Dissertation
Basolateral amygdala projections to the nucleus accumbens shell in the modulation of cued-response and inhibitory avoidance memory consolidation
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2024
DOI: 10.25820/etd.007787
Abstract
The basolateral amygdala (BLA) modulates different types of memory consolidation via distinct projections to downstream brain regions. Prior studies indicate that the BLA and dorsolateral striatum (DLS) interact to influence the consolidation of both cued-response and inhibitory avoidance (IA), but not spatial, learning. However, the BLA does not densely innervate the DLS, leaving the circuit mechanism by which the BLA modulates the consolidation of cued-response and IA learning unclear. Nonetheless, previous work suggests that the nucleus accumbens shell (NAshell), which receives significant BLA input, influences DLS activity. Moreover, previous pharmacological work suggests the BLA and NAshell interact to influence memory. However, the precise role of the BLA-NAshell pathway has never been directly investigated in the consolidation of cued-response, spatial, or IA memory consolidation. To address this, male and female Sprague-Dawley rats received optogenetic manipulations of the BLA-NAshell pathway immediately following training in different learning tasks. An initial experiment found that optogenetically inhibiting the BLA itself immediately after training impaired cued-response retention in a Barnes maze task, confirming earlier pharmacological work in males alone. Subsequent experiments found that BLA-NAshell pathway inhibition impaired retention of cued-response and IA learning but had no effect on retention of spatial learning. However, the present work did not observe any effects of pathway stimulation immediately after cued-response or IA learning. Together, the present findings suggest the BLA modulates the consolidation of cued-response and IA, but not spatial, memory consolidation via NAshell projections.
Details
- Title: Subtitle
- Basolateral amygdala projections to the nucleus accumbens shell in the modulation of cued-response and inhibitory avoidance memory consolidation
- Creators
- Bess Glickman
- Contributors
- Ryan T LaLumiere (Advisor)John H Freeman (Committee Member)Jason J Radley (Committee Member)Hanna E Stevens (Committee Member)Michelle W Voss (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Neuroscience
- Date degree season
- Summer 2024
- Publisher
- University of Iowa
- DOI
- 10.25820/etd.007787
- Number of pages
- xiii, 92 pages
- Copyright
- Copyright 2024 Bess Glickman
- Language
- English
- Date submitted
- 05/27/2024
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (page 66-78).
- Public Abstract (ETD)
Memory is a fundamental component of who we are and underlies our daily functioning. As we experience the world, different regions of our brain are responsible for creating and storing different types of memories that we can retrieve at future timepoints. The amygdala plays a unique role in influencing memory consolidation. Specifically, the basolateral amygdala is broadly connected to many downstream brain regions and influences the storage of different types of emotionally arousing experiences by altering activity in these regions after learning. One such region the amygdala interacts with is the nucleus accumbens shell, however, the role of this neural projection in memory consolidation has not been directly investigated.
The present work addressed this by examining the role of basolateral amygdala inputs to the nucleus accumbens shell in the consolidation of three different types of learning: cued-response, spatial, and inhibitory avoidance. Cued-response and inhibitory avoidance retention are thought to be influenced by the same memory system, the dorsolateral striatum, whereas spatial retention is thought to be influenced by a different memory system, the dorsal hippocampus. The findings from the present study indicate that inhibition of amygdala projections to the nucleus accumbens shell in rats impairs cued-response and inhibitory avoidance memory. Contrastingly, inhibition of this pathway does not influence spatial memory. Together, the present work identifies a neural pathway by which the amygdala selectively modulates the consolidation of cued-response and inhibitory avoidance, but not spatial, learning through projections to the nucleus accumbens shell.
- Academic Unit
- Interdisciplinary Studies Program
- Record Identifier
- 9984698054602771
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