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Full-Text Articles in Systems Neuroscience
How To Search For The Engram: Optogenetics And Network Dynamics, Claudia Garcia Jou
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 …
Prelimbic Neuronal Ensembles In Natural Reward Seeking, Roger Ian Grant
Prelimbic Neuronal Ensembles In Natural Reward Seeking, Roger Ian Grant
MUSC Theses and Dissertations
External cues can become powerful motivators of behavior when paired with rewarding stimuli, such as natural rewards or drugs of abuse, as is the case in individuals with substance use disorder (SUD). The dorsomedial prefrontal cortex (dmPFC) has been implicated as a neural substrate which encodes cue-reward associations and has been shown to exert top-down control over both natural and drug reward seeking. We and others have shown that activity within the dmPFC is heterogeneous during reward seeking, with some neurons displaying excitatory responses to reward-predictive cues, and others showing inhibitory responses to the same cues. Furthermore, this response heterogeneity …
The Functional Role Of Anatomical Feedback Connections In Visual Attention, Samantha Debes
The Functional Role Of Anatomical Feedback Connections In Visual Attention, Samantha Debes
Dissertations and Theses (Open Access)
Entrenched in a dense, highly connected network, cortical neurons receive heterogeneous inputs from diverse connections, including local feedforward and feedback signals. Over the years, neuroscientists have focused on feedforward and local connections, amassing a wealth of information on the purpose of these signals. However, the functional role of feedback connections remains a mystery, despite their sheer abundance and prevalence when compared to feedforward connections. The field has long hypothesized that feedback acts as a conduit for attentional signals, carrying them throughout the brain. Previous work on this topic has been variable. Though cognitively demanding neural processes, like attention, have traditionally …
Optogenetic Interrogation Of Primary Visual Cortex And Its Impact On Neural Coding And Behavior, Ariana R. Andrei
Optogenetic Interrogation Of Primary Visual Cortex And Its Impact On Neural Coding And Behavior, Ariana R. Andrei
Dissertations and Theses (Open Access)
Understanding the mechanism by which the brain transforms simple sensory inputs into rich perceptual experiences is one of the great mysteries of systems neuroscience. Undoubtedly this involves the activity of large populations of interconnected neurons, but while the responses of individual neurons to a variety of sensory stimuli have been well-characterized, how populations of such neurons organize their activity to create our sensory perceptions is almost entirely unknown. To investigate this complex circuitry requires the ability to causally manipulate the activity of neural populations and monitor the resultant effects. Here we focus on primary visual cortex (V1), which has been …