The Journal of Neuroscience, March 15, 2003, 23(6):2459
Behavioral Transitions Modulate Hippocampal Electroencephalogram
Correlates of Open Field Behavior in the Rat: Support for a
Sensorimotor Function of Hippocampal Rhythmical Synchronous
Activity
H.
van Lier1,
A. M. L.
Coenen1, and
W. H. I. M.
Drinkenburg2
1 Nijmegen Institute for Cognition and
Information, Department of Biological Psychology, University of
Nijmegen, 6500 HE Nijmegen, The Netherlands, and 2 Johnson
& Johnson Pharmaceutical Research and Development, a Division of
Janssen Pharmaceutica, B-2340 Beerse, Belgium
A clear relationship exists between moment-to-moment behavioral
elements and hippocampal rhythmical synchronous activity (RSA) (theta
rhythm). However, behavioral elements are not isolated events but are
part of behavioral sequences in a context of behavioral activity. By
concurrently monitoring open field behavior and hippocampal EEG, EEG
correlates of open field behavior in relation to preceding and
following behavior were studied in Sprague Dawley rats to determine whether the behavioral context influences EEG correlates of
behavior. Results show that preceding and subsequent behavioral patterns influenced the spectral power correlates of behavior. RSA
power was increased when a "type 1 behavior" (voluntary movement) preceded the behavior compared with when a "type 2 behavior"
(automatic movement, awake immobility) preceded it. The modulating
effect of behavioral transitions was shown for several types of
behaviors, and systematic modulation of hippocampal EEG correlates of
behavior was demonstrated. The present report shows that the strong and systematic relationship between hippocampal RSA and behavior is modulated by the behavioral-sequential context. Thus, in addition to
the well established relationship between RSA and motor activity, a
second nonmotor process seems to contribute to hippocampal RSA. A
likely candidate is a sensory process, which is in accordance with
theories on the sensorimotor function of hippocampal RSA.
Key words:
EEG; behavior; open field; sequential analysis; transitions; rats; hippocampal RSA; sensorimotor integration
Copyright © 2003 Society for Neuroscience 0270-6474/03/2362459-07$05.00/0