The intralaminar thalamus—an expressway linking visual stimuli to circuits determining agency and action selection

Abstract

Anatomical investigations have revealed connections between the intralaminar thalamic nuclei and areas such as the superior colliculus (SC) that receive short latency input from visual and auditory primary sensory areas. The intralaminar nuclei in turn project to the major input nucleus of the basal ganglia, the striatum, providing this nucleus with a source of subcortical excitatory input. Together with a converging input from the cerebral cortex, and a neuromodulatory dopaminergic input from the midbrain, the components previously found necessary for reinforcement learning in the basal ganglia are present. With this intralaminar sensory input, the basal ganglia are thought to play a primary role in determining what aspect of an organism’s own behavior has caused salient environmental changes. Additionally, subcortical loops through thalamic and basal ganglia nuclei are proposed to play a critical role in action selection. In this mini review we will consider the anatomical and physiological evidence underlying the existence of these circuits. We will propose how the circuits interact to modulate basal ganglia output and solve common behavioral learning problems of agency determination and action selection.

Deep Brain Stimulation for Movement Disorders of Basal Ganglia Origin: Restoring Function or Functionality?

“…1). The CM/Pf-striatal system is seen as providing sensory and salience information to the basal ganglia, which may assist in procedural and reinforcement learning and action selection (see below) [56,57]. Lesions of CM, the motor portions of CM/Pf, have little or no effect in relieving akinesia/ bradykinesia in the MPTP-treated primate [58], although DBS of CM in patients with PD has been reported to be beneficial for dyskinesias in limited studies [59].…”

Cytoarchitecure and Connectivity of the Superior Colliculus in Mouse Brain

“…The superficial layers (ZO, SGR and OP) receive information from visual systems, while the deep layers (IGR, IW, DGR, and DW layer) receive visual, auditory, somatosensory signal from cortex, and inputs from the frontal eyes fields. Therefore, the SC is almost multimodal and associational [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. As shown in the six slices, the superficial layers are significantly different from the deep layers.…”

“…Therefore, the SC is considered recognized as a visual motor integration center of the central nervous system. The superficial layers receive direct visual inputs, but the deep layers receive indirect visual inputs [10][11]. The superficial layer and deep layer cells in morphology differ with respect to two main points: the superficial layer cells have short and dense but not overlapping dendrites, similar to the structure found in the perception of the neurons, with significant differences compared to the relatively long and overlapping neuronal dendrites in the deep layer.…”

Viral vector-based tools advance knowledge of basal ganglia anatomy and physiology

“…The indirect pathway has the longest latency for information to pass from the cortex to the BG output nuclei (Nambu et al 2000). For all of these pathways, information is sent from the GPi and SNr to the ventral motor and intralaminar thalamic nuclei before it is returned to associative and motor cortical areas or to the brain stem and spinal cord (Bosch-Bouju et al 2013;Fisher and Reynolds 2014).…”