What do the basal ganglia do? A modeling perspective

Abstract

Basal ganglia (BG) constitute a network of seven deep brain nuclei involved in a variety of crucial brain functions including: action selection, action gating, reward based learning, motor preparation, timing, etc. In spite of the immense amount of data available today, researchers continue to wonder how a single deep brain circuit performs such a bewildering range of functions. Computational models of BG have focused on individual functions and fail to give an integrative picture of BG function. A major breakthrough in our understanding of BG function is perhaps the insight that activities of mesencephalic dopaminergic cells represent some form of 'reward' to the organism. This insight enabled application of tools from 'reinforcement learning,' a branch of machine learning, in the study of BG function. Nevertheless, in spite of these bright spots, we are far from the goal of arriving at a comprehensive understanding of these 'mysterious nuclei.' A comprehensive knowledge of BG function has the potential to radically alter treatment and management of a variety of BG-related neurological disorders (Parkinson's disease, Huntington's chorea, etc.) and neuropsychiatric disorders (schizophrenia, obsessive compulsive disorder, etc.) also. In this article, we review the existing modeling literature on BG and hypothesize an integrative picture of the function of these nuclei.

The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere

“…Fluctuations in incentive motivation were also found to correlate with activity in brain regions involved in attention and motor function, as well as with activity in the dopaminergic midbrain and its projection sites such as the ventral striatum (Knutson et al, 2001a;Knutson et al, 2005;Tobler et al, 2005). These findings, together with findings highlighting a crucial role for DA in activational aspects of behaviour Everitt, 1992, 2007), have led researchers to suggest that the impact of motivation on behaviour is mediated by DA (Chakravarthy et al, 2010;Salamone and Correa, 2012;Wise, 2004). Several studies have also shown that the same neural circuitry may also represent the expected value of stimuli presented to one hemifield, but largely restricted to the contralateral hemisphere (Gershman et al, 2009;Palminteri et al, 2009;Wunderlich et al, 2009), suggesting the possibility of unilaterally activating the brain's motivational system.…”

Visual object categorization in birds and primates: Integrating behavioral, neurobiological, and computational evidence within a “general process” framework

“…Several of the functions that are ascribed to the basal ganglia, together with the role of prediction error in each of these functions, can be captured through reinforcement learning models (Chakravarthy, Joseph, & Bapi, 2010).…”

Role of Basal Ganglia in Swallowing Process: A Systematic Review

“…Studies on functional magnetic resonance imaging (fMRI) have recognized the anatomic sections, which are active during swallowing, including the chief sensory and motor cortex, additional motor area (SMA), cingulate cortex, insula, operculum, prefrontal and inferior frontal cortices, BG, thalamus, and cerebellum [43][44][45][46][47][48]. As mentioned earlier, automatic movements of swallowing are controlled by BG that establishes accurate timing and spacing in this process [37,38].…”

“…Recognized swallow-associated augmented blood in the putamen PET Hartnick et al [29] Rise in swallow-induced local activity in putamen, globus pallidus, and substantia nigra f-MRI Suzuki et al [30] The right putamen was introduced as a focal point for activation f-MRI Martin et al [31] Discovered BG activation through water oral combination f-MRI PET Hamdy et al [20] I ranian R ehabilitation Journal which are primary and secondary somato-sensory, primary motor cortex, and premotor areas [37,38]. In addition, BG has extensive connections with the thalamus and other sub-cortical structures [39,40].…”