Synchronized oscillations at alpha and theta frequencies in the lateral geniculate nucleus.
In relaxed wakefulness, the EEG exhibits robust rhythms in the alpha band (8-13 Hz), which decelerate to theta (approximately 2-7 Hz) frequencies during early sleep. In animal models, these rhythms occur coherently with synchronized activity in the thalamus. However, the mechanisms of this thalamic activity are unknown. Here we show that, in slices of the lateral geniculate nucleus maintained in vitro, activation of the metabotropic glutamate receptor (mGluR) mGluR1a induces synchronized oscillations at alpha and theta frequencies that share similarities with thalamic alpha and theta rhythms recorded in vivo. These in vitro oscillations are driven by an unusual form of burst firing that is present in a subset of thalamocortical neurons and are synchronized by gap junctions. We propose that mGluR1a-induced oscillations are a potential mechanism whereby the thalamus promotes EEG alpha and theta rhythms in the intact brain.
Hughes
Stuart W
SW
School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, United Kingdom. hughessw@cardiff.ac.uk
Lörincz
Magor
M
Cope
David W
DW
Blethyn
Kate L
KL
Kékesi
Katalin A
KA
Parri
H Rheinallt
HR
Juhász
Gábor
G
Crunelli
Vincenzo
V
D000200:Action Potentials / Q000502:physiology*; D000513:Alpha Rhythm / Q000379:methods*; D000818:Animals; D002415:Cats; D003344:Cortical Synchronization / Q000379:methods*; D005829:Geniculate Bodies / Q000502:physiology*; D013826:Theta Rhythm / Q000379:methods*