Rats conserve passive avoidance retention level throughout the light phase of diurnal cycle

Physiol Behav. 2023 Sep 1:268:114234. doi: 10.1016/j.physbeh.2023.114234. Epub 2023 May 10.

Abstract

Emotions and memory formation are sensible to circadian rhythm. Here we study whether the time of day during the light phase of the diurnal cycle affects emotional memory in male Wistar rats using the passive avoidance (PA) test. Experiments were conducted at the beginning of Zeitgeber time (ZT) (ZT0.5-2), mid-time (ZT5-6.5), and end (ZT10.5-12) of the light period. Our results suggest that time of day has no impact on emotional response during acquisition trials, but slightly influences cognitive response during the 24-hour retention trial. Retention response was highest for ZT5-6.5, followed by ZT0.5-2, and lowest for ZT10.5-12.

Keywords: Emotional memory; Passive avoidance test; Rat; Time-of-day.

MeSH terms

  • Animals
  • Circadian Rhythm* / physiology
  • Male
  • Rats
  • Rats, Wistar