A computational perspective of the role of Thalamus in cognition
This work offers a revised theoretical framework for understanding thalamic function in cognition, which could inform neuroscience research and potential interventions for cognitive disorders.
The paper challenges the traditional view of the thalamus as a simple relay for cortical inputs, proposing instead that it plays a role in dynamically selecting cortical representations to optimize information processing. It highlights the mediodorsal nucleus's involvement in modulating cortical computations through intrinsic thalamic mechanisms.
Thalamus has traditionally been considered as only a relay source of cortical inputs, with hierarchically organized cortical circuits serially transforming thalamic signals to cognitively-relevant representations. Given the absence of local excitatory connections within the thalamus, the notion of thalamic `relay' seemed like a reasonable description over the last several decades. Recent advances in experimental approaches and theory provide a broader perspective on the role of the thalamus in cognitively-relevant cortical computations, and suggest that only a subset of thalamic circuit motifs fit the relay description. Here, we discuss this perspective and highlight the potential role for the thalamus -- and specifically mediodorsal (MD) nucleus -- in dynamic selection of cortical representations through a combination of intrinsic thalamic computations and output signals that change cortical network functional parameters. We suggest that through the contextual modulation of cortical computation, thalamus and cortex jointly optimize the information/cost tradeoff in an emergent fashion. We emphasize that coordinated experimental and theoretical efforts will provide a path to understanding the role of the thalamus in cognition, along with an understanding to augment cognitive capacity in health and disease.