Basal ganglia: structure and computations

Abstract

Until recently the basal ganglia of the mammalian brain have attracted little attention from theoretical neurobiologists. Traditional views of the functioning of the basal ganglia are based on their biomedical importance in disorders such as Parkinson's disease. Their contribution to normal brain functions has remained poorly understood. Experimental investigations over the past few decades have produced a wealth of detailed information about the structure of the basal ganglia and the physiological properties of their component neurones. It has become evident that the basal ganglia play a role in the selection and performance of learnt behaviours, and also in the effects of reinforcement on acquisition and maintenance of new behaviours. At present it is difficult to link the symptoms of basal ganglia disorders to these basic facts, in part because very few theoretical models attempt to incorporate the information that is now available. Computational modelling can help to advance theoretical understanding in this area by establishing explicit links between different levels of organization: from the effects of neurotransmitters such as dopamine on synaptic plasticity, through the dynamic interactions within subpopulations of neurons, to system-level interactions between the basal ganglia and cerebral cortex. The aim of this review is to outline existing knowledge of the basal ganglia in relation to previous computer modelling work, and to suggest ways of making use of the new experimental findings in the next generation of models.

Incidental learning of rewarded associations bolsters learning on an associative task.

“…These findings are consistent with current models of the basal ganglia, where dopamine acts as a teaching signal to train the dorsal striatum to make accurate and efficient responses (Frank, 2005;Wickens, 1997). Although we did not measure neural activity in our experiments, the current results are consistent with gradual basal-ganglia mediated learning (Ashby & Maddox, 2011;Delgado et al, 2005;Frank, 2005;Galvan et al, 2005;Palminteri et al, 2011;Palminteri et al, 2009).…”

A computational model of action selection in the basal ganglia. I. A new functional anatomy

“…The anatomical and physiological data which form the basis of our model are well known, and are described in several recent reviews (Gerfen and Wilson 1996;Mink 1996;Wickens 1997;Redgrave et al 1999). The primate basal ganglia sub-nuclei and their intrinsic connections are shown in schematic form in Fig.…”

What do the basal ganglia do? A modeling perspective

“…Wickens (1997) investigated the dynamics of such local neighborhoods of striatal neurons using network models. Under varying assumptions of topology and size, it was observed that reciprocal inhibition will usually lead to a network dynamic of competition, that is, the most active neurons will tend to suppress activity in their less active neighbors.…”