Waveforms for early thalamic and cortical population responses to unil
ateral median nerve stimulation at the wrist were determined non-invas
ively for six subjects from 122-channel magnetoencephalographic data.
Biphasic responses in contralateral ventral thalamus were obtained in
9 hemispheres similar to depth-electrode results reported for patients
. Thalamic responses occurred at 15.1-17.4 and at 19.2-24 ms. Response
s in contralateral sensorimotor cortex began at 16.3-18.8 ms.