M1, lateral premotor, SMA, Lateral prefrontal cortex, OFC, ACC and association cortex SMI (6). Basal ganglia circuits have a direct pathway and an indirect pathway. The direct pathway facilitates a particular behavior while the indirect pathway suppresses the competing behavior. The hyper direct pathway connects the cerebral cortex and the Subthalamic nuclei which are responsible for termination of the behavior (6). The Striatum receives major input from the cerebral cortex and has an inhibitory effect on the Globus Pallidus(6). The STN provides glutamatergic input to G.P (Internal and external). The globus pallidus is the source of output to thalamus which is under inhibitory control(6). From here the thalamus sends information back to the cortical areas with which it forms a closed loop(M1, SMA, lateral PM, Lateral prefrontal cingulated, ACC and MOFC)(6). The B.G acts as a funnel which receives information (motor, cognitive) from different regions of the cortex (motor, cognitive and limbic) resulting in the partial integration of data which is then passed on to the thalamus where the information is fully integrated and sent to the cortex(6). Cortico-strial connections are responsible for the goal-directed behavior and are associated with processes that lead to movement such as cognition, motivation, and emotion(25).The BG has connections with different areas of the cortex, such as the OFC & medial PFC …show more content…
For the execution of goal-directed volition motor plan, a model consisting of minicolumn is hypothesized which makes the interaction between cortical and association areas possible. This model gives the ‘ready,set-go’ sequence of events making the execution of goal-directed volitional motor plan possible(6). Different substructures are connected by these minicolumns, such as pons and cortex and striatum, cortex and spinal cord which have the motor and cognitive function depending on whether it is an intention or action. The Go/No-Go minicolumns are under strict inhibitory control provided by the double bouquet cells and Chandelier or basket cells. GO or N0-Go are regulated by the process of dis-inhibition or inhibition respectively(6). The activation pattern of these minicolumns differs according to the stage of learning(6). During the process of learning networks across the B.G, cerebellum, brainstem, spinal center and cortex are facilitated by the sensorimotor system(6). In the early stage, the activation is widespread, slow and feedback dependent. Later with practice, the pattern of activation is consolidated, fast, and efficient with ever more consolidation and precision(6). BG and cerebellum are active in overt volitions actions such as reading, writing, speaking but also with