfinding behaviour to known goal locations. No sex differences were found in spatial performance. However, female participants showed a stronger increase in theta oscillations during processing of landmarks as navigational aids compared to a baseline condition than men. Additionally, a higher theta power was associated with an increased navigation performance in women, whereas an increase in theta power was associated with a decreased navigation performance in men. These results might indicate a stronger sensorimotor integration in females than in males. Possible explanations for the emerged sex differences in cortical theta activity are discussed. PMID:21146566

  10. Aged rats show dominant modulation of lower frequency hippocampal theta rhythm during running.

    PubMed

    Li, Jia-Yi; Kuo, Terry B J; Yang, Cheryl C H

    2016-10-01

    Aging causes considerable decline in both physiological and mental functions, particularly cognitive function. The hippocampal theta rhythm (4-12Hz) is related to both cognition and locomotion. Aging-related findings of the frequency and amplitude of hippocampal theta oscillations are inconsistent and occasionally contradictory. This inconsistency may be due to the effects of the sleep/wake state and different frequency subbands being overlooked. We assumed that aged rats have lower responses of the hippocampal theta rhythm during running, which is mainly due to the dominant modulation of theta frequency subbands related to cognition. By simultaneously recording electroencephalography, physical activity (PA), and the heart rate (HR), this experiment explored the theta oscillations before, during, and after treadmill running at a constant speed in 8-week-old (adult) and 60-week-old (middle-aged) rats. Compared with adult rats, the middle-aged rats exhibited lower theta activity in all frequency ranges before running. Running increased the theta frequency (Frq, 4-12Hz), total activity of the whole theta band (total power, TP), activity of the middle theta frequency (MT, 6.5-9.5Hz), and PA in both age groups. However, the middle-aged rats still showed fewer changes in these parameters during the whole running process. After the waking baseline values were substracted, middle-aged rats showed significantly fewer differences in ΔFrq, ΔTP, and ΔMT but significantly more differences in low-frequency theta activity (4.0-6.5Hz) and HR than the adult rats did. Therefore, the decreasing activity and response of the whole theta band in the middle-aged rats resulted in dominant modulation of the middle to lower frequency (4.0-9.5Hz) theta rhythm. The different alterations in the theta rhythm during treadmill running in the two groups may reflect that learning decline with age. PMID:27496645

  11. Theta brain rhythms index perceptual narrowing in infant speech perception

    PubMed Central

    Bosseler, Alexis N.; Taulu, Samu; Pihko, Elina; Mäkelä, Jyrki P.; Imada, Toshiaki; Ahonen, Antti; Kuhl, Patricia K.

    2013-01-01

    The development of speech perception shows a dramatic transition between infancy and adulthood. Between 6 and 12 months, infants' initial ability to discriminate all phonetic units across the world's languages narrows—native discrimination increases while non-native discrimination shows a steep decline. We used magnetoencephalography (MEG) to examine whether brain oscillations in the theta band (4–8 Hz), reflecting increases in attention and cognitive effort, would provide a neural measure of the perceptual narrowing phenomenon in speech. Using an oddball paradigm, we varied speech stimuli in two dimensions, stimulus frequency (frequent vs. infrequent) and language (native vs. non-native speech syllables) and tested 6-month-old infants, 12-month-old infants, and adults. We hypothesized that 6-month-old infants would show increased relative theta power (RTP) for frequent syllables, regardless of their status as native or non-native syllables, reflecting young infants' attention and cognitive effort in response to highly frequent stimuli (“statistical learning”). In adults, we hypothesized increased RTP for non-native stimuli, regardless of their presentation frequency, reflecting increased cognitive effort for non-native phonetic categories. The 12-month-old infants were expected to show a pattern in transition, but one more similar to adults than to 6-month-old infants. The MEG brain rhythm results supported these hypotheses. We suggest that perceptual narrowing in speech perception is governed by an implicit learning process. This learning process involves an implicit shift in attention from frequent events (infants) to learned categories (adults). Theta brain oscillatory activity may provide an index of perceptual narrowing beyond speech, and would offer a test of whether the early speech learning process is governed by domain-general or domain-specific processes. PMID:24130536

  12. Theta-Pinch Thruster for Piloted Deep Space Exploration

    NASA Technical Reports Server (NTRS)

    LaPointe, Mike R.; Reddy, Dhanireddy (Technical Monitor)

    2000-01-01

    A new high-power propulsion concept that combines a rapidly pulsed theta-pinch discharge with upstream particle reflection by a magnetic mirror was evaluated under a Phase 1 grant awarded through the NASA Institute for Advanced Concepts. Analytic and numerical models were developed to predict the performance of a theta-pinch thruster operated over a wide range of initial gas pressures and discharge periods. The models indicate that a 1 m radius, 10 m long thruster operated with hydrogen propellant could provide impulse-bits ranging from 1 N-s to 330 N-s with specific impulse values of 7,500 s to 2,500 s, respectively. A pulsed magnetic field strength of 2 T is required to compress and heat the preionized hydrogen over a 10(exp -3) second discharge period, with about 60% of the heated plasma exiting the chamber each period to produce thrust. The unoptimized thruster efficiency is low, peaking at approximately 16% for an initial hydrogen chamber pressure of 100 Torr. The specific impulse and impulse-bit at this operating condition are 3,500 s and 90 N-s, respectively, and the required discharge energy is approximately 9x10(exp 6) J. For a pulse repetition rate of 10 Hz, the engine would produce an average thrust of 900 N at 3,500 s specific impulse. Combined with the electrodeless nature of the device, these performance parameters indicate that theta-pinch thrusters could provide unique, long-life propulsion systems for piloted deep space mission applications.

  13. Chiral symmetry breaking and {theta} vacuum structure in QCD

    SciTech Connect

    Morchio, G. Strocchi, F.

    2009-10-15

    The solution of the axial U(1) problem, the role of the topology of the gauge group in forcing the breaking of axial symmetry in any irreducible representation of the observable algebra and the {theta} vacua structure are revisited in the temporal gauge with attention to the mathematical consistency of the derivations. Both realizations with strong and weak Gauss law are discussed; the control of the general mechanisms and structures is obtained on the basis of the localization of the (large) gauge transformations and the local generation of the chiral symmetry. The Schwinger model in the temporal gauge exactly reproduces the general results.

  14. The effective chiral Lagrangian from the theta term

    SciTech Connect

    Mereghetti, E.; Hockings, W.H.; Kolck, U. van

    2010-11-15

    We construct the effective chiral Lagrangian involving hadronic and electromagnetic interactions originating from the QCD {theta}-bar term. We impose vacuum alignment at both quark and hadronic levels, including field redefinitions to eliminate pion tadpoles. We show that leading time-reversal-violating (TV) hadronic interactions are related to isospin-violating interactions that can in principle be determined from charge-symmetry-breaking experiments. We discuss the complications that arise from TV electromagnetic interactions. Some implications of the expected sizes of various pion-nucleon TV interactions are presented, and the pion-nucleon form factor is used as an example.

  15. Bilateral diabetic thigh muscle infarction.

    PubMed

    Barohn, R J; Bazan, C; Timmons, J H; Tegeler, C

    1994-01-01

    A 19-year-old woman with insulin-dependent diabetes mellitus developed pain and tenderness in the medial aspect of the left thigh and calf, followed 1 week later by similar symptoms in the right leg. Technetium 99m pyrophosphate (PYP) radionuclide scans showed increased flow and uptake in the medial thigh muscles. Magnetic resonance imaging (MRI) of the thigh showed increased signal on proton density and T2-weighted images in the medial and lateral thigh compartments. High-resolution B-mode ultrasound showed hyperechoic changes in the anteromedial thigh muscles, with loss of normal myofascial interfaces, and a mixed appearance, bilaterally. Two months later, after the symptoms had begun to resolve, the images had improved. This case documents bilateral diabetic thigh infarction identified by abnormal technetium 99m PYP flow studies, MRI signal, and B-mode ultrasound imaging. PMID:8136579

  16. Associative Memory Storage and Retrieval: Involvement of Theta Oscillations in Hippocampal Information Processing

    PubMed Central

    Stella, Federico; Treves, Alessandro

    2011-01-01

    Theta oscillations are thought to play a critical role in neuronal information processing, especially in the hippocampal region, where their presence is particularly salient. A detailed description of theta dynamics in this region has revealed not only a consortium of layer-specific theta dipoles, but also within-layer differences in the expression of theta. This complex and articulated arrangement of current flows is reflected in the way neuronal firing is modulated in time. Several models have proposed that these different theta modulators flexibly coordinate hippocampal regions, to support associative memory formation and retrieval. Here, we summarily review different approaches related to this issue and we describe a mechanism, based on experimental and simulation results, for memory retrieval in CA3 involving theta modulation. PMID:21961072

  17. Bilateral posterior cerebral artery infarction.

    PubMed

    Ryan, Davinia; Murphy, Sinead M; Hennessey, Michael J

    2010-01-01

    We report the case of a 70-year-old man who presented with short-term memory impairment and a homonymous left inferior quadrantanopia secondary to simultaneous bilateral posterior cerebral artery (PCA) territory infarction. As in more than a quarter of cases of PCA infarction, no aetiological cause was identified. Unlike the transient nature of symptoms in some cases following unilateral infarction, his deficits persisted on 2-month follow-up. PMID:22798298

  18. Compensation Following Bilateral Vestibular Damage

    PubMed Central

    McCall, Andrew A.; Yates, Bill J.

    2011-01-01

    Bilateral loss of vestibular inputs affects far fewer patients than unilateral inner ear damage, and thus has been understudied. In both animal subjects and human patients, bilateral vestibular hypofunction (BVH) produces a variety of clinical problems, including impaired balance control, inability to maintain stable blood pressure during postural changes, difficulty in visual targeting of images, and disturbances in spatial memory and navigational performance. Experiments in animals have shown that non-labyrinthine inputs to the vestibular nuclei are rapidly amplified following the onset of BVH, which may explain the recovery of postural stability and orthostatic tolerance that occurs within 10 days. However, the loss of the vestibulo-ocular reflex and degraded spatial cognition appear to be permanent in animals with BVH. Current concepts of the compensatory mechanisms in humans with BVH are largely inferential, as there is a lack of data from patients early in the disease process. Translation of animal studies of compensation for BVH into therapeutic strategies and subsequent application in the clinic is the most likely route to improve treatment. In addition to physical therapy, two types of prosthetic devices have been proposed to treat individuals with bilateral loss of vestibular inputs: those that provide tactile stimulation to indicate body position in space, and those that deliver electrical stimuli to branches of the vestibular nerve in accordance with head movements. The relative efficacy of these two treatment paradigms, and whether they can be combined to facilitate recovery, is yet to be ascertained. PMID:22207864

  19. Correlation of the Hippocampal theta rhythm to changes in hypothalamic temperature

    NASA Technical Reports Server (NTRS)

    Saleh, M. A.; Horowitz, J. M.; Hsieh, A. C. L.

    1974-01-01

    Warming and cooling the preoptic anterior hypothalamic area in awake, loosely restrained rabbits was found to evoke theta rhythm. This is consistent with previous studies indicating that theta rhythm is a nonspecific response evoked by stimulation of several sensory modalities. Several studies have correlated theta rhythm with alertness. A neural pathway involving the hypothalamus, the hippocampus, the septal area, and the reticular formation is proposed. Thus, a role of this pathway may be to alert the animal to changes in its body temperature.

  20. Light-front description for the theta dependence of meson masses in the massive Schwinger model

    SciTech Connect

    Burkardt, M.; Harada, K.

    1998-05-01

    We present a continuum formulation for {theta} vacua in the massive Schwinger model on the light front, where {theta} enters as a background electric field. The effective coupling of the external field is partially screened due to vacuum polarization processes. For small fermion masses and small {theta}, we calculate the mass of the meson and find agreement with results from bosonization. {copyright} {ital 1998} {ital The American Physical Society}

  1. Theta and gamma coherence across the septotemporal axis during distinct behavioral states.

    PubMed

    Penley, Stephanie C; Hinman, James R; Sabolek, Helen R; Escabí, Monty A; Markus, Etan J; Chrobak, James J

    2012-05-01

    Theta (4-12 Hz) and gamma (40-100 Hz) field potentials represent the interaction of synchronized synaptic input onto distinct neuronal populations within the hippocampal formation. Theta is quite prominent during exploratory activity, locomotion, and REM sleep. Although it is generally acknowledged that theta is coherent throughout most of the hippocampus, there is significant variability in theta, as well as gamma, coherence across lamina at any particular septotemporal level of the hippocampus. Larger differences in theta coherence are observed across the septotemporal (long) axis. We have reported that during REM sleep there is a decrease in theta coherence across the long axis that varies with the topography of CA3/mossy cell input rather than the topography of the prominent entorhinal input. On the basis of differences in the rat's behavior as well as the activity of neuromodulatory inputs (e.g., noradrenergic and serotonergic), we hypothesized that theta coherence across the long axis would be greater during locomotion than REM sleep and exhibit a pattern more consistent with the topography of entorhinal inputs. We examined theta and gamma coherence indices at different septotemporal and laminar sites during distinct theta states: locomotion during maze running, REM sleep, following acute treatment with a θ-inducing cholinomimetic (physostigmine) and for comparison during slow-wave sleep. The results demonstrate a generally consistent pattern of theta and gamma coherence across the septotemporal axis of the hippocampus that is quite indifferent to sensory input and overt behavior. These results are discussed with regards to the neurobiological mechanisms that generate theta and gamma and the growing body of evidence linking theta and gamma indices to memory and other cognitive functions. PMID:21748821

  2. Pentaquark {Theta}{sup +} production from the reaction {gamma}p {yields} {pi}{sup +} K{sup -} {Theta}{sup +}

    SciTech Connect

    W. Liu; C. M. Ko; V. Kubarovsky

    2004-02-01

    The cross section for {Theta}{sup +} production from the reaction {gamma}p {yields} {pi}{sup +} K{sup -} {Theta}{sup +}, which was observed in the CLAS experiment at the Jefferson National Laboratory, is evaluated in a hadronic model that includes couplings of {Theta}{sup +} to both KN and K*N. With their coupling constants determined from the empirical {pi} NN(1710) and {rho} NN(1710) coupling constants using the SU(3) symmetry, the cross section for this reaction has been evaluated by taking {Theta}{sup +} to have spin 1/2 and isospin 0 but either positive or negative parity. We find that the cross section is 10-15 nb if {Theta}{sup +} has positive parity as predicted by the chiral soliton model. The cross section is reduced by more than a factor of 10 if {Theta}{sup +} has negative parity as given by lattice QCD studies. For both parities, the differential distribution peaks at small negative four momentum transfer as expected from the dominating t-channel kaon-exchange diagram that involves only the coupling of {Theta}{sup +} to KN.

  3. The use of cubic Nd-Ba-Cu-O seeds to create {theta}[100], 90{degree}-{theta}[100], and {theta}[001] tilt Y-Ba-Cu-O grain boundaries.

    SciTech Connect

    Field, M. B.

    1998-10-20

    Using seeding techniques to control the orientation of grains, we have been able to create a wide variety of YBa{sub 2}Cu{sub 3}O{sub 6+x}, grain boundaries. In addition to five domain samples with 90{degree}[100] twist and tilt grain boundaries, we have now developed a method to produce grain boundaries in the same sample that have the misorientations {theta}[001] tilt, {theta}[100] tilt, and 90{degree} {approximately} {theta}[100], where the disorientation angle {theta} is fully controllable. We will demonstrate how these boundaries can be synthesized, give experimental evidence via polarized light microscopy and electron backscatter patterns (EBSP) that the intended grain boundaries were indeed formed, and discuss the importance of these boundaries in future grain boundary studies.

  4. Cholinergic Blockade Reduces Theta-Gamma Phase Amplitude Coupling and Speed Modulation of Theta Frequency Consistent with Behavioral Effects on Encoding

    PubMed Central

    Gillet, Shea N.; Climer, Jason R.; Hasselmo, Michael E.

    2013-01-01

    Large-scale neural activation dynamics in the hippocampal-entorhinal circuit local field potential, observable as theta and gamma rhythms and coupling between these rhythms, is predictive of encoding success. Behavioral studies show that systemic administration of muscarinic acetylcholine receptor antagonists selectively impairs encoding, suggesting that they may also disrupt the coupling between the theta and gamma bands. Here, we tested the hypothesis that muscarinic antagonists selectively disrupt coupling between theta and gamma. Specifically, we characterized the effects of systemically administered scopolamine on movement-induced theta and gamma rhythms recorded in the superficial layers of the medial entorhinal cortex (MEC) of freely moving rats. We report the novel result that gamma power at the peak of theta was most reduced following muscarinic blockade, significantly shifting the phase of maximal gamma power to occur at later phases of theta. We also characterize the existence of multiple distinct gamma bands in the superficial layers of the MEC. Further, we observed that theta frequency was significantly less modulated by movement speed following muscarinic blockade. Finally, the slope relating speed to theta frequency, a correlate of familiarity with a testing enclosure, increased significantly less between the preinjection and recovery trials when scopolamine was administered during the intervening injection session than when saline was administered, suggesting that scopolamine reduced encoding of the testing enclosure. These data are consistent with computational models suggesting that encoding and retrieval occur during the peak and trough of theta, respectively, and support the theory that acetylcholine regulates the balance between encoding versus retrieval. PMID:24336727

  5. Theta variation and spatiotemporal scaling along the septotemporal axis of the hippocampus

    PubMed Central

    Long, Lauren L.; Bunce, Jamie G.; Chrobak, James J.

    2015-01-01

    Hippocampal theta has been related to locomotor speed, attention, anxiety, sensorimotor integration and memory among other emergent phenomena. One difficulty in understanding the function of theta is that the hippocampus (HPC) modulates voluntary behavior at the same time that it processes sensory input. Both functions are correlated with characteristic changes in theta indices. The current review highlights a series of studies examining theta local field potential (LFP) signals across the septotemporal or longitudinal axis of the HPC. While the theta signal is coherent throughout the entirety of the HPC, the amplitude, but not the frequency, of theta varies significantly across its three-dimensional expanse. We suggest that the theta signal offers a rich vein of information about how distributed neuronal ensembles support emergent function. Further, we speculate that emergent function across the long axis varies with respect to spatiotemporal scale. Thus, septal HPC processes details of the proximal spatiotemporal environment while more temporal aspects process larger spaces and wider time-scales. The degree to which emergent functions are supported by the synchronization of theta across the septotemporal axis is an open question. Our working model is that theta synchrony serves to bind ensembles representing varying resolutions of spatiotemporal information at interdependent septotemporal areas of the HPC. Such synchrony and cooperative interactions along the septotemporal axis likely support memory formation and subsequent consolidation and retrieval. PMID:25852496

  6. Multiresolution Bilateral Filtering for Image Denoising

    PubMed Central

    Zhang, Ming; Gunturk, Bahadir K.

    2008-01-01

    The bilateral filter is a nonlinear filter that does spatial averaging without smoothing edges; it has shown to be an effective image denoising technique. An important issue with the application of the bilateral filter is the selection of the filter parameters, which affect the results significantly. There are two main contributions of this paper. The first contribution is an empirical study of the optimal bilateral filter parameter selection in image denoising applications. The second contribution is an extension of the bilateral filter: multiresolution bilateral filter, where bilateral filtering is applied to the approximation (low-frequency) subbands of a signal decomposed using a wavelet filter bank. The multiresolution bilateral filter is combined with wavelet thresholding to form a new image denoising framework, which turns out to be very effective in eliminating noise in real noisy images. Experimental results with both simulated and real data are provided. PMID:19004705

  7. D3-instantons, mock theta series and twistors

    NASA Astrophysics Data System (ADS)

    Alexandrov, Sergei; Manschot, Jan; Pioline, Boris

    2013-04-01

    The D-instanton corrected hypermultiplet moduli space of type II string theory compactified on a Calabi-Yau threefold is known in the type IIA picture to be determined in terms of the generalized Donaldson-Thomas invariants, through a twistorial construction. At the same time, in the mirror type IIB picture, and in the limit where only D3-D1-D(-1)-instanton corrections are retained, it should carry an isometric action of the S-duality group SL(2, {Z} ). We prove that this is the case in the one-instanton approximation, by constructing a holomorphic action of SL(2, {Z} ) on the linearized twistor space. Using the modular invariance of the D4-D2-D0 black hole partition function, we show that the standard Darboux coordinates in twistor space have modular anomalies controlled by period integrals of a Siegel-Narain theta series, which can be canceled by a contact transformation generated by a holomorphic mock theta series.

  8. Increased oscillatory theta activation evoked by violent digital game events.

    PubMed

    Salminen, Mikko; Ravaja, Niklas

    2008-04-11

    The authors examined electroencephalographic (EEG) oscillatory responses to two violent events, the player character wounding and killing an opponent character with a gun, in the digital game James Bond 007: NightFire. EEG was recorded from 25 (16 male) right-handed healthy young adults. EEG data were segmented into one 1-s baseline epoch before each event and two 1-s epochs after event onset. Power estimates (microV(2)) were derived with the fast Fourier transform (FFT) for each artefact free event. Both of the studied events evoked increased occipital theta (4-6Hz) responses as compared to the pre-event baseline. The wounding event evoked also increased occipital high theta (6-8Hz) response and the killing event evoked low alpha (8-10Hz) asymmetry over the central electrodes, both relative to the pre-event baseline. The results are discussed in light of facial electromyographic and electrodermal activity responses evoked by these same events, and it is suggested that the reported EEG responses may be attributable to affective processes related to these violent game events. PMID:18325669

  9. Theta responses are abnormal in mild cognitive impairment: evidence from analysis of theta event-related synchronization during a temporal expectancy task.

    PubMed

    Caravaglios, Giuseppe; Muscoso, Emma Gabriella; Di Maria, Giulia; Costanzo, Erminio

    2013-07-01

    We examined the hypothesis that the attention/executive deficits in mild cognitive impairment (MCI) due to Alzheimer's disease is associated to an abnormal cortical activation, revealed by the method of event-related synchronization/desynchronization (ERS/ERD) in the theta band during a paradigm of temporal orienting of attention. MCI patients (n = 25) and healthy elderly (HE) matched controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial theta responses were measured, respectively, before and after the motor response. Then, theta responses were compared to theta power during eyes closed resting state (ERD/ERS method).The temporal course of the task was characterized by two different behavioural conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event (after button pressing) epoch, in which the subject was in a post-motor response condition. The most important findings are summarized as follows: (1) in both groups, the pre-event epoch was characterized by theta ERS on temporal electrodes, but HE had a greater theta ERS compared to that of MCI group; (2) in both groups, during the post-motor condition, there was a theta ERS on prefrontal regions, and, also in this case, HE showed a greater theta enhancement compared to that of MCI patients; (3) HE showed evidence of lateralization: during the waiting epoch, theta ERS was dominant on the right posterior temporal lead (T6), whilst, during the post-motor epoch, theta ERS was greater on the left, as well as the midline prefrontal leads. Compared to the traditional neuropsychological measures for the episodic memory, these theta ERS indicators were less accurate in differentiating MCI patients from healthy elderly. The clinical relevance of these findings is that the weaker theta reactivity in MCI would indicate an early impairment in the

  10. Continuous Tuning and Calibration of Vibratory Gyroscopes

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken

    2003-01-01

    A method of control and operation of an inertial reference unit (IRU) based on vibratory gyroscopes provides for continuously repeated cycles of tuning and calibration. The method is intended especially for application to an IRU containing vibratory gyroscopes that are integral parts of microelectromechanical systems (MEMS) and that have cloverleaf designs, as described in several previous NASA Tech Briefs articles. The method provides for minimization of several measures of spurious gyroscope output, including zero-rate offset (ZRO), angle random walk (ARW), and rate drift. These benefits are afforded both at startup and thereafter during continuing operation, in the presence of unknown rotation rates and changes in temperature. A vibratory gyroscope contains a precision mechanically resonant structure containing two normal modes of vibration nominally degenerate in frequency and strongly coupled via a Coriolis term. In the case of the cloverleaf design MEMS gyro, these normal modes of vibration are plate rocking modes. The rocking motion of the plate is described by giving two angles, theta(sub 1) and theta(sub 2). A proof mass consisting of a post orthogonal to the plate ensures a high degree of Coriolis coupling of vibratory energy from one mode into the other under inertial rotation. The plate is driven and sensed capacitively across a few-microns-wide gap, and the normal mode frequencies can be tuned electrostatically by DC voltages applied across this gap. In order to sense rotation, the resonator plate is caused to rock in the theta(sub 1) direction, then any small motions in the theta(sub 2) direction are sensed, rebalanced, and interpreted as inertial rotation. In this scenario, the "drive" has been assigned to the theta(sub 1) direction, and the "sense" has been assigned to the theta(sub 2) direction.

  11. Structure of auroral precipitation during a theta aurora from multisatellite observations

    SciTech Connect

    Feldstein, Y.I.; Newell, P.T.; Sandahl, I.

    1995-09-01

    A {theta} aurora previously discussed on the basis of Viking images (northern hemisphere) and DE 1 images (southern hemisphere) is reexamined in light of additional data, primarily the auroral plasma distribution as determined from the Viking, DMSP F6, and DMSP F7 satellites. This event, which occurred before a substorm expansion phase on August 3, 1986, appeared in the images to consist of a single arc along the morning side in the northern hemisphere and along the evening side in the southern hemisphere and was isolated from the auroral oval in both sets of images. On the basis of the auroral plasma distribution inferred from three satellites, the brightest arcs do occur at the locations indicated by the imagers, both the arcs are in fact connected to the main oval with continuous precipitation, and weaker secondary arcs (not observed by the imagers) occur in the opposite hemisphere magnetically conjugate to the bright arcs. These observations support the interpretation of the {theta} aurora as occurring on closed field lines as a result of the expansion of the morning and evening sector ovals into the polar cap. A careful examination of the characteristics of the observed auroral energy plasma suggests additional conclusions. It appears that the ionospheric manifestation of the recently discovered low-energy electron layer can be identified with a complicated structure of soft precipitation at the poleward edge of the main precipitation region. Finally, unlike recent reports, the ions were not observed to have a cutoff in the polar cap that is any sharper than that of the electrons. 48 refs., 13 figs.

  12. Theta-burst Transcranial Magnetic Stimulation Alters the Functional Topography of the Cortical Motor Network

    PubMed Central

    NOH, Nor Azila; FUGGETTA, Giorgio; MANGANOTTI, Paolo

    2015-01-01

    Background: Transcranial magnetic stimulation (TMS) is a non-invasive tool that is able to modulate the electrical activity of the brain depending upon its protocol of stimulation. Theta burst stimulation (TBS) is a high-frequency TMS protocol that is able to induce prolonged plasticity changes in the brain. The induction of plasticity-like effects by TBS is useful in both experimental and therapeutic settings; however, the underlying neural mechanisms of this modulation remain unclear. The aim of this study was to investigate the effects of continuous TBS (cTBS) on the intrahemispheric and interhemispheric functional connectivity of the resting and active brain. Methods: A total of 26 healthy humans were randomly divided into two groups that received either real cTBS or sham (control) over the left primary motor cortex. Surface electroencephalogram (EEG) was used to quantify the changes of neural oscillations after cTBS at rest and after a choice reaction time test. The cTBS-induced EEG oscillations were computed using spectral analysis of event-related coherence (ERCoh) of theta (4–7.5 Hz), low alpha (8–9.5 Hz), high alpha (10–12.5 Hz), low beta (13–19.5 Hz), and high beta (20–30 Hz) brain rhythms. Results: We observed a global decrease in functional connectivity of the brain in the cTBS group when compared to sham in the low beta brain rhythm at rest and high beta brain rhythm during the active state. In particular, EEG spectral analysis revealed that high-frequency beta, a cortically generated brain rhythm, was the most sensitive band that was modulated by cTBS. Conclusion: Overall, our findings suggest that cTBS, a TMS protocol that mimics the mechanism of long-term depression of synaptic plasticity, modulates motor network oscillations primarily at the cortical level and might interfere with cortical information coding. PMID:27006636

  13. A case of simultaneous bilateral spontaneous pneumothorax after the Nuss procedure.

    PubMed

    Matsuoka, Shunichiro; Miyazawa, Masahisa; Kashimoto, Kentaro; Kobayashi, Hiroaki; Mitsui, Fumihiko; Tsunoda, Hajime; Kunitomo, Kazuyoshi; Chisuwa, Hisanao; Haba, Yoshiaki

    2016-06-01

    We present a case of simultaneous bilateral spontaneous pneumothorax caused by a pleuro-pleural communication formed from Nuss procedure for pectus excavatum. A 17-year-old man with a history of Nuss operation complained chest pain and dyspnea. A chest roentgenogram demonstrated a tiny bilateral pneumothorax and two metallic bars inserted at the Nuss procedure. Computed tomography revealed furthermore a bulla in the apex of the left lung. The bilateral pneumothorax critically deteriorated after 4 days from onset and urgent bilateral chest drainages were performed. Nevertheless the drainages the full expansion of both lungs was not obtained and air leakage only from left side was continued. A video-assisted left bullectomy was performed 9 days after the tube insertion. The two bars penetrating anterior mediastinal pleura were thought to be a cause of the simultaneous bilateral spontaneous pneumothorax. PMID:25352312

  14. Bilateral ECT induces bilateral increases in regional cortical thickness.

    PubMed

    van Eijndhoven, P; Mulders, P; Kwekkeboom, L; van Oostrom, I; van Beek, M; Janzing, J; Schene, A; Tendolkar, I

    2016-01-01

    Electroconvulsive therapy (ECT) is the most effective treatment for patients suffering from severe or treatment-resistant major depressive disorder (MDD). Unfortunately its underlying neurobiological mechanisms are still unclear. One line of evidence indicates that the seizures produced by ECT induce or stimulate neuroplasticity effects. Although these seizures also affect the cortex, the effect of ECT on cortical thickness is not investigated until now. We acquired structural magnetic resonance imaging data in 19 treatment-resistant MDD patients before and after a bilateral ECT course, and 16 healthy controls at 2 time points, and compared changes in cortical thickness between the groups. Our results reveal that ECT induces significant, bilateral increases in cortical thickness, including the temporal pole, inferior and middle temporal cortex and the insula. The pattern of increased cortical thickness was predominant in regions that are associated with seizure onset in ECT. Post hoc analyses showed that the increase in thickness of the insular cortex was larger in responders than in non-responders, which may point to a specific relationship of this region with treatment effects of ECT. PMID:27552587

  15. Multistep joint bilateral depth upsampling

    NASA Astrophysics Data System (ADS)

    Riemens, A. K.; Gangwal, O. P.; Barenbrug, B.; Berretty, R.-P. M.

    2009-01-01

    Depth maps are used in many applications, e.g. 3D television, stereo matching, segmentation, etc. Often, depth maps are available at a lower resolution compared to the corresponding image data. For these applications, depth maps must be upsampled to the image resolution. Recently, joint bilateral filters are proposed to upsample depth maps in a single step. In this solution, a high-resolution output depth is computed as a weighted average of surrounding low-resolution depth values, where the weight calculation depends on spatial distance function and intensity range function on the related image data. Compared to that, we present two novel ideas. Firstly, we apply anti-alias prefiltering on the high-resolution image to derive an image at the same low resolution as the input depth map. The upsample filter uses samples from both the high-resolution and the low-resolution images in the range term of the bilateral filter. Secondly, we propose to perform the upsampling in multiple stages, refining the resolution by a factor of 2×2 at each stage. We show experimental results on the consequences of the aliasing issue, and we apply our method to two use cases: a high quality ground-truth depth map and a real-time generated depth map of lower quality. For the first use case a relatively small filter footprint is applied; the second use case benefits from a substantially larger footprint. These experiments show that the dual image resolution range function alleviates the aliasing artifacts and therefore improves the temporal stability of the output depth map. On both use cases, we achieved comparable or better image quality with respect to upsampling with the joint bilateral filter in a single step. On the former use case, we feature a reduction of a factor of 5 in computational cost, whereas on the latter use case, the cost saving is a factor of 50.

  16. Bilateral Impedance Control For Telemanipulators

    NASA Technical Reports Server (NTRS)

    Moore, Christopher L.

    1993-01-01

    Telemanipulator system includes master robot manipulated by human operator, and slave robot performing tasks at remote location. Two robots electronically coupled so slave robot moves in response to commands from master robot. Teleoperation greatly enhanced if forces acting on slave robot fed back to operator, giving operator feeling he or she manipulates remote environment directly. Main advantage of bilateral impedance control: enables arbitrary specification of desired performance characteristics for telemanipulator system. Relationship between force and position modulated at both ends of system to suit requirements of task.

  17. Bilateral molariform mandibular second premolars.

    PubMed

    Acharya, Sonu; Kumar Mandal, Pradip; Ghosh, Chiranjit

    2015-01-01

    Macrodontia is a rare dental anomaly that refers to teeth that appear larger than normal. Generalised macrodontia can be associated with certain medical conditions and syndromes. This case report presents clinical and radiographic findings of isolated bilateral macrodontia in a 14-year-old child. The patient was referred to the clinic with local crowding of maxillary and mandibular teeth. Radiographic findings revealed the presence of impacted macrodont mandibular second premolar on one side and erupted macrodontic premolar on the other side and their distinct morphological appearance, characterized by large, multitubercular, and molariform crowns and tapering, single roots. PMID:25685564

  18. Structural Organization of the Corpus Callosum Predicts Attentional Shifts after Continuous Theta Burst Stimulation

    PubMed Central

    Humphreys, Glyn W.; Sotiropoulos, Stamatios N.; Kennard, Christopher; Cazzoli, Dario

    2015-01-01

    Repetitive transcranial magnetic stimulation (rTMS) applied over the right posterior parietal cortex (PPC) in healthy participants has been shown to trigger a significant rightward shift in the spatial allocation of visual attention, temporarily mimicking spatial deficits observed in neglect. In contrast, rTMS applied over the left PPC triggers a weaker or null attentional shift. However, large interindividual differences in responses to rTMS have been reported. Studies measuring changes in brain activation suggest that the effects of rTMS may depend on both interhemispheric and intrahemispheric interactions between cortical loci controlling visual attention. Here, we investigated whether variability in the structural organization of human white matter pathways subserving visual attention, as assessed by diffusion magnetic resonance imaging and tractography, could explain interindividual differences in the effects of rTMS. Most participants showed a rightward shift in the allocation of spatial attention after rTMS over the right intraparietal sulcus (IPS), but the size of this effect varied largely across participants. Conversely, rTMS over the left IPS resulted in strikingly opposed individual responses, with some participants responding with rightward and some with leftward attentional shifts. We demonstrate that microstructural and macrostructural variability within the corpus callosum, consistent with differential effects on cross-hemispheric interactions, predicts both the extent and the direction of the response to rTMS. Together, our findings suggest that the corpus callosum may have a dual inhibitory and excitatory function in maintaining the interhemispheric dynamics that underlie the allocation of spatial attention. SIGNIFICANCE STATEMENT The posterior parietal cortex (PPC) controls allocation of attention across left versus right visual fields. Damage to this area results in neglect, characterized by a lack of spatial awareness of the side of space contralateral to the brain injury. Transcranial magnetic stimulation over the PPC is used to study cognitive mechanisms of spatial attention and to examine the potential of this technique to treat neglect. However, large individual differences in behavioral responses to stimulation have been reported. We demonstrate that the variability in the structural organization of the corpus callosum accounts for these differences. Our findings suggest novel dual mechanism of the corpus callosum function in spatial attention and have broader implications for the use of stimulation in neglect rehabilitation. PMID:26586822

  19. The synchronous activity of lateral habenular neurons is essential for regulating hippocampal theta oscillation.

    PubMed

    Aizawa, Hidenori; Yanagihara, Shin; Kobayashi, Megumi; Niisato, Kazue; Takekawa, Takashi; Harukuni, Rie; McHugh, Thomas J; Fukai, Tomoki; Isomura, Yoshikazu; Okamoto, Hitoshi

    2013-05-15

    Lateral habenula (LHb) has attracted growing interest as a regulator of serotonergic and dopaminergic neurons in the CNS. However, it remains unclear how the LHb modulates brain states in animals. To identify the neural substrates that are under the influence of LHb regulation, we examined the effects of rat LHb lesions on the hippocampal oscillatory activity associated with the transition of brain states. Our results showed that the LHb lesion shortened the theta activity duration both in anesthetized and sleeping rats. Furthermore, this inhibitory effect of LHb lesion on theta maintenance depended upon an intact serotonergic median raphe, suggesting that LHb activity plays an essential role in maintaining hippocampal theta oscillation via the serotonergic raphe. Multiunit recording of sleeping rats further revealed that firing of LHb neurons showed significant phase-locking activity at each theta oscillation cycle in the hippocampus. LHb neurons showing activity that was coordinated with that of the hippocampal theta were localized in the medial LHb division, which receives afferents from the diagonal band of Broca (DBB), a pacemaker region for the hippocampal theta oscillation. Thus, our findings indicate that the DBB may pace not only the hippocampus, but also the LHb, during rapid eye movement sleep. Since serotonin is known to negatively regulate theta oscillation in the hippocampus, phase-locking activity of the LHb neurons may act, under the influence of the DBB, to maintain the hippocampal theta oscillation by modulating the activity of serotonergic neurons. PMID:23678132

  20. Decrease of theta response in euthymic bipolar patients during an oddball paradigm.

    PubMed

    Atagün, M İ; Güntekin, B; Ozerdem, A; Tülay, E; Başar, E

    2013-06-01

    Theta oscillations are related to cognitive functions and reflect functional integration of frontal and medial temporal structures into coherent neurocognitive networks. This study assessed event-related theta oscillations in medication-free, euthymic patients with bipolar disorder upon auditory oddball paradigm. Twenty-two DSM-IV euthymic bipolar I (n = 19) and II (n = 3) patients and twenty-two healthy subjects were included. Patients were euthymic for at least 6 months, and psychotropic-free for at least 2 weeks. EEG was recorded at 30 electrode sites. Auditory oddball paradigm and sensory stimuli were used. Event-related Oscillations were analyzed using adaptive filtering in two different theta frequency bands (4-6 Hz, 6-8 Hz). In healthy subjects, slow theta (4-6 Hz) responses were significantly higher than those of euthymic patients upon target, non-target and sensory stimuli (p < 0.05). Fast theta (6-8 Hz) responses of healthy subjects were significantly higher than those of euthymic patients upon target-only stimuli (p < 0.05). Reduced theta oscillations during auditory processing provide strong quantitative evidence of activation deficits in related networks in bipolar disorder. Fast theta responses are related to cognitive functions, whereas slow theta responses are related to sensory processes more than cognitive processes. PMID:24427202

  1. Spike-timing error backpropagation in theta neuron networks.

    PubMed

    McKennoch, Sam; Voegtlin, Thomas; Bushnell, Linda

    2009-01-01

    The main contribution of this letter is the derivation of a steepest gradient descent learning rule for a multilayer network of theta neurons, a one-dimensional nonlinear neuron model. Central to our model is the assumption that the intrinsic neuron dynamics are sufficient to achieve consistent time coding, with no need to involve the precise shape of postsynaptic currents; this assumption departs from other related models such as SpikeProp and Tempotron learning. Our results clearly show that it is possible to perform complex computations by applying supervised learning techniques to the spike times and time response properties of nonlinear integrate and fire neurons. Networks trained with our multilayer training rule are shown to have similar generalization abilities for spike latency pattern classification as Tempotron learning. The rule is also able to train networks to perform complex regression tasks that neither SpikeProp or Tempotron learning appears to be capable of. PMID:19431278

  2. Axial laser heating of three meter theta pinch plasma columns

    NASA Astrophysics Data System (ADS)

    Hoffman, A. L.; Lowenthal, D. D.

    1980-10-01

    A 3-m long plasma column formed and confined by a fast rising solenoidal field was irradiated from one end by a powerful pulsed CO2 laser. It was found that beam trapping density minima could be maintained for the length of the laser pulse if the plasma diameter exceeded about 1.5 cm. The erosion of the density minimum was governed by classical diffusion processes. Three meter long plasmas in 2.6 cm bore plasma tubes could be fairly uniformly heated by 3.0 kJ of CO2 laser irradiation. Best results were obtained when heating began before or during the theta pinch implosion phase and the plasma fill pressure exceeded 1.0 torr H2. Plasma line energies of about 1 kJ/m could be obtained in a magnetic field rising to 6 T in 4.7 microseconds.

  3. Sequentially evolved bilateral epidural haematomas.

    PubMed

    Rochat, P; Johannesen, H H; Poulsgård, L; Bøgeskov, L

    2002-12-01

    Sequentially evolved bilateral epidural haematomas, where the second haematoma evolves after surgical removal of the first haematoma, are rarely reported. We report two cases of this entity. One patient was involved in a road traffic accident and the other was suffering from a head injury after an assault. CT scans showed that both patients had an unilateral epidural haematoma with a thin presumably epidural haemorrhage on the opposite side. Both patients were operated for their epidural haematomas, but did not improve after surgical treatment, and postoperative CT scans revealed evolving of an epidural haematoma on the opposite side. After evacuation of the second epidural haematoma both patients recovered quickly. Sequentially evolved bilateral epidural haematomas are rare, but must be considered in the postoperative intensive care treatment in patients with epidural haematomas. Both cases emphasize the need for intensive care monitoring after an operation for an epidural haematoma and the need for CT scans if the patient does not improve quickly after removal of the haematoma. This is especially important if a small contralateral haematoma is seen on the initial CT scan. PMID:12445923

  4. [Simultaneous bilateral pneumothorax. Case report].

    PubMed

    Paolini, A; Caminiti, F; Tosato, F; Ruggieri, M; Paolini, G; Carnevale, L; Corsini, F; Marano, S; Monsellato, I

    2001-04-01

    A case report of a 44 year-old white man admitted to the surgical unit for a bilateral simultaneous pneumothorax is presented. The pneumothorax occurred on day one after a surgical operation for discal hernia; in the past the patient already presented a right spontaneous pneumothorax at 32 years of age and a left pneumothorax at 37 years of age, both treated with a pleural drainage. A thoracic drain was bilaterally positioned with a good result only in the right side. The persistence of the left pneumothorax induced the authors to perform a postero-lateral thoracotomy bullae excision and pleurectomy with a good postoperative course. After a few months a new right pneumothorax occurred and the patient was treated with a right postero-lateral thoracotomy, bullae resection and pleurectomy. On the basis of the case reported, the authors consider the different opportunities in the treatment of spontaneous pneumothorax in relation to the present knowledges and technologies. Surgical procedure is to be preferred in case of persistence of pneumothorax despite a pleural drain and in case of pneumothorax in high risk subjects. Even if thoracoscopy seems to give better results regarding postoperative pain, it is not always possible with such a method to perform a careful pleurectomy neither to obtain it in all cases (above all in secondary pneumothorax). Every case must then be carefully studied to choose the best treatment at present available. PMID:11353349

  5. Bilateral internal thoracic artery grafting

    PubMed Central

    2013-01-01

    The effectiveness of the left internal mammary artery graft to the anterior descending coronary artery as a surgical strategy has been shown to improve the survival rate and decrease the risk of adverse cardiac events in patients undergoing coronary bypass surgery. These clinical benefits appear to be related to the superior short and long-term patency rates of the internal thoracic artery graft. Although the advantages of using of both internal thoracic arteries (ITA) for bypass grafting have taken longer to prove, recent results from multiple data sets now support these findings. The major advantage of bilateral ITA grafting appears to be improved survival rate, while the disadvantages of complex ITA grafting include the increased complexity of operation, and an increased risk of wound complications. While these short-term disadvantages have been mitigated in contemporary surgical practice, they have not eliminated. Bilateral ITA grafting should be considered the procedure of choice for patients undergoing coronary bypass surgery that have a predicted survival rate of longer than ten years. PMID:23977627

  6. Bilateral adaptive deep brain stimulation is effective in Parkinson's disease

    PubMed Central

    Little, Simon; Beudel, Martijn; Zrinzo, Ludvic; Foltynie, Thomas; Limousin, Patricia; Hariz, Marwan; Neal, Spencer; Cheeran, Binith; Cagnan, Hayriye; Gratwicke, James; Aziz, Tipu Z; Pogosyan, Alex; Brown, Peter

    2016-01-01

    Introduction & objectives Adaptive deep brain stimulation (aDBS) uses feedback from brain signals to guide stimulation. A recent acute trial of unilateral aDBS showed that aDBS can lead to substantial improvements in contralateral hemibody Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores and may be superior to conventional continuous DBS in Parkinson’s disease (PD). We test whether potential benefits are retained with bilateral aDBS and in the face of concurrent medication. Methods We applied bilateral aDBS in 4 patients with PD undergoing DBS of the subthalamic nucleus. aDBS was delivered bilaterally with independent triggering of stimulation according to the amplitude of β activity at the corresponding electrode. Mean stimulation voltage was 3.0±0.1 volts. Motor assessments consisted of double-blinded video-taped motor UPDRS scores that included both limb and axial features. Results UPDRS scores were 43% (p=0.04; Cohen’s d=1.62) better with aDBS than without stimulation. Motor improvement with aDBS occurred despite an average time on stimulation (ToS) of only 45%. Levodopa was well tolerated during aDBS and led to further reductions in ToS. Conclusion Bilateral aDBS can improve both axial and limb symptoms and can track the need for stimulation across drug states. PMID:26424898

  7. Bayer bilateral denoising on TriMedia3270

    NASA Astrophysics Data System (ADS)

    Phelippeau, H.; Akil, M.; Dias Rodrigues, B.; Talbot, H.; Bara, S.

    2009-02-01

    Digital cameras are now commonly included in several digital devices such as mobile phones. They are present everywhere and have become the principal image capturing tool. Inherent to light and semiconductors properties, sensor noise [10] continues to be an important factor of image quality [12], especially in low light conditions. Removing the noise with mathematical solutions appears thus unavoidable to obtain an acceptable image quality. However, embedded devices are limited by processing capabilities and power consumption and thus cannot make use of the full range of complex mathematical noise removing solutions. The bilateral filter [6] appears to be an interesting compromise between implementation complexity and noise removing performances. Especially, the Bayer [5] bilateral filter proposed in [11] is well adapted for single sensor devices. In this paper, we simulate and optimize the Bayer bilateral filter execution on a common media-processor: the TM3270 [4] from the NXP Semiconductors TriMedia family. To do so we use the TriMedia Compilation System (TCS). We applied common optimization techniques (such as LUT, loop unrolling, convenient data type representation) as well as custom TriMedia operations. We finally propose a new Bayer bilateral filter formulation dedicated to the TM3270 architecture that yields an execution improvement of 99.6% compared to the naÃve version. This improvement results in real-time video processing at VGA resolution at the 350MHz clock rate.

  8. Public Kepler Data on the Bright Star Theta Cygni

    NASA Astrophysics Data System (ADS)

    Haas, Michael Robert; Bryson, S. T.; Rowe, J. F.; Still, M. D.

    2011-01-01

    The bright star Theta Cygni (Kepler ID 11918630) has been observed by Kepler in both short (59 sec) and long (29.4 min) cadence for a period of approximately 50 days starting on MJD 55410. These observations were made at the request of the Kepler Guest Observer Office and are intended for immediate public release. The purpose is to demonstrate Kepler's exquisite photometric precision on bright, highly saturated targets. Theta Cygni is a F3V/M3V binary with a visual magnitude of 4.9/13.0. The short-cadence data show evidence of granulation (i.e., convection) out to about 1 mHz ( 100 c/d) and clear detection of numerous p-modes with a peak near 1.8 mHz ( 150 c/d). The high-frequency noise floor has a 3-sigma upper envelope of 0.4 ppm. The amplitude of the p-modes agrees with the stellar effective temperature, indicating that the star has a thin convective layer. Since a custom aperture was employed, the light curves will be constructed manually and placed on the Guest Observer website (http://keplergo.arc.nasa.gov/). The corresponding pixel-level data will be available from the Kepler archive (http://archive.stsci.edu/kepler/). The Kepler mission can accommodate a small number of such bright targets every quarter. Observing proposals can be submitted annually to the peer-reviewed Guest Observer Program, or much less formally on a quarterly basis for Director's Discretionary Time (see http://keplergo.arc.nasa.gov/GOprogramDDT.shtml). Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

  9. Unusual Bilateral Paramolars Associated with Clinical Complications

    PubMed Central

    Sulabha, A. N.; Sameer, C.

    2015-01-01

    Paramolars are rare supernumerary structures of maxillofacial complex that occur buccally or lingually near the molar row. Predominantly these occur singly; bilateral presentation is very rare. This paper reports two unusual bilateral presentations of paramolars with clinical complication and its management. One of the cases in the present paper also documents the cooccurrence of bilateral paramolars and microdontia of single tooth and one of its paramolars presented with multilobed crown with an anomalous buccal tubercle. PMID:26078890

  10. Loss of hippocampal theta rhythm results in spatial memory deficit in the rat.

    PubMed

    Winson, J

    1978-07-14

    Rats learned, using distal room cues, to run to a goal on an elevated, circular track starting from any position on the track. The goal was one of eight equidistant, recessed cups set around the track, the goal cup being distinguished from the others solely by its position in the room. After learning, electrolytic lesions were made in the medial septal nucleus eliminating hippocampal theta rhythm in some animals but not in others. Rats without theta rhythm were no longer able to perform the spatial task, whereas rats with undisturbed theta rhythm retrained normal performance. Although rats without theta rhythm could not find their way directly to the goal, they recognized its location when they came upon it by chance. This type of spatial deficit appears similar to that shown by hippocampally lesioned patient H.M. Subsequent tests demonstrated that rats deprived of theta rhythm before training could nevertheless learn the task. PMID:663646

  11. Can induced theta vacua be created in heavy-Ion collisions?

    PubMed

    Buckley; Fugleberg; Zhitnitsky

    2000-05-22

    We discuss a phenomenon important to the development of the early Universe which may be experimentally testable in heavy-ion collisions. An arbitrary induced straight theta vacuum state should be created in heavy-ion collisions, similar to the creation of the disoriented chiral condensate. It should be a large domain with a wrong straight theta(ind) not equal0 orientation which will mimic the physics of the early Universe when it is believed that the fundamental parameter straight theta(fund) not equal0. We test this idea numerically in a simple model where we study the evolution of the phases of the chiral condensates in QCD with two quark flavors with nonzero straight theta(ind) parameter. We see the formation of a nonzero straight theta(ind) vacuum on a time scale of 10(-23) s. PMID:10990805

  12. Theta lingua franca: a common mid-frontal substrate for action monitoring processes.

    PubMed

    Cavanagh, James F; Zambrano-Vazquez, Laura; Allen, John J B

    2012-02-01

    We present evidence that a multitude of mid-frontal event-related potential (ERP) components partially reflect a common theta band oscillatory process. Specifically, mid-frontal ERP components in the N2 time range and error-related negativity time range are parsimoniously characterized as reflections of theta band activities. Forty participants completed three different tasks with varying stimulus-response demands. Permutation tests were used to identify the dominant time-frequency responses of stimulus- and response-locked conditions as well as the enhanced responses to novelty, conflict, punishment, and error. A dominant theta band feature was found in all conditions, and both ERP component amplitudes and theta power measures were similarly modulated by novelty, conflict, punishment, and error. The findings support the hypothesis that generic and reactive medial prefrontal cortex processes are parsimoniously reflected by theta band activities. PMID:22091878

  13. Age-related oscillatory theta modulation of multisensory integration in frontocentral regions.

    PubMed

    Yan, Tianyi; Bi, Xiaoshan; Zhang, Mengmeng; Wang, Wenhui; Yao, Zhiqi; Yang, Weiping; Wu, Jinglong

    2016-08-01

    This study used electroencephalogram measurements to investigate the effects of aging on oscillatory theta modulation during an audiovisual discrimination task. By a wavelet-based time-frequency analysis, age-related theta oscillation response differences were observed within a relatively restricted time range (0-500 ms) over frontal-central regions. Older adults showed stronger theta spectral power during visual and audiovisual stimuli in the left frontal regions; however, young adults showed stronger theta spectral power during auditory and audiovisual stimuli in the central regions. These findings suggest that multisensory oscillatory theta responses differ according to age, which further proves that the left frontal regions play an important role in audiovisual integration. PMID:27272690

  14. Radiative generation of {theta}{sub 13} with the seesaw threshold effect

    SciTech Connect

    Mei Jianwei; Xing Zhizhong

    2004-09-01

    We examine whether an appreciable value of the lepton flavor mixing angle {theta}{sub 13} at the electroweak scale {lambda}{sub EW} can be radiatively generated from {theta}{sub 13}=0 deg. at the grand unified theory (GUT) scale {lambda}{sub GUT}. It is found that the renormalization-group running and seesaw threshold effects may lead to {theta}{sub 13}{approx}5 deg. at low energies for two simple large-maximal mixing patterns of the Maki-Nakagawa-Sakata matrix in the minimal supersymmetric standard model. If {theta}{sub 12} is sufficiently large at {lambda}{sub GUT}, it will be possible to radiatively produce {theta}{sub 13}{approx}5 deg. at {lambda}{sub EW} both in the standard model and in its supersymmetric extensions. The mass spectrum of three heavy right-handed Majorana neutrinos and the cosmological baryon number asymmetry via leptogenesis are also calculated.

  15. Effects of thienodiazepine derivatives, etizolam and clotiazepam on the appearance of Fm theta.

    PubMed

    Nakamura, J; Mukasa, H

    1992-12-01

    The effects of new thienodiazepine anxiolytics, etizolam and clotiazepam, on the appearance of frontal midline theta activity (Fm theta) were studied by the double-blind crossover method. The results were as follows; 1) Both clotiazepam and placebo tended to increase the Fm theta appearance in all subjects, but etizolam showed no such tendency. 2) Clotiazepam significantly increased the Fm theta appearance as compared with placebo in subjects with a high neurotic tendency (N-scale of MPI above 19). 3) Clotiazepam tended to increase the Fm theta appearance as compared with placebo and etizolam in subjects with a high anxiety level (MAS score above 14). 4) Apparently more subjects complained of drowsiness after the administration of etizolam than after clotiazepam or placebo. PMID:1363923

  16. A clinical analysis of bilateral orbital fracture.

    PubMed

    Roh, Joon Ho; Jung, Jee Woong; Chi, Mijung

    2014-03-01

    Although bilateral orbital fracture can cause serious eyeball and facial skeletal problems, few reports have been issued on the topic. We analyzed the clinical features of bilateral orbital fracture by reviewing the medical records of 147 patients and compared bilateral and unilateral fractures by reviewing the literature.Bilateral orbital fracture was most common in men aged between 50 and 59 years. A traffic accident was the leading cause of trauma, and average time between trauma and surgery was 12.2 days. Bilateral medial fracture accompanied by nasal fracture accounted for the overwhelming majority, and impure blowout fracture in at least 1 eye occurred in 69.4% of the 147 patients. Associated ocular injuries seemed to be similar for bilateral and unilateral fracture. Thirty-five patients (23.8%) had other multiple traumas affecting other than the eyes, and this significantly increased the need for surgery (P < 0.05). Of the 48 patients who underwent surgery, including 4 cases of bilateral surgery, 21 patients who had ocular motility restriction with central diplopia within 30 degrees almost completely recovered. No significant relation between the timing of surgery and improvement was found. Although unilateral surgery was performed in most cases, facial asymmetry related to enophthalmos was unclear at 6 months postoperatively.In summary, bilateral orbital fracture was found to be clinically distinguishable from unilateral fracture in several aspects. We hope these findings provide a reference guide to the approach and management of bilateral orbital fracture. PMID:24514894

  17. Fast bilateral filtering using recursive moving sum

    NASA Astrophysics Data System (ADS)

    Igarashi, Masaki; Ikebe, Masayuki; Shimoyama, Sohsuke; Motohisa, Junichi

    We propose a constant-time algorithm for a bilateral filter. Bilateral filter can be converted into the operation of three-dimensional (3D) convolution. By using recursive moving sum, we can reduce the number of calculations needed to construct a pseudo-Gaussian filter. Applying one-dimensional Gaussian filter to the 3D convolution, we achieved a constant-time bilateral filter. We used a 3-GHz CPU without SIMD instructions, or multi-thread operations. We confirmed our proposed bilateral filter to be processed in constant time. In practical conditions, high PSNR values over 40 dB are obtained.

  18. Evidence that the recently discovered theta 1-globin gene is functional in higher primates.

    PubMed

    Shaw, J P; Marks, J; Shen, C K

    A new subfamily of the alpha-globin-like family has recently been identified in higher primates, rabbit, galago and possibly the horse. One member of this subfamily, theta 1, is downstream from the adult alpha 1-globin gene. In orang-utan, but not in rabbit or galago, the theta 1-gene appears to be structurally intact, suggesting that it may be functional in this species. The orang-utan theta 1-gene possesses initiation and termination codons, and the predicted polypeptide differs from the orang-utan alpha 1-globin by 55 amino acids. The upstream promoter boxes CCAAT and ATA are present, although approximately 150 base pairs (bp) farther upstream than in the alpha 1-gene. This structural difference in the promoter between the orang-utan theta 1- and alpha 1-genes has led Proudfoot to speculate that the theta 1-gene may be inactive. We have now cloned the theta 1- and alpha 1-globin genes from the olive baboon, and have compared their sequences with those of orang-utan. The unique promoter structure of the orang-utan theta 1-gene is highly conserved in baboon, although the orang-utan and baboon diverged nearly 30 million years ago. The coding sequences of the two theta 1-genes differ by only 6.3% with 22 out of 27 nucleotide substitutions being codon third position silent changes. These data support the view that the theta 1-gene has been functional in the baboon, orang-utan, and by implication, in man. We also estimate that the duplication event generating the theta 1- and alpha-globin-like subfamilies may have occurred as much as 260 million years ago. PMID:3561513

  19. Movement-Related Theta Rhythm in Humans: Coordinating Self-Directed Hippocampal Learning

    PubMed Central

    Kaplan, Raphael; Doeller, Christian F.; Barnes, Gareth R.; Litvak, Vladimir; Düzel, Emrah; Bandettini, Peter A.; Burgess, Neil

    2012-01-01

    The hippocampus is crucial for episodic or declarative memory and the theta rhythm has been implicated in mnemonic processing, but the functional contribution of theta to memory remains the subject of intense speculation. Recent evidence suggests that the hippocampus might function as a network hub for volitional learning. In contrast to human experiments, electrophysiological recordings in the hippocampus of behaving rodents are dominated by theta oscillations reflecting volitional movement, which has been linked to spatial exploration and encoding. This literature makes the surprising cross-species prediction that the human hippocampal theta rhythm supports memory by coordinating exploratory movements in the service of self-directed learning. We examined the links between theta, spatial exploration, and memory encoding by designing an interactive human spatial navigation paradigm combined with multimodal neuroimaging. We used both non-invasive whole-head Magnetoencephalography (MEG) to look at theta oscillations and Functional Magnetic Resonance Imaging (fMRI) to look at brain regions associated with volitional movement and learning. We found that theta power increases during the self-initiation of virtual movement, additionally correlating with subsequent memory performance and environmental familiarity. Performance-related hippocampal theta increases were observed during a static pre-navigation retrieval phase, where planning for subsequent navigation occurred. Furthermore, periods of the task showing movement-related theta increases showed decreased fMRI activity in the parahippocampus and increased activity in the hippocampus and other brain regions that strikingly overlap with the previously observed volitional learning network (the reverse pattern was seen for stationary periods). These fMRI changes also correlated with participant's performance. Our findings suggest that the human hippocampal theta rhythm supports memory by coordinating exploratory

  20. Experimental search for radiative decays of the pentaquark baryon {Theta}{sup +}(1540)

    SciTech Connect

    Barmin, V. V.; Asratyan, A. E.; Borisov, V. S.; Curceanu, C.; Davidenko, G. V.; Dolgolenko, A. G.; Guaraldo, C.; Kubantsev, M. A.; Larin, I. F.; Matveev, V. A.; Shebanov, V. A.; Shishov, N. N.; Sokolov, L. I.; Tumanov, G. K.; Verebryusov, V. S.

    2010-07-15

    The data on the reactions K{sup +}Xe {sup {yields}}K{sup 0{gamma}}X and K{sup +}Xe {sup {yields}}K{sup +{gamma}}X, obtained with the bubble chamber DIANA, have been analyzed for possible radiative decays of the {Theta}{sup +}(1540) baryon: {Theta}{sup +} {sup {yields}}K{sup 0}p{gamma} and {Theta}{sup +} {sup {yields}}K{sup +}n{gamma}. No signals have been observed, and we derive the upper limits {Gamma}({Theta}{sup +} {sup {yields}}K{sup 0}p{gamma})/{Gamma}({Theta}{sup +} {sup {yields}}K{sup 0}p) < 0.032 and {Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma})/{Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma}) < 0.041 which, using our previous measurement of {Gamma}({Theta}{sup +} {sup {yields}}KN) = 0.39 {+-} 0.10 MeV, translate to {Gamma}({Theta}{sup +} {sup {yields}}K{sup 0}p{gamma}) < 8 keV and {Gamma}({Theta}{sup +} {sup {yields}}K{sup +}n{gamma}) < 11 keV at 90% confidence level. We have also measured the cross sections of K{sup +}-induced reactions involving emission of a neutral pion: {sigma}(K{sup +}n {sup {yields}}K{sup 0}p{pi}{sup 0}) = 68 {+-} 18 {mu}b and {sigma}(K{sup +}N {sup {yields}}K{sup +}N{pi}{sup 0}) = 30 {+-} 8 {mu}b for incident K{sup +} momentum of 640 MeV.

  1. The presence of pacemaker HCN channels identifies theta rhythmic GABAergic neurons in the medial septum

    PubMed Central

    Varga, Viktor; Hangya, Balázs; Kránitz, Kinga; Ludányi, Anikó; Zemankovics, Rita; Katona, István; Shigemoto, Ryuichi; Freund, Tamás F; Borhegyi, Zsolt

    2008-01-01

    The medial septum (MS) is an indispensable component of the subcortical network which synchronizes the hippocampus at theta frequency during specific stages of information processing. GABAergic neurons exhibiting highly regular firing coupled to the hippocampal theta rhythm are thought to form the core of the MS rhythm-generating network. In recent studies the hyperpolarization-activated, cyclic nucleotide-gated non-selective cation (HCN) channel was shown to participate in theta synchronization of the medial septum. Here, we tested the hypothesis that HCN channel expression correlates with theta modulated firing behaviour of MS neurons by a combined anatomical and electrophysiological approach. HCN-expressing neurons represented a subpopulation of GABAergic cells in the MS partly overlapping with parvalbumin (PV)-containing neurons. Rhythmic firing in the theta frequency range was characteristic of all HCN-expressing neurons. In contrast, only a minority of HCN-negative cells displayed theta related activity. All HCN cells had tight phase coupling to hippocampal theta waves. As a group, PV-expressing HCN neurons had a marked bimodal phase distribution, whereas PV-immunonegative HCN neurons did not show group-level phase preference despite significant individual phase coupling. Microiontophoretic blockade of HCN channels resulted in the reduction of discharge frequency, but theta rhythmic firing was perturbed only in a few cases. Our data imply that HCN-expressing GABAergic neurons provide rhythmic drive in all phases of the hippocampal theta activity. In most MS theta cells rhythm genesis is apparently determined by interactions at the level of the network rather than by the pacemaking property of HCN channels alone. PMID:18565991

  2. Frontal and rostral anterior cingulate (rACC) theta EEG in depression: implications for treatment outcome?

    PubMed

    Arns, Martijn; Etkin, Amit; Hegerl, Ulrich; Williams, Leanne M; DeBattista, Charles; Palmer, Donna M; Fitzgerald, Paul B; Harris, Anthony; deBeuss, Roger; Gordon, Evian

    2015-08-01

    In major depressive disorder (MDD), elevated theta current density in the rostral anterior cingulate (rACC), as estimated by source localization of scalp-recorded electroencenphalogram (EEG), has been associated with response to antidepressant treatments, whereas elevated frontal theta has been linked to non-response. This study used source localization to attempt to integrate these apparently opposite results and test, whether antidepressant response is associated with elevated rACC theta and non-response with elevated frontal theta and whether theta activity is a differential predictor of response to different types of commonly used antidepressants. In the international Study to Predict Optimized Treatment in Depression (iSPOT-D), a multi-center, international, randomized, prospective practical trial, 1008 MDD participants were randomized to escitalopram, sertraline or venlafaxine-XR. The study also recruited 336 healthy controls. Treatment response and remission were established after eight weeks using the 17-item Hamilton Rating Scale for Depression (HRSD17). The resting-state EEG was assessed at baseline with eyes closed and source localization (eLORETA) was employed to extract theta from the rACC and frontal cortex. Patients with MDD had elevated theta in both frontal cortex and rACC, with small effect sizes. High frontal and rACC theta were associated with treatment non-response, but not with non-remission, and this effect was most pronounced in a subgroup with previous treatment failures. Low theta in frontal cortex and rACC are found in responders to antidepressant treatments with a small effect size. Future studies should investigate in more detail the role of previous treatment (failure) in the association between theta and treatment outcome. PMID:25936227

  3. Bilateral Neck of Femur Fractures in a Bilateral Below-Knee Amputee: A Unique Case.

    PubMed

    Lancer, Hannah R; Smitham, Peter; Ray, Pinak

    2016-01-01

    According to the National Hip Fracture Database, over 64,000 patients were admitted with a hip fracture across England, Wales, and Northern Ireland in 2013, but very few are bilateral, and there are no current cases in the literature of bilateral neck of femur fractures in a patient with bilateral below-knee amputations. We present a case of a 69-year-old bilateral below-knee amputee male admitted to the emergency department with bilateral hip pain and radiological evidence of bilateral displaced neck of femur fractures. The patient subsequently underwent synchronous bilateral total hip replacements under general anaesthetic and an epidural and then went on to make a full recovery. He was discharged 27 days after arrival in hospital. Outpatient follow-up at 3 months has shown that the patient has returned to a similar level of preinjury function and is still able to carry out his daily activities with walking aids and bilateral leg prostheses. PMID:26881162

  4. Bilateral Neck of Femur Fractures in a Bilateral Below-Knee Amputee: A Unique Case

    PubMed Central

    Lancer, Hannah R.

    2016-01-01

    According to the National Hip Fracture Database, over 64,000 patients were admitted with a hip fracture across England, Wales, and Northern Ireland in 2013, but very few are bilateral, and there are no current cases in the literature of bilateral neck of femur fractures in a patient with bilateral below-knee amputations. We present a case of a 69-year-old bilateral below-knee amputee male admitted to the emergency department with bilateral hip pain and radiological evidence of bilateral displaced neck of femur fractures. The patient subsequently underwent synchronous bilateral total hip replacements under general anaesthetic and an epidural and then went on to make a full recovery. He was discharged 27 days after arrival in hospital. Outpatient follow-up at 3 months has shown that the patient has returned to a similar level of preinjury function and is still able to carry out his daily activities with walking aids and bilateral leg prostheses. PMID:26881162

  5. 14 CFR 60.37 - FSTD qualification on the basis of a Bilateral Aviation Safety Agreement (BASA).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Bilateral Aviation Safety Agreement (BASA). 60.37 Section 60.37 Aeronautics and Space FEDERAL AVIATION... CONTINUING QUALIFICATION AND USE § 60.37 FSTD qualification on the basis of a Bilateral Aviation Safety... on International Civil Aviation for the sponsor of an FSTD located in that contracting State may...

  6. 14 CFR 60.37 - FSTD qualification on the basis of a Bilateral Aviation Safety Agreement (BASA).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Bilateral Aviation Safety Agreement (BASA). 60.37 Section 60.37 Aeronautics and Space FEDERAL AVIATION... CONTINUING QUALIFICATION AND USE § 60.37 FSTD qualification on the basis of a Bilateral Aviation Safety... on International Civil Aviation for the sponsor of an FSTD located in that contracting State may...

  7. 14 CFR 60.37 - FSTD qualification on the basis of a Bilateral Aviation Safety Agreement (BASA).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Bilateral Aviation Safety Agreement (BASA). 60.37 Section 60.37 Aeronautics and Space FEDERAL AVIATION... CONTINUING QUALIFICATION AND USE § 60.37 FSTD qualification on the basis of a Bilateral Aviation Safety... on International Civil Aviation for the sponsor of an FSTD located in that contracting State may...

  8. 14 CFR 60.37 - FSTD qualification on the basis of a Bilateral Aviation Safety Agreement (BASA).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Bilateral Aviation Safety Agreement (BASA). 60.37 Section 60.37 Aeronautics and Space FEDERAL AVIATION... CONTINUING QUALIFICATION AND USE § 60.37 FSTD qualification on the basis of a Bilateral Aviation Safety... on International Civil Aviation for the sponsor of an FSTD located in that contracting State may...

  9. 14 CFR 60.37 - FSTD qualification on the basis of a Bilateral Aviation Safety Agreement (BASA).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Bilateral Aviation Safety Agreement (BASA). 60.37 Section 60.37 Aeronautics and Space FEDERAL AVIATION... CONTINUING QUALIFICATION AND USE § 60.37 FSTD qualification on the basis of a Bilateral Aviation Safety... on International Civil Aviation for the sponsor of an FSTD located in that contracting State may...

  10. Bilateral treatment for alopecia areata.

    PubMed

    Torchia, Daniele; Schachner, Lawrence A

    2010-01-01

    A 4-year-old, otherwise healthy white girl was referred for a 15-month history of alopecia areata. Anthralin 0.1% cream was prescribed for the left side of the scalp, while corticosteroids for the right side. After 4 months, only the right side of the scalp showed hair regrowth. Half-side strategy, that is, treating one side and managing the other--divided by the mid sagittal suture--as an internal control for no treatment, placebo or other treatment, has been commonly used in clinical studies for decades. In everyday practice, bilateral treatment is useful to evaluate the responsiveness to two topically delivered interventions and diminishes the time necessary to identify an effective one. PMID:20653874

  11. A case of bilateral testicular calcifications in a bicycle motocross rider accompanied by bulbar urethral injury.

    PubMed

    Izumi, Kouji; Konaka, Hiroyuki; Seto, Chikashi; Komatsu, Kazuto; Yokoyama, Osamu; Namiki, Mikio

    2006-05-01

    A 21-year-old Japanese man who was a professional bicycle motocross rider injured his perineum during a competition. Chief complaints were gross hematuria, perineal pain, and subcutaneous ecchymosis of the scrotum. Urethrocystography revealed a torn bulbar urethra and extravasation in the same region. Scrotal ultrasonography revealed small calcifications in the bilateral testes. Here, we report a case of bilateral testicular calcifications caused by the continuous shock and vibration of the saddle in an off-road bicycle rider. PMID:16758731

  12. Localization ability with bimodal hearing aids and bilateral cochlear implants

    NASA Astrophysics Data System (ADS)

    Seeber, Bernhard U.; Baumann, Uwe; Fastl, Hugo

    2004-09-01

    After successful cochlear implantation in one ear, some patients continue to use a hearing aid at the contralateral ear. They report an improved reception of speech, especially in noise, as well as a better perception of music when the hearing aid and cochlear implant are used in this bimodal combination. Some individuals in this bimodal patient group also report the impression of an improved localization ability. Similar experiences are reported by the group of bilateral cochlear implantees. In this study, a survey of 11 bimodally and 4 bilaterally equipped cochlear implant users was carried out to assess localization ability. Individuals in the bimodal implant group were all provided with the same type of hearing aid in the opposite ear, and subjects in the bilateral implant group used cochlear implants of the same manufacturer on each ear. Subjects adjusted the spot of a computer-controlled laser-pointer to the perceived direction of sound incidence in the frontal horizontal plane by rotating a trackball. Two subjects of the bimodal group who had substantial residual hearing showed localization ability in the bimodal configuration, whereas using each single device only the subject with better residual hearing was able to discriminate the side of sound origin. Five other subjects with more pronounced hearing loss displayed an ability for side discrimination through the use of bimodal aids, while four of them were already able to discriminate the side with a single device. Of the bilateral cochlear implant group one subject showed localization accuracy close to that of normal hearing subjects. This subject was also able to discriminate the side of sound origin using the first implanted device alone. The other three bilaterally equipped subjects showed limited localization ability using both devices. Among them one subject demonstrated a side-discrimination ability using only the first implanted device.

  13. Kolmogorov and trigonometric widths of the Besov classes B^r_{p,\\theta} of multivariate periodic functions

    NASA Astrophysics Data System (ADS)

    Romanyuk, A. S.

    2006-02-01

    Precise (in order) estimates of the Kolmogorov widths in the space L_q, 1, of the classes B^r_{1,\\theta} and B^r_{\\infty,\\theta} and also of the trigonometric widths of the classes B^r_{p,\\theta} in L_q for p and q satisfying certain relations are obtained.

  14. EVOLUTION OF SYNCHRONOUS BILATERAL BREAST CARCINOMA IN A YOUNG PATIENT.

    PubMed

    Manea, Elena; Munteanu, Anca

    2016-01-01

    Bilateral breast cancer incidence is appreciated to be between 0.3 to 12% and is determined either by a hereditary load associated with chromosomal instability under the effect of environmental factors, or by the evolution in a particular hormonal context which gives biological aggressiveness. We present the case of a patient, aged 38 years, clinically, imagistic and bioptic diagnosed with left axillary lymph node metastases of breast carcinoma NST invasive G3, IHC-RE = 60%, RP = 30%, HER2neu = 2 +, Ki67 = 20%, in August 2013. Patient followed neoadjuvant chemotherapy treatment during September-October 2013. In December 2013 she was clinically and imaging diagnosed with bilateral breast cancer, for which surgical intervention was done which consisted of bilateral radical Madden mastectomy with bilateral axillary lymphadenectomy. BAP-invasive carcinoma NST: left breast-pT2mN3a G2, right breast--pT3mN3a G2, IHC-RE = 90%, RP =70% HER2neu = 2 +, Ki67 = 50%. During the period of January-March 2014, the patient followed adjuvant chemotherapy and Herceptin. Bilateral breast ultrasound assessment in April 2014 revealed: left axilla--liquid blade 29 / 6mm; right axilla--oval ganglion 9/5 mm. Abdominal and pelvic ultrasound: empty uterine cavity, bosselated contour; at left ovary level multiple cystic formations. During the period of May-June 2014, adjuvant radiation therapy and ovarian irradiationwas administered to the patient. Subsequently hormone therapy was initiated. Following CHT / ovarian irradiation patient continues to experience intermittent uterine bleeding, which is why a total hysterectomy with bilateral ovariectomy was done, and BAP: cervical, endometrialand left ovary with tumor multifocal infiltration with histopathological aspect of invasive breast carcinoma NST. Periodic imaging evaluations do not reveal local or distant recurrence. The particularity of this case is synchronous bilateral breast cancer diagnosis in a young patient complicated in its

  15. Simultaneous and spontaneous bilateral quadriceps tendons rupture.

    PubMed

    Celik, Evrim Coşkun; Ozbaydar, Mehmet; Ofluoglu, Demet; Demircay, Emre

    2012-07-01

    Simultaneous and spontaneous bilateral quadriceps tendon rupture is an uncommon injury that is usually seen in association with multiple medical conditions and some medications. We report a case of simultaneous and spontaneous bilateral quadriceps tendon rupture that may be related to the long-term use of a statin. PMID:22561379

  16. Spontaneous bilateral adrenal hemorrhage following cholecystectomy

    PubMed Central

    Dahan, Meryl; Lim, Chetana; Salloum, Chady

    2016-01-01

    Postoperative bilateral adrenal hemorrhage is a rare but potentially life-threatening complication. This diagnosis is often missed because the symptoms and laboratory results are usually nonspecific. We report a case of bilateral adrenal hemorrhage associated with acute primary adrenal insufficiency following laparoscopic cholecystectomy. The knowledge of this uncommon complication following any abdominal surgery allows timey diagnosis and rapid treatment. PMID:27275469

  17. Bilateral microperc in a severe kyphoscoliosis.

    PubMed

    Dağgülli, Mansur; Penbegül, Necmettin; Dede, Onur; Utanğaç, Mehmet Mazhar

    2016-03-01

    Percutaneous nephrolithotomy is the standard modality for large renal calculi in normal and abnormal renal anatomic situations. This case report describes a 57-year-old male patient who presented with bilateral kidney stones and severe kyphoscoliosis. He had successfully been treated with a bilateral microperc technique. PMID:27011881

  18. Bilateral pulmonary sequestration: computed tomographic appearance

    SciTech Connect

    Wimbish, K.J.; Agha, F.P.; Brady, T.M.

    1983-04-01

    Intralobar pulmonary sequestration is one manifestation of the wide spectrum of congenital bronchopulmonary foregut malformations. Bilateral intralobar pulmonary sequestration is an exceedingly rare anomaly. Only two pathologically proven cases and one possible case have been reported. We report a case presenting as bilateral paraspinal masses, studied by computed tomograpy (CT) and angiography.

  19. Bilateral parotid swelling: a radiological review

    PubMed Central

    Gadodia, A; Bhalla, A S; Sharma, R; Thakar, A; Parshad, R

    2011-01-01

    Bilateral parotid swelling is not an uncommon occurrence and may pose a challenge for clinicians and radiologists. Numerous causes of bilateral parotid swellings have been identified. The purpose of this pictorial review is to display this wide array with a focus on multimodality approach. PMID:21960397

  20. Submaximal Expression of the Bilateral Deficit

    ERIC Educational Resources Information Center

    McLean, Scott P.; Vint, Peter F.; Stember, Amanda J.

    2006-01-01

    Thirty-six participants performed bilateral and unilateral isometric elbow flexion trials at what they perceived to be 100, 75, 50, and 25% of maximal effort. Absolute bilateral deficits ranged from -16% at 25% effort to -10% at 100% effort. The deficit included a component independent of consciousness and a component inversely related to…

  1. Bilateral microperc in a severe kyphoscoliosis

    PubMed Central

    Dağgülli, Mansur; Penbegül, Necmettin; Dede, Onur; Utanğaç, Mehmet Mazhar

    2016-01-01

    Percutaneous nephrolithotomy is the standard modality for large renal calculi in normal and abnormal renal anatomic situations. This case report describes a 57-year-old male patient who presented with bilateral kidney stones and severe kyphoscoliosis. He had successfully been treated with a bilateral microperc technique. PMID:27011881

  2. CT demonstration of bilateral adrenal hemorrhage

    SciTech Connect

    Ling, D.; Korobkin, M.; Silverman, P.M.; Dunnick, N.R.

    1983-08-01

    Bilateral adrenal hemorrhage with subsequent adrenal insufficiency is a recognized complication of anticoagulant therapy. Because the clinical manifestations are often nonspecific, the antemortem diagnosis of adrenal hemorrhage has been a difficult clinical problem. Computed tomography (CT) provides detailed images of the adrenal glands that are not possible with conventional imaging methods. The CT findings of bilateral adrenal hemorrhage in an anticoagulated patient are reported.

  3. Someone has to give in: theta oscillations correlate with adaptive behavior in social bargaining

    PubMed Central

    Zamorano, Francisco; López, Tamara; Rodriguez, Carlos; Cosmelli, Diego; Aboitiz, Francisco

    2014-01-01

    During social bargain, one has to both figure out the others’ intentions and behave strategically in such a way that the others’ behaviors will be consistent with one’s expectations. To understand the neurobiological mechanisms underlying these behaviors, we used electroencephalography while subjects played as proposers in a repeated ultimatum game. We found that subjects adapted their offers to obtain more acceptances in the last round and that this adaptation correlated negatively with prefrontal theta oscillations. People with higher prefrontal theta activity related to a rejection did not adapt their offers along the game to maximize their earning. Moreover, between-subject variation in posterior theta oscillations correlated positively with how individual theta activity influenced the change of offer after a rejection, reflecting a process of behavioral adaptation to the others’ demands. Interestingly, people adapted better their offers when they knew that they where playing against a computer, although the behavioral adaptation did not correlate with prefrontal theta oscillation. Behavioral changes between human and computer games correlated with prefrontal theta activity, suggesting that low adaptation in human games could be a strategy. Taken together, these results provide evidence for specific roles of prefrontal and posterior theta oscillations in social bargaining. PMID:24493841

  4. Photoproduction of the \\Theta^+ resonance on the nucleon in a Regge model

    SciTech Connect

    H. Kwee; M. Guidal; M. Polyakov; M. Vanderhaeghen

    2005-09-15

    We estimate the reaction mechanisms for the photoproduction of the {Theta}{sup +}(1540) resonance on the nucleon, through K and K* Regge exchanges. We compare the size of the cross sections for the {gamma}n {yields} K{sup -} {Theta}{sup +} and {gamma}p {yields} {bar K}{sup 0} {Theta}{sup +} reactions, and investigate their sensitivity to the spin-parity assignments J{sup P} = (1/2){sup {+-}}, (3/2){sup {+-}} for the {Theta}{sup +} resonance. The model allows to estimate the cross sections corresponding with a given upper bound on the width of the {Theta}{sup +}. Within this model, the cross sections on the neutron are found to be around a factor 5 larger than the ones on the proton, due to the presence of charged K exchange for the reaction on a neutron target. Furthermore, the photon asymmetry is found to display a pronounced sensitivity to the parity of the {Theta}{sup +}, making it a very promising observable to help determining the quantum numbers of the {Theta}{sup +} resonance.

  5. Spin asymmetries in {gamma} N {yields} {bar K}* {Theta}{sup +}

    SciTech Connect

    Yongseok Oh; Hungchong Kim; Su Houng Lee

    2004-11-01

    The photoproduction processes of the exotic {Theta}{sup +}(1540) baryon and the K* meson from the nucleon targets, i.e., {gamma}n {yields} K*{sup -} {Theta}{sup +} and {gamma}p {yields} {bar K}*{sup 0}{Theta}{sup +} are investigated in a hadronic model. We consider K and K* exchanges as well as the s and u channel nucleon and {Theta} terms. Various spin asymmetries together with cross sections are first computed in order to study the production mechanisms and the parity of the {Theta}{sup +}(1540) baryon. Within the uncertainties arising from the model-dependence of the production mechanisms and several coupling constants, we find that some target-recoil double spin asymmetries, C{sub xx{prime}}{sup TR} and C{sub xx{prime}}{sup TR} are sensitive to the parity of {Theta}{sup +}. In addition, the parity asymmetry of this reaction on the neutron target, which can be obtained by analyzing K* decay distribution, is found to be useful to estimate the K* N{Theta} coupling.

  6. Sarcoidosis Presenting as Bilateral Vocal Cord Paralysis due to Bilateral Vagal Nerve Involvement.

    PubMed

    Yamasue, Mari; Nureki, Shin-Ichi; Ushijima, Ryoichi; Mukai, Yutaka; Goto, Akihiko; Kadota, Jun-Ichi

    2016-01-01

    We herein report a rare case of sarcoidosis presenting as bilateral vocal cord paralysis due to bilateral vagal nerve involvement. A 72-year-old woman with uveitis of the left eye complained of hoarseness and aspiration due to bilateral vocal cord paralysis. An endobronchial needle aspiration biopsy specimen of the mediastinal lymph nodes showed non-caseating epithelioid cell granuloma. Total protein and cell concentrations in the cerebrospinal fluid were increased. We diagnosed her to have sarcoidosis with bilateral vagal nerve involvement. Corticosteroid therapy improved her symptoms of hoarseness and aspiration. Sarcoidosis should therefore be taken into consideration as a potential cause of bilateral vocal cord paralysis. PMID:27150886

  7. Hippocampal Non-Theta-Contingent Eyeblink Classical Conditioning: A Model System for Neurobiological Dysfunction

    PubMed Central

    Cicchese, Joseph J.; Berry, Stephen D.

    2016-01-01

    Typical information processing is thought to depend on the integrity of neurobiological oscillations that may underlie coordination and timing of cells and assemblies within and between structures. The 3–7 Hz bandwidth of hippocampal theta rhythm is associated with cognitive processes essential to learning and depends on the integrity of cholinergic, GABAergic, and glutamatergic forebrain systems. Since several significant psychiatric disorders appear to result from dysfunction of medial temporal lobe (MTL) neurochemical systems, preclinical studies on animal models may be an important step in defining and treating such syndromes. Many studies have shown that the amount of hippocampal theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning and attainment of asymptotic performance. Our lab has developed a brain–computer interface that makes eyeblink training trials contingent upon the explicit presence or absence of hippocampal theta. The behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to fourfold increase in learning speed over non-theta states. The non-theta behavioral impairment is accompanied by disruption of the amplitude and synchrony of hippocampal local field potentials, multiple-unit excitation, and single-unit response patterns dependent on theta state. Our findings indicate a significant electrophysiological and behavioral impact of the pretrial state of the hippocampus that suggests an important role for this MTL system in associative learning and a significant deleterious impact in the absence of theta. Here, we focus on the impairments in the non-theta state, integrate them into current models of psychiatric disorders, and suggest how improvement in our understanding of neurobiological oscillations is critical for theories and treatment of psychiatric

  8. A critical test of the hippocampal theta model of anxiolytic drug action.

    PubMed

    Yeung, Michelle; Treit, Dallas; Dickson, Clayton T

    2012-01-01

    Hippocampal theta rhythms have been associated with a number of behavioural processes, including learning, memory and arousal. Recently it has been argued that the suppression of hippocampal theta is a valid indicator of anxiolytic drug action. Like all such models, however, it has relied almost exclusively on the experimental effects of well-known, clinically proven anxiolytic compounds for validation. The actual predictive validity of putative models of anxiolytic drug action, however, cannot be rigorously tested with this approach alone. The present study provides a stringent test of the predictive validity of the theta suppression model, using the drug phenytoin (50 mg/kg and 10 mg/kg), and a positive comparison compound, diazepam (2 mg/kg). Phenytoin has two important properties that are advantageous for assessing the validity of the theta suppression model: 1) it is a standard antiepileptic drug with no known anxiolytic effects, and 2) its primary mechanism of action is through suppression of the persistent sodium current, an effect that should also suppress hippocampal theta. Because of the latter property, we also directly compared the effects of phenytoin in the theta suppression model with its effects in the most widely tested behavioural model of anxiolytic drug action, the elevated plus-maze. While an anxiolytic-like effect of phenytoin in the theta suppression model might be expected simply due to its suppressive effects on sodium channel currents, anxiolytic effects in both tests would provide strong support for the predictive validity of the theta suppression model. Surprisingly, phenytoin produced clear anxiolytic-like effects in both neurophysiological and behavioural models, thus providing strong evidence of the predictive validity of the theta suppression model. This article is part of a Special Issue entitled 'Anxiety and Depression'. PMID:21723303

  9. Hippocampal Non-Theta-Contingent Eyeblink Classical Conditioning: A Model System for Neurobiological Dysfunction.

    PubMed

    Cicchese, Joseph J; Berry, Stephen D

    2016-01-01

    Typical information processing is thought to depend on the integrity of neurobiological oscillations that may underlie coordination and timing of cells and assemblies within and between structures. The 3-7 Hz bandwidth of hippocampal theta rhythm is associated with cognitive processes essential to learning and depends on the integrity of cholinergic, GABAergic, and glutamatergic forebrain systems. Since several significant psychiatric disorders appear to result from dysfunction of medial temporal lobe (MTL) neurochemical systems, preclinical studies on animal models may be an important step in defining and treating such syndromes. Many studies have shown that the amount of hippocampal theta in the rabbit strongly predicts the acquisition rate of classical eyeblink conditioning and that impairment of this system substantially slows the rate of learning and attainment of asymptotic performance. Our lab has developed a brain-computer interface that makes eyeblink training trials contingent upon the explicit presence or absence of hippocampal theta. The behavioral benefit of theta-contingent training has been demonstrated in both delay and trace forms of the paradigm with a two- to fourfold increase in learning speed over non-theta states. The non-theta behavioral impairment is accompanied by disruption of the amplitude and synchrony of hippocampal local field potentials, multiple-unit excitation, and single-unit response patterns dependent on theta state. Our findings indicate a significant electrophysiological and behavioral impact of the pretrial state of the hippocampus that suggests an important role for this MTL system in associative learning and a significant deleterious impact in the absence of theta. Here, we focus on the impairments in the non-theta state, integrate them into current models of psychiatric disorders, and suggest how improvement in our understanding of neurobiological oscillations is critical for theories and treatment of psychiatric

  10. Theta-rhythmic drive between medial septum and hippocampus in slow-wave sleep and microarousal: a Granger causality analysis.

    PubMed

    Kang, D; Ding, M; Topchiy, I; Shifflett, L; Kocsis, B

    2015-11-01

    Medial septum (MS) plays a critical role in controlling the electrical activity of the hippocampus (HIPP). In particular, theta-rhythmic burst firing of MS neurons is thought to drive lasting HIPP theta oscillations in rats during waking motor activity and REM sleep. Less is known about MS-HIPP interactions in nontheta states such as non-REM sleep, in which HIPP theta oscillations are absent but theta-rhythmic burst firing in subsets of MS neurons is preserved. The present study used Granger causality (GC) to examine the interaction patterns between MS and HIPP in slow-wave sleep (SWS, a nontheta state) and during its short interruptions called microarousals (a transient theta state). We found that during SWS, while GC revealed a unidirectional MS→HIPP influence over a wide frequency band (2-12 Hz, maximum: ∼8 Hz), there was no theta peak in the hippocampal power spectra, indicating a lack of theta activity in HIPP. In contrast, during microarousals, theta peaks were seen in both MS and HIPP power spectra and were accompanied by bidirectional GC with MS→HIPP and HIPP→MS theta drives being of equal magnitude. Thus GC in a nontheta state (SWS) vs. a theta state (microarousal) primarily differed in the level of HIPP→MS. The present findings suggest a modification of our understanding of the role of MS as the theta generator in two regards. First, a MS→HIPP theta drive does not necessarily induce theta field oscillations in the hippocampus, as found in SWS. Second, HIPP theta oscillations entail bidirectional theta-rhythmic interactions between MS and HIPP. PMID:26354315

  11. Mammalian Polymerase Theta Promotes Alternative-NHEJ and Suppresses Recombination

    PubMed Central

    Mateos-Gomez, Pedro A.; Gong, Fade; Nair, Nidhi; Miller, Kyle M.; Lazzerini-Denchi, Eros; Sfeir, Agnel

    2016-01-01

    The alternative nonhomologous end-joining (alt-NHEJ) machinery facilitates a number of genomic rearrangements, some of which can lead to cellular transformation. This error-prone repair pathway is triggered upon telomere de-protection to promote the formation of deleterious chromosome end-to-end fusions1,2,3. Using next-generation sequencing technology, we found that repair by alt-NHEJ yields non-TTAGGG nucleotide insertions at fusion breakpoints of dysfunctional telomeres. Investigating the enzymatic activity responsible for the random insertions enabled us to identify Polymerase theta (Polθ; encoded by PolQ) as a critical alt-NHEJ factor in mammalian cells. PolQ inhibition suppresses alt-NHEJ at dysfunctional telomeres, and hinders chromosomal translocations at non-telomeric loci. In addition, we found that PolQ loss results in increased rates of homology directed repair (HDR), evident by recombination of dysfunctional telomeres and accumulation of Rad51 at double stranded breaks. Lastly, we show that depletion of PolQ has a synergistic impact on cell survival in the absence of BRCA genes, suggesting that the inhibition of this mutagenic polymerase represents a valid therapeutic avenue for tumors carrying mutations in HDR genes. PMID:25642960

  12. Effects of intermittent theta burst stimulation on spasticity after stroke.

    PubMed

    Kim, Dae Hyun; Shin, Ji Cheol; Jung, Seungsoo; Jung, Tae-Min; Kim, Deog Young

    2015-07-01

    Spasticity is a common cause of long-term disability in poststroke hemiplegic patients. We investigated whether intermittent theta burst stimulation (iTBS) could reduce upper-limb spasticity after a stroke. Fifteen hemiplegic stroke patients were recruited for a double-blind sham-controlled cross-over design study. A single session of iTBS or sham stimulation was delivered on the motor hotspot of the affected flexor carpi radialis muscle in a random and counterbalanced order with a 1-week interval. Modified Ashworth scale (MAS), modified Tardieu scale (MTS), H-wave/M-wave amplitude ratio, peak torque (PT), peak torque angle (PTA), work of affected wrist flexor, and rectified integrated electromyographic activity of the flexor carpi radialis muscle were measured before, immediately after, 30 min after, and 1 week after iTBS or sham stimulation. Repeated-measures analysis of variance showed a significant interaction between time and intervention for the MAS, MTS, PT, PTA, and rectified integrated electromyographic activity (P<0.05), indicating that these parameters were significantly improved by iTBS compared with sham stimulation. However, the H-wave/M-wave amplitude ratio and work were not affected. MAS and MTS significantly improved for at least 30 min after iTBS, but the other parameters only improved immediately after iTBS (P<0.05). In conclusion, iTBS on the affected hemisphere may help to reduce poststroke spasticity transiently. PMID:26011507

  13. ''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

    SciTech Connect

    Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

    1985-11-01

    We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs.

  14. Rehabilitation for bilateral amputation of fingers

    USGS Publications Warehouse

    Stapanian, Martin A.; Stapanian, Adrienne M.P.; Staley, Keith E.

    2010-01-01

    We describe reconstructive surgeries, therapy, prostheses, and adaptations for a patient who experienced bilateral amputation of all five fingers of both hands through the proximal phalanges in January 1992. The patient made considerable progress in the use of his hands in the 10 mo after amputation, including nearly a 120% increase in the active range of flexion of metacarpophalangeal joints. In late 1992 and early 1993, the patient had "on-top plasty" surgeries, in which the index finger remnants were transferred onto the thumb stumps, performed on both hands. The increased web space and functional pinch resulting from these procedures made many tasks much easier. The patient and occupational therapists set challenging goals at all times. Moreover, the patient was actively involved in the design and fabrication of all prostheses and adaptations or he developed them himself. Although he was discharged from occupational therapy in 1997, the patient continues to actively find new solutions for prehension and grip strength 18 yr after amputation.

  15. The observation of theta wave modulation on brain training by 5 Hz-binaural beat stimulation in seven days.

    PubMed

    Yamsa-Ard, Traisak; Wongsawat, Yodchanan

    2015-08-01

    Traditional buddhist meditation method maybe easy for someone with high experience. However, for the beginner, it is very difficult to keep mental concentration with the tradition way for more than 5 minutes. This research aims to observe effect of the new method for meditation in various analysis methods. A piano music mixed with a 5 Hz (theta band enhancement) binaural beat frequency was used to modulate the brain signals continuously for 7 days. Male of the average age of 33.5±3.84 and female of the average age of 28.6±2.49 were participated. All participants were acquired EEGs twice, before the experiment and seven days after the experiment. We also proposed the observations on the changes of absolute powers, relative powers and brain connectivity (coherence) of the participants. After seven days of training, the absolute power, relative power, and coherence were clearly closer to the normative database. We can initially say that the recommended meditation method can efficiently mimic the effect of having the traditional buddhist meditation on enhancing the delta and theta powers in the brain. PMID:26737822

  16. Heterochronic bilateral ectopic pregnancy after ovulation induction*

    PubMed Central

    Zhu, Bo; Xu, Gu-feng; Liu, Yi-feng; Qu, Fan; Yao, Wei-miao; Zhu, Yi-min; Gao, Hui-juan; Zhang, Dan

    2014-01-01

    Ectopic pregnancy is identified with the widely-applied assisted reproductive technology (ART). Bilateral ectopic pregnancy is a rare form of ectopic pregnancy which is difficult to be diagnosed at the pre-operation stage. In this paper, we presented an unusual case of heterochronic bilateral ectopic pregnancy after stimulated intrauterine insemination (IUI), where there has been a delay of 22 d between the diagnoses of the two ectopic pregnancies. Literature was reviewed on the occurrence of bilateral ectopic pregnancy during the past four years in the MEDLINE database. We found 16 cases of bilateral ectopic pregnancy reported since 2008, and analyzed the characteristics of those cases of bilateral ectopic pregnancy. We emphasize that ovulation induction and other ARTs may increase the risk of bilateral ectopic pregnancy. Because of the difficulty in identification of bilateral ectopic pregnancy by ultrasonography, the clinician should be aware that the treatment of one ectopic pregnancy does not preclude the occurrence of a second ectopic pregnancy in the same patient and should pay attention to the intra-operation inspection of both side fallopian tubes in any ectopic pregnancy case. PMID:25091994

  17. Bilateral inferior petrosal sinus sampling

    PubMed Central

    Grossrubatscher, Erika; Dalino Ciaramella, Paolo; Boccardi, Edoardo

    2016-01-01

    Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing’s syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88–100% and 67–100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50–70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres. PMID:27352844

  18. Bilateral inferior petrosal sinus sampling.

    PubMed

    Zampetti, Benedetta; Grossrubatscher, Erika; Dalino Ciaramella, Paolo; Boccardi, Edoardo; Loli, Paola

    2016-07-01

    Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres. PMID:27352844

  19. Bilateral symmetry across Aphrodite Terra

    NASA Technical Reports Server (NTRS)

    Crumpler, L. S.; Head, J. W.; Campbell, D. B.

    1987-01-01

    There are three main highland areas on Venus: Beta Regio, Ishtar Terra and Aphrodite Terra. The latter is least known and the least mapped, yet existing analyses of Aphrodite Terra based on available Pioneer-Venus orbiter data suggest that it may be the site of extensive rifting. Some of the highest resolution (30 km) PV data (SAR) included most of the western half of Aphrodite Terra. Recent analysis of the SAR data together with Arecibo range-doppler topographic profiling (10 X 100 km horizontal and 10 m vertical resolution) across parts of Aphrodite, further characterized the nature of possible tectonic processes in the equatorial highlands. The existence of distinct topographic and radar morphologic linear discontinuities across the nearly east-west strike of Aphrodite Terra is indicated. Another prominent set of linear features is distinctly parallel to and orthogonal to the ground tracks of the PV spacecraft and are not included because of the possibility that they are artifacts. Study of the northwest trending cross-strike discontinuities (CSD's) and the nature of topographic and morphologic features along their strike suggest the presence of bilateral topographic and morphologic symmetry about the long axis of Aphrodite Terra.

  20. Bilateral extensor digitorum brevis manus.

    PubMed

    Froelich, John M; Bidgoli-Moghaddam, Mahsa; Moran, Steven L

    2012-09-01

    Dorsal wrist pain and swelling is commonly attributed to a dorsal wrist ganglion. However, based on the authors' experience, a cautious surgeon should keep the uncommonly symptomatic diagnosis of an extensor digitorum brevis manus in their differential despite classic ganglion presentation and suggestive advanced imaging. This article describes a case of a young patient who presented with bilateral symptomatic extensor digitorum brevis manus anomalies that required surgical intervention. An extensor digitorum brevis manus is present in 3% of the population in a classic anatomy study from Japan and is most commonly symptomatic with heavy activity and extremes of wrist extension. Anatomically, the extensor digitorum brevis manus is located in the fourth wrist compartment and most commonly inserts on the index finger extensor mechanism. Examination often reveals a spindle-shaped mass that is palpable distal to the extensor mechanism and moves with extensor tendon motion. Magnetic resonance imaging shows a typical dorsal mass distal to the common extensors with a similar signal as muscle with all image sequencing. Treatment includes activity alterations to relieve symptoms or surgical excision of the muscle belly for refractory cases with care taken to preserve the index extensor mechanism. PMID:22955414

  1. Bilateral pneumothorax after orthognatic surgery

    PubMed Central

    Bertossi, Dario; Malchiodi, Luciano; Turra, Matteo; Bondi, Vincenzo; Albanese, Massimo; Lucchese, Alessandra; Carinci, Francesco; Nocini, Pierfrancesco

    2012-01-01

    Among complications in orthognathic surgery, the insurgence of pneumothorax is very rare. Pneumothorax is the presence of air or gas in the pleural cavity and it is rare complications in the postoperative oral and maxillofacial surgery patient. The clinical results are dependent on the degree of collapse of the lung on the affected side. Pneumothorax can impair oxygenation and/or ventilation. If the pneumothorax is significant, it can cause a shift of the mediastinum and compromise haemodynamic stability. While 10% of pneumothoraces are asymptomatic, patients often complain of acute chest pain and difficulty breathing. There is a reduction in vital capacity, tachycardia, tachypnoea and a decrease in partial pressure of oxygen with an inability to maintain oxygen saturations. We observed this unusual surgical consequence in a 28-year-old female with negative clinical history and instrumental evaluation after Le Fort I osteotomy and bilateral sagittal split osteotomy (BSSO). No further consequences, no neurological sequelae, no infections and no other osteotomies sequelae were seen. Sudden post-surgical dispnea associated to sub-cutaneous emphysema of the neck and of the thorax must be adequately observed with the aim of monitoring further severe sequelae. The anaesthetic management of the emergency difficult airway in any post-surgical orthognatic treatment can be extremely difficult requiring a multi-disciplinary approach. PMID:23814593

  2. Retroperitoneal laparoscopic bilateral lumbar sympathectomy.

    PubMed

    Segers, B; Himpens, J; Barroy, J P

    2007-06-01

    The first retroperitoneal lumbar sympathectomy was performed in 1924 by Julio Diez. The classic procedure for sympathectomy is open surgery. We report a unilateral laparoscopic retroperitoneal approach to perform bilateral lumbar sympathectomy. This approach was performed for a 43-year-old man with distal arterial occlusive disease and no indication for direct revascularization. His predominant symptoms were intermittent claudication at 100 metres and cold legs. The patient was placed in a left lateral decubitus position. The optical system was placed first in an intra-abdominal position to check that the trocars were well positioned in the retroperitoneal space. The dissection of retroperitoneum was performed by CO2 insufflation. The inferior vena cava was reclined and the right sympathetic chain was individualized. Two ganglia (L3-L4) were removed by bipolar electro-coagulation. The aorta was isolated on a vessel loop and careful anterior traction allowed a retro-aortic pre-vertebral approach between the lumbar vessels. The left sympathetic chain was dissected. Two ganglia (L3-L4) were removed by bipolar electro-coagulation. PMID:17685269

  3. Validity and reliability of electroencephalographic frontal alpha asymmetry and frontal midline theta as biomarkers for depression.

    PubMed

    Gold, Christian; Fachner, Jörg; Erkkilä, Jaakko

    2013-04-01

    Electroencephalographic (EEG) frontal alpha asymmetry (FAA) and frontal midline (FM) theta have been suggested as biomarkers for depression and anxiety, but have mostly been assessed in small and non-clinical studies. In a clinical sample of 79 adults with depression (ICD-10: F32), resting EEG and scales of depression (MADRS) and anxiety (HADS-A) were measured at intake and after 3 months. FAA and FM theta values were referenced to a normative population database. Internal consistency, test-retest reliability, and correlations with psychiatric tests were examined. Reliability was sufficient. However, FAA and FM theta values were close to the general population, and correlations with psychiatric tests were mostly small and non-significant, with the exception of FAA on F7-F8 z-scores and HADS-A. We conclude that the validity of FAA and FM theta and therefore their potential as biomarkers for depression and anxiety remain unclear. PMID:23278257

  4. Beam heated linear theta-pinch device for producing hot plasmas

    DOEpatents

    Bohachevsky, Ihor O.

    1981-01-01

    A device for producing hot plasmas comprising a single turn theta-pinch coil, a fast discharge capacitor bank connected to the coil, a fuel element disposed along the center axis of the coil, a predetermined gas disposed within the theta-pinch coil, and a high power photon, electron or ion beam generator concentrically aligned to the theta-pinch coil. Discharge of the capacitor bank generates a cylindrical plasma sheath within the theta-pinch coil which heats the outer layer of the fuel element to form a fuel element plasma layer. The beam deposits energy in either the cylindrical plasma sheath or the fuel element plasma layer to assist the implosion of the fuel element to produce a hot plasma.

  5. Status of the iota (1440) and theta (1640) as gluonium candidates

    SciTech Connect

    Lockman, W.S.

    1983-04-01

    A review of the experimental evidence for the iota (1440) and theta (1640) states is presented. The measured properties of these states are compared with various theoretical predictions. A likely interpretation is that these states contain a large gluonic admixture.

  6. Theta rhythm and the encoding and retrieval of space and time

    PubMed Central

    Hasselmo, Michael E.; Stern, Chantal E.

    2013-01-01

    Physiological data demonstrates theta frequency oscillations associated with memory function and spatial behavior. Modeling and data from animals provides a perspective on the functional role of theta rhythm, including correlations with behavioral performance and coding by timing of spikes relative to phase of oscillations. Data supports a theorized role of theta rhythm in setting the dynamics for encoding and retrieval within cortical circuits. Recent data also supports models showing how network and cellular theta rhythmicity allows neurons in the entorhinal cortex and hippocampus to code time and space as a possible substrate for encoding events in episodic memory. Here we discuss these models and relate them to current physiological and behavioral data. PMID:23774394

  7. Correlation of hippocampal theta rhythm with changes in cutaneous temperature. [evoked neuron response in thermoregulation

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Saleh, M. A.; Karem, R. D.

    1974-01-01

    A possible role for the hippocampus in alerting an animal to changes in cutaneous temperature was examined. Following local warming or cooling of the ears of unanesthetized, loosely restrained rabbits, theta waves (4-7 Hz EEG waves) were recorded from electrodes straddling the hippocampus. The onset of the hippocampal theta rhythm was correlated with changes in cutaneous temperature, an observation consistent with studies indicating that the theta rhythm is a nonspecific response evoked by stimulation of several sensory modalities. Additional data from cats and rabbits were correlated with specific neurons within the hippocampus, namely pyramidal cells. Post stimulus time histograms obtained by excitation of the dorsal fornix were interpreted in terms of excitatory and inhibitory inputs to pyramidal cells. Thus, the theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hippocampal neuron which is in turn connected with other areas of the brain involved in temperature regulation.

  8. Hippocampal Theta Input to the Amygdala Shapes Feedforward Inhibition to Gate Heterosynaptic Plasticity

    PubMed Central

    Bazelot, Michaël; Bocchio, Marco; Kasugai, Yu; Fischer, David; Dodson, Paul D.; Ferraguti, Francesco; Capogna, Marco

    2015-01-01

    Summary The dynamic interactions between hippocampus and amygdala are critical for emotional memory. Theta synchrony between these structures occurs during fear memory retrieval and may facilitate synaptic plasticity, but the cellular mechanisms are unknown. We report that interneurons of the mouse basal amygdala are activated during theta network activity or optogenetic stimulation of ventral CA1 pyramidal cell axons, whereas principal neurons are inhibited. Interneurons provide feedforward inhibition that transiently hyperpolarizes principal neurons. However, synaptic inhibition attenuates during theta frequency stimulation of ventral CA1 fibers, and this broadens excitatory postsynaptic potentials. These effects are mediated by GABAB receptors and change in the Cl− driving force. Pairing theta frequency stimulation of ventral CA1 fibers with coincident stimuli of the lateral amygdala induces long-term potentiation of lateral-basal amygdala excitatory synapses. Hence, feedforward inhibition, known to enforce temporal fidelity of excitatory inputs, dominates hippocampus-amygdala interactions to gate heterosynaptic plasticity. Video Abstract PMID:26402610

  9. The effects of theta-burst stimulation on sleep and vigilance in humans

    PubMed Central

    Mensen, Armand; Gorban, Corina; Niklaus, Marcel; Kuske, Eva; Khatami, Ramin

    2014-01-01

    Repetitive transcranial magnetic stimulation (TMS) has become a popular tool to modulate neuronal networks and associated brain functions in both clinical and basic research. Yet few studies have examined the potential effects of cortical stimulation on general levels of vigilance. In this exploratory study, we used theta-burst protocols, both continuous (cTBS) and intermittent (iTBS) patterns, to examine whether inhibition or excitation of the left dorso-lateral prefrontal cortex (dlPFC) was able to induce reliable and acute changes to vigilance measures, compared to the left dorso-lateral associative visual cortex (dlAVC) as a control site in line with previous work. Partially sleep restricted participants underwent four separate sessions in a single day, in a between subjects design for TBS stimulation type and within subjects for locaton, each consisting of maintenance of wakefulness test (MWT), a sleep latency test, and a psychomotor vigilance task (PVT). TBS significantly affected measures of sleep consolidation, namely latency to sleep stage 2 and sleep efficiency, but had no effects on sleep drive or psychomotor vigilance levels for either TBS type or location. Contrary to our initial hypothesis of the dlAVC as a control site, stimulation to this region resulted in the largest differential effects between stimulation types. Moreover, the effect of TBS was found to be consistent throughout the day. These data may provide the basis for further investigation into therapeutic applications of TBS in sleep disorders. PMID:24971057

  10. Cerebellar theta burst stimulation dissociates memory components in eyeblink classical conditioning.

    PubMed

    Monaco, J; Casellato, C; Koch, G; D'Angelo, E

    2014-11-01

    The cerebellum plays a critical role in forming precisely timed sensory-motor associations. This process is thought to proceed through two learning phases: one leading to memory acquisition; and the other leading more slowly to memory consolidation and saving. It has been proposed that fast acquisition occurs in the cerebellar cortex, while consolidation is dislocated into the deep cerebellar nuclei. However, it was not clear how these two components could be identified in eyeblink classical conditioning (EBCC) in humans, a paradigm commonly used to investigate associative learning. In 22 subjects, we show that EBCC proceeded through a fast acquisition phase, returned toward basal levels during extinction and then was consolidated, as it became evident from the saving effect observed when re-testing the subjects after 1 week of initial training. The results were fitted using a two-state multi-rate learning model extended to account for memory consolidation. Transcranial magnetic stimulation was used to apply continuous theta-burst stimulation (cTBS) to the lateral cerebellum just after the first training session. Half of the subjects received real cTBS and half sham cTBS. After cTBS, but not sham cTBS, consolidation was unaltered but the extinction process was significantly impaired. These data suggest that cTBS can dissociate EBCC extinction (related to the fast learning process) from consolidation (related to the slow learning process), probably by acting through a selective alteration of cerebellar plasticity. PMID:25185744