Life Sciences Commons^™

Jun Upregulation Drives Aberrant Transposable Element Mobilization, Associated Innate Immune Response, And Impaired Neurogenesis In Alzheimer’S Disease, Chiara Scopa, Samantha Barnada, Maria Cicardi, Mo Singer, Davide Trotti, Marco Trizzino

Farber Institute for Neuroscience Faculty Papers

Adult neurogenic decline, inflammation, and neurodegeneration are phenotypic hallmarks of Alzheimer's disease (AD). Mobilization of transposable elements (TEs) in heterochromatic regions was recently reported in AD, but the underlying mechanisms are still underappreciated. Combining functional genomics with the differentiation of familial and sporadic AD patient derived-iPSCs into hippocampal progenitors, CA3 neurons, and cerebral organoids, we found that the upregulation of the AP-1 subunit, c-Jun, triggers decondensation of genomic regions containing TEs. This leads to the cytoplasmic accumulation of HERVK-derived RNA-DNA hybrids, the activation of the cGAS-STING cascade, and increased levels of cleaved caspase-3, suggesting the initiation of programmed cell death …

An Erp Measure Of Non-Conscious Memory Reveals Dissociable Implicit Processes In Human Recognition Using An Open-Source Automated Analytic Pipeline, Richard J. Addante, Javier Lopez-Calderon, Nathan Allen, Carter Luck, Alana Muller, Lindsey Sirianni, Cory S. Inman, Daniel L. Drake

Psychology Student Publications

Non-conscious processing of human memory has traditionally been difficult to objectively measure and thus understand. A prior study on a group of hippocampal amnesia (N = 3) patients and healthy controls (N = 6) used a novel procedure for capturing neural correlates of implicit memory using event-related potentials (ERPs): old and new items were equated for varying levels of memory awareness, with ERP differences observed from 400 to 800 ms in bilateral parietal regions that were hippocampal-dependent. The current investigation sought to address the limitations of that study by increasing the sample of healthy subjects (N = …

Glutamate, And Its Relationship To Task-Induced Functional Connectivity In The Human Brain: A Focus On Schizophrenia, Kathleen Liu Young, John Kopchick, Jeffrey Stanley, Vaibhav Diwadkar

Medical Student Research Symposium

Glutamate is the brain’s major excitatory neurotransmitter mediating both neuroplasticity and network function (Zhou & Danbolt, 2014). Basal glutamate (Glu) measured using proton magnetic resonance spectroscopy (1H-MRS) provides insight into a region’s density of neuropil related to the glutamatergic system. Moreover, given the role of glutamate in mediating brain network function, Glu levels may play a role in the brain’s functional connectivity (FC), which is typically estimated from functional magnetic resonance imaging (fMRI) time series data. These questions converge when considering the clinical syndrome of schizophrenia (SCZ). Patients with SCZ show abnormalities in basal Glu in the hippocampus and prefrontal …

Case Study: Effects Of Ultrasonic Vocalizations On Rat Behavior And Place Cell Remapping In The Hippocampus, Qingli Hu

Honors Scholar Theses

Spatial information is known to be encoded in the hippocampus, and small changes in the environment can alter the way that it is represented by our hippocampal place cells in a process called remapping. Hearing is an important sense that can be used to orient ourselves and react to the environment accordingly. In this case study, a rat model is used to test the effects of emotional auditory stimuli, behaviorally significant ultrasonic vocalizations (USVs) (50 kHz, emitted during play; 22 kHz, emitted during danger), on rat behavior on a linear track and place cell remapping in the hippocampus. Behaviorally, it …

Therapeutic Treatment With The Anti-Inflammatory Drug Candidate Mw151 May Partially Reduce Memory Impairment And Normalizes Hippocampal Metabolic Markers In A Mouse Model Of Comorbid Amyloid And Vascular Pathology, David J. Braun, David K. Powell, Christopher J. Mclouth, Saktimayee M. Roy, D. Martin Watterson, Linda J. Van Eldik

Neuroscience Faculty Publications

Alzheimer's disease (AD) is the leading cause of dementia in the elderly, but therapeutic options are lacking. Despite long being able to effectively treat the ill-effects of pathology present in various rodent models of AD, translation of these strategies to the clinic has so far been disappointing. One potential contributor to this situation is the fact that the vast majority of AD patients have other dementia-contributing comorbid pathologies, the most common of which are vascular in nature. This situation is modeled relatively infrequently in basic AD research, and almost never in preclinical studies. As part of our efforts to develop …

Contributions Of Emotion Regulation And Brain Structure And Function To Adolescent Internalizing Problems And Stress Vulnerability During The Covid-19 Pandemic: A Longitudinal Study, David G. Weissman, Alexandra M. Rodman, Maya L. Rosen, Steven Kasparek, Makeda Mayes, Margaret A. Sheridan, Lilliana J. Lengua, Andrew N. Meltzoff, Katie A. Mclaughlin

Neuroscience: Faculty Publications

Background: Adolescence is a period of increased vulnerability for internalizing problems, particularly following stressful life events. We examined how emotion regulation and brain structure and function were associated with internalizing problems during the COVID-19 pandemic and moderated the association between pandemic-related stressors and internalizing problems. Methods: Data are from a longitudinal sample (N = 145, age range, 10–15 years) strategically assessed at 3 crucial time points: before the COVID-19 pandemic, early during the stay-at-home order period, and again 6 months later. We examined associations of amygdala and hippocampal volume and amygdala activation during an emotional processing task before the pandemic, …

Investigation Of Memory Related Cortical Thalamic Circuitry In The Human Brain, Puck C. Reeders

FIU Electronic Theses and Dissertations

This dissertation examined the role of medial prefrontal cortex (mPFC) and the hippocampus (HC) in episodic memory, and provides a novel approach to identify the midline thalamus mediating mPFC-HC interactions in humans. The mPFC and HC are critical to the temporal organization of episodic memory, and these interactions are disrupted in several mental health and neurological disorders. In the first study, I provide evidence that the mPFC is involved in ordinal retrieval, and the HC is active in temporal context retrieval in remembering the order of when events happen. In the second study, I focus on the anatomical basis of …

Placenta-Expanded Stromal Cell Therapy In A Rodent Model Of Simulated Weightlessness, Amber M. Paul, Linda Rubinstein, Charles Houseman, Metadel Abegaz, Steffy Tabares Ruiz

Publications

Long duration spaceflight poses potential health risks to astronauts during flight and re-adaptation after return to Earth. There is an emerging need for NASA to provide successful and reliable therapeutics for long duration missions when capability for medical intervention will be limited. Clinically relevant, human placenta-derived therapeutic stromal cells (PLX-PAD) are a promising therapeutic alternative. We found that treatment of adult female mice with PLX-PAD near the onset of simulated weightlessness by hindlimb unloading (HU, 30 d) was well-tolerated and partially mitigated decrements caused by HU. Specifically, PLX-PAD treatment rescued HU-induced thymic atrophy, and mitigated HU-induced changes in percentages of …

Wild Mice With Different Social Network Sizes Vary In Brain Gene Expression, Patricia C. Lopes, Barbara König

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Background

Appropriate social interactions influence animal fitness by impacting several processes, such as mating, territory defense, and offspring care. Many studies shedding light on the neurobiological underpinnings of social behavior have focused on nonapeptides (vasopressin, oxytocin, and homologues) and on sexual or parent-offspring interactions. Furthermore, animals have been studied under artificial laboratory conditions, where the consequences of behavioral responses may not be as critical as when expressed under natural environments, therefore obscuring certain physiological responses. We used automated recording of social interactions of wild house mice outside of the breeding season to detect individuals at both tails of a distribution …

Remapping Of Place Cells In The Dorsal And Ventral Hippocampus In Response To Environmental Change, Aditi Anam

Honors Scholar Theses

The hippocampus is an important brain structure involved in memory and navigation of both rats and humans. Neurons in the hippocampus can be “spatially” tuned, meaning they fire in specific physical locations. These spatially tuned cells are referred to as place cells. Collectively, they are thought to provide a map-like representation of the environment around us. If the environment is changed, some place cells can adjust by “remapping”, or altering their firing patterns. There are multiple sub-regions within the hippocampus. During experiments, cells were recorded simultaneously from the dorsal and ventral hippocampus of rats running on a track for food …

Sexually Dimorphic Alterations In Brain Morphology Of Astrocyte Conditional System Xc- Knockout Mice, Gabrielle Emily Samulewicz

Biology - All Scholarship

Astrocytes play a vital role in orchestrating the precise brain wiring that occurs during development and are essential for maintaining homeostasis into adulthood. The cystine/glutamate antiporter, system xc-, in the central nervous system is especially abundant in astrocytes and itself is known to contribute importantly to the basal extracellular glutamate concentration as well as the intracellular and extracellular glutathione levels, either of which, if perturbed, could alter brain development and/or contribute to degeneration. Thus, to determine whether loss of astrocyte system xc- might alter brain morphology, I studied a conditional astrocyte system xc- knockout mouse (AcKO). Tissue was harvested from …

Effect Of Reduced Neurogenesis On Microglial Activation, Amelia Smith

Honors Scholars Collaborative Projects

The geriatric population of America has grown exponentially in the past century. Health degradations and expensive medical care are characteristic of this population with many of these costs due to age-related cognitive decline. It is essential to completely understand the mechanisms of normal and abnormal aging in the search for treatments for cognitive decline. A reduction of neurogenesis is a common factor in aging, but this reduction is even more drastic in individuals experiencing cognitive decline. It is unclear what effect reduced neurogenesis has on the extracellular environment, including glial cells. In particular, changes in microglial activation could be related …

Cognitively Normal Women With Alzheimer’S Disease Proteinopathy Show Relative Preservation Of Memory But Not Of Hippocampal Volume, Jessica Z.K. Caldwell, Jeffrey L. Cummings, Sarah J. Banks, Sebastian Palmqvist, Oskar Hansson

School of Medicine Faculty Publications

Background: We examined interactive effects of sex, diagnosis, and cerebrospinal fluid (CSF) amyloid beta/phosphorylated tau ratio (Aβ/P-tau) on verbal memory and hippocampal volumes. Methods: We assessed 682 participants (350 women) from BioFINDER (250 cognitively normal [CN]; and 432 symptomatic: 186 subjective cognitive decline [SCD], 246 mild cognitive impairment [MCI]). General linear models evaluated effects of Alzheimer’s disease (AD) proteinopathy (CSF Aß/p-tau ratio), diagnosis, and sex on verbal memory (ADAS-cog 10-word recall), semantic fluency (animal naming fluency), visuospatial skills (cube copy), processing speed/attention functions (Symbol Digit Modalities Test and Trail Making Part A), and hippocampal volumes. Results: Amyloid-positive (Aβ/P-tau+) CN women …

Altered Development Of Hippocampus-Dependent Associative Learning Following Early-Life Adversity, Hilary K. Lambert, Matthew Peverill, Kelly A. Sambrook, Maya L. Rosen, Margaret A. Sheridan, Katie A. Mclaughlin

Neuroscience: Faculty Publications

Little is known about how childhood adversity influences the development of learning and memory and underlying neural circuits. We examined whether violence exposure in childhood influenced hippocampus-dependent associative learning and whether differences: a) were broad or specific to threat cues, and b) exhibited developmental variation. Children (n = 59; 8–19 years, 24 violence-exposed) completed an associative learning task with angry, happy, and neutral faces paired with objects during fMRI scanning. Outside the scanner, participants completed an associative memory test for face-object pairings. Violence-exposed children exhibited broad associative memory difficulties that became more pronounced with age, along with reduced recruitment of …

Acc Theta Improves Hippocampal Contextual Processing During Remote Recall, Ryan A. Wirt, James M. Hyman

Psychology Faculty Research

Consolidation studies show that, over time, memory recall becomes independent of the medial temporal lobes. Multiple lines of research show that the medial frontal cortex, including the anterior cingulate cortex (ACC), is involved with contextual information processing and remote recall. We hypothesize that interactions between the ACC and hippocampal area CA1 will change as memories became more remote. Animals are re-exposed to multiple environments at different retention intervals. During remote recall, ACC-CA1 theta coherence increases, with the ACC leading area CA1. ACC theta regulates unit spike timing, gamma oscillations, and ensemble and single-neuron information coding in CA1. Over the course …

Disruption Of The Hippocampal And Hypothalamic Blood-Brain Barrier In A Diet-Induced Obese Model Of Type Ii Diabetes: Prevention And Treatment By The Mitochondrial Carbonic Anhydrase Inhibitor, Topiramate, Therese S. Salameh, William G. Mortell, Aric F. Logsdon, D. Allan Butterfield, William A. Banks

Chemistry Faculty Publications

Background: Type II diabetes is a vascular risk factor for cognitive impairment and increased risk of dementia. Disruption of the blood–retinal barrier (BRB) and blood–brain barrier (BBB) are hallmarks of subsequent retinal edema and central nervous system dysfunction. However, the mechanisms by which diet or metabolic syndrome induces dysfunction are not understood. A proposed mechanism is an increase in reactive oxygen species (ROS) and oxidative stress. Inhibition of mitochondrial carbonic anhydrase (mCA) decreases ROS and oxidative stress. In this study, topiramate, a mCA inhibitor, was examined for its ability to protect the BRB and BBB in diet-induced obese type II …

Contextual Fear Memory Modulates Psd95 Phosphorylation, Ampar Subunits, Pkmζ And Pi3k Differentially Between Adult And Juvenile Rats, Roseanna M. Zanca, Shirley Sanay, Jorge A. Avila, Edgar Rodriguez, Harry N. Shair, Peter A. Serrano

Publications and Research

It is well known that young organisms do not maintain memories as long as adults, but the mechanisms for this ontogenetic difference are undetermined. Previous work has revealed that the α-amino-3-hydroxy-5-methyl-4isoxazolepropionic acidreceptor (AMPAr)subunits aretraffickedinto the synaptic membranefollowing memory retrieval in adults. Additionally, phosphorylated PSD-95-pS295 promotes AMPAr stabilization at the synapse. We investigated these plasticity related proteins as potential mediators in the differential contextual stress memory retrieval capabilities observed between adult and juvenile rats. Rats were assigned to either pedestal stress (1h) or no stress control (home cage). Each animal was placed alone in an open field for 5minat the base …

Adaptation Of Microelectrode Array Technology For The Study Of Anesthesia-Induced Neurotoxicity In The Intact Piglet Brain, Emily D. Geyer, Prithvi A. Shetty, Christopher J. Suozzi, David Z. Allen, Pamela P. Benavidez, Joseph Liu, Charles N. Hollis, Greg A. Gerhardt, Jorge E. Quintero, Jason J. Burmeister, Emmett E. Whitaker

Neuroscience Faculty Publications

Every year, millions of children undergo anesthesia for a multitude of procedures. However, studies in both animals and humans have called into question the safety of anesthesia in children, implicating anesthetics as potentially toxic to the brain in development. To date, no studies have successfully elucidated the mechanism(s) by which anesthesia may be neurotoxic. Animal studies allow investigation of such mechanisms, and neonatal piglets represent an excellent model to study these effects due to their striking developmental similarities to the human brain.

This protocol adapts the use of enzyme-based microelectrode array (MEA) technology as a novel way to study the …

Binge Alcohol Exposure Causes Neurobehavioral Deficits And Gsk3Β Activation In The Hippocampus Of Adolescent Rats, Zhe Ji, Lin Yuan, Xiong Lu, Hanqing Ding, Jia Luo, Zun-Ji Ke

Pharmacology and Nutritional Sciences Faculty Publications

Heavy alcohol exposure causes profound damage to the adolescent brain, particularly the hippocampus, which underlie some behavioral deficits. However, the underlying molecular mechanisms remain inconclusive. The current study sought to determine whether binge alcohol exposure affects the hippocampus-related behaviors and key signaling proteins that may mediate alcohol neurotoxicity in adolescent rats. Alcohol exposure reduced the number of both NeuN-positive and doublecortin-positive cells in the hippocampus. Alcohol also induced neurodegeneration which was confirmed by ultrastructural analysis by electronic microscopy and was accompanied with the activation of microglia. Binge alcohol exposure impaired spatial learning and memory which was evaluated by the Morris …

Baseline White Matter Hyperintensities And Hippocampal Volume Are Associated With Conversion From Normal Cognition To Mild Cognitive Impairment In The Framingham Offspring Study., Katherine J Bangen, Sarah R Preis, Lisa Delano-Wood, Philip A Wolf, David J Libon, Mark W Bondi, Rhoda Au, Charles Decarli, Adam M Brickman

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

INTRODUCTION: We examined associations between magnetic resonance imaging (MRI) markers of cerebrovascular disease and neurodegeneration with mild cognitive impairment (MCI) diagnosis at baseline and conversion from normal cognition to MCI at follow-up.

METHODS: Framingham Offspring participants underwent brain MRI and neuropsychological assessment at baseline (n=1049) and follow-up (n=561). Participants were classified at baseline and at follow-up as cognitively normal or MCI using sensitive neuropsychological criteria. White matter hyperintensity (WMH) volume, covert brain infarcts, hippocampal volume, and total cerebral brain volume were quantified.

RESULTS: Baseline measures of WMH and hippocampal volume were associated with MCI status cross-sectionally and also with conversion …

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 …

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 …

Single-Base Resolution Mapping Of 5-Hydroxymethylcytosine Modifications In Hippocampus Of Alzheimer's Disease Subjects, Elizabeth M. Ellison, Melissa A. Bradley-Whitman, Mark A. Lovell

Chemistry Faculty Publications

Epigenetic modifications to cytosine have been shown to regulate transcription in cancer, embryonic development, and recently neurodegeneration. While cytosine methylation studies are now common in neurodegenerative research, hydroxymethylation studies are rare, particularly genome-wide mapping studies. As an initial study to analyze 5-hydroxymethylcytosine (5-hmC) in the Alzheimer’s disease (AD) genome, reduced representation hydroxymethylation profiling (RRHP) was used to analyze more than 2 million sites of possible modification in hippocampal DNA of sporadic AD and normal control subjects. Genes with differentially hydroxymethylated regions were filtered based on previously published microarray data for altered gene expression in hippocampal DNA of AD subjects. Our …

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) …

Using Enzyme-Based Biosensors To Measure Tonic And Phasic Glutamate In Alzheimer's Mouse Models, Holly C. Hunsberger, Sharay E. Setti, Ryan T. Heslin, Jorge E. Quintero, Greg A. Gerhardt, Miranda N. Reed

Neuroscience Faculty Publications

Neurotransmitter disruption is often a key component of diseases of the central nervous system (CNS), playing a role in the pathology underlying Alzheimer's disease, Parkinson's disease, depression, and anxiety. Traditionally, microdialysis has been the most common (lauded) technique to examine neurotransmitter changes that occur in these disorders. But because microdialysis has the ability to measure slow 1-20 minute changes across large areas of tissue, it has the disadvantage of invasiveness, potentially destroying intrinsic connections within the brain and a slow sampling capability. A relatively newer technique, the microelectrode array (MEA), has numerous advantages for measuring specific neurotransmitter changes within discrete …

Carisbamate Blockade Of T-Type Voltage-Gated Calcium Channels, Do Young Kim, Fang-Xiong Zhang, Stan T. Nakanishi, Timothy Mettler, Ik-Hyun Cho, Younghee Ahn, Florian Hiess, Lina Chen, Patrick G. Sullivan, S. R. Wayne Chen, Gerald W. Zamponi, Jong M. Rho

Spinal Cord and Brain Injury Research Center Faculty Publications

Objectives

Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca²⁺]_i.

Methods

We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload‐Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca²⁺]_i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T‐type voltage‐gated Ca²⁺ channels.

Results

In CA3 pyramidal neurons, kainic …

Rod-Shaped Microglia Morphology Is Associated With Aging In 2 Human Autopsy Series, Adam D. Bachstetter, Eseosa T. Ighodaro, Yasmin Hassoun, Danah Aldeiri, Janna H. Neltner, Ela Patel, Erin L. Abner, Peter T. Nelson

Spinal Cord and Brain Injury Research Center Faculty Publications

A subtype of microglia is defined by the morphological appearance of the cells as rod-shaped. Little is known about this intriguing cell type, as there are only a few case reports describing rod-shaped microglia in the neuropathological literature. Rod-shaped microglia were shown recently to account for a substantial proportion of the microglia cells in the hippocampus of both demented and cognitively intact aged individuals. We hypothesized that aging could be a defining feature in the occurrence of rod-shaped microglia. To test this hypothesis, two independent series of autopsy cases (total n=168 cases), which covered the adult lifespan from 20 – …

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 …

Are There Place Cells In The Avian Hippocampus?, David F Sherry, Stephanie L Grella, Mélanie F Guigueno, David J White, Diano F Marrone

Psychology Publications

Birds possess a hippocampus that serves many of the same spatial and mnemonic functions as the mammalian hippocampus but achieves these outcomes with a dramatically different neuroanatomical organization. The properties of spatially responsive neurons in birds and mammals are also different. Much of the contemporary interest in the role of the mammalian hippocampus in spatial representation dates to the discovery of place cells in the rat hippocampus. Since that time, cells that respond to head direction and cells that encode a grid-like representation of space have been described in the rat brain. Research with homing pigeons has discovered hippocampal cells, …

Associative Spike Timing-Dependent Potentiation Of The Basal Dendritic Excitatory Synapses In The Hippocampus In Vivo., Thomas K Fung, Clayton S Law, L Stan Leung

Physiology and Pharmacology Publications

Spike timing-dependent plasticity in the hippocampus has rarely been studied in vivo. Using extracellular potential and current source density analysis in urethane-anesthetized adult rats, we studied synaptic plasticity at the basal dendritic excitatory synapse in CA1 after excitation-spike (ES) pairing; E was a weak basal dendritic excitation evoked by stratum oriens stimulation, and S was a population spike evoked by stratum radiatum apical dendritic excitation. We hypothesize that positive ES pairing-generating synaptic excitation before a spike-results in long-term potentiation (LTP) while negative ES pairing results in long-term depression (LTD). Pairing (50 pairs at 5 Hz) at ES intervals of -10 …