The Cognitive Thalamus as a Gateway to Mental Representations

Abstract

Historically, the thalamus has been viewed as little more than a relay, simply transferring information to key players of the cast, the cortex and hippocampus, without providing any unique functional contribution. In recent years, evidence from multiple laboratories researching different thalamic nuclei has contradicted this idea of the thalamus as a passive structure. Dated models of thalamic functions are being pushed aside, revealing a greater and far more complex contribution of the thalamus for cognition. In this Viewpoints article, we show how recent data support novel views of thalamic functions that emphasize integrative roles in cognition, ranging from learning and memory to flexible adaption. We propose that these apparently separate cognitive functions may indeed be supported by a more general role in shaping mental representations. Several features of thalamocortical circuits are consistent with this suggested role, and we highlight how divergent and convergent thalamocortical and corticothalamic pathways may complement each other to support these functions. Furthermore, the role of the thalamus for subcortical integration is highlighted as a key mechanism for maintaining and updating representations. Finally, we discuss future areas of research and stress the importance of incorporating new experimental findings into existing knowledge to continue developing thalamic models. The presence of thalamic pathology in a number of neurological conditions reinforces the need to better understand the role of this region in cognition.

Metastable neural dynamics underlies cognitive performance across multiple behavioural paradigms

“…Figure 3 shows the largest connected sub-graph of increased metastability detected by the NBS at a fixed threshold for all seven tasks where each node is scaled to reflect its relative importance within the sub-graph (the sum of its effect sizes). Cortical regions associated with top-down attentional/cognitive control (including fronto-parietal and dorsal attention networks) were the most active across the seven tasks along with thalamo-cortical interactions linked to memory, learning, and flexible adaptation (Alcaraz et al, 2018;Wolff and Vann, 2018). Increases in metastability were more widespread than equivalent increases in synchrony…”

Mammillothalamic disconnection alters hippocampo-cortical oscillatory activity and microstructure: Implications for diencephalic amnesia

“…According to mnemonic models based on the Papez circuit, the mammillary bodies and anterior thalamic nuclei relay information from the hippocampal formation to the cingulate cortex (Delay and Brion, 1969;Papez, 1937). These models place the medial mammillary nuclei and anterior thalamic nuclei downstream from the hippocampus and, as such, attribute little intrinsic importance to these structures; instead, they are merely considered passive relays of hippocampal information (Wolff and Vann, 2019).…”

Static and Dynamic Aspects of Cerebro-Cerebellar Functional Connectivity are Associated with Self-reported Measures of Impulsivity: A Resting-State fMRI Study

“…Finally, the thalamus is known for being a hub that relays sensory input towards the cerebral cortex and provide channels for the cerebellum and basal-ganglia to communicate at the cortical and sub-cortical levels (Hintzen et al, 2018). The thalamus is connected to many brain regions and is involved in response inhibition, emotion, arousal, memory, and cognitive flexibility (Taber et al, 2004;Rikhye et al, 2018;Wolff and Vann, 2019).…”