Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Hippocampus

2013

Articles 1 - 9 of 9

Full-Text Articles in Life Sciences

Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry Nov 2013

Short Duration Waveforms Recorded Extracellularly From Freely Moving Rats Are Representative Of Axonal Activity, Ashlee A. Robbins, Steven E. Fox, Gregory L. Holmes, Rod C. Scott, Jeremy M. Barry

Dartmouth Scholarship

While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We report direct extracellular tetrode recordings of putative axons whose principal feature is a short duration waveform (SDW) with an average peak-trough length less than 179 μs. While SDW recordings using tetrodes have previously been treated as questionable or classified as cells, we hypothesize that they are representative of axonal activity. These waveforms have significantly shorter duration than somatic action potentials, are triphasic and are therefore similar to classic descriptions of microelectrode recordings in white matter and of in vitro action potential propagation …

Go to article

Synaptic And Systems Memory Consolidation In The Black-Capped Chickadee (Poecile Atricapillus), Matthew Barrett Oct 2013

Synaptic And Systems Memory Consolidation In The Black-Capped Chickadee (Poecile Atricapillus), Matthew Barrett

Matthew J. Barrett

ABSTRACT Memory consolidation - the time-dependent stabilization of information- involves two processes: 1) synaptic consolidation and 2) systems consolidation. Synaptic consolidation uses a series of protein synthesis cascades that make lasting changes in the underlying neural architecture of a memory. Systems consolidation involves the reorganization of memory such that, with the passage of time, memory that is initially hippocampus-dependent can be retrieved and activated independent of the hippocampus. Black-capped chickadees (Poecile atricapillus) store and relocate food using hippocampus-dependent spatial memory. In Chapter 2 inhibition of protein synthesis by anisomycin, either 0 and 2 h or 4 and 6 h after …

Go to article

Cognitive Representation In Transitive Inference: A Comparison Of Four Corvid Species, Alan B. Bond, Cynthia A. Wei, Alan C. Kamil May 2013

Cognitive Representation In Transitive Inference: A Comparison Of Four Corvid Species, Alan B. Bond, Cynthia A. Wei, Alan C. Kamil

Alan B. Bond

During operant transitive inference experiments, subjects are trained on adjacent stimulus pairs in an implicit linear hierarchy in which responses to higher ranked stimuli are rewarded. Two contrasting forms of cognitive representation are often used to explain resulting choice behavior. Associative representation is based on memory for the reward history of each stimulus. Relational representation depends on memory for the context in which stimuli have been presented. Natural history characteristics that require accurate configural memory, such as social complexity or reliance on cached food, should tend to promote greater use of relational representation. To test this hypothesis, four corvid species …

Go to article

Locus Coeruleus And Hippocampal Tyrosine Hydroxylase Levels In A Pressure-Overload Model Of Heart Disease, Luke A. Johnson Mar 2013

Locus Coeruleus And Hippocampal Tyrosine Hydroxylase Levels In A Pressure-Overload Model Of Heart Disease, Luke A. Johnson

Undergraduate Honors Theses

Studies have indicated that approximately 30% of people with heart disease experience major depressive disorder (MDD). Despite strong clinical evidence of a link between the two diseases, the neurobiological processes involved in the relationship are poorly understood. A growing number of studies are revealing similar neuroanatomical and neurochemical abnormalities resulting from both depression and heart disease. The locus coeruleus (LC) is a group of neurons in the pons that synthesize and release norepinephrine, and that is known to play a significant role in depression pathobiology. For example, there is evidence that tyrosine hydroxylase (TH) is elevated in the LC in …

Go to article

Delayed Amyloid Plaque Deposition And Behavioral Deficits In Outcrossed Aβpp/Ps1 Mice, Brian A. Couch, Meghan E. Kerrisk, Adam C. Kaufman, Haakon B. Nygaard, Stephen M. Strittmatter, Anthony J. Koleske Jan 2013

Delayed Amyloid Plaque Deposition And Behavioral Deficits In Outcrossed Aβpp/Ps1 Mice, Brian A. Couch, Meghan E. Kerrisk, Adam C. Kaufman, Haakon B. Nygaard, Stephen M. Strittmatter, Anthony J. Koleske

School of Biological Sciences: Faculty Publications

Alzheimer’s disease (AD) is a progressive neurodegenerative dementia characterized by amyloid plaque accumulation, synapse/dendrite loss, and cognitive impairment. Transgenic mice expressing mutant forms of amyloid-β precursor protein (AβPP) and presenilin-1 (PS1) recapitulate several aspects of this disease and provide a useful model system for studying elements of AD progression. AβPP/PS1 mice have been previously shown to exhibit behavioral deficits and amyloid plaque deposition between 4–9 months of age. We crossed AβPP/PS1 animals with mice of a mixed genetic background (C57BL/6 × 129/SvJ) and investigated the development of AD-like features in the resulting outcrossed mice. The onset of memory-based behavioral impairment …

Go to article

Effect Of Estrogen On Manganese-Induced Toxicity On Embryonic Astrocytes, Tyler T. Huynh, Kimberly J. Baker, Harold L. Komiskey Jan 2013

Effect Of Estrogen On Manganese-Induced Toxicity On Embryonic Astrocytes, Tyler T. Huynh, Kimberly J. Baker, Harold L. Komiskey

PCOM Scholarly Papers

Manganese (Mn) is a natural trace metal that is essential for many physiological functions in the human body. Astrocytes in the central nervous system are susceptible reservoirs for Mn accumulation. Estrogen, a steroidal hormone, has been shown to mitigate Mn-induced toxicity in cultures of postnatal astrocytes. However, differences in expression/inducibility of glutamate transporters and glutamine synthetase, transmitters, and the natural gonadal steroids and their receptors are known to occur in astrocyte cultures derived from various stages of fetal and postnatal development. Cultures of embryonic (E18) hippocampal astrocytes were examined in this study for the ability of 17 β-estradiol (E2) to …

Go to article

Differences In Relative Hippocampus Volume And Number Of Hippocampus Neurons Among Five Corvid Species, Kristy L. Gould, Karl E. Gilbertson, Andrew J. Hrvol, Joseph C. Nelson, Abigail L. Seyfer, Rose M. Brantner, Alan C. Kamil Jan 2013

Differences In Relative Hippocampus Volume And Number Of Hippocampus Neurons Among Five Corvid Species, Kristy L. Gould, Karl E. Gilbertson, Andrew J. Hrvol, Joseph C. Nelson, Abigail L. Seyfer, Rose M. Brantner, Alan C. Kamil

Avian Cognition Papers

The relative size of the avian hippocampus (Hp) has been shown to be related to spatial memory and food storing in two avian families, the parids and corvids. Basil et al. [Brain Behav Evol 1996;47: 156-164] examined North American food-storing birds in the corvid family and found that Clark’s nutcrackers had a larger relative Hp than pinyon jays and Western scrub jays. These results correlated with the nutcracker’s better performance on most spatial memory tasks and their strong reliance on stored food in the wild. However, Pravosudov and de Kort [Brain Behav Evol 67 (2006), 1-9] raised questions …

Go to article

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung Jan 2013

Loss Of Dendritic Inhibition In The Hippocampus After Repeated Early-Life Hyperthermic Seizures In Rats., Richard Boyce, L Stan Leung

Physiology and Pharmacology Publications

Seizures are relatively common in children and are a risk factor for subsequent temporal lobe epilepsy. To investigate whether early-life seizures themselves are detrimental to the proper function of the adult brain, we studied whether dendritic excitation and inhibition in the hippocampus of adult rats were altered after hyperthermia-induced seizures in immature rats. In particular, we hypothesized that apical dendritic inhibition in hippocampal CA1 pyramidal cells would be disrupted following hyperthermia-induced seizures in early life. Seizure rats were given three hyperthermia-induced seizures per day for three days from postnatal day (PND) 13 to 15; control rats were handled similarly but …

Go to article

Functional Roles Of The Insulin-Regulated Glucose Transporter-4 In The Hippocampus, Jiah Pearson-Leary Jan 2013

Functional Roles Of The Insulin-Regulated Glucose Transporter-4 In The Hippocampus, Jiah Pearson-Leary

Legacy Theses & Dissertations (2009 - 2024)

Although a great deal of research has elucidated both localization and function of many glucose transporters (GluTs) throughout the brain, the function of brain insulin-responsive glucose transporter-4 (GluT4) remains unclear (McEwen & Reagan, 2004). Because type 2 diabetes mellitus (T2DM; insulin resistance, i.e., impaired insulin signaling) is a risk factor for Alzheimer's disease (AD), and because the signaling mechanisms insulin uses to mediate hippocampal processes and memory are unclear, a major purpose of this dissertation was to determine whether hippocampal GluT4, which is responsible for insulin's glucoregulatory and canonical effects in the periphery, is necessary for insulin's effects in the …

Go to article