Acute ethanol has biphasic effects on short- and long-term memory in both foreground and background contextual fear conditioning in C57BL/6 mice.
BACKGROUND
Ethanol is a frequently abused, addictive drug that impairs cognitive function. Ethanol may disrupt cognitive processes by altering attention, short-term memory, and/or long-term memory. Interestingly, some research suggests that ethanol may enhance cognitive processes at lower doses. The current research examined the dose-dependent effects of ethanol on contextual and cued fear conditioning. In addition, the present studies assessed the importance of stimulus salience in the effects of ethanol and directly compared the effects of ethanol on short-term and long-term memory.


METHODS
This study employed both foreground and background fear conditioning, which differ in the salience of contextual stimuli, and tested conditioning at 4 hours, 24 hours, and 1 week in order to assess the effects of ethanol on short-term and long-term memory. Foreground conditioning consisted of 2 presentations of a foot shock unconditioned stimulus (US) (2 seconds, 0.57 mA). Background conditioning consisted of 2 auditory conditioned stimulus (30 seconds, 85 dB white noise)-foot shock (US; 2 seconds, 0.57 mA) pairings.


RESULTS
For both foreground and background conditioning, ethanol enhanced short-term and long-term memory for contextual and cued conditioning at a low dose (0.25 g/kg) and impaired short-term and long-term memory for contextual and cued conditioning at a high dose (1.0 g/kg).


CONCLUSIONS
These results suggest that ethanol has long-lasting, biphasic effects on short-term and long-term memory for contextual and cued conditioning. Furthermore, the effects of ethanol on contextual fear conditioning are independent of the salience of the context.
Gulick
Danielle
D
Department of Psychology, Neuroscience Program, Temple University, Philadelphia, Pennsylvania, USA.
Gould
Thomas J
TJ
D000818:Animals; D002492:Central Nervous System Depressants / Q000097:blood / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects / Q000502:physiology; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D013997:Time Factors
D002492:Central Nervous System Depressants; D000431:Ethanol