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Clinically Silent Alzheimer's And Vascular Pathologies Influence Brain Networks Supporting Executive Function In Healthy Older Adults, Brian T. Gold, Christopher A. Brown, Jonathan G. Hakun, Leslie M. Shaw, John Q. Trojanowski, Charles D. Smith

Neuroscience Faculty Publications

Aging is associated with declines in executive function. We examined how executive functional brain systems are influenced by clinically silent Alzheimer’s disease (AD) pathology and cerebral white matter hyperintensities (WMHs). Twenty-nine younger adults and thirty-four cognitively normal older adults completed a working memory paradigm while functional magnetic resonance imaging (fMRI) was performed. Older adults further underwent lumbar cerebrospinal fluid (CSF) draw for assessment of AD pathology and FLAIR imaging for assessment of WMHs. Accurate working memory performance in both age groups was associated with high fronto-visual functional connectivity (fC). However, in older adults, higher expression of fronto-visual fC was linked …

Acute Treatment With Doxorubicin Affects Glutamate Neurotransmission In The Mouse Frontal Cortex And Hippocampus, Theresa Currier Thomas, Joshua A. Beitchman, Francois Pomerleau, Teresa Noel, Paiboon Jungsuwadee, D. Allan Butterfield, Daret K. St. Clair, Mary Vore, Greg A. Gerhardt

Spinal Cord and Brain Injury Research Center Faculty Publications

Doxorubicin (DOX) is a potent chemotherapeutic agent known to cause acute and long-term cognitive impairments in cancer patients. Cognitive function is presumed to be primarily mediated by neuronal circuitry in the frontal cortex (FC) and hippocampus, where glutamate is the primary excitatory neurotransmitter. Mice treated with DOX (25 mg/kg i.p.) were subjected to in vivo recordings under urethane anesthesia at 24h post-DOX injection or 5 consecutive days of cognitive testing (Morris Water Maze; MWM). Using novel glutamate-selective microelectrode arrays, amperometric recordings measured parameters of extracellular glutamate clearance and potassium-evoked release of glutamate within the medial FC and dentate gyrus (DG) …

Combined Mnemonic Strategy Training And High-Definition Transcranial Direct Current Stimulation For Memory Deficits In Mild Cognitive Impairment, Benjamin M. Hampstead, Krishnankutty Sathian, Marom Bikson, Anthony Y. Stringer

Publications and Research

Introduction: Memory deficits characterize Alzheimer’s dementia and the clinical precursor stage known as mild cognitive impairment. Nonpharmacologic interventions hold promise for enhancing functioning in these patients, potentially delaying functional impairment that denotes transition to dementia. Previous findings revealed that mnemonic strategy training (MST) enhances long-term retention of trained stimuli and is accompanied by increased blood oxygen level–dependent signal in the lateral frontal and parietal cortices as well as in the hippocampus. The present study was designed to enhance MST generalization, and the range of patients who benefit, via concurrent delivery of transcranial direct current stimulation (tDCS).

Methods: This protocol describes …

Species Differences In Egocentric Navigation: The Effect Of Burrowing Ecology On A Spatial Cognitive Trait In Mice, Jason N. Bruck, Noah A. Allen, Kelsey E. Brass, Brian A. Horn, Polly Campbell

Faculty Publications

© 2017 The Association for the Study of Animal Behaviour Efficient navigation is a critical component of fitness for most animals. While most species use a combination of allocentric (external) and egocentric (internal) cues to navigate through their environment, subterranean environments present a unique challenge in that visually mediated allocentric cues are unavailable. The relationship between egocentric spatial cognition and species differences in ecology is surprisingly understudied. We used a maze-learning task to test for differences in egocentric navigation between two closely related species of mice, the eastern house mouse, Mus musculus musculus, and the mound-building mouse, Mus spicilegus. The …

Functional Human Grin2b Promoter Polymorphism And Variation Of Mental Processing Speed In Older Adults, Yang Jiang, Ming Kuan Lin, Gregory A. Jicha, Xiuhua Ding, Sabrina L. Mcilwrath, David W. Fardo, Lucas S. Broster, Frederick A. Schmitt, Richard J. Kryscio, Robert H. Lipsky

Behavioral Science Faculty Publications

We investigated the role of a single nucleotide polymorphism rs3764030 (G > A) within the human GRIN2B promoter in mental processing speed in healthy, cognitively intact, older adults. In vitro DNA-binding and reporter gene assays of different allele combinations in transfected cells showed that the A allele was a gain-of-function variant associated with increasing GRIN2B mRNA levels. We tested the hypothesis that individuals with A allele will have better memory performance (i.e. faster reaction times) in older age. Twenty-eight older adults (ages 65-86) from a well-characterized longitudinal cohort were recruited and performed a modified delayed match-to-sample task. The rs3764030 polymorphism was …

Neuroimaging Biomarkers Of Caloric Restriction On Brain Metabolic And Vascular Functions, Ai-Ling Lin, Ishita Parikh, Jared D. Hoffman, David Ma

Sanders-Brown Center on Aging Faculty Publications

Purpose of Review

Non-invasive neuroimaging methods have been developed as powerful tools for identifying in vivo brain functions for studies in humans and animals. Here, we review the imaging biomarkers that are being used to determine the changes within brain metabolic and vascular functions induced by caloric restriction (CR) and their potential usefulness for future studies with dietary interventions in humans.

Recent Findings

CR causes an early shift in brain metabolism of glucose to ketone bodies and enhances ATP production, neuronal activity, and cerebral blood flow (CBF). With age, CR preserves mitochondrial activity, neurotransmission, CBF, and spatial memory. CR also …

Hippocampal Contribution To Context Encoding Across Development Is Disrupted Following Early-Life Adversity, Hilary K. Lambert, Margaret A. Sheridan, Kelly A. Sambrook, Maya L. Rosen, Mary K. Askren, Katie A. Mclaughlin

Neuroscience: Faculty Publications

Context can drastically influence responses to environmental stimuli. For example, a gunshot should provoke a different response at a public park than a shooting range. Little is known about how contextual processing and neural correlates change across human development or about individual differences related to early environmental experiences. Children (N = 60; 8–19 years, 24 exposed to interpersonal violence) completed acon text encoding task during fMRI scanning using a delayed match-to-sample design with neutral, happy, and angry facial cues embedded in realistic background scenes. Outside the scanner, participants completed a memory test for context-face pairings. Context memory and neural correlates …

A Cognitive Electrophysiological Signature Differentiates Amnestic Mild Cognitive Impairment From Normal Aging, Juan Li, Lucas S. Broster, Gregory A. Jicha, Nancy B. Munro, Frederick A. Schmitt, Erin L. Abner, Richard J. Kryscio, Charles D. Smith, Yang Jiang

Behavioral Science Faculty Publications

Background: Noninvasive and effective biomarkers for early detection of amnestic mild cognitive impairment (aMCI) before measurable changes in behavioral performance remain scarce. Cognitive event-related potentials (ERPs) measure synchronized synaptic neural activity associated with a cognitive event. Loss of synapses is a hallmark of the neuropathology of early Alzheimer’s disease (AD). In the present study, we tested the hypothesis that ERP responses during working memory retrieval discriminate aMCI from cognitively normal controls (NC) matched in age and education.

Methods: Eighteen NC, 17 subjects with aMCI, and 13 subjects with AD performed a delayed match-to-sample task specially designed not only to be …

Pearls And Perils Of Pupillometry Using A Webcam, Mason Kadem, Rhodri Cusack

Undergraduate Honors Posters

Current methods to measure infants’ cognitive repertoire (i.e., collection of cognitive abilities) are limited. Previous testing paradigms required acquisition of non-age contextualized responses, and relied on measures that involved acquisition of other functions (e.g., language, motor). In addition to response limitations, cognitive functions may be difficult to observe in infants due to the difficulty in infant recruitment. Online testing has increased infant recruitment efforts and physiological responses have bypassed the motor, behavioural and linguistic limitations of infants. Recently, it has been shown that heart rate measures can be acquired through a webcam. Another feasible and reliable physiological measure is pupillometery, …