Article
Neurosciences
Megha Sehgal, Vanessa E. Ehlers, James R. Moyer Jr
Summary: New learning results in modulation of intrinsic plasticity in the underlying brain regions. Such changes in intrinsic plasticity can influence allocation and encoding of future memories. In this study, the authors investigated the time course of changes in intrinsic excitability within lateral amygdala neurons using auditory fear conditioning as a behavioral paradigm. They found transient changes in the intrinsic excitability of amygdala neurons, which lasted for up to 4 days post-learning. Additionally, the study showed that the enhanced neuronal intrinsic excitability was evident in many of the same neurons that had undergone synaptic plasticity immediately following fear conditioning.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Mitjan Morr, Jeanine Noell, Daphne Sassin, Jule Daniels, Alexandra Philipsen, Benjamin Becker, Birgit Stoffel-Wagner, Rene Hurlemann, Dirk Scheele
Summary: Loneliness may contribute to vulnerability to intrusive memories after trauma in healthy men, with altered limbic processing of fear signals being a potential underlying mechanism. Lonely men showed more intrusions and altered amygdala activity, while loneliness did not have the same impact on women.
Article
Behavioral Sciences
Nura W. Lingawi, Vincent Laurent, R. Frederick Westbrook, Nathan M. Holmes
Summary: Studies investigating second-order fear conditioning using complex stimuli such as contexts found that neuronal activity in the basolateral amygdala is essential for the acquisition and extinction of fear. The second-order fear can be reduced through extinction of its first-order conditioned stimulus associate, but it can be restored when fear of the first-order stimulus spontaneously recovers or is reconditioned.
NEUROBIOLOGY OF LEARNING AND MEMORY
(2021)
Article
Neurosciences
Franklin B. Krasne, Raphael Zinn, Bryce Vissel, Michael S. Fanselow
Summary: The study focuses on the extinction of contextual fear in exposure therapy for fear disorders, introducing a new neurocomputational model BaconX. The model explains how contextual representations are formed and associated with fear, and predicts factors influencing successful extinction, such as session length and context change.
Article
Biology
Yu-Ling Lin, Zhu-Sen Yang, Wai-Yi Wong, Shih-Che Lin, Shuu-Jiun Wang, Shih-Pin Chen, Jen-Kun Cheng, Hui Lu, Cheng-Chang Lien
Summary: This study investigates the cellular and synaptic alterations in the central nucleus of the amygdala (CeA) in a mouse model of chronic muscle pain. They found that targeting the somatostatin-expressing CeA (CeA-SST) neurons during the priming phase can prevent the development of chronic pain. Furthermore, they discovered that the CeA-SST neurons have increased excitatory synaptic drive and enhanced neuronal excitability in the chronic pain states. Chemogenetic inactivation of these neurons or suppression of nociceptive afferents from the brainstem to the CeA-SST neurons can alleviate chronic pain and anxiety-depressive symptoms.
Article
Behavioral Sciences
Louise Urien, Nicole Stein, Abigail Ryckman, Lindsey Bell, Elizabeth P. Bauer
Summary: The study focused on the role of BNST-AL in fear expression in male rats, revealing an upregulation of the ARC gene in BNST-AL specifically in male rats during fear expression. Excitotoxic lesions of the BNST reduced context fear expression in both sexes, suggesting that females may recruit different BNST subnuclei for fear and anxiety-like behaviors.
NEUROBIOLOGY OF LEARNING AND MEMORY
(2021)
Article
Neurosciences
Hui-dong Li, Dan-ni Li, Li Yang, Cheng Long
Summary: The Cyld gene mutation in mice impairs amygdala-dependent tone-cued fear memory and may be related to aberrant neuronal activation and reduced excitability in the BLA.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2021)
Article
Biochemistry & Molecular Biology
Kyuhyun Choi, Kyungjoon Park, Soonje Lee, Jee Hyun Yi, Changsu Woo, Shin Jung Kang, Ki Soon Shin
Summary: The lateral amygdala (LA) is a main sensory input site from the cortical and thalamic regions, which strongly projects to the basal amygdala (BA). Our study found that high-frequency stimulation ex vivo resulted in long-term potentiation (LTP) and enhanced neurotransmitter release at LA-BA synapses. Auditory fear conditioning also led to presynaptic facilitation at LA-BA synapses, with no changes in the AMPA/NMDA current ratio, suggesting the involvement of presynaptic mechanisms in fear conditioning.
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
(2021)
Article
Neurosciences
Zhe Yu, Alexandre Kisner, Amy Bhatt, Abigail M. Polter, Paul J. Marvar
Summary: This study examined the role of angiotensin II receptor type 1 (AT1R) neurons in the central amygdala (CeA) in fear and anxiety-related behavior using AT1R transgenic mice. It was found that AT1R+ neurons were localized to GABA expressing neurons in the CeL, and their deletion enhanced extinction learning. Furthermore, the application of angiotensin II increased inhibitory synaptic currents and decreased the excitability of CeL-AT1R+ neurons. These findings provide new insights into the neurobiological mechanisms underlying fear extinction.
Article
Neurosciences
Louise Urien, Stacey Cohen, Sophia Howard, Alexandrina Yakimov, Rachel Nordlicht, Elizabeth P. Bauer
Summary: Many anxiety disorders are characterized by abnormal threat detection and learning, as well as the inability to reduce fear responses in non-threatening environments. The vSUB-BNST pathway plays an important role in eliciting appropriate responses to contexts and is modulated by context fear conditioning.
Article
Multidisciplinary Sciences
Allison M. Burns, Melissa Farinelli-Scharly, Sandrine Hugues-Ascery, Jose Vicente Sanchez-Mut, Giulia Santoni, Johannes Graeff
Summary: Long-term memory formation is influenced by synaptic plasticity, neuronal activity-dependent gene transcription, and epigenetic modifications. Studies have shown that HDAC inhibitors (HDACi) can enhance these processes and act as potential cognitive enhancers. This study explores the effects of combining the HDACi CI-994 with contextual fear conditioning (CFC) in mice and demonstrates that CI-994 treatment improves memory formation by enhancing long-term potentiation in the hippocampus, a brain region involved in fear learning. Furthermore, RNA sequencing analysis reveals that HDACi treatment increases synaptic plasticity-promoting gene expression, specifically in the dentate gyrus of the hippocampus, when paired with CFC. Chromatin immunoprecipitation-sequencing experiments show that the combined action of HDACi application and conditioning is necessary for enhancer histone acetylation in pathways underlying improved memory performance. These findings suggest that systemic administration of HDACi amplifies brain region-specific processes induced by learning.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Review
Neurosciences
Christine Stubbendorff, Carl W. Stevenson
Summary: Research has shown that dopamine plays a crucial role in regulating various contextual fear processes, although the related neurochemical mechanisms are still not fully understood. Understanding how dopamine regulates contextual fear can provide novel insights into the neurochemical modulation of neural circuit function underlying memory processing.
EUROPEAN JOURNAL OF NEUROSCIENCE
(2021)
Review
Neurosciences
Kyoung-Doo Hwang, Sang Jeong Kim, Yong-Seok Lee
Summary: The cerebellum plays a critical role in modulating fear memory network and prediction, with involvement at the cellular and synaptic levels. Understanding the contributions of distinct cerebellar structures to fear learning and memory may lead to more effective treatment strategies for fear-related affective disorders.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2022)
Article
Biochemistry & Molecular Biology
Marcin Piechota, Urszula Skupio, Malgorzata Borczyk, Barbara Ziolkowska, Slawomir Golda, Lukasz Szumiec, Klaudia Szklarczyk-Smolana, Wiktor Bilecki, Jan Manuel Rodriguez Parkitna, Michal Korostynski
Summary: The expression of Ca2+/Calmodulin-Dependent Protein Kinase I gamma (Camk1g) is regulated by stress and glucocorticoid receptors (GR) in neuronal cells of the limbic system. It is involved in anxiety-related behaviors and responses conditioned by aversive stimuli.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Biochemistry & Molecular Biology
Einat Elharrar, Yahav Dikshtein, Sapir Meninger-Mordechay, Yehuda Lichtenstein, Gal Yadid
Summary: Recent research shows that inhibiting PARP-1 activity can interfere with fear conditioning and reduce freezing behavior. By controlling the pharmacokinetic timing, it is possible to specifically disrupt cue-associated fear memories without interfering with other natural memories.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Psychology, Biological
Justine Fam, Mark J. Huff, R. Fred Westbrook, Nathan M. Holmes
Summary: The study tested the impact of early DRM list items on false memories of lures through two manipulations. It discussed the findings in relation to various theories explaining false memory and the role of category/context information in generating false memories.
QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY
(2021)
Article
Behavioral Sciences
Justine Fam, Kelly J. Clemens, R. Fred Westbrook, Margaret J. Morris, Michael D. Kendig
Summary: This study found that diet-induced obesity significantly impacts rats' preference for sweet taste, but this is not due to differences in liking for the food.
Review
Behavioral Sciences
Nathan M. Holmes, Francesca S. Wong, Youcef Bouchekioua, R. Fred Westbrook
Summary: This paper reviews studies on sensory preconditioning in different animals and humans to determine how memory is integrated. The results show that memory integration can occur through chaining when stimuli are presented repeatedly or serially, while online integration occurs when stimuli are relatively novel or presented simultaneously.
NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS
(2022)
Article
Multidisciplinary Sciences
P. Railton, A. J. Delaney, B. G. Goodyear, J. Matyas, S. Lama, G. R. Sutherland, J. N. Powell
Summary: The functional connectivity between brain regions associated with pain is altered in hip osteoarthritis patients, and this connectivity is also modulated by painful activity.
SCIENTIFIC REPORTS
(2022)
Article
Neurosciences
Justine Fam, Billy Chieng, R. Frederick Westbrook, Vincent Laurent, Nathan M. Holmes
Summary: This study investigated how animals process contradictory information by conducting second-order fear conditioning in rats. The results showed that the brain is capable of encoding competing associations in different brain regions to resolve the contradiction.
Article
Neurosciences
Matthew J. Williams-Spooner, Andrew J. Delaney, R. Frederick Westbrook, Nathan M. Holmes
Summary: This study challenges the widely accepted view that activation of NMDA receptors (NMDAR) is required for fear memory formation. The findings show that the involvement of NMDAR in Pavlovian fear conditioning depends on prediction errors related to aversive events. NMDAR activation is not necessary when danger occurs as expected, but is required when danger occurs unexpectedly.
JOURNAL OF NEUROSCIENCE
(2022)
Review
Behavioral Sciences
Nathan M. Holmes, Justine P. Fam, Kelly J. Clemens, Vincent Laurent, R. Fred Westbrook
Summary: This paper reviews the neural substrates of sensory preconditioning and second-order conditioning and discusses the similarities and differences in these conditioning protocols, as well as their contribution to our understanding of how the brain encodes and retrieves information.
NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS
(2022)
Article
Food Science & Technology
Michael D. Kendig, Kyoko Hasebe, Aynaz Tajaddini, Nadeem O. Kaakoush, R. Frederick Westbrook, Margaret J. Morris
Summary: This study examines the effects of a diet switch intervention in a rat model of maternal obesity. The results show that the intervention leads to reductions in body weight and adiposity, improvements in place recognition memory, and changes in gut microbiota composition.
MOLECULAR NUTRITION & FOOD RESEARCH
(2023)
Article
Neurosciences
Omar A. Qureshi, Jessica Leake, Andrew J. Delaney, Simon Killcross, R. Frederick Westbrook, Nathan M. Holmes
Summary: The study investigated how danger affects the consolidation of neutral information in the perirhinal cortex (PRh) and basolateral amygdala complex (BLA) of male and female rats. The findings revealed that when a shocked context exposure follows the sensory preconditioning session, the consolidation of the association between the auditory and visual stimuli (S2-S1) shifts from the PRh to the BLA. This shift is influenced by the encoding processes of the S2-S1 pairings. The study also found that the BLA encodes the initial S2-S1 pairing, while the PRh encodes the later pairings. In contrast, when a context alone exposure follows the sensory preconditioning session, the BLA-dependent memory trace of the early pairings decays while the PRh-dependent trace of the later pairings consolidates. However, in the presence of a shocked context exposure, the PRh-dependent memory trace of the later pairings is suppressed, and the BLA-dependent trace of the initial pairings consolidates.
JOURNAL OF NEUROSCIENCE
(2023)
Article
Psychology, Biological
Nicholas G. W. Kennedy, Nathan M. Holmes, R. Frederick Westbrook
Summary: This study tested the predictions of the Hall-Rodriguez theory regarding latent inhibition, demonstrating that facilitation of latent inhibition depends on coterminations of target and nontarget stimuli in preexposure. The findings confirm that the temporal relation of a second stimulus in preexposure can impact latent inhibition to a target.
JOURNAL OF EXPERIMENTAL PSYCHOLOGY-ANIMAL LEARNING AND COGNITION
(2021)
