The striatum is the input component of the basal ganglia from the cerebral cortex. It includes the caudate, putamen,
and nucleus accumbens. Thus, the striatum is an important component in limbic frontal-subcortical circuitry and is
believed to be relevant both for reward-guided behaviors and for the expression of psychosis. The dorsal striatum is
composed of the caudate and putamen, both of which are further subdivided into pre- and post-commissural components.
The ventral striatum (VS) is primarily composed of the nucleus accumbens. The striatum can be functionally divided
into three broad regions: 1) a limbic; 2) a cognitive and 3) a sensor-motor region. The approximate corresponding
anatomic subregions for these 3 functional regions are: 1) the VS; 2) the pre/post-commissural caudate and the pre-commissural
putamen and 3) the post-commissural putamen.
We believe assessing these subregions, separately, in disorders with limbic and cognitive impairment such as
schizophrenia may yield more informative group differences in comparison with normal controls than prior parcellation
strategies of the striatum such as assessing the caudate and putamen. The manual parcellation of the striatum into these
subregions is currently defined using certain landmark points and geometric rules. Since identification of these areas is
important to clinical research, a reliable and fast parcellation technique is required.
Currently, only full manual parcellation using editing software is available; however, this technique is extremely
time intensive. Previous work has shown successful application of heuristic rules into a semi-automatic platform1. We
present here a semi-automatic algorithm which implements the rules currently used for manual parcellation of the
striatum, but requires minimal user input and significantly reduces the time required for parcellation.