Posterior parietal cortex as part of a neural network for directed attention in rats

A rodent model of directed attention has been developed based upon behavioral analysis of contralateral neglect, pharmacological manipulations, and anatomical analysis of neural circuitry. In each of these three domains the rodent model exhibits striking similarities to humans. We hypothesize that there is a specific thalamo-cortical-basal ganglia network that subserves spatial attentional functions. Key components of this network are medial agranular and posterior parietal cortex, dorsocentral striatum, and the lateral posterior thalamic nucleus. Several issues need to be addressed before we can hope to realistically understand or model the functions of this network. Among these are the roles of medial versus lateral posterior parietal cortex; cholinergic mechanisms in attention; interhemispheric interactions; the role of synchronous firing at the cortical, striatal, and thalamic levels; interactions between cortical and thalamic projections to the striatum; interactions between cortical and nigral inputs to the thalamus; the role of collicular inputs to the lateral posterior thalamic nucleus; the role of cerebral cortex versus superior colliculus in driving the motor output expressed as orienting behavior during directed attention; the extent to which the circuitry we describe for directed attention also plays a role in other forms of attention.