F. Amzica et al., INSTRUMENTAL-CONDITIONING OF FAST (20 TO 50-HZ) OSCILLATIONS IN CORTICOTHALAMIC NETWORKS, Proceedings of the National Academy of Sciences of the United Statesof America, 94(5), 1997, pp. 1985-1989
Cats were instrumentally conditioned to generate grouped fast (20- to
50-Hz) oscillations in motor cortex (area 4). Over seven experimental
sessions, there was a spatially selective increased generation of grou
ped fast oscillations in that electroencephalogram lead. This locally
increased generation of fast oscillations in cortex was associated wit
h a widespread increase in synchrony of fast oscillations in thalamoco
rtical networks, as demonstrated by crosscorrelations between intracor
tical, corticothalamic, and intrathalamic field potentials, A three-se
ssion extinction period abolished the local increase in generation of
grouped fast oscillations and reset the thalamocortical synchrony of f
ast oscillations to control values, A subsequent series of seven sessi
ons with instrumental conditioning of fast oscillations in visual cort
ex (area 17) reproduced the results from area 4, with a spatially sele
ctive increased generation of grouped fast oscillations in the criteri
on lead, associated with a widespread increase in thalamocortical sync
hrony of fast oscillations, In addition to their presence during the c
onditioning sessions, the changes in synchrony of fast oscillations we
re expressed during periods of quiet waking, rapid-eye-movement sleep,
and nonrapid-eye-movement sleep recorded during the first hour after
the end of the conditioning.