Neurosciences Commons^™

Prefrontal Activity Links Nonoverlapping Events In Memory, Marieke R. Gilmartin, Hiroyuki Miyawaki, Fred J. Helmstetter, Kamran Diba

Biomedical Sciences Faculty Research and Publications

The medial prefrontal cortex (mPFC) plays an important role in memory. By maintaining a working memory buffer, neurons in prelimbic (PL) mPFC may selectively contribute to learning associations between stimuli that are separated in time, as in trace fear conditioning (TFC). Until now, evidence for this bridging role was largely descriptive. Here we used optogenetics to silence neurons in the PL mPFC of rats during learning in TFC. Memory formation was prevented when mPFC was silenced specifically during the interval separating the cue and shock. Our results provide support for a working memory function for these cells and indicate that …

Dynamic And Opposing Adjustment Of Movement Cancellation And Generation In An Oculomotor Countermanding Task., Brian D Corneil, Joshua C Cheng, Samanthi C Goonetilleke

Brain and Mind Institute Researchers' Publications

Adaptive adjustments of strategies help optimize behavior in a dynamic and uncertain world. Previous studies in the countermanding (or stop-signal) paradigm have detailed how reaction times (RTs) change with trial sequence, demonstrating adaptive control of movement generation. Comparatively little is known about the adaptive control of movement cancellation in the countermanding task, mainly because movement cancellation implies the absence of an outcome and estimates of movement cancellation require hundreds of trials. Here, we exploit a within-trial proxy of movement cancellation based on recordings of neck muscle activity while human subjects attempted to cancel large eye-head gaze shifts. On a subset …

Restricted Likelihood Ratio Tests For Functional Effects In The Functional Linear Model, Bruce J. Swihart, Jeff Goldsmith, Ciprian M. Crainiceanu

Johns Hopkins University, Dept. of Biostatistics Working Papers

The goal of our article is to provide a transparent, robust, and computationally feasible statistical approach for testing in the context of scalar-on-function linear regression models. In particular, we are interested in testing for the necessity of functional effects against standard linear models. Our methods are motivated by and applied to a large longitudinal study involving diffusion tensor imaging of intracranial white matter tracts in a susceptible cohort. In the context of this study, we conduct hypothesis tests that are motivated by anatomical knowledge and which support recent findings regarding the relationship between cognitive impairment and white matter demyelination. R-code …

Intracranial Injection Of Gammagard, A Human Ivig, Modulates The Inflammatory Response Of The Brain And Lowers AΒ In App/Ps1 Mice Along A Different Time Course Than Anti-AΒ Antibodies, Tiffany L. Sudduth, Abigail Greenstein, Donna M. Wilcock

Sanders-Brown Center on Aging Faculty Publications

Gammagard IVIg is a therapeutic approach to treat Alzheimer's disease currently in phase 3 clinical trials. Despite the reported efficacy of the approach the mechanism of action is poorly understood. We have previously shown that intracranial injection of anti-Aβ antibodies into the frontal cortex and hippocampus reveals important information regarding the time course of events once the agent is in the brain. In the current study we compared IVIg, mouse-pooled IgG, and the anti-Aβ antibody 6E10 injected intracranially into the frontal cortex and hippocampus of 7-month-old APP/PS1 mice. We established a time course of events ranging from 1 …

Two Distinct Ipsilateral Cortical Representations For Individuated Finger Movements., Jörn Diedrichsen, Tobias Wiestler, John W Krakauer

Brain and Mind Institute Researchers' Publications

Movements of the upper limb are controlled mostly through the contralateral hemisphere. Although overall activity changes in the ipsilateral motor cortex have been reported, their functional significance remains unclear. Using human functional imaging, we analyzed neural finger representations by studying differences in fine-grained activation patterns for single isometric finger presses. We demonstrate that cortical motor areas encode ipsilateral movements in 2 fundamentally different ways. During unimanual ipsilateral finger presses, primary sensory and motor cortices show, underneath global suppression, finger-specific activity patterns that are nearly identical to those elicited by contralateral mirror-symmetric action. This component vanishes when both motor cortices are …

Nr2a- And Nr2b-Containing Nmda Receptors In The Prelimbic Medial Prefrontal Cortex Differentially Mediate Trace, Delay, And Contextual Fear Conditioning, Marieke R. Gilmartin, Janine L. Kwapis, Fred J. Helmstetter

Biomedical Sciences Faculty Research and Publications

Activation of N-methyl-D-aspartate receptors (NMDAR) in the prelimbic medial prefrontal cortex (PL mPFC) is necessary for the acquisition of both trace and contextual fear memories, but it is not known how specific NR2 subunits support each association. The NR2B subunit confers unique properties to the NMDAR and may differentially regulate these two fear memories. Here we show that NR2A-containing NMDARs mediate trace, delay, and contextual fear memories, but NR2B-containing NMDARs are required only for trace conditioning, consistent with a role for PL mPFC in working memory.

Prefrontal Neurons Of Opposite Spatial Preference Display Distinct Target Selection Dynamics., Therese Lennert, Julio C Martinez-Trujillo

Brain and Mind Institute Researchers' Publications

Neurons in the primate dorsolateral prefrontal cortex (dlPFC) of one hemisphere are selective for the location of attended targets in both visual hemifields. Whether dlPFC neurons with selectivity for opposite hemifields directly compete with each other for target selection or instead play distinct roles during the allocation of attention remains unclear. We explored this issue by recording neuronal responses in the right dlPFC of two macaques while they allocated attention to a target in one hemifield and ignored a distracter on the opposite side. Forty-nine percent of the recorded neurons were target location selective. Neurons selective for contralateral targets (58%) …

Decoding The Neural Mechanisms Of Human Tool Use., Jason P Gallivan, D Adam Mclean, Kenneth F Valyear, Jody C Culham

Brain and Mind Institute Researchers' Publications

Sophisticated tool use is a defining characteristic of the primate species but how is it supported by the brain, particularly the human brain? Here we show, using functional MRI and pattern classification methods, that tool use is subserved by multiple distributed action-centred neural representations that are both shared with and distinct from those of the hand. In areas of frontoparietal cortex we found a common representation for planned hand- and tool-related actions. In contrast, in parietal and occipitotemporal regions implicated in hand actions and body perception we found that coding remained selectively linked to upcoming actions of the hand whereas …

Cannabis And Psychosis: Transition To Psychosis, Amresh Srivastava, Kristen , Terpstra, Yves Bureau

Data and Test Instruments

Cannabis has been implicated as a risk factor for the development of schizophrenia, however, but the pathway of cannabis causing psychosis is not well understood. It appears that cannabis does not cause any structural changes per say but deficits in areas of the brain responsible for memory and emotion do show some changes. Recent studies suggest that cannabinoids such as CB1 have a pharmacological profile similar to that of atypical antipsychotic drugs. This mechanisms may involve dopamine, GABA, and glutamate neurotransmission; It is still not known if these changes are transitory or permanent, and whether or not they contribute to …

The Human Brain Processes Syntax In The Absence Of Conscious Awareness., Laura Batterink, Helen J Neville

Brain and Mind Institute Researchers' Publications

Syntax is the core computational component of language. A longstanding idea about syntactic processing is that it is generally not available to conscious access, operating autonomously and automatically. However, there is little direct neurocognitive evidence on this issue. By measuring event-related potentials while human observers performed a novel cross-modal distraction task, we demonstrated that syntactic violations that were not consciously detected nonetheless produced a characteristic early neural response pattern, and also significantly delayed reaction times to a concurrent task. This early neural response was distinct from later neural activity that was observed only to syntactic violations that were consciously detected. …

Evidence For Covalent Linkage Between Some Plasma Α2-Antiplasmin Molecules And Aα Chains Of Circulating Fibrinogen, Michael W. Mosesson, Trudy Holyst, Irene Hernandez, Kevin R. Siebenlist

Biomedical Sciences Faculty Research and Publications

Plasma alpha₂-antiplasmin (α₂AP) is a single-chain serine protease inhibitor acting mainly through the fibrinolytic system. Its physiological importance is underscored by the observation that homozygous α₂AP deficiency results in a severe hemorrhagic disorder due to rapid fibrin clot lysis (hyperfibrinolysis).

The Effects Of Chronic Calcium Dysregulation On Behavioral And Pathological Features Of Alzheimer's Disease, Jonathan Sabbagh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alzheimer's disease (AD) is a progressive neurodegenerative disorder whose etiology is unknown. Recent studies have implicated alterations in calcium homeostasis as a pathogenic contributor to AD. Calcium dysregulation has been observed in aged and AD brains, an event which could potentially facilitate the development of multiple pathologies observed in AD. Specifically, disrupting intracellular calcium levels in vitro has been demonstrated to increase amyloid-beta (Aβ) production, tau phosphorylation, and neuronal loss. However, there is a paucity of data on the behavioral and biochemical consequences of chronic in vivo perturbation of calcium homeostasis. In a series of experiments designed to evaluate the …

Activation And Suppression Of The Innate Immune System: Effects On Alcohol Intake, Marjorie Levinstein

Seton Hall University Dissertations and Theses (ETDs)

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Using Over-The-Counter Ear Filters As A Treatment To Improve Dizziness And Balance In Patients Diagnosed With A Traumatic Brain, Brandy Sue Whitney

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background and purpose: People diagnosed with a Traumatic Brain Injury (TBI) usually have physical, cognitive, emotional, and sleep deficits. Sensory overload is a common symptom of TBI. One treatment prescribed for sensory overload is over the counter ear filters. Ear filters have shown to decrease sensory input. Could the ear filters have an effect on balance and dizziness without much cost to the patient or the clinic?

Subjects: Patients diagnosed with a mild or moderate brain injury, ages of 18-65 years old. They needed to be medically stable, potential to walk, and have complaints of dizziness and/or balance problems.

Methods: …

Concurrent Neurological And Behavioral Assessment Of Number Line Estimation Performance In Children And Adults, Joseph Michael Baker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the brain’s response to common math-learning activities may help improve math education. For example, by imaging the brains of typically developing children and adults throughout a number line estimation task, it is possible to establish a baseline of what “typical” brains do in such situations. Thus, comparisons may be made to determine the degree to which brain functioning differs between typical and atypical math learners. Moreover, by identifying methods that may increase the brain’s response to real-world math activities, it may be possible to improve the math learning process for typical and atypical learners alike.

Brain imaging devices such …

Shared Neural Substrates Of Emotionally Enhanced Perceptual And Mnemonic Vividness, Rebecca M. Todd, Taylor W. Schmitz, Josh Susskind, Adam K. Anderson

Brain and Mind Institute Researchers' Publications

It is well known that emotionally salient events are remembered more vividly than mundane ones. Our recent research has demonstrated that such memory vividness is due in part to the subjective experience of emotional events as more perceptually vivid, an effect we call emotion-enhanced vividness, or EEV. The present study built on previously reported research in which fMRI data were collected while participants rated relative levels of visual noise overlaid on emotionally salient and neutral images. Ratings of greater EEV were associated with greater activation in the amygdala, visual cortex, and posterior insula. In the present study, we measured BOLD …

A Study Of Small Rnas From Cerebral Neocortex Of Pathology-Verified Alzheimer's Disease, Dementia With Lewy Bodies, Hippocampal Sclerosis, Frontotemporal Lobar Dementia, And Non-Demented Human Controls, Sébastien S. Hébert, Wang-Xia Wang, Qi Zhu, Peter T. Nelson

Sanders-Brown Center on Aging Faculty Publications

MicroRNAs (miRNAs) are small (20-22 nucleotides) regulatory non-coding RNAs that strongly influence gene expression. Most prior studies addressing the role of miRNAs in neurodegenerative diseases (NDs) have focused on individual diseases such as Alzheimer's disease (AD), making disease-to-disease comparisons impossible. Using RNA deep sequencing, we sought to analyze in detail the small RNAs (including miRNAs) in the temporal neocortex gray matter from non-demented controls (n = 2), AD (n = 5), dementia with Lewy bodies (n = 4), hippocampal sclerosis of aging (n = 4), and frontotemporal lobar dementia (FTLD) (n = 5) cases, together accounting for the most prevalent …

Microglial Disruption In Young Mice With Early Chronic Exposure To Lead, Christina Sobin, Mayra Flores Montoya, Natali Parisi, Tanner Schaub, Miguel Cervantes, Rodrigo Armijos

Selected Works Temporary Series

The mechanisms by which early chronic lead (Pb) exposure alters brain development have not been identified. We examined neuroimmune system effects in C57BL/6J mice with Pb exposure, including levels that may be common among children in lower socioeconomic income environments. Pups were exposed via dams’ drinking water from birth to post-natal day 28 to low, high or no Pb conditions. We compared gene expression of neuroinflammatory markers (study 1); and microglial mean cell body volume and mean cell body number in dentate gyrus, and dentate gyrus volume (study 2). Blood Pb levels in exposed animals at sacrifice (post-natal day 28) …

The P38Α Mapk Regulates Microglial Responsiveness To Diffuse Traumatic Brain Injury, Adam D. Bachstetter, Rachel K. Rowe, Machi Kaneko, Danielle Goulding, Jonathan Lifshitz, Linda J Van Eldik

Sanders-Brown Center on Aging Faculty Publications

Neuropathology after traumatic brain injury (TBI) is the result of both the immediate impact injury and secondary injury mechanisms. Unresolved post-traumatic glial activation is a secondary injury mechanism that contributes to a chronic state of neuroinflammation in both animal models of TBI and human head injury patients. We recently demonstrated, using in vitro models, that p38α MAPK signaling in microglia is a key event in promoting cytokine production in response to diverse disease-relevant stressors and subsequent inflammatory neuronal dysfunction. From these findings, we hypothesized that the p38α signaling pathway in microglia could be contributing to the secondary neuropathologic sequelae after …

The Effects Of Mindfulness Meditation On Rumination In Depressed People, Rachel A. Sluder

Honors Theses and Capstones

Mindfulness meditation is a practice of focus, awareness, and non-judgmental acceptance of one's thoughts (Deyo et al., 2009; Kenny et al., 2007). Rumination is a maladaptive pattern of thought that is common in people with depression and other mood disorders. It can lead to further episodes of depression, and can be very destructive in that way (Nolen-Hoeksema, 2008). This paper reviews several studies on mindfulness meditation, depression, and rumination, with a focus on certain areas and phenomena such as alpha asymmetry (Keune et al 2013) and gamma band activity (Berkovich-Ohana et al., 2012). Modalities such as fMRI and EEG are …

Health-Related Resource Use And Costs In Elderly Adults With And Without Mild Cognitive Impairment, Carolyn Zhu, Peter J. Whitehouse, Marian B. Patterson

Faculty Scholarship

Objectives To assess differences in resource use and cost between older adults with and without mild cognitive impairment (MCI) over time. Design Multicenter, longitudinal study. Setting Sixty-eight Alzheimer's Disease Cooperative Study (ADCS) sites in the United States. Participants Two hundred fifty-nine individuals diagnosed with MCI and 107 cognitively normal elderly adults followed annually for 3 years. Measurements The Resource Use Instrument (RUI) was used to capture medical and nonmedical care use. Generalized linear latent and mixed models were used to estimate differences in resource use and costs in older adults with and without MCI after controlling for clinical and demographic …

The Challenge Of Neuroscience Growing Pains: Optimizing Patient Flow, Holly Tavianini Rn, Bsn, Mshsa, Cnrn, Donald J. Butz Rn, Cnrn

Patient Care Services / Nursing

No abstract provided.

Diagnosis And Evaluation Of Peripheral Neuropathies, Jay D. Varrato Do

Neurology Update for the Non-Neurologist

No abstract provided.

Diagnosis And Treatment Options For Multiple Sclerosis, Gary Clauser Md

Neurology Update for the Non-Neurologist

No abstract provided.

Current Standards For Treatment Of Stroke: Management Of Acute Ischemic Stroke, John E. Castaldo Md

Neurology Update for the Non-Neurologist

No abstract provided.

Diagnosis, Evaluation And Treatments For Dementia, John W. Margraf Md

Neurology Update for the Non-Neurologist

No abstract provided.

Treatment Options For Seizures: Practical Points In Epilepsy Management, Soraya E. Jiménez Md

Neurology Update for the Non-Neurologist

No abstract provided.

Diagnosis, Assessment And Evaluation For Seizures, John W. Margraf Md

Neurology Update for the Non-Neurologist

No abstract provided.

Special Populations And Considerations In Migraine Therapy, Gary Clauser Md

Neurology Update for the Non-Neurologist

No abstract provided.

Migraine Diagnosis And Treatment, Vitaliy Koss Md

Neurology Update for the Non-Neurologist

No abstract provided.