Spatiotemporal characteristics of human intrathalamic high-frequency (>400Hz) SEP components.
Somatosensory evoked potentials (SEP) were recorded in 11 awake patients from intrathalamic electrodes implanted for tremor treatment. A brief (7ms) polyphasic SEP burst (mean frequency > 1000 Hz, with occasional drops to 600 Hz) was found to be superimposed onto the primary thalamic low-frequency response at 16 ms (tP16) and preceeded a scalp-derived 600 Hz burst by 4 ms. Thalamic burst and tP16 generators had a close intrathalamic co-localization. The thalamic burst strength varied more than and independently from tP16. High-frequency thalamic SEP bursts probably reflect a superposition of slightly asynchronously triggered population spikes, generated e.g. by bursting thalamocortical relay cells. The thalamic burst amplitude fluctuations independent from low-frequency responses suggest a peculiar role for thalamic burst coding in awake subjects.
Klostermann
F
F
Neurophysics Group, Department of Neurology, Klinikum Benjamin Franklin, Freie Universität, Berlin, Germany.
Funk
T
T
Vesper
J
J
Curio
G
G
D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D012535:Scalp; D013788:Thalamus / Q000166:cytology / Q000502:physiology*; D013997:Time Factors; D014202:Tremor / Q000628:therapy; D014851:Wakefulness