Neurophysiology of rule switching in the corticostriatal circuit

Abstract

The ability to adjust behavioral responses to cues in a changing environment is crucial for survival. Activity in the medial Prefrontal Cortex (mPFC) is thought to both represent rules to guide behavior as well as detect and resolve conflicts between rules in changing contingencies. While lesion and pharmacological studies have supported a crucial role for mPFC in this type of set-shifting, an understanding of how mPFC represents current rules or detects and resolves conflict between different rules is still unclear. Meanwhile, medial dorsal striatum (mDS) receives major projections from mPFC and neural activity of mDS is closely linked to action selection, making the mDS a potential major player for enacting rule-guided action policies. However, exactly what is signaled by mPFC and how this impacts neural signals in mDS is not well known. In this review, we will summarize what is known about neural signals of rules and set shifting in both prefrontal cortex and dorsal striatum, as well as provide questions and directions for future experiments.

Reversible fronto-occipitotemporal signaling complements task encoding and switching under ambiguous cues

“…Shifting between different types of behavior is one of the core executive control functions (3,4), and switching paradigms have been often used to investigate behavioral flexibility and its underlying neural mechanisms. Previous neuropsychological and neuroimaging studies of human and non-human animals suggest a critical role of the prefrontal cortex in switching tasks and rules (5)(6)(7)(8)(9)(10)(11)(12)(13) (Fig. 1A).…”

Cognitive control involves theta power within trials and beta power across trials in the prefrontal-subthalamic network

“…To our knowledge, this is the first study to provide evidence that STN beta band activity increases in response to higher levels of cognitive control required by a previous trial, and that these increases are associated with slower response times. It is possible that the higher levels of beta power we observed on Go trials that followed a Conflict trial are due to the rule change that occurred across trials (Bissonette and Roesch, 2017). However, this is unlikely as an analysis of the trials that exhibited a rule change in the opposite direction (Conflict trials that followed a Go trial) showed no significant differences.…”

“…Increasing evidence suggests that cortical processing is optimized for predictive coding, and that such top-down predictions are conveyed through beta oscillations (Engel et al, 2001; Buschman and Miller, 2007; van Ede et al, 2011; Brown et al, 2013). The neural mechanisms for predicting a set of task rules should be analogous, and in this case would involve areas like the mPFC that have been implicated in setting goals and rules (Miller and Cohen, 2001; Ridderinkhof et al, 2004; Cohen, 2014; Bissonette and Roesch, 2017). The reductions in mPFC power following Conflict or errors would, according to this paradigm, reflect a switch from a top-down state in which predictions are weighed more heavily to a bottom-up state in which there is greater uncertainty regarding previously held expectations (van Ede et al, 2011; Brown et al, 2013).…”

Cross-hemispheric gamma synchrony between prefrontal parvalbumin interneurons supports behavioral adaptation during rule shift learning

“…An important future direction is determining whether specific classes of prefrontal pyramidal neurons, projecting to particular targets, exhibit increased gamma synchrony during rule shifts. This may be true for projections to dorsomedial striatum, nucleus accumbens, and/or mediodorsal thalamus, because these projections are important for cognitive flexibility 15 , 36 , 37 and PV interneurons strongly inhibit mPFC neurons which project bilaterally to these structures 38 .…”