Coherent spike-wave oscillations in the cortex and subthalamic nucleus of the freely moving rat
Neuroscience. 2005-01-01; 132(3): 659-664
DOI: 10.1016/j.neuroscience.2005.01.006
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1. Neuroscience. 2005;132(3):659-64.
Coherent spike-wave oscillations in the cortex and subthalamic nucleus of the
freely moving rat.
Magill PJ(1), Sharott A, Harnack D, Kupsch A, Meissner W, Brown P.
Author information:
(1)Medical Research Council Anatomical Neuropharmacology Unit, University of
Oxford, Oxford OX1 3TH, UK.
The basal ganglia play a critical role in controlling seizures in animal models
of idiopathic non-convulsive (absence) epilepsy. Inappropriate output from the
substantia nigra pars reticulata (SNr) is known to exacerbate seizures, but the
precise neuronal mechanisms underlying abnormal activity in SNr remain unclear.
To test the hypothesis that cortical spike-wave oscillations, often considered
indicative of absence seizures, propagate to the subthalamic nucleus, an
important afferent of SNr, we simultaneously recorded local field potentials from
the frontal cortex and subthalamic nucleus of freely moving rats. Spontaneous
spike-wave oscillations in cortex (mean dominant frequency of 7.4 Hz) were
associated with similar oscillations in the subthalamic nucleus (mean of 7.9 Hz).
The power of oscillations at 5-9 Hz was significantly higher during spike-wave
activity as compared with rest periods without this activity. Importantly,
spike-wave oscillations in cortex and subthalamic nucleus were significantly
coherent across a range of frequencies (3-40 Hz), and the dominant (7-8 Hz)
oscillatory activity in the subthalamic nucleus typically followed that in cortex
with a small time lag (mean of 2.7 ms). In conclusion, these data suggest that
ensembles of subthalamic nucleus neurons are rapidly recruited into oscillations
during cortical spike-wave activity, thus adding further weight to the importance
of the subthalamic nucleus in absence epilepsy. An increase in synchronous
oscillatory input from the subthalamic nucleus could thus partly underlie the
expression of pathological activity in SNr that could, in turn, aggravate
seizures. Finally, these findings also reiterate the importance of oscillations
in these circuits in normal behaviour.
DOI: 10.1016/j.neuroscience.2005.01.006
PMID: 15837127 [Indexed for MEDLINE]