Chemistry of the Adaptive Mind: Lessons from Dopamine

Abstract

The brain faces various computational tradeoffs, such as the stability-flexibility dilemma. The major ascending neuromodulatory systems are well suited to dynamically regulate these tradeoffs depending on changing task demands. This follows from various general principles of chemical neuromodulation, which are illustrated with evidence from pharmacological neuroimaging studies on striatal dopamine's role in output gating and cost-benefit choice of cognitive tasks. The work raises open questions, including those regarding the top-down cortical control of the midbrain dopamine system, and begins to elucidate the mechanisms underlying the variability in catecholaminergic drug effects. Such drug effects depend on the baseline state of distinct target brain regions, reflecting, in part, the systems' self-regulatory capacity to maintain equilibrium. It is hypothesized that the basal tone of different dopaminergic projection systems reflects the perceived statistics of the environment computed in frontal cortex. By normalizing dopamine levels, dopaminergic drugs might counteract the bias elicited by the perceived environment.

Catecholaminergic Modulation of Semantic Processing in Sentence Comprehension

“… Hypothesized neurotransmitter mechanisms of the catecholaminergic system’s gating function. The figure is adapted from Figure 4 in Cools (2019) . We hypothesized that the CAergic system could up- and downregulate language processing by modifying the striatum to prefrontal cortex (PFC) projections.…”

A computational perspective on the roles of affect in cognitive control

“…More recently, it has been proposed that positive affect can lower the updating 444 threshold of working memory and thus increase flexibility (Dreisbach & Fröber, 2018). These 445 mechanisms are assumed to be mediated by dopamine, a neurotransmitter crucial for reward 446 processing and cognitive control (Cools, 2019). While our current work does not examine affect's 447 influences at each of these levels, it does not preclude the possibility that these function in parallel.…”

Rationalizing Constraints on the Capacity for Cognitive Control

“…In addition, reward and positive affect can bias individuals toward greater flexibility, at the expense of cognitive stability [106,107,108]. A growing body of work suggests that the neurotransmitter dopamine may play a role in regulating this balance (for a comprehensive review, see [109]). .…”

“…An understanding of the fundamental computational dilemmas faced by the representation and processing of information in neural architectures may also provide a novel perspective on cognitive function in psychiatric disorders, manyof which involve deficits in control-dependent behavior[123]. One example concerns the role of dopamine function in the stability-flexibility tradeoff[109]:…”