Cj. Slawecki et al., Neurophysiological findings and drinking levels in high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rats, ALC CLIN EX, 24(10), 2000, pp. 1492-1499
Background: Specific neurophysiological profiles, such as reduced P300 ampl
itude or altered spectral power in the EEG, have been associated with a ris
k for alcoholism in several clinical populations. In certain rodent models,
high versus low alcohol consumption is associated with similar neurophysio
logical differences. For example, alcohol-preferring (P) rats have increase
d spectral power and decreased P300 amplitudes compared with alcohol-nonpre
ferring (NP) rats. In the present study, the neurophysiological profiles of
high-alcohol-drinking (HAD) and low-alcohol-drinking (LAD) rats were asses
sed (1) to determine if their electrophysiological profiles are similar to
P and NP rats and (2) to examine the relationship of these neurophysiologic
al indices to ethanol drinking.
Methods: Ethanol-naive HAD and LAD rats were implanted with cortical and am
ygdalar recording electrodes. Baseline EEG and event-related potentials (ER
Ps) then were assessed. Subsequently, all rats were trained to self-adminis
ter ethanol by using a sucrose-substitution procedure.
Results: Baseline EEG and ERP (i.e., pre-ethanol exposure) were assessed ba
sed on line (HAD versus LAD) and actual ethanol consumption (high drinkers
versus low drinkers). At baseline, ethanol-naive HAD rats displayed signifi
cantly greater power in the cortical EEG and decreased amygdala N1 ERP ampl
itude compared with ethanol-naive LAD rats. Similar EEG and ERP profiles ha
ve been observed when P and NP rats are compared. No differences in P300 be
tween lines were observed, but high-drinking rats, independent of line, had
significantly decreased P300 amplitude in the amygdala compared with low-d
rinking rats.
Conclusions: These data suggest there are some similarities in EEG and ERP
profiles of P and HAD rats compared with NP and LAD rats. Furthermore, the
data suggest that decreased P300 amplitude in the amygdala is associated wi
th increased limited access ethanol drinking.