Pre-stress performance in an operant learning predicts post-stress behavioral alterations in chronically stressed rats

2014 Fiscal Year Final Research Report

• Project/Area Number: 25860994
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Psychiatric science
• Research Institution: Kanazawa University
• Principal Investigator: IGUCHI Yoshio 金沢大学, 医学系, 博士研究員 (20452097)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: うつ病 / 慢性ストレス / ストレス反応性 / 個体差 / 意欲 / 柔軟な意思決定 / 欲求性オペラント学習 / 側坐核

Outline of Final Research Achievements

Although chronic stress has been widely used to induce depression-like phenotypes in preclinical studies, a few models have been developed to study causal relationship between the individual differences in the depression-like phenotypes and the pre-existing individual differences prior to stress exposure, which might genetically/epigenetically determine the fate of each animal after stress. We focused on a large inter-individual variability of a group of outbred rats in performance of an appetitive operant (leverpress) trained on a progressive ratio (PR) schedule. Based on the PR performance, we classified animals into 4 subgroups, which were found to show distinctive cognitive/behavioral characteristics. Moreover, the 4 subgroups revealed different behavioral responses to a chronic unpredictable stress (CUS) on short- and long-term bases. These results suggest that the individual differences in the pre-CUS PR performance can predict the distinctive post-CUS behavioral phenotypes.

Free Research Field

精神薬理学