Neonatal alcohol exposure impairs acquisition of eyeblink conditioned responses during discrimination learning and reversal in weanling rats.
Discrimination and reversal of the classically conditioned eyeblink response depends on cerebellar-brainstem interactions with the hippocampus. Neonatal "binge" exposure to alcohol at doses of 5 g/kg/day or more has been shown to impair single-cue eyeblink conditioning in both weanling and adult rats. The present study exposed neonatal rats to acute alcohol intubations across different developmental periods (postnatal day [PND] 4-9 or PND7-9) and tested them from PND26-31 on discriminative classical eyeblink conditioning and reversal. A high dose of alcohol (5 g/kg/day) dramatically impaired conditioning relative to controls when exposure occurred over PND4-9, but produced mild or no impairments when delivered over PND7-9. These findings support previous claims that developmental exposure period plays a critical role in determining the deleterious effects of alcohol on the developing brain. A lower dose of alcohol (4 g/kg/day) delivered from PND4-9--lower than has previously been shown to affect single-cue eyeblink conditioning--also produced deficits on the discrimination task, suggesting that discrimination learning and acquisition of responding to CS+ during reversal may be especially sensitive behavioral indicators of alcohol-induced brain damage in this rat model.
Brown
Kevin L
KL
Department of Psychology, University of Delaware, Newark, DE 19716, USA.
Calizo
Lyngine H
LH
Goodlett
Charles R
CR
Stanton
Mark E
ME
D000435:Alcoholic Intoxication / Q000523:psychology*; D000818:Animals; D000831:Animals, Newborn; D001925:Brain Damage, Chronic / Q000523:psychology; D001933:Brain Stem / Q000187:drug effects; D002531:Cerebellum / Q000187:drug effects; D003215:Conditioning, Eyelid / Q000187:drug effects*; D004193:Discrimination Learning / Q000187:drug effects*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000633:toxicity*; D005260:Female; D006624:Hippocampus / Q000187:drug effects; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012193:Reversal Learning / Q000187:drug effects*; D014886:Weaning
D000431:Ethanol