Task-related variation in corticospinal output evoked by transcranial magnetic stimulation in the macaque monkey.
AUTOR(ES)
Baker, S N
RESUMO
1. A volley evoked by transcranial magnetic stimulation (TMS) over the motor cortex was recorded from the medullary pyramid in an awake monkey performing a precision grip task. It was identified as corticospinal using a collision test. 2. The volley latency was 0.50 ms, indicating that it was produced by direct activation of corticospinal neurones. 3. A mean modulation of 13% in the amplitude of this volley was seen during task performance, with the largest volley occurring during the hold phase of the task. A similar pattern of modulation was seen in the EMG responses of hand and forearm muscles to TMS. 4. No comparable modulation was observed in a volley evoked by electrical stimulation of the corticospinal fibres via chronically implanted electrodes in the cerebral peduncle. 5. The results are compatible with direct activation of the corticospinal neurones by TMS at a site close to the soma, with the probability of activation by TMS depending on the current level of cortical excitability.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1156745Documentos Relacionados
- Task-related changes in the effect of magnetic brain stimulation on spinal neurones in man.
- Excitation of the corticospinal tract by electromagnetic and electrical stimulation of the scalp in the macaque monkey.
- Task-related and item-related brain processes of memory retrieval
- Inhibition of motor unit discharge in humans evoked by transcranial magnetic stimulation.
- Direct comparison of corticospinal volleys in human subjects to transcranial magnetic and electrical stimulation.