Neuroscience and Neurobiology Commons^™

Analysis Of Neuronal And Microglial Responses To Implanted Silicon Devices Through Immunohistochemistry And Clarity, Michael A. Leathers, Kevin J. Otto

The Summer Undergraduate Research Fellowship (SURF) Symposium

Brain computer interfaces (BCI’s) and implantable cortical devices have recently emerged in research as promising treatment methods for a variety of neurological problems such as motor dysfunction, memory loss, and sudden onset seizures. The number of people currently suffering from a loss of nervous system function as a result of neurodegenerative diseases or injury creates a need for reliable neural prostheses. The autoimmune response of the Central Nervous System (CNS) when introduced with a foreign object such as an electrode shank quickly impedes signal strength and degrades the functional life of the device. Two different experimental methods were used to …

Social Compass Curriculum: Three Descriptive Case Studies Of Social Skills Outcomes For Students With Autism, Louanne E. Boyd, Deborah M. Ward

Engineering Faculty Articles and Research

The Social Compass Curriculum (SCC) was investigated for its effectiveness in improving core social skills in three descriptive case studies of students with autism. Treatment fidelity of the SCC was also measured in the school setting. The Social Responsiveness Scale and the Autism Social Skills Profile were completed by parents to measure pre- and postintervention social skills for three students aged 8 to 11 years who participated in the present multisite pilot study. Fidelity of implementation data were collected via a checklist during observations for three educators who implemented the intervention. Results indicate that the SCC improved core social deficits …

An Investigation Into The Presynaptic Actions By Which Amphetamine Activates Dopamine Signaling Within Striatal Subregions Of The Rat., Dan P. Covey

Theses and Dissertations

Despite decades of intense research and a consensus view in the field, the work presented herein provides strong evidence that the primary mechanism of amphetamine action should be re-evaluated. Rather than depleting vesicular dopamine stores and promoting non-exocytotic efflux through the dopamine transporter in vivo, recent evidence demonstrates that amphetamine augments phasic dopamine signaling instead. This signaling modality is critical for reinforcement learning and is dependent on intact vesicular stores. The new findings support over-activation of phasic dopamine signaling as a common mechanism in the addiction process.

Day-Night Differences In Neural Activation In Histaminergic And Serotonergic Areas With Putative Projections To The Cerebrospinal Fluid In A Diurnal Brain, Alexandra Castillo-Ruiz, Andrew J. Gall, Laura Smale, Antonio A. Nunez

Faculty Publications

In nocturnal rodents, brain areas that promote wakefulness have a circadian pattern of neural activation that mirrors the sleep/wake cycle, with more neural activation during the active phase than during the rest phase. To investigate whether differences in temporal patterns of neural activity in wake-promoting regions contribute to differences in daily patterns of wakefulness between nocturnal and diurnal species, we assessed Fos expression patterns in the tuberomammillary (TMM), supramammillary (SUM), and raphe nuclei of male grass rats maintained in a 12:12 h light-dark cycle. Day-night profiles of Fos expression were observed in the ventral and dorsal TMM, in the SUM, …

Sex Differences In White Matter Development During Adolescence: A Dti Study, Yingying Wang, Chris Adamson, Weihong Yuan, Mekibib Altaye, Anna W. Byars, Scott K. Holland

Center for Brain, Biology, and Behavior: Faculty Publications

Adolescence is a complex transitional period in human development, composing physical maturation, cognitive and social behavioral changes. The objective of this study is to investigate sex differences in white matter development and the associations between intelligence and white matter microstructure in the adolescent brain using diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS). In a cohort of 16 typically-developing adolescents aged 13 to 17 years, longitudinal DTI data were recorded from each subject at two time points that were one year apart. We used TBSS to analyze the diffusion indices including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity …

Cervicothoracic Multisegmental Transpinal Evoked Potentials In Humans, Jonathan Einhorn, Alan Li, Royi Hazan, Maria Knikou

Publications and Research

The objectives of this study were to establish the neurophysiological properties of the transpinal evoked potentials (TEPs) following transcutaneous electric stimulation of the spine (tsESS) over the cervicothoracic region, changes in the amplitude of the TEPs preceded by median nerve stimulation at group I threshold, and the effects of tsESS on the flexor carpi radialis (FCR) H-reflex in thirteen healthy human subjects while seated. Two re-usable self-adhering electrodes, connected to function as one electrode (cathode), were placed bilaterally on the clavicles. A re-usable electrode (anode) was placed on the cervicothoracic region covering from Cervical 4 – Thoracic 2 and held …

Combined Erp/Fmri Evidence For Early Word Recognition Effects In The Posterior Inferior Temporal Gyrus, Joseph Dien, Eric S. Brian, Dennis L. Molfese, Brian T. Gold

Center for Brain, Biology, and Behavior: Faculty Publications

Two brain regions with established roles in reading are the posterior middle temporal gyrus and the posterior fusiform gyrus. Lesion studies have also suggested that the region located between them, the posterior inferior temporal gyrus (pITG), plays a central role in word recognition. However, these lesion results could reflect disconnection effects since neuroimaging studies have not reported consistent lexicality effects in pITG. Here we tested whether these reported pITG lesion effects are due to disconnection effects or not using parallel ERP/fMRI studies. We predicted that the Recognition Potential (RP), a left-lateralized ERP negativity that peaks at about 200–250 ms, might …

Reasoning Across Language And Vision In Machines And Humans, Andrei Barbu

Open Access Dissertations

Humans not only outperform AI and computer-vision systems, but use an unknown computational mechanism to perform tasks for which no suitable approaches exist. I present work investigating both novel tasks and how humans approach them in the context of computer vision and linguistics. I demonstrate a system which, like children, acquires high-level linguistic knowledge about the world. Robots learn to play physically-instantiated board games and use that knowledge to engage in physical play. To further integrate language and vision I develop an approach which produces rich sentential descriptions of events depicted in videos. I then show how to simultaneously detect …

Effects Of Dip-Coated Films On The Properties Of Implantable Intracortical Microelectrodes, Salah Sommakia

Open Access Dissertations

The successful clinical use of implantable intracortical microelectrodes (ICMs) to treat certain types of deafness, blindness, and paralysis is limited by a reactive tissue response (RTR) of the brain. This RTR culminates in the formation of a tight glial scar and a loss of neuronal density around implanted ICMs, and is accompanied by a decrease in signal to noise ratio and an increase in impedance. While no comprehensive mechanistic understanding of the underlying biology is currently agreed upon in the field, a general consensus exists around a highly volatile acute RTR phase. During this acute phase, the electrical properties of …

Smooth Muscle-Specific Removal Of Brain-Derived Neurotrophic Factor Results In Increased Vagal Afferent Innervation To The Intestine And Increased Satiation In Mice, Jessica Erin Biddinger

Open Access Dissertations

Vagal afferents transmit signals regarding food-derived stimuli in the gastrointestinal (GI) tract to the brain. Vagal mechanoreceptors called intraganglionic laminar endings (IGLEs) innervate the smooth muscle wall of GI organs and detect stretch and tension to regulate GI reflexes and satiation. Brain-derived neurotrophic factor (BDNF) is expressed in the smooth muscle of developing GI organs when vagal afferents from the nodose ganglion begin to innervate the GI tract. Therefore, it was hypothesized BDNF is necessary for development of vagal afferents that innervate this tissue. Targeted smooth muscle-specific BDNF homozygous knockout (BDNF SM -/-) mice were generated and .vagal afferent innervation …

Effects Of Hearing Aid Amplification On Robust Neural Coding Of Speech, Jonathan Daniel Boley

Open Access Dissertations

Hearing aids are able to restore some hearing abilities for people with auditory impairments, but background noise remains a significant problem. Unfortunately, we know very little about how speech is encoded in the auditory system, particularly in impaired systems with prosthetic amplifiers. There is growing evidence that relative timing in the neural signals (known as spatiotemporal coding) is important for speech perception, but there is little research that relates spatiotemporal coding and hearing aid amplification.

This research uses a combination of computational modeling and physiological experiments to characterize how hearing aids affect vowel coding in noise at the level of …

Network Structure And Dynamics Of The Mental Workspace, Alexander Schlegel, Peter J. Kohler, Sergei V. Fogelson, Prescott Alexander

Dartmouth Scholarship

The conscious manipulation of mental representations is central to many creative and uniquely human abilities. How does the human brain mediate such flexible mental operations? Here, multivariate pattern analysis of functional MRI data reveals a widespread neural network that performs specific mental manipulations on the contents of visual imagery. Evolving patterns of neural activity within this mental workspace track the sequence of informational transformations carried out by these manipulations. The network switches between distinct connectivity profiles as representations are maintained or manipulated.

Differential Joint-Specific Corticospinal Tract Projections Within The Cervical Enlargement, Curtis O. Asante, John H. Martin

Publications and Research

The motor cortex represents muscle and joint control and projects to spinal cord interneurons and–in many primates, including humans–motoneurons, via the corticospinal tract (CST). To examine these spinal CST anatomical mechanisms, we determined if motor cortex sites controlling individual forelimb joints project differentially to distinct cervical spinal cord territories, defined regionally and by the locations of putative last-order interneurons that were transneuronally labeled by intramuscular injection of pseudorabies virus. Motor cortex joint-specific sites were identified using intracorticalmicrostimulation. CST segmental termination fields from joint-specific sites, determined using anterograde tracers, comprised a high density core of terminations that was consistent between animals …

Cholinergic Enhancement Of Brain Activation In Mild Cognitive Impairment During Episodic Memory Encoding, Shannon L. Risacher, Yang Wang, Heather A. Wishart, Laura A. Rabin, Laura A. Flashman, Brenna C. Mcdonald, John D. West, Robert B. Santulli, Andrew J. Saykin

Publications and Research

Objective: To determine the physiological impact of treatment with donepezil (Aricept) on neural circuitry supporting episodic memory encoding in patients with amnestic mild cognitive impairment (MCI) using functional magnetic resonance imaging (fMRI).

Methods: Eighteen patients with MCI and 20 age-matched healthy controls (HC) were scanned twice while performing an event-related verbal episodic encoding task. MCI participants were scanned before treatment and after approximately 3 months on donepezil; HCwere untreated but rescanned at the same interval.Voxel-level analyses assessed treatment effects on activation profiles in MCI patients relative to retest changes in non-treated HC. Changes in task-related connectivity in medial temporal circuitry …

Transient And Selective Suppression Of Neural Activity With Infrared Light, Michael W. Jenkins, Hui Lu, Jeffrey M. Mcmanus, Hillel J. Chiel

Faculty Scholarship

Analysis and control of neural circuitry requires the ability to selectively activate or inhibit neurons. Previous work showed that infrared laser light selectively excited neural activity in endogenous unmyelinated and myelinated axons. However, inhibition of neuronal firing with infrared light was only observed in limited cases, is not well understood and was not precisely controlled. Using an experimentally tractable unmyelinated preparation for detailed investigation and a myelinated preparation for validation, we report that it is possible to selectively and transiently inhibit electrically- initiated axonal activation, as well as to both block or enhance the propagation of action potentials of specific …

Myelin Basic Protein And Glial Fibrillary Acidic Protein Antibodies In Autism, Edward Stevenson, Dr. Erin Bigler

Journal of Undergraduate Research

Autism is a developmental disorder. There has been an increasing trend in the diagnosis of autism in the past 15 years. After years of research there is still little agreement as to the causes of autism. It has been hypothesized that autistics could be the result of the body’s immune system attacking the brain through cytotoxicity and antibody mediated responses.2 Studies between immune factors and autism have had some interesting results, yet due to the complexities of the central nervous system and immune system, solid conclusions have not been reached.

Title, Jordan Yorgason

Journal of Undergraduate Research

We had four main objectives when I applied for the mentoring grant: to measure locomotor habituation to an environment, acoustic prepulse/startle inhibition, memory with a morris land maze, and to present findings in a neuroscience journal and on a poster for a convention. The results are as follows:

Understanding Less Than Nothing: Children's Neural Response To Negative Numbers Shifts Across Age And Accuracy, Margaret M. Gullick, George Wolford

Dartmouth Scholarship

We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that …

Visual-Motor Development In South Indian School Children: Environmental Complexity’S Relationship With Cortical Development, Christine H. Walton

Journal of Undergraduate Research

Previous neurological studies have found the degree of environmental complexity influences the acquisition and development of motor skills in human infants as well as animal models. During a critical period in human development, which is believed to span the first 6-10 years for human visual-motor development, neurons grow and solidify appropriate connections. Signals sent from cell to cell are insulated by additional protective cells in a process called myelination. These postnatal cognitive developments are influenced by sensory input and experience. It appears that deprivation of appropriate stimuli in a subject’s surroundings at this time results in decreased cognitive development as …

The Flexible Fairness: Equality, Earned Entitlement, And Self-Interest, Chunliang Feng, Yi Luo, Ruolei Gu, Lucas S. Broster, Xueyi Shen, Tengxiang Tian, Yue-Jia Luo, Frank Krueger

Behavioral Science Faculty Publications

The current study explored whether earned entitlement modulated the perception of fairness in three experiments. A preliminary resource earning task was added before players decided how to allocate the resource they jointly earned. Participants' decision in allocation, their responses to equal or unequal offers, whether advantageous or disadvantageous, and subjective ratings of fairness were all assessed in the current study. Behavioral results revealed that participants proposed more generous offers and showed enhanced tolerance to disadvantageous unequal offers from others when they performed worse than their presumed "partners," while the reverse was true in the better-performance condition. The subjective ratings also …