Neural Centers Research Articles

Efficacy of stimulus intensity increases and decreases as inhibitors of the acoustic startle response.

The human startle eyeblink response can be inhibited by a change in the stimulus environment briefly before the startling stimulus; both stimulus presentation (prepulse) and cessation of background sound (gap) can result in startle inhibition. More intense prepulses often result in greater inhibition, and this study (N=53 college students) examined whether graded decreases in sound energy relative to a steady background noise (a "partial gap") would follow this same pattern of inhibition. Embedded in a 65dB steady background noise were 100dB white noise startle stimuli preceded at 120ms on some trials by stimulus intensity increases or decreases of 5, 10, or 15dB relative to background. Results showed that startle inhibition was graded by amount of change relative to background, such that greater increases or decreases resulted in greater inhibition. Also, increases were more effective startle inhibitors than decreases at equivalent levels of change from background. These results demonstrate that the neural centers responsible for startle inhibition are responsive to both increases and decreases in stimulus intensity, and are sensitive to amount of change, not simply whether a change occurs. These findings may have implications for the development of a screening method for a hearing disorder called tinnitus.

TCTAP A-010 Association of Brain Amygdalar Activity with Plaque Burden and Vulnerability in Coronary Artery

Emotional stimulation was reported to be related to coronary events, but, there is a lack of direct mechanistic evidence between metabolic activity of the amygdala, a neural stress center, and coronary artery disease (CAD) including acute coronary syndrome. In this study, we aimed to evaluate

Growth Patterns of the Neurocentral Synchondrosis (NCS) in Immature Cadaveric Vertebra.

Gross anatomic study of osteological specimens. To evaluate the age of closure for the neurocentral synchondrosis (NCS) in all 3 regions of the spine in children aged 1 to 18 years old. The ossification of the human vertebra begins from a vertebral body ossification center and a pair of neural ossification centers located within the centrum called the NCS. These bipolar cartilaginous centers of growth contribute to the growth of the vertebral body, spinal canal, and posterior elements of the spine. The closure of the synchondroses is dependent upon location of the vertebra and previous studies range from 2 to 16 years of age. Although animal and cadaveric studies have been performed regarding NCS growth and early instrumentation's effect on its development, the effects of NCS growth disturbances are still not completely understood. The vertebrae of 32 children (1 to 18 y old) from the Hamann-Todd Osteological collection were analyzed (no 2 or 9 y old specimens available). Vertebrae studied ranged from C1 to L5. A total of 768 vertebral specimens were photographed on a background grid to allow for measurement calibration. Measurements of the right and left NCS, pedicle width at the NCS, and spinal canal area were taken using Scandium image-analysis software (Olympus Soft Imaging Solutions, Germany). The percentage of the growth plate still open was found by dividing the NCS by the pedicle width and multiplying by 100. Data were analyzed with JMP 11 software (SAS Institute Inc., Cary, NC). The NCS was 100% open in all 3 regions of the spine in the 1- to 3-year age group. The cervical NCS closed first with completion around 5 years of age. The lumbar NCS was nearly fully closed by age 11. Only the thoracic region remained open through age 17 years. The left and right NCS closed simultaneously as there was no statistical difference between them. In all regions of the spine, the NCS appeared to close sooner in males than in females. Spinal canal area increased with age up to 12 years old in the cervical and thoracic spine but did not significantly change after age 3 in the lumbar spine. In conclusion, closure of the NCS differed among the cervical, thoracic, and lumbar spine regions. The NCS reached closure in males before females even though females mature faster and reach skeletal maturity sooner than males. However, it is not determined whether the continued open NCS in females to a later age may be a factor in their increased rate of scoliosis.

A Comparison of Effectiveness of Dohsa‐hou and the Alexander Technique on Happiness, Social Adjustment, Hope, Mental Health, and Quality of Life in Patients with Parkinson's Disease

AbstractThe purpose of this study was to compare the effectiveness of Dohsa‐hou and the Alexander Technique on happiness, social adjustment, hope, mental health, and quality of life in patients with Parkinson's disease. The statistical population of this study included all of the patients with Parkinson's disease who were clients of neural therapeutic centers in Isfahan City in 2015. Among this population, 28 patients were selected through convenience sampling as the sample of the study. The Oxford Happiness Questionnaire, the Social Adjustment Scale, the Adult Hope Scale, the General Health Questionnaire, and the Word Health Quality of Life Questionnaire were used as the instruments of the study. Data were analyzed by analyses of variance with repeated measures. The results showed that both interventions of this study can improve happiness, hope, and quality of life in patients with Parkinson's disease, but Dohsa‐hou is more effective than the Alexander Technique in the improvement of happiness and hope. Probable explanations have been discussed.

Haptic Cues for Balance: Use of a Cane Provides Immediate Body Stabilization.

Haptic cues are important for balance. Knowledge of the temporal features of their effect may be crucial for the design of neural prostheses. Touching a stable surface with a fingertip reduces body sway in standing subjects eyes closed (EC), and removal of haptic cue reinstates a large sway pattern. Changes in sway occur rapidly on changing haptic conditions. Here, we describe the effects and time-course of stabilization produced by a haptic cue derived from a walking cane. We intended to confirm that cane use reduces body sway, to evaluate the effect of vision on stabilization by a cane, and to estimate the delay of the changes in body sway after addition and withdrawal of haptic input. Seventeen healthy young subjects stood in tandem position on a force platform, with eyes closed or open (EO). They gently lowered the cane onto and lifted it from a second force platform. Sixty trials per direction of haptic shift (Touch → NoTouch, T-NT; NoTouch → Touch, NT-T) and visual condition (EC-EO) were acquired. Traces of Center of foot Pressure (CoP) and the force exerted by cane were filtered, rectified, and averaged. The position in space of a reflective marker positioned on the cane tip was also acquired by an optoelectronic device. Cross-correlation (CC) analysis was performed between traces of cane tip and CoP displacement. Latencies of changes in CoP oscillation in the frontal plane EC following the T-NT and NT-T haptic shift were statistically estimated. The CoP oscillations were larger in EC than EO under both T and NT (p < 0.001) and larger during NT than T conditions (p < 0.001). Haptic-induced effect under EC (Romberg quotient NT/T ~ 1.2) was less effective than that of vision under NT condition (EC/EO ~ 1.5) (p < 0.001). With EO cane had little effect. Cane displacement lagged CoP displacement under both EC and EO. Latencies to changes in CoP oscillations were longer after addition (NT-T, about 1.6 s) than withdrawal (T-NT, about 0.9 s) of haptic input (p < 0.001). These latencies were similar to those occurring on fingertip touch, as previously shown. Overall, data speak in favor of substantial equivalence of the haptic information derived from both “direct” fingertip contact and “indirect” contact with the floor mediated by the cane. Cane, finger and visual inputs would be similarly integrated in the same neural centers for balance control. Haptic input from a walking aid and its processing time should be considered when designing prostheses for locomotion.

Parkinson's disease as a neuron disease

The history of discoveries related to Parkinson's disease shows how difficult it was to conceive of an etiology based on anatomo-pathology in the 19th century. The difficulty in finding characteristic lesions led to overestimations of an hereditary etiology and an epistemological deadlock at a time when the central origins of some neurological diseases were being discussed, at the turn of the 20th century, and in the context of introducing the neuron theory in neurology. This was the challenge faced in the study of particular clinical cases and led neurologists to question the novel etiology, based on the selective destruction of special nerve cells, while the concept of “neuron disease” remained somewhat theoretical. However, by placing the anatomo-pathological studies of Parkinson's disease within the context of the evolution of the concept of neuron diseases, my intention is to clarify how this idea, defined mainly by other neurological diseases, influenced those studies. The focus is particularly on how the rationale behind those studies led to the identification of not only the neural centers involved, but also their associations and neuronal networks. In addition, there is an evaluation of how the neuron theory has shaped the dynamics of cytological studies, and the definition of neuronal pathways and their neurotransmitters, into the present etiological model of Parkinson's disease.

Relationship Between Persistent Excitation Levels and RBF Network Structures, With Application to Performance Analysis of Deterministic Learning.

Based on the notion of persistent excitation (PE), a deterministic learning theory is recently proposed for RBF network-based identification of nonlinear systems. In this paper, we study the relationship between the PE levels, the structures of RBF networks and the performance of deterministic learning. Specifically, given a state trajectory generated from a nonlinear dynamical system, we investigate how to construct the RBF networks in order to guarantee sufficient PE levels (especially the level of excitation) for deterministic learning. It is revealed that the PE levels decrease with the density of neural centers, denoted by explicit formulas. As an illustration, these formulas are applied to convergence analysis of deterministic learning. We present exact theoretical conclusions that a finite and definite number of centers can achieve the same performance as global centers. In addition, a tradeoff exists between a relatively high level of excitation and the good approximation capabilities of RBF networks, which indicates that we cannot always obtain better convergence accuracy by increasing the density of centers. These results provide a new perspective for performance analysis of RBF network algorithms based on the notion of PE. Simulation studies are included to illustrate the results.

The impact of bilateral vagotomy on the physostigmine-induced airway constriction in ferrets

Vagal innervations have a great role in the respiratory function and are the main route of signal transmission from respiratory neural centers into the trachea and others conducting airways.We have investigated the role of central mechanisms related to vagal neural pathways and the cholinergic outflow in tracheobronchial smooth muscle tone and lung mechanics parameters.Parameters of lung mechanics such as lung resistance (RL), dynamic compliance (Cdyn) and pressure in bypassed tracheal segment (Ptseg) were measured before and after vagotomy and asphyxia test. Before vagotomy (BV), the control measurements were obtained and physostigmine was administered systemically, in increasing dose 10, 40 and 100μg/kg body weight (bw) with 15min interval between doses. After vagotomy (AV), administration of physostigmine with the same doses as BV has been done and the asphyxia challenge was conducted as per study protocol. The values of Ptseg and RL after physostigmine administration, BV vs. AV, respectively, at maximal dose of 100μg/kg bw were 32.5±3.3cm H2O, and 10.6±1.5cm H2O (p<0.0001); 0.16±0.04cm H2O/mL/s, and 0.067±0.006cm H2O/mL/s AV (P<0.05). The Cydn values were affected after physostigmine administration only at the lowest dose of 10μg/kg bw, and BV was 0.75±0.05mL/cm H2O vs. 0.53±0.04mL/cm H2O AV (P<0.004).Cholinergic outflow produced increases in tracheal tone, lung resistance and a decrease in dynamic compliance before, but not after vagotomy. Our results show the high impact of central neuronal mechanism in parameters of lung mechanics and respiration.This study indicates that vagal nerves have a crucial role, in the transmission of impulses initiated from central nervous system, in regulating the respiration by contraction or relaxation of airway smooth muscle tone.

Examining gray matter structure associated with academic performance in a large sample of Chinese high school students

Achievement in school is crucial for students to be able to pursue successful careers and lead happy lives in the future. Although many psychological attributes have been found to be associated with academic performance, the neural substrates of academic performance remain largely unknown. Here, we investigated the relationship between brain structure and academic performance in a large sample of high school students via structural magnetic resonance imaging (S-MRI) using voxel-based morphometry (VBM) approach. The whole-brain regression analyses showed that higher academic performance was related to greater regional gray matter density (rGMD) of the left dorsolateral prefrontal cortex (DLPFC), which is considered a neural center at the intersection of cognitive and non-cognitive functions. Furthermore, mediation analyses suggested that general intelligence partially mediated the impact of the left DLPFC density on academic performance. These results persisted even after adjusting for the effect of family socioeconomic status (SES). In short, our findings reveal a potential neuroanatomical marker for academic performance and highlight the role of general intelligence in explaining the relationship between brain structure and academic performance.

Patterns of eeg coherence associated with emotional burnout

One of the main problems is evaluation of the influence of emotiongenic factors in everyday life and interpersonal communication on an individual. Burnout is a mechanism of psychological defense, which is responsible for partial or total loss of emotions in response to stressful situations during interpersonal communication. The changes of functional connectivity between different regions of brain in the rest state depends on the current level of brain activation, which, in turn, depends on the initial emotional state. The development of emotional burnout is characterized by decrease of information capacity of the brain: reduction of spatial synchronization provides delayed and less efficient spread of excitation in the cerebral cortex. The decrease of interhemispheric coherence of low and high-frequency components of EEG may indicate the increase of level of differentiation of neuronal groups. In women, decrease of coherence in theta-subband indicates the influence of burnout on attention concentration, working memory, and emotional processes. In men weakening of the relationship between left frontal and right occipital zones indicates the weakness of informational aggregation, reducing readiness of the neural centers for processing information in the “cognitive axis”. Reduction of the level of coherence of alpha band may indicate problems of psychological adaptation within the experiment in examined groups of men with the Resistance stage of burnout. These EEG features allow us to conclude that participants with Resistance stage were concentrated on negative emotional reactions. Study indicates that men are more vulnerable to stress-induced conditions, which lead to burnout.Disclosure of interestThe authors have not supplied their declaration of competing interest.

From East to West and Return: A Western Interpretation of Acupuncture

Acupuncture, a complementary therapy originated in China over 3000 years ago, is widely practiced in western countries. There is an urgent need to define the mechanisms underlying some clinical effects obtained by acupuncture. A placebo effect is sustained by neuroimaging evidence indicating the activation of areas in the brain that are involved in expectation after real and sham acupuncture. However, only real acupuncture modulates the activity of specific regions in the brain some of which involved in the perception of pain. Basic research applied to the field of acupuncture is beginning to offer a scientific interpretation to these events. Indeed, the stimulation of acupoints alters the architecture of the connective tissue and this local mechanical stress is delivered to the keratinocytes, mast cells and fibroblasts, which react in several manners, including the release of various molecules that act on peripheral nerve endings. Consequently, locally generated signals can be transmitted to the neural centers. In the light of these achievements and urging more research in the field, it can be concluded that there are common denominators between acupuncture and western medicine.

Supraspinal Control Predicts Locomotor Function and Forecasts Responsiveness to Training after Spinal Cord Injury.

Restoration of walking ability is an area of great interest in the rehabilitation of persons with spinal cord injury. Because many cortical, subcortical, and spinal neural centers contribute to locomotor function, it is important that intervention strategies be designed to target neural elements at all levels of the neuraxis that are important for walking ability. While to date most strategies have focused on activation of spinal circuits, more recent studies are investigating the value of engaging supraspinal circuits. Despite the apparent potential of pharmacological, biological, and genetic approaches, as yet none has proved more effective than physical therapeutic rehabilitation strategies. By making optimal use of the potential of the nervous system to respond to training, strategies can be developed that meet the unique needs of each person. To complement the development of optimal training interventions, it is valuable to have the ability to predict future walking function based on early clinical presentation, and to forecast responsiveness to training. A number of clinical prediction rules and association models based on common clinical measures have been developed with the intent, respectively, to predict future walking function based on early clinical presentation, and to delineate characteristics associated with responsiveness to training. Further, a number of variables that are correlated with walking function have been identified. Not surprisingly, most of these prediction rules, association models, and correlated variables incorporate measures of volitional lower extremity strength, illustrating the important influence of supraspinal centers in the production of walking behavior in humans.

Neurally adjusted ventilatory assist in patients with acute respiratory failure: study protocol for a randomized controlled trial.

BackgroundPatient-ventilator asynchrony is a common problem in mechanically ventilated patients with acute respiratory failure. It is assumed that asynchronies worsen lung function and prolong the duration of mechanical ventilation (MV). Neurally Adjusted Ventilatory Assist (NAVA) is a novel approach to MV based on neural respiratory center output that is able to trigger, cycle, and regulate the ventilatory cycle. We hypothesized that the use of NAVA compared to conventional lung-protective MV will result in a reduction of the duration of MV. It is further hypothesized that NAVA compared to conventional lung-protective MV will result in a decrease in the length of ICU and hospital stay, and mortality.Methods/designThis is a prospective, multicenter, randomized controlled trial in 306 mechanically ventilated patients with acute respiratory failure from several etiologies. Only patients ventilated for less than 5 days, and who are expected to require prolonged MV for an additional 72 h or more and are able to breathe spontaneously, will be considered for enrollment. Eligible patients will be randomly allocated to two ventilatory arms: (1) conventional lung-protective MV (n = 153) and conventional lung-protective MV with NAVA (n = 153). Primary outcome is the number of ventilator-free days, defined as days alive and free from MV at day 28 after endotracheal intubation. Secondary outcomes are total length of MV, and ICU and hospital mortality.DiscussionThis is the first randomized clinical trial examining, on a multicenter scale, the beneficial effects of NAVA in reducing the dependency on MV of patients with acute respiratory failure.Trial registrationClinicalTrials.gov website (NCT01730794). Registered on 15 November 2012.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1625-5) contains supplementary material, which is available to authorized users.

The Binaural Interaction Component in Barn Owl (Tyto alba) Presents few Differences to Mammalian Data.

The auditory brainstem response (ABR) is an evoked potential that reflects the responses to sound by brainstem neural centers. The binaural interaction component (BIC) is obtained by subtracting the sum of the monaural ABR responses from the binaural response. Its latency and amplitude change in response to variations in binaural cues. The BIC is thus thought to reflect the activity of binaural nuclei and is used to non-invasively test binaural processing. However, any conclusions are limited by a lack of knowledge of the relevant processes at the level of individual neurons. The aim of this study was to characterize the ABR and BIC in the barn owl, an animal where the ITD-processing neural circuits are known in great detail. We recorded ABR responses to chirps and to 1 and 4kHz tones from anesthetized barn owls. General characteristics of the barn owl ABR were similar to those observed in other bird species. The most prominent peak of the BIC was associated with nucleus laminaris and is thus likely to reflect the known processes of ITD computation in this nucleus. However, the properties of the BIC were very similar to previously published mammalian data and did not reveal any specific diagnostic features. For example, the polarity of the BIC was negative, which indicates a smaller response to binaural stimulation than predicted by the sum of monaural responses. This is contrary to previous predictions for an excitatory-excitatory system such as nucleus laminaris. Similarly, the change in BIC latency with varying ITD was not distinguishable from mammalian data. Contrary to previous predictions, this behavior appears unrelated to the known underlying neural delay-line circuitry. In conclusion, the generation of the BIC is currently inadequately understood and common assumptions about the BIC need to be reconsidered when interpreting such measurements.

Morphometric study of the neural ossification centers of the atlas and axis in the human fetus

PurposesThe knowledge of the developing cervical spine and its individual vertebrae, including their neural processes may be useful in the diagnostics of congenital vertebral malformations. This study was performed to quantitatively examine the neural ossification centers of the atlas and axis with respect to their linear, planar and volumetric parameters.MethodsUsing the methods of CT, digital-image analysis and statistics, the size of neural ossification centers in the atlas and axis in 55 spontaneously aborted human fetuses aged 17–30 weeks was studied.ResultsWithout any male–female and right–left significant differences, the best fit growth dynamics for the neural ossification centers of the atlas and axis were, respectively, modelled by the following functions: for length: y = −13.461 + 6.140 × ln(age) ± 0.570 and y = −15.683 + 6.882 × ln(age) ± 0.503, for width: y = −4.006 + 1.930 × ln(age) ± 0.178 and y = −3.054 + 1.648 × ln(age) ± 0.178, for cross-sectional area: y = −7.362 + 0.780 × age ± 1.700 and y = −9.930 + 0.869 × age ± 1.911, and for volume: y = −6.417 + 0.836 × age ± 1.924 and y = −11.592 + 1.087 × age ± 2.509.ConclusionsThe size of neural ossification centers of the atlas and axis shows neither sexual nor bilateral differences. The neural ossification centers of the atlas and axis grow logarithmically in both length and width and linearly in both cross-sectional area and volume. The numerical data relating to the size of neural ossification centers of the atlas and axis derived from the CT and digital-image analysis are considered specific-age reference values of potential relevance in both the ultrasound monitoring and the early detection of spinal abnormalities relating to the neural processes of the first two cervical vertebrae in the fetus.

Effect of differential photostimulation on induction of Fos-like immune-reactivity in the MBH region of Indian weaver bird

This study investigated the neuronal activation (c-fos) in the mediobasal hypothalamus (MBH) of the Indian weaver bird, after exposure to a single long-day. Wild-caught photosensitive birds were exposed to the short-days (LD 8L:16D). After four days of short-days photoperiod, the LD cycle was programmed such that the light illumination was continuous after zeitgeber time (ZT) 8. Birds were perfused on the same day at ZT 4 or ZT 20. Brains were processed for the immunohistochemistry of c-fos (Fos) in the MBH. We found a significant higher activation of Fos in neurons within the ventral tuberal division (containing infundibular nucleus) of the MBH, in group that received 20-h light than that received 4-h light on first long-day. But in the dorsal tuberal division, there was no noticeable difference in Fos-lir activation on after 4-h and 24-h light exposure. The results suggest that the ventral tuberal division of mediobasal hypothalamus is principally involved in detecting the photoperiodic information from the external environment, and hence, suggested as the key neural center, involved in the photoperiodic mechanism in Indian weaver bird.

Learning defects in Drosophila growth restricted chico mutants are caused by attenuated adenylyl cyclase activity.

BackgroundReduced insulin/insulin-like growth factor signaling (IIS) is a major cause of symmetrical intrauterine growth retardation (IUGR), an impairment in cell proliferation during prenatal development that results in global growth defects and mental retardation. In Drosophila, chico encodes the only insulin receptor substrate. Similar to other animal models of IUGR, chico mutants have defects in global growth and associative learning. However, the physiological and molecular bases of learning defects caused by chico mutations, and by symmetrical IUGR, are not clear.ResultsIn this study, we found that chico mutations impair memory-associated synaptic plasticity in the mushroom bodies (MBs), neural centers for olfactory learning. Mutations in chico reduce expression of the rutabaga-type adenylyl cyclase (rut), leading to decreased cAMP synthesis in the MBs. Expressing a rut+ transgene in the MBs restores memory-associated plasticity and olfactory associative learning in chico mutants, without affecting growth. Thus chico mutations disrupt olfactory learning, at least in part, by reducing cAMP signaling in the MBs.ConclusionsOur results suggest that some cognitive defects associated with reduced IIS may occur, independently of developmental defects, from acute reductions in cAMP signaling.

(328) Divergent PAG neuronal populations drive nociceptive and pruritus processing

Chronic itch, like chronic pain, is a major clinical problem. Despite the similarities between itch and pain, the underlying neural circuitry for itch is poorly understood, as is the mechanism by which itch is suppressed by pain. Profound analgesia occurs with stimulation of the periaqueductal gray, however the precise role of the PAG in itch is unknown. We hypothesized that specific subsets of neurons within the PAG could suppress itch and provide a neural substrate for the inverse interaction between itch and pain. To determine the role of PAG in mediating itch and pain, we activated or inhibited PAG neurons using engineered G-protein coupled receptors (GPCRs) activated exclusively by synthetic, systemically administered small molecules (i.e., DREADD technology). Engineered excitatory (Gq) or inhibitory (Gi) GPCRs were expressed in PAG neurons via adeno-associated viral vectors. We found that chemogenetic activation of non-specific PAG neurons produced a reduction of both itch and pain, whereas inhibition of non-specific PAG neurons resulted in enhanced itch and pain. In contrast, when only the GABAergic neurons in the PAG were targeted using VGAT Cre mice, activation resulted in decreased itch, but increased behaviors. Conversely, inhibition of PAG GABAergic neurons resulted in increased itch, but decreased pain behaviors. When glutamatergic neurons in the PAG were selectively targeted we found that activation led to enhanced itch and decreased pain, while inhibition neurons produced decreased itch and increased pain. We conclude that the PAG bidirectionally modulates itch and pain signaling and is a neural control center for pruritus.

Impact of Auditory Context on Executed Motor Actions.

The auditory and motor systems are strongly coupled, as is evident in the specifically tight motor synchronization that occurs in response to regularly occurring auditory cues compared with cues of other modalities. Timing of rhythmic action is known to rely on multiple neural centers including the cerebellum and the basal-ganglia which have access to both motor cortical and spinal circuitries. To date, however, there is little information on the motor mechanisms that operate during preparation and execution of rhythmic vs. non-rhythmic movements. We measured acceleration profile and muscle activity while subjects performed tapping movements in response to auditory cues. We found that when tapping at random intervals there was a higher variability of both acceleration profile and muscle activity during motor preparation compared to rhythmic tapping. However, the specific rhythmic context (cued, self-paced, or syncopation) did not affect the motor parameters of the executed taps. Finally, during entrainment we found a gradual as opposed to episodic change in low-level motor parameters (i.e., preparatory muscle activity) that was strongly correlated with changes in high-level parameters (i.e., shift in the reaction time to negative asynchrony). These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters that are related to its production. These changes in motor output were insensitive to the specifics of the rhythmic cue: although it took subjects different times to become entrained to different types of rhythmic cues, the motor actions produced once entrainment was obtained were indistinguishable. These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters related to its production. The reduced variability of muscle activity during the preparatory period could be one mechanism used by the motor system to enhance the accuracy of motor timing.

Antisaccadic Eye Movements Are Correlated with Corpus Callosum White Matter Mean Diffusivity, Stroop Performance, and Symptom Burden in Mild Traumatic Brain Injury and Concussion.

Antisaccades are thought to involve higher level inputs from neural centers involved in rapid eye movement inhibition and control. Previous work has demonstrated that performance on the antisaccade task can help in the assessment of injury in acute and/or chronic mild traumatic brain injury (mTBI). In this exploratory study, we performed cross-sectional and longitudinal comparisons of rapid eye movement, followed by correlations of antisaccade performance with assessments of symptom burden, diffusion tensor imaging, and a neuropsychological test of response inhibition. Significant deficits in antisaccade median latency, F(2, 31) = 3.65, p = 0.04 and prosaccade error mean duration, F(2, 31) = 3.63, p = 0.04 were found between patient groups and controls: the former was correlated with loss of white matter integrity in the splenium of the corpus callosum in acute mTBI, rho = 0.90, p = 0.0005. Furthermore, increased antisaccade median latency was also correlated with poor performance on an executive functioning task, r2 = 0.439, p = 0.03, and greater symptom burden, r2 = 0.480, p = 0.02 in the acute mTBI patients. Our preliminary research suggests that the antisaccade task could be useful as a neurological marker for mTBI and concussion, but more work is required.