Premium
Exploring the connectivity between the cerebellum and motor cortex in humans
Author(s) -
Daskalakis Zafiris J.,
Paradiso Guillermo O.,
Christensen Bruce K.,
Fitzgerald Paul B.,
Gunraj Carolyn,
Chen Robert
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2003.059808
Subject(s) - transcranial magnetic stimulation , neuroscience , motor cortex , excitatory postsynaptic potential , inhibitory postsynaptic potential , cerebellum , stimulation , primary motor cortex , psychology , stimulus (psychology) , silent period , cerebellar cortex , psychotherapist
Animal studies have shown that cerebellar projections influence both excitatory and inhibitory neurones in the motor cortex but this connectivity has yet to be demonstrated in human subjects. In human subjects, magnetic or electrical stimulation of the cerebellum 5–7 ms before transcranial magnetic stimulation (TMS) of the motor cortex decreases the TMS‐induced motor‐evoked potential (MEP), indicating a cerebellar inhibition of the motor cortex (CBI). TMS also reveals inhibitory and excitatory circuits of the motor cortex, including a short‐interval intracortical inhibition (SICI), long‐interval intracortical inhibition (LICI) and intracortical facilitation (ICF). This study used magnetic cerebellar stimulation to investigate connections between the cerebellum and these cortical circuits. Three experiments were performed on 11 subjects. The first experiment showed that with increasing test stimulus intensities, LICI, CBI and ICF decreased, while SICI increased. The second experiment showed that the presence of CBI reduced SICI and increased ICF. The third experiment showed that the interaction between CBI and LICI reduced CBI. Collectively, these findings suggest that cerebellar stimulation results in changes to both inhibitory and excitatory neurones in the human motor cortex.