Article
Neurosciences
Jun Liu, Longnian Lin, Dong Wang
Summary: Specific BLA neurons exhibit increased firing rates, accompanied by increased heart rate and freezing, in response to height threats. These neurons are only activated under height threats, not other conditions, and develop conditioned responses to the context after fear conditioning, indicating a convergence in processing of dangerous/risky contextual information.
JOURNAL OF NEUROSCIENCE
(2021)
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)
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
Pan Feng, Benjamin Becker, Feng Zhou, Tingyong Feng, Zhiyi Chen
Summary: Sleep deprivation may lead to fear and anxiety-related emotional disorders. This study found that sleep deprivation facilitated fear acquisition, possibly through threat-specific encoding in the basolateral amygdala.
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
A. Ezequiel Pereyra, Camilo J. Mininni, B. Silvano Zanutto
Summary: The study demonstrates that serotonin modulates reward-driven learning, and 5-HT1A receptors in the BLA play a crucial role in extinction. Fluoxetine treatment accelerates extinction learning, while BLA lesions partially revert this effect.
BEHAVIOURAL BRAIN RESEARCH
(2021)
Article
Biology
Mayumi Machida, Brook Sweeten, Austin Adkins, Laurie Wellman, Larry Sanford
Summary: This study utilizes optogenetics to investigate the role of BLA glutamate neurons in regulating fear memory, stress, and sleep indices. The findings suggest that BLA activity during post-ST REM integrates behavioral and sleep indices of fear memory through processes associated with theta oscillations.
Article
Cell Biology
Rongzhen Yan, Tianyu Wang, Xiaoyan Ma, Xinyang Zhang, Rui Zheng, Qiang Zhou
Summary: The probabilistic association between cause and effect plays a crucial role in memory formation, especially in psychiatric diseases. Research shows that 50% association between conditioned and unconditioned stimuli can reduce fear responses and neural spiking activity in the dorsomedial prefrontal cortex. The formation of probabilistic memory involves enhanced inhibition from PV-neurons, increased synaptic inputs, and activation of the ventral hippocampus to detect mismatch during conditioning. Stress can impair the formation of probabilistic memory by affecting PV-neuronal plasticity, while prior stress to memory retrieval can revert enhanced PV-neuron activity.
Article
Biochemistry & Molecular Biology
Jessica C. Gaspar, Bright N. Okine, David Dinneen, Michelle Roche, David P. Finn
Summary: There is evidence suggesting that peroxisome proliferator-activated receptors (PPARs) are involved in pain, cognition, and anxiety. However, their role in pain-fear interactions is still unclear. This study investigated the effects of PPAR antagonists on nociceptive behavior, fear-conditioned analgesia (FCA), and conditioned fear in the amygdala. The results indicate that PPAR alpha and PPAR gamma in the amygdala play a role in the expression or extinction of conditioned fear.
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
Clinical Neurology
Dayan Knox, Rebecca Della Valle, Negin Mohammadmirzaei, Brianna Shultz, Matt Biddle, Abigail Farkash, Marisa Chamness, Emily Moulton
Summary: The study found that traumatic stress enhances Akt phosphorylation in the Amy of rats, and inhibiting PI3K->Akt signaling in the BLA can reduce freezing behavior during extinction in stressed rats. This suggests that PI3K->Akt signaling may be a mechanism through which traumatic stress leads to fear memory resistant to extinction.
INTERNATIONAL JOURNAL OF NEUROPSYCHOPHARMACOLOGY
(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
Behavioral Sciences
Tatiane Ferreira Tavares, Jose Lino Oliveira Bueno, Valerie Doyere
Summary: Reinforcement learning theories suggest that prediction error drives memory updating. This study investigates the role of temporal prediction error in appetitive operant conditioning. The results demonstrate the involvement of the basolateral amygdala nucleus (BLA) in long-term memory updating and the importance of temporal and reward contingencies.
FRONTIERS IN BEHAVIORAL NEUROSCIENCE
(2023)
Article
Biochemistry & Molecular Biology
Saurabh Sonkusare, Ding Qiong, Yijie Zhao, Wei Liu, Ruoqi Yang, Alekhya Mandali, Luis Manssuer, Chencheng Zhang, Chunyan Cao, Bomin Sun, Shikun Zhan, Valerie Voon
Summary: Using intracranial electroencephalography, this study investigated the amygdala, orbitofrontal cortex (OFC), and medial prefrontal cortex (mPFC) and found that they play important roles in the emotion circuit. The three regions showed different emotion-induced responses and interactions. The results demonstrated greater broadband gamma activity in the negative condition, increased beta activity in the amygdala and OFC, and decreased beta activity in mPFC during the emotional picture viewing task. Furthermore, model-based computational analyses revealed unidirectional connectivity from mPFC to the amygdala and bidirectional communication between OFC-amygdala and OFC-mPFC.
MOLECULAR PSYCHIATRY
(2023)
Article
Neurosciences
Ka Ng, Michael Pollock, Abraham Escobedo, Brent Bachman, Nanami Miyazaki, Edward L. L. Bartlett, Susan Sangha
Summary: Stressful events can disrupt regulation of fear and reward processing, leading to maladaptive fear responses. Post-traumatic stress disorder (PTSD) is characterized by persistent fear reactions to safety cues. In this study, the necessity of specific projections from the infralimbic cortex (IL) to the basolateral amygdala (BLA) or central amygdala (CeA) during safety recall was tested. The IL->CeA pathway was found to be necessary for suppressing fear responses in the presence of a learned safety cue, similar to the behavioral disruption seen in individuals with PTSD.
NEUROPSYCHOPHARMACOLOGY
(2023)