Hippocampal Arc protein expression and conditioned fear

Caleb Hudgins, Tim Otto

Research output: Contribution to journalArticle

Abstract

Arc (Activity-regulated cytoskeleton-associated protein) is an effector neuronal immediate-early gene (IEG) and has been closely linked to behaviorally-induced neuronal plasticity. The present studies examined the regionally-selective, dissociable patterns of Arc expression induced by Pavlovian trace fear conditioning, delay fear conditioning, and contextual fear conditioning as well as novel context exposure. This research was guided by anatomical studies identifying heterogeneity of connectivity across the transverse (CA1, CA3) and septo-temporal (dorsal vs. ventral) axes of the hippocampus; companion neuropsychological experiments suggest that these subregions likely play functionally dissociable roles in different forms of hippocampal-dependent learning. Hence the primary goal of the present study was to characterize the expression of Arc protein across both the septotemporal and transverse axes of the hippocampus induced by hippocampal dependent trace fear conditioning and compare these expression patterns to those induced by other fear conditioning paradigms. A second goal of these studies was to explore which specific paradigmatic features of the fear conditioning task itself are responsible for the observed patterns of Arc expression. The results of these studies suggest that, within the dorsal hippocampus, Arc expression in CA3 induced by trace fear conditioning may play a unique role in representing the context, while Arc protein expression within ventral CA3 may reflect CS processing. Arc protein expression in dorsal and ventral CA1 are likely not meaningfully involved in trace fear conditioning as there is either a lack of significant enhancement (dorsal CA1) or enhancement is not unique to subjects trained in trace fear conditioning (ventral CA1). The specific regional pattern of Arc protein enhancement induced by trace fear conditioning may reflect the unique temporal parameters of the task which critically engages the hippocampus in processing both contextual representations as well as the explicit CS. This additional hippocampal processing may account for the greater enhancement in Arc protein in dorsal and ventral CA3 for subjects trained in trace fear conditioning compared to novel context exposure, or contextual and delay fear conditioning.

Original languageEnglish (US)
Pages (from-to)175-191
Number of pages17
JournalNeurobiology of Learning and Memory
Volume161
DOIs
StatePublished - May 2019

Fingerprint

Cytoskeleton
Fear
Proteins
Hippocampus
Conditioning (Psychology)
Neuronal Plasticity
Immediate-Early Genes
Learning

All Science Journal Classification (ASJC) codes

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience

Keywords

  • Arc
  • Contextual fear conditioning
  • Delay fear conditioning
  • Hippocampus
  • Immunohistochemistry
  • Trace fear conditioning

Cite this

@article{0c54d94a06784a38846c0ed0a904aa5f,
title = "Hippocampal Arc protein expression and conditioned fear",
abstract = "Arc (Activity-regulated cytoskeleton-associated protein) is an effector neuronal immediate-early gene (IEG) and has been closely linked to behaviorally-induced neuronal plasticity. The present studies examined the regionally-selective, dissociable patterns of Arc expression induced by Pavlovian trace fear conditioning, delay fear conditioning, and contextual fear conditioning as well as novel context exposure. This research was guided by anatomical studies identifying heterogeneity of connectivity across the transverse (CA1, CA3) and septo-temporal (dorsal vs. ventral) axes of the hippocampus; companion neuropsychological experiments suggest that these subregions likely play functionally dissociable roles in different forms of hippocampal-dependent learning. Hence the primary goal of the present study was to characterize the expression of Arc protein across both the septotemporal and transverse axes of the hippocampus induced by hippocampal dependent trace fear conditioning and compare these expression patterns to those induced by other fear conditioning paradigms. A second goal of these studies was to explore which specific paradigmatic features of the fear conditioning task itself are responsible for the observed patterns of Arc expression. The results of these studies suggest that, within the dorsal hippocampus, Arc expression in CA3 induced by trace fear conditioning may play a unique role in representing the context, while Arc protein expression within ventral CA3 may reflect CS processing. Arc protein expression in dorsal and ventral CA1 are likely not meaningfully involved in trace fear conditioning as there is either a lack of significant enhancement (dorsal CA1) or enhancement is not unique to subjects trained in trace fear conditioning (ventral CA1). The specific regional pattern of Arc protein enhancement induced by trace fear conditioning may reflect the unique temporal parameters of the task which critically engages the hippocampus in processing both contextual representations as well as the explicit CS. This additional hippocampal processing may account for the greater enhancement in Arc protein in dorsal and ventral CA3 for subjects trained in trace fear conditioning compared to novel context exposure, or contextual and delay fear conditioning.",
keywords = "Arc, Contextual fear conditioning, Delay fear conditioning, Hippocampus, Immunohistochemistry, Trace fear conditioning",
author = "Caleb Hudgins and Tim Otto",
year = "2019",
month = "5",
doi = "10.1016/j.nlm.2019.04.004",
language = "English (US)",
volume = "161",
pages = "175--191",
journal = "Neurobiology of Learning and Memory",
issn = "1074-7427",
publisher = "Academic Press Inc.",

}

Hippocampal Arc protein expression and conditioned fear. / Hudgins, Caleb; Otto, Tim.

In: Neurobiology of Learning and Memory, Vol. 161, 05.2019, p. 175-191.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Hippocampal Arc protein expression and conditioned fear

AU - Hudgins, Caleb

AU - Otto, Tim

PY - 2019/5

Y1 - 2019/5

N2 - Arc (Activity-regulated cytoskeleton-associated protein) is an effector neuronal immediate-early gene (IEG) and has been closely linked to behaviorally-induced neuronal plasticity. The present studies examined the regionally-selective, dissociable patterns of Arc expression induced by Pavlovian trace fear conditioning, delay fear conditioning, and contextual fear conditioning as well as novel context exposure. This research was guided by anatomical studies identifying heterogeneity of connectivity across the transverse (CA1, CA3) and septo-temporal (dorsal vs. ventral) axes of the hippocampus; companion neuropsychological experiments suggest that these subregions likely play functionally dissociable roles in different forms of hippocampal-dependent learning. Hence the primary goal of the present study was to characterize the expression of Arc protein across both the septotemporal and transverse axes of the hippocampus induced by hippocampal dependent trace fear conditioning and compare these expression patterns to those induced by other fear conditioning paradigms. A second goal of these studies was to explore which specific paradigmatic features of the fear conditioning task itself are responsible for the observed patterns of Arc expression. The results of these studies suggest that, within the dorsal hippocampus, Arc expression in CA3 induced by trace fear conditioning may play a unique role in representing the context, while Arc protein expression within ventral CA3 may reflect CS processing. Arc protein expression in dorsal and ventral CA1 are likely not meaningfully involved in trace fear conditioning as there is either a lack of significant enhancement (dorsal CA1) or enhancement is not unique to subjects trained in trace fear conditioning (ventral CA1). The specific regional pattern of Arc protein enhancement induced by trace fear conditioning may reflect the unique temporal parameters of the task which critically engages the hippocampus in processing both contextual representations as well as the explicit CS. This additional hippocampal processing may account for the greater enhancement in Arc protein in dorsal and ventral CA3 for subjects trained in trace fear conditioning compared to novel context exposure, or contextual and delay fear conditioning.

AB - Arc (Activity-regulated cytoskeleton-associated protein) is an effector neuronal immediate-early gene (IEG) and has been closely linked to behaviorally-induced neuronal plasticity. The present studies examined the regionally-selective, dissociable patterns of Arc expression induced by Pavlovian trace fear conditioning, delay fear conditioning, and contextual fear conditioning as well as novel context exposure. This research was guided by anatomical studies identifying heterogeneity of connectivity across the transverse (CA1, CA3) and septo-temporal (dorsal vs. ventral) axes of the hippocampus; companion neuropsychological experiments suggest that these subregions likely play functionally dissociable roles in different forms of hippocampal-dependent learning. Hence the primary goal of the present study was to characterize the expression of Arc protein across both the septotemporal and transverse axes of the hippocampus induced by hippocampal dependent trace fear conditioning and compare these expression patterns to those induced by other fear conditioning paradigms. A second goal of these studies was to explore which specific paradigmatic features of the fear conditioning task itself are responsible for the observed patterns of Arc expression. The results of these studies suggest that, within the dorsal hippocampus, Arc expression in CA3 induced by trace fear conditioning may play a unique role in representing the context, while Arc protein expression within ventral CA3 may reflect CS processing. Arc protein expression in dorsal and ventral CA1 are likely not meaningfully involved in trace fear conditioning as there is either a lack of significant enhancement (dorsal CA1) or enhancement is not unique to subjects trained in trace fear conditioning (ventral CA1). The specific regional pattern of Arc protein enhancement induced by trace fear conditioning may reflect the unique temporal parameters of the task which critically engages the hippocampus in processing both contextual representations as well as the explicit CS. This additional hippocampal processing may account for the greater enhancement in Arc protein in dorsal and ventral CA3 for subjects trained in trace fear conditioning compared to novel context exposure, or contextual and delay fear conditioning.

KW - Arc

KW - Contextual fear conditioning

KW - Delay fear conditioning

KW - Hippocampus

KW - Immunohistochemistry

KW - Trace fear conditioning

UR - http://www.scopus.com/inward/record.url?scp=85064928718&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064928718&partnerID=8YFLogxK

U2 - 10.1016/j.nlm.2019.04.004

DO - 10.1016/j.nlm.2019.04.004

M3 - Article

C2 - 30991091

AN - SCOPUS:85064928718

VL - 161

SP - 175

EP - 191

JO - Neurobiology of Learning and Memory

JF - Neurobiology of Learning and Memory

SN - 1074-7427

ER -