الفهرس 
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Abstract
The basal ganglia (BG) are a group of sub-cortical nuclei involved in a variety of
processes including motor, associative and cognitive functions (Mink, 1996, Bolam, 2000).
The BG circuits form a complex loop of nuclei that connect the cortex to the thalamus and are
important for the selection and initiation of motor plans and suppression of unwanted
actions(Schmidt ,et al, 2013). BG output connections to thalamus are inhibitory and these
inhibitory signals might play a key role to selectively inhibit competing motor programs in
order to prevent them from interfering with voluntary movements that have been selected in
goal-directed behavior. The importance of the BG in movement is perhaps best illustrated by
the motor impairments that follow the dysfunction of BG neuronal network dynamics. Indeed,
in neurological disorder, such as Parkinson’s disease, movements become more difficult to
make, as if the body were somehow made rigid and resistive to changes in position. In others,
such as Huntington’s disease, useless movements interfere with the useful ones. These
symptoms only affect voluntary goal-directed movements and the neuronal changes induced
by those disorders have help to establishing classic models of basal ganglia anatomofunctional
organization and defining their key role in movement control (Gordon-M, 2004,
Mink, 1996).