Impairment of contextual conditioned fear extinction after microinjection of alpha-1-adrenergic blocker prazosin into the medial prefrontal cortex

2010 ◽  
Vol 211 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Fabrício H.M. Do-Monte ◽  
Melody Allensworth ◽  
Antônio P. Carobrez
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Conditioned Fear ◽  
Fear Extinction ◽  
Adrenergic Blocker

scholarly journals The Role of the Medial Prefrontal Cortex-Amygdala Circuit in Stress Effects on the Extinction of Fear

2007 ◽  
Vol 2007 ◽  
pp. 1-11 ◽  
Author(s):  
Irit Akirav ◽  
Mouna Maroun
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Conditioned Fear ◽  
Fear Extinction ◽  
Primary Role ◽  
Gamma Aminobutyric Acid ◽  
Stressful Experience ◽  
Behavioral Sequelae ◽  
Cognition And Learning ◽  
Gaba Transmission

Stress exposure, depending on its intensity and duration, affects cognition and learning in an adaptive or maladaptive manner. Studies addressing the effects of stress on cognitive processes have mainly focused on conditioned fear, since it is suggested that fear-motivated learning lies at the root of affective and anxiety disorders. Inhibition of fear-motivated response can be accomplished by experimental extinction of the fearful response to the fear-inducing stimulus. Converging evidence indicates that extinction of fear memory requires plasticity in both the medial prefrontal cortex and the amygdala. These brain areas are also deeply involved in mediating the effects of exposure to stress on memory. Moreover, extensive evidence indicates that gamma-aminobutyric acid (GABA) transmission plays a primary role in the modulation of behavioral sequelae resulting from a stressful experience, and may also partially mediate inhibitory learning during extinction. In this review, we present evidence that exposure to a stressful experience may impair fear extinction and the possible involvement of the GABA system. Impairment of fear extinction learning is particularly important as it may predispose some individuals to the development of posttraumatic stress disorder. We further discuss a possible dysfunction in the medial prefrontal cortex-amygdala circuit following a stressful experience that may explain the impaired extinction caused by exposure to a stressor.

scholarly journals The role of the medial prefrontal cortex in trace fear extinction

2014 ◽  
Vol 22 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Janine L. Kwapis ◽  
Timothy J. Jarome ◽  
Fred J. Helmstetter
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Fear Extinction ◽  
Trace Fear

scholarly journals Layer- and subregion-specific differences in the neurophysiological properties of rat medial prefrontal cortex pyramidal neurons

2018 ◽  
Vol 119 (1) ◽  
pp. 177-191 ◽  
Author(s):  
Chenghui Song ◽  
James R. Moyer
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Conditioned Fear ◽  
Input Resistance ◽  
Underlying Mechanism ◽  
Fear Memory ◽  
Membrane Properties ◽  
Spike Threshold ◽  
Memory Acquisition

Medial prefrontal cortex (mPFC) is critical for the expression of long-term conditioned fear. However, the neural circuits involving fear memory acquisition and retrieval are still unclear. Two subregions within mPFC that have received a lot of attention are the prelimbic (PL) and infralimbic (IL) cortices (e.g., Santini E, Quirk GJ, Porter JT. J Neurosci 28: 4028–4036, 2008; Song C, Ehlers VL, Moyer JR Jr. J Neurosci 35: 13511–13524, 2015). Interestingly, PL and IL may play distinct roles during fear memory acquisition and retrieval but the underlying mechanism is poorly understood. One possibility is that the intrinsic membrane properties differ between these subregions. Thus, the current study was carried out to characterize the basic membrane properties of mPFC neurons in different layers and subregions. We found that pyramidal neurons in L2/3 were more hyperpolarized and less excitable than in L5. This was observed in both IL and PL and was associated with an enhanced h-current in L5 neurons. Within L2/3, IL neurons were more excitable than those in PL, which may be due to a lower spike threshold and higher input resistance in IL neurons. Within L5, the intrinsic excitability was comparable between neurons obtained in IL and PL. Thus, the heterogeneity in physiological properties of mPFC neurons may underlie the observed subregion-specific contribution of mPFC in cognitive function and emotional control, such as fear memory expression. NEW & NOTEWORTHY This is the first study to demonstrate that medial prefrontal cortical (mPFC) neurons are heterogeneous in both a layer- and a subregion-specific manner. Specifically, L5 neurons are more depolarized and more excitable than those neurons in L2/3, which is likely due to variations in h-current. Also, infralimbic neurons are more excitable than those of prelimbic neurons in layer 2/3, which may be due to differences in certain intrinsic properties, including input resistance and spike threshold.

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