Journal of Neuroscience, Vol 14, 1623-1633, Copyright © 1994 by Society for Neuroscience
Neuronal activity within the nucleus basalis and conditioned neocortical electroencephalographic activation
PJ Whalen, BS Kapp and JP Pascoe
Department of Psychology, University of Vermont, Burlington 05405.
The relationship between neuronal activity within the nucleus basalis (NB)
and conditioned neocortical EEG activation was investigated in New Zealand
rabbits during Pavlovian differential conditioning. Twenty- seven of 56
neurons recorded in conditioned animals demonstrated a significantly
greater change in activity to a tone (CS+) that predicted the occurrence of
a mildly aversive unconditioned stimulus when compared to a tone (CS-) that
did not. Twenty-four of these 27 neurons demonstrated a significant
increase in activity to the CS+ compared to the CS-, while the remaining
three neurons demonstrated a significant decrease in activity to the CS+
compared to the CS-. In 24 of these 27 neurons (89%) these changes in
neuronal activity during CS presentations correlated significantly with a
decrease in the power of delta activity in the EEG. In addition, 13 of
these 24 neurons (54%) demonstrated significant correlations between
neuronal activity and the power of delta activity during CS-free periods.
In experimentally naive animals, the activity of 10 of 22 neurons (45%)
recorded within the region of the NB correlated with the power of delta
activity in the EEG during stimulus-free periods. These results complement
a growing body of evidence and provide strong support for the hypothesis
that the NB contributes to neocortical activation in the conscious animal.