Neonatal Alcohol Exposure Impairs Acquisition of Eyeblink Conditioned Responses During Discrimination Learning and Reversal in Weanling Rats

Dev Psychobiol. 2007 Apr;49(3):243-57. doi: 10.1002/dev.20178.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alcoholic Intoxication / psychology*
  • Animals
  • Animals, Newborn
  • Brain Damage, Chronic / psychology
  • Brain Stem / drug effects
  • Cerebellum / drug effects
  • Conditioning, Eyelid / drug effects*
  • Discrimination Learning / drug effects*
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Ethanol / toxicity*
  • Female
  • Hippocampus / drug effects
  • Male
  • Rats
  • Rats, Long-Evans
  • Reversal Learning / drug effects*
  • Weaning

Substances

  • Ethanol