• Rohit Kanojia
• Kamal Jaiswal
• Dinesh Raj Modi

Fear is psychological and psycho physiological response to a perceived external threat that is consciously recognized as a danger. Failure to extinguish traumatic memories can lead to the development of fear associated with anxiety. This is a major challenge amongst researchers and scientists to come up with newer paradigms of exposure therapies for the effective treatment of fear related anxiety disorders. Fear conditioning in rats is a valuable model for study of cellular/molecular mechanism related to learning as well as memory. Intercalated Cell Mass (ITCs) within the amygdala are key regulatory elements controlling emotional responses by controlling amygdala circuits. Central Amygdala (CeA) is the main output relay for the fear response and has innervations of fear traces from Basolateral Amygdala (BLA) as well as from ITCs. Histone methylation is one of the important mechanisms amongst other histone modifications for controlling behavioral outcome through the regulation of gene. In the present report the expression of histone H3/H4 methylation during fear learning and extinction in rats may change the behavioral outcomes as well as the role of histone modifications especially histone methylation was studied in correlation to ARC, CREB, p-CREB to find out whether fear extinction is a inhibitory learning, erasure of memory or both. We found that the expression of p-CREB was found to be higher in extinction group as compared to their respective control groups in the LA region. However, the changes were insignificant between immediate and delayed extinction group while BA, the expression of p-CREB was significantly higher in delayed extinction group .While the CREB expression was higher in extinction groups as compared to their respective control groups but no significant changes were observed between immediate and delayed extinction groups in LA region. Similarly the ARC, expression was higher in extinction groups as compared to their respective control groups but no significant changes were observed between immediate and delayed extinction groups in LA region. Moreover, the level of histone methylation in amygdale is suppressed. The present research highlights the analysis of molecular events in parts of brain and inturn has a great impact on the methods of physiological and psychological researches specially in the field of behavioral science.

Behavior, Fear, PTSD, Amygdala, Histone metylation

"Behavioral acclimatization of fear memory and its relation with histone methylation in correlation with accurate nucleus of the hypothalamus, cAMP response element-binding protein and its target gene.", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 6, page no.61-71, June 2019, Available :http://www.jetir.org/papers/JETIR1907K07.pdf

"Behavioral acclimatization of fear memory and its relation with histone methylation in correlation with accurate nucleus of the hypothalamus, cAMP response element-binding protein and its target gene.", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 6, page no. pp61-71, June 2019, Available at : http://www.jetir.org/papers/JETIR1907K07.pdf