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Full-Text Articles in Systems Neuroscience

How To Search For The Engram: Optogenetics And Network Dynamics, Claudia Garcia Jou Feb 2026

How To Search For The Engram: Optogenetics And Network Dynamics, Claudia Garcia Jou

Dissertations, Theses, and Capstone Projects

Memories are thought to be encoded by ensembles of neurons called "engram cells", because their artificial activation with optogenetics leads to the behavioral expression of a memory. However, the physiological mechanisms that mediate this process remain unknown. In this thesis, I investigate how optogenetic stimulation of memory-tagged cells changes neuronal firing, spatial coding, and the geometry of neural manifolds. I used an active place avoidance task and a foraging task to label engram cells in the dorsal hippocampus with Channelrhodopsin2 (ChR2). I then recorded the hippocampal activity response to optogenetic stimulation in mice under anesthesia, head-fixed, or freely moving. I …


Interhemispheric Communication And Lateralization In The Mouse Hippocampus, Jake Jordan May 2019

Interhemispheric Communication And Lateralization In The Mouse Hippocampus, Jake Jordan

Dissertations, Theses, and Capstone Projects

The hippocampus is essential for memory and spatial navigation. Many theories have been proposed to explain how the hippocampus contributes to cognition; however, none has fully explained relevant neurophysiological and behavioral data. Hemispheric lateralization of hippocampal function has been reported in humans and in rodents, and lateralization of hippocampal neural circuitry has been reported in rodents. Most theories of hippocampal function fail to consider the hippocampus as a bilateral structure with hemispheric differences. Further, proposed theories of hippocampal lateralization have their own limitations in explaining empirical data concerning left/right function. Little is known about communication between the hippocampi across hemispheres. …


Moderate Prenatal Alcohol Exposure Impairs Performance In An Object-Place-Paired-Associate Task, Lilliana May Sanchez Apr 2018

Moderate Prenatal Alcohol Exposure Impairs Performance In An Object-Place-Paired-Associate Task, Lilliana May Sanchez

Psychology ETDs

Memory impairments, including spatial and object processing, are often observed in individuals with Fetal Alcohol Spectrum Disorder. Much attention has been directed towards the hippocampus, which displays significant alterations after moderate prenatal alcohol exposure (PAE). In the present study, we tested a moderate PAE rat model in an object-place-paired-associate (OPPA) task, previously shown to require hippocampal processing. The OPPA task was composed of training rats to discriminate between an identical pair of objects presented in 180° opposite arms of a radial arm maze. Animals were given a total of 10 trials per day over 14 consecutive days of training and …


The Effects Of The Hiv-1 Tat Protein And Morphine On The Structure And Function Of The Hippocampal Ca1 Subfield, William D. Marks Jan 2017

The Effects Of The Hiv-1 Tat Protein And Morphine On The Structure And Function Of The Hippocampal Ca1 Subfield, William D. Marks

Theses and Dissertations

HIV is capable of causing a set of neurological diseases collectively termed the HIV Associated Neurocognitive Disorders (HAND). Worsening pathology is observed in HIV+ individuals who use opioid drugs. Memory problems are often observed in HAND, implicating HIV pathology in the hippocampus, and are also known to be exacerbated by morphine use. HIV-1 Tat was demonstrated to reduce spatial memory performance in multiple tasks, and individual subsets of CA1 interneurons were found to be selectively vulnerable to the effects of Tat, notably nNOS+/NPY- interneurons of the pyramidal layer and stratum radiatum, PV+ neurons of the pyramidal layer, and SST+ neurons …


An Integrative Neurological Model For Basic Observable Human Behavior, Ryan M. Francis Jan 2016

An Integrative Neurological Model For Basic Observable Human Behavior, Ryan M. Francis

Calvert Undergraduate Research Awards

The scientific method uncovers information from the natural world in small increments. This spurs the design of models to explain how the pieces fit together and to identify future targets of research. This is especially the case in psychology, where visualizing concepts is an advantageous practice. One all too common criticism of cognitive and behavioral models in psychology is the lack of a biological basis. This paper aims to alleviate part of this issue by integrating currently understood biological and neurological mechanisms that drive psychological phenomena into a predictive and descriptive model for basic human behavior. To accomplish this task, …