Neuroscience and Neurobiology Commons^™

Glutamylation Regulates Transport, Specializes Function, And Sculpts The Structure Of Cilia, Robert O'Hagan, Malan Silva, Ken Cq Nguyen, Winnie Zhang, Sebastian Bellotti, Yasmin Ramadan, David Hall, Maureen M. Barr

Department of Biology Faculty Scholarship and Creative Works

Ciliary microtubules (MTs) are extensively decorated with post-translational modifications (PTMs), such as glutamylation of tubulin tails. PTMs and tubulin isotype diversity act as a “Tubulin Code” that regulates cytoskeletal stability and the activity of MT-associated proteins such as kinesins. We previously showed that, in C. elegans cilia, the deglutamylase CCPP-1 affects ciliary ultrastructure, localization of the TRP channel PKD-2 and the kinesin-3 KLP-6, and velocity of kinesin-2 OSM-3/KIF17, while a cell-specific α-tubulin isotype regulates ciliary ultrastructure, intraflagellar transport, and ciliary functions of extracellular vesicle (EV)-releasing neurons. Here, we examine the role of PTMs and the Tubulin Code in the cililary …

Novel Calcium-Related Targets Of Insulin In Hippocampal Neurons, Shaniya Maimaiti, Hilaree N. Frazier, Katie L. Anderson, Adam O. Ghoweri, Lawrence D. Brewer, Nada M. Porter, Olivier Thibault

Pharmacology and Nutritional Sciences Faculty Publications

Both insulin signaling disruption and Ca²⁺ dysregulation are closely related to memory loss during aging and increase the vulnerability to Alzheimer's disease (AD). In hippocampal neurons, aging-related changes in calcium regulatory pathways have been shown to lead to higher intracellular calcium levels and an increase in the Ca²⁺-dependent afterhyperpolarization (AHP), which is associated with cognitive decline. Recent studies suggest that insulin reduces the Ca²⁺-dependent AHP. Given the sensitivity of neurons to insulin and evidence that brain insulin signaling is reduced with age, insulin-mediated alterations in calcium homeostasis may underlie the beneficial actions of insulin in …

P2x2 Dominant Deafness Mutations Have No Negative Effect On Wild-Type Isoform: Implications For Functional Rescue And In Deafness Mechanism, Yan Zhu, Juline Beudez, Ning Yu, Thomas Grutter, Hong-Bo Zhao

Otolaryngology--Head & Neck Surgery Faculty Publications

The P2X2 receptor is an ATP-gated ion channel, assembled by three subunits. Recently, it has been found that heterozygous mutations of P2X2 V60L and G353R can cause autosomal dominant nonsyndromic hearing loss. However, the underlying mechanism remains unclear. The fact that heterozygous mutations cause deafness suggests that the mutations may have dominant-negative effect (DNE) on wild-type (WT) P2X2 isoforms and/or other partners leading to hearing loss. In this study, the effect of these dominant deafness P2X2 mutations on WT P2X2 was investigated. We found that sole transfection of both V60L and G353R deafness mutants could efficiently target to the plasma …

Modeling Aggregation Of Proliferating Microglia In Response To Amyloid-Beta In Dementia, Adrienne C. Kinney, Ellen R. Swanson

Spora: A Journal of Biomathematics

Amyloid-beta plaques are prominent biological markers in dementia brains. In response to plaque formation, the brain's immune cells, microglia, become reactive. Microglia are measurable cells that surround amyloid-beta plaques, indicating their location. A system of partial differential equations describes the concentration of microglia in dementia brains by incorporating chemotactic signaling. However, this system fails to incorporate increasing numbers of reactive microglia cells in response to amyloid-beta aggregation. A system of ordinary differential equations describing the number of significant cells and proteins in the brain suggests the amount of reactive microglia increases significantly during the progression of dementia. We couple these …

Low Arousal Positive Emotional Stimuli Attenuate Aberrant Working Memory Processing In Persons With Mild Cognitive Impairment, Lucas S. Broster, Shonna L. Jenkins, Sarah D. Holmes, Gregory A. Jicha, Yang Jiang

Behavioral Science Faculty Publications

Emotional enhancement effects on memory have been reported to mitigate the pathophysiology of Alzheimer’s disease (AD). However, relative to their manifestation in persons without pathologic aging, these effects may be reduced in magnitude or even deleterious, especially in tasks that more closely model ecologic memory performance. Based upon a synthesis of such reports, we hypothesized that in persons with AD low arousal positive stimuli would evoke relatively intact emotional enhancement effects, but that high arousal negative stimuli would evoke disordered emotional enhancement effects. To assess this, participants with and without mild cognitive impairment (MCI) presumed to be due to AD …

Language Experience With A Native-Language Phoneme Sequence Modulates The Effects Of Attention On Cortical Sensory Processing, Valerie L. Shafer, Monica Wagner, Jungmee Lee, Francesca Mingino, Colleen O'Brien, Adam Constantine, Mitchell Steinschneider

Publications and Research

Auditory evoked potentials (AEP) reflect spectro-temporal feature changes within the spoken word and are sufficiently reliable to probe deficits in auditory processing. The current research assessed whether attentional modulation would alter the morphology of these AEPs and whether native-language experience with phoneme sequences would influence the effects of attention. Native-English and native-Polish adults listened to nonsense word pairs that contained the phoneme sequence onsets /st/, /sət/, /pət/ that occur in both the Polish and English languages and the phoneme sequence onset /pt/ that occurs in the Polish language, but not the English language. Participants listened to word pairs within two …

Neuronal Degeneration And Short-Term Memory Impairment After Tbi, Obiamaraije Igwe

Posters-at-the-Capitol

Traumatic brain injury (TBI) was associated with impaired short-term memory with causes of vehicle accidents and falls. Protein plaques containing fibrinogen (Fg), are associated with memory loss. After TBI, Fg in blood was higher than normal (>~2 mg/ml), which resulted in increased Fg in extravascular space. Therefore, Fg bonded to its endothelial receptor intercellular adhesion molecule-1 (ICAM-1). Fg then interacted with cellular prion protein (PrPC), which had a strong effect on the loss of memory and cognition. Mechanisms of Fg and PrPC complex formation and its functional implication are not known. This present study tested the level of Fg-PrPC …

Brain Wellness: Team Leaders And Steering Committee, University Of Mississippi. Brain Wellness Constellation

Brain Wellness

No abstract provided.

Disruption Of Hippocampal Multisynaptic Networks By General Anesthetics., Min-Ching Kuo, L Stan Leung

Physiology and Pharmacology Publications

BACKGROUND: Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.

METHODS: Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).

RESULTS: Monosynaptic population excitatory postsynaptic potentials at the …

The Effect Of Co2, Intracellular Ph And Extracellular Ph On Mechanosensory Proprioceptor Responses In Crayfish And Crab, Viresh Dayaram, Cole A. Malloy, Sarah Martha, Brenda Alvarez, Ikenna Chukwudolue, Nadera Dabbain, Dlovan D.Mahmood, Slavina Goleva, Tori Hickey, Angel Ho, Molly King, Paige Kington, Matthew Mattingly, Samuel Potter, Landon Simpson, Amanda Spence, Henry Uradu, Jacob Van Doorn, Dlovan Faiq, Robin L. Cooper

Biology Faculty Publications

Proprioceptive neurons monitor the movements of limbs and joints to transduce the movements into electrical signals. These neurons function similarly in species from arthropods to humans. These neurons can be compromised in disease states and in adverse environmental conditions such as with changes in external and internal pH. We used two model preparations (the crayfish muscle receptor organ and a chordotonal organ in the limb of a crab) to characterize the responses of these proprioceptors to external and internal pH changes as well as raised CO₂. The results demonstrate the proprioceptive organs are not highly sensitive to changes …

Songbirds Work Around Computational Complexity By Learning Song Vocabulary Independently Of Sequence, Dina Lipkind, Anja T. Zai, Alexander Hanuschkin, Gary F. Marcus, Ofer Tchernichovski, Richard H.R. Hahnloser

Publications and Research

While acquiring motor skills, animals transform their plastic motor sequences to match desired targets. However, because both the structure and temporal position of individual gestures are adjustable, the number of possible motor transformations increases exponentially with sequence length. Identifying the optimal transformation towards a given target is therefore a computationally intractable problem. Here we show an evolutionary workaround for reducing the computational complexity of song learning in zebra finches. We prompt juveniles to modify syllable phonology and sequence in a learned song to match a newly introduced target song. Surprisingly, juveniles match each syllable to the most spectrally similar sound …

Chronic Traumatic Encephalopathy-Integration Of Canonical Traumatic Brain Injury Secondary Injury Mechanisms With Tau Pathology, Jacqueline R. Kulbe, Edward D. Hall

Spinal Cord and Brain Injury Research Center Faculty Publications

In recent years, a new neurodegenerative tauopathy labeled Chronic Traumatic Encephalopathy (CTE), has been identified that is believed to be primarily a sequela of repeated mild traumatic brain injury (TBI), often referred to as concussion, that occurs in athletes participating in contact sports (e.g. boxing, football, football, rugby, soccer, ice hockey) or in military combatants, especially after blast-induced injuries. Since the identification of CTE, and its neuropathological finding of deposits of hyperphosphorylated tau protein, mechanistic attention has been on lumping the disorder together with various other non-traumatic neurodegenerative tauopathies. Indeed, brains from suspected CTE cases that have come to autopsy …

Dynamic Range Of Frontoparietal Functional Modulation Is Associated With Working Memory Capacity Limitations In Older Adults, Jonathan G. Hakun, Nathan F. Johnson

Physical Therapy Faculty Publications

Older adults tend to over-activate regions throughout frontoparietal cortices and exhibit a reduced range of functional modulation during WM task performance compared to younger adults. While recent evidence suggests that reduced functional modulation is associated with poorer task performance, it remains unclear whether reduced range of modulation is indicative of general WM capacity-limitations. In the current study, we examined whether the range of functional modulation observed over multiple levels of WM task difficulty (N-Back) predicts in-scanner task performance and out-of-scanner psychometric estimates of WM capacity. Within our sample (60–77 years of age), age was negatively associated with frontoparietal modulation range. …

Low Frequency Transcranial Electrical Stimulation Does Not Entrain Sleep Rhythms Measured By Human Intracranial Recordings, Belen Lafon, Simon Henin, Yu Huang, Daniel Friedman, Lucia Melloni, Thomas Thesen, Werner Doyle, György Buzsáki, Orrin Devinsky, Lucas C. Parra, Anli A. Liu

Publications and Research

Transcranial electrical stimulation has widespread clinical and research applications, yet its effect on ongoing neural activity in humans is not well established. Previous reports argue that transcranial alternating current stimulation (tACS) can entrain and enhance neural rhythms related to memory, but the evidence from non-invasive recordings has remained inconclusive. Here, we measure endogenous spindle and theta activity intracranially in humans during low-frequency tACS and find no stable entrainment of spindle power during non-REM sleep, nor of theta power during resting wakefulness. As positive controls, we find robust entrainment of spindle activity to endogenous slow-wave activity in 66% of electrodes as …

Reliability And Concurrent Validity Of Select C3 Logix Test Components, Madeline Simon, Arthur C. Maerlender, Katelyn Metzger, Laura Decoster, Amy Hollingworth, Tamara Valovich Mcleod

Center for Brain, Biology, and Behavior: Faculty Publications

We sought to investigate the one-week and within-session reliability of the instrumented balance error scoring system test and the concurrent validity/one-week reliability of two neurocognitive assessments available through C3 Logix. (n = 37) Participants completed two balance error scoring system tests separated by the Trails A, Trails B, and Symbol Digit Modality test available through C3 Logix, and with paper and pencil. We found that the instrumented balance error scoring system test demonstrated strong one-week reliability and that neuropsychological tests available through C3 Logix show acceptable concurrent validity with standard (comparable) paper and pencil measures.

Pattern Discovery In Brain Imaging Genetics Via Scca Modeling With A Generic Non-Convex Penalty, Lei Du, Kefei Liu, Xiaohui Yao, Jingwen Yan, Shannon L. Risacher, Junwei Han, Lei Guo, Andrew J. Saykin, Li Shen, Michael W. Weiner, Paul Aisen, Ronald Petersen, Clifford R. Jack, William Jagust, John Q. Trojanowki, Arthur W. Toga, Laurel Beckett, Robert C. Green, John Morris, Leslie M. Shaw, Zaven Khachaturian, Greg Sorensen, Maria Carrillo, Lew Kuller, Marc Raichle, Steven Paul, Peter Davies, Howard Fillit, Franz Hefti, David Holtzman, Charles D. Smith, Gregory Jicha, Peter A. Hardy, Partha Sinha, Elizabeth Oates, Gary Conrad

Neurology Faculty Publications

Brain imaging genetics intends to uncover associations between genetic markers and neuroimaging quantitative traits. Sparse canonical correlation analysis (SCCA) can discover bi-multivariate associations and select relevant features, and is becoming popular in imaging genetic studies. The L1-norm function is not only convex, but also singular at the origin, which is a necessary condition for sparsity. Thus most SCCA methods impose ℓ₁-norm onto the individual feature or the structure level of features to pursuit corresponding sparsity. However, the ℓ₁-norm penalty over-penalizes large coefficients and may incurs estimation bias. A number of non-convex penalties are proposed to reduce …

Environmental Effects On Drosophila Brain Development And Learning, Xia Wang, Amei Amei, J. Steven De Belle, Stephen P. Roberts

School of Medicine Faculty Research

Brain development and behavior are sensitive to a variety of environmental influences including social interactions and physicochemical stressors. Sensory input in situ is a mosaic of both enrichment and stress, yet little is known about how multiple environmental factors interact to affect brain anatomical structures, circuits and cognitive function. In this study, we addressed these issues by testing the individual and combined effects of sub-adult thermal stress, larval density and early-adult living spatial enrichment on brain anatomy and olfactory associative learning in adult Drosophila melanogaster. In response to heat stress, the mushroom bodies (MBs) were the most volumetrically impaired among …

A Latent Propriospinal Network Can Restore Diaphragm Function After High Cervical Spinal Cord Injury, Jared M. Cregg, Kevin A. Chu, Lydia E. Hager, Rachel S. J. Maggard, Daimen R. Stoltz, Michaela Edmond, Warren J. Alilain, Polyxeni Philippidou, Lynn T. Landmesser, Jerry Silver

Spinal Cord and Brain Injury Research Center Faculty Publications

Spinal cord injury (SCI) above cervical level 4 disrupts descending axons from the medulla that innervate phrenic motor neurons, causing permanent paralysis of the diaphragm. Using an ex vivo preparation in neonatal mice, we have identified an excitatory spinal network that can direct phrenic motor bursting in the absence of medullary input. After complete cervical SCI, blockade of fast inhibitory synaptic transmission caused spontaneous, bilaterally coordinated phrenic bursting. Here, spinal cord glutamatergic neurons were both sufficient and necessary for the induction of phrenic bursts. Direct stimulation of phrenic motor neurons was insufficient to evoke burst activity. Transection and pharmacological manipulations …

Early And Late Components Of Eeg Delay Activity Correlate Differently With Scene Working Memory Performance, Timothy M. Ellmore, Kenneth Ng, Chelsea P. Reichert

Publications and Research

Sustained and elevated activity during the working memory delay period has long been considered the primary neural correlate for maintaining information over short time intervals. This idea has recently been reinterpreted in light of findings generated from multiple neural recording modalities and levels of analysis. To further investigate the sustained or transient nature of activity, the temporal-spectral evolution (TSE) of delay period activity was examined in humans with high density EEG during performance of a Sternberg working memory paradigm with a relatively long six second delay and with novel scenes as stimuli. Multiple analyses were conducted using different trial window …

Distinct Combinations Of Premotor Neuronal Activation Encode Multimodal Information And Predict Motor Output, Chris Goldsmith

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.