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Hensbroek R.A.,New York University | Ruigrok T.J.H.,Erasmus University Rotterdam | Maruta J.,Brain Trauma Foundation | Simpson J.I.,New York University
Cerebellum | Year: 2015

The unipolar brush cell (UBC) is a glutamatergic granular layer interneuron that is predominantly located in the vestibulocerebellum and parts of the vermis. In rat and rabbit, we previously found using juxtacellular labeling combined with spontaneous activity recording that cells with highly regular spontaneous activity belong to the UBC category. Making use of this signature, we recorded from floccular UBCs in both anesthetized and awake rabbits while delivering visuo-vestibular stimulation by using sigmoidal rotation of the whole animal. In the anesthetized rabbit, the activity of the presumed UBC units displayed a wide variety of modulation profiles that could be related to aspects of head velocity or acceleration. These modulation profiles could also be found in the awake rabbit where, in addition, they could also carry an eye position signal. Furthermore, units in the awake rabbit could demonstrate rather long response latencies of up to 0.5 s. We suggest that the UBCs recorded in this study mostly belong to the type I UBC category (calretinin-positive) and that they can play diverse roles in floccular visuo-vestibular information processing, such as transformation of velocity-related signals to acceleration-related signals. © 2015, The Author(s).

Maruta J.,Brain Trauma Foundation
F1000Research | Year: 2015

This correspondence points out a need for clarification concerning the methodology utilized in the study "Eye tracking detects disconjugate eye movements associated with structural traumatic brain injury and concussion?, recently published in Journal of Neurotrauma. The authors of the paper state that binocular eye movements were recorded using a single-camera video-oculography technique and that binocular disconjugate characteristics were analyzed without calibration of eye orientation. It is claimed that a variance-based disconjugacy metric was found to be sensitive to the severity of a concussive brain injury and to the status of recovery after the original injury. However, the reproducibility of the paper's findings may be challenged simply by the paucity of details in the methodological description. More importantly, from the information supplied or cited in the paper, it is difficult to evaluate the validity of the potentially interesting conclusions of the paper. © 2015 Maruta J.

Bayley M.T.,University of Toronto | Teasell R.W.,Lawson Health Research Institute | Wolfe D.L.,Lawson Health Research Institute | Gruen R.L.,Monash University | And 6 more authors.
Journal of Head Trauma Rehabilitation | Year: 2014

INTRODUCTION:: Treatment of patients with traumatic brain injury (TBI) should be based upon the strongest evidence to achieve optimal patient outcomes. Given the challenges, efforts involved, and delays in uptake of evidence into practice, priorities for knowledge translation (KT) should be chosen carefully. An international workshop was convened to identify KT priorities for acute and rehabilitation care of TBI and develop KT projects addressing these priorities. METHODS:: An expert panel of 25 neurotrauma clinicians, researchers, and KT scientists representing 4 countries examined 66 neurotrauma research topics synthesized from 2 neurotrauma evidence resources: Evidence Based Review of Acquired Brain Injury and Global Evidence Mapping projects. The 2-day workshop combined KT theory presentations with small group activities to prioritize topics using a modified Delphi method. RESULTS:: Four acute care topics and 3 topics in the field of rehabilitation were identified. These were focused into 3 KT project proposals: optimization of intracranial pressure and nutrition in the first week following TBI; cognitive rehabilitation following TBI; and vocational rehabilitation following TBI. CONCLUSION:: Three high-priority KT projects were developed: the first combined 2 important topics in acute TBI management of intracranial pressure management and nutrition, and the other projects focused on cognitive rehabilitation and vocational rehabilitation. Copyright © 2014 Lippincott Williams & Wilkins.

Contreras R.,University of Missouri-St. Louis | Ghajar J.,Brain Trauma Foundation | Ghajar J.,New York Medical College | Bahar S.,University of Missouri-St. Louis | Suh M.,Sungkyunkwan University
Brain Research | Year: 2011

In mild traumatic brain injury (mTBI), the fiber tracts that connect the frontal cortex with the cerebellum may suffer shear damage, leading to attention deficits and performance variability. This damage also disrupts the enhancement of eye-target synchronization that can be affected by cognitive load when subjects are tested using a concurrent eye-tracking test and word-recall test. We investigated the effect of cognitive load on eye-target synchronization in normal and mTBI patients using the nonlinear dynamical technique of stochastic phase synchronization. Results demonstrate that eye-target synchronization was negatively affected by cognitive load in mTBI subjects. In contrast, eye-target synchronization improved under intermediate cognitive load in young (≤ 40 years old) normal subjects. © 2011 Elsevier B.V. All rights reserved.

Maruta J.,Brain Trauma Foundation | Spielman L.A.,Brain Trauma Foundation | Yarusi B.B.,Brain Trauma Foundation | Wang Y.,Brain Trauma Foundation | And 3 more authors.
Frontiers in Human Neuroscience | Year: 2016

Individuals who sustain a concussion may continue to experience problems long after their injury. However, it has been postulated in the literature that the relationship between a concussive injury and persistent complaints attributed to it is mediated largely by the development of symptoms associated with posttraumatic stress disorder (PTSD) and depression. We sought to characterize cognitive deficits of adult patients who had persistent symptoms after a concussion and determine whether the original injury retains associations with these deficits after accounting for the developed symptoms that overlap with PTSD and depression. We compared the results of neurocognitive testing from 33 patients of both genders aged 18-55 at 3 months to 5 years post-injury with those from 140 control subjects. Statistical comparisons revealed that patients generally produced accurate responses on reaction time-based tests, but with reduced efficiency. On visual tracking, patients increased gaze position error variability following an attention demanding task, an effect that may reflect greater fatigability. When neurocognitive performance was examined in the context of demographic- and symptom-related variables, the original injury retained associations with reduced performance at a statistically significant level. For some patients, reduced cognitive efficiency and fatigability may represent key elements of interference when interacting with the environment, leading to varied paths of recovery after a concussion. Poor recovery may be better understood when these deficits are taken into consideration. © 2016 Maruta, Spielman, Yarusi, Wang, Silver and Ghajar.

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