The Evolution of the Pulvinar Complex in Primates and Its Role in the Dorsal and Ventral Streams of Cortical Processing

Abstract

Current evidence supports the view that the visual pulvinar of primates consists of at least five nuclei, with two large nuclei, lateral pulvinar ventrolateral (PLvl) and central lateral nucleus of the inferior pulvinar (PIcl), contributing mainly to the ventral stream of cortical processing for perception, and three smaller nuclei, posterior nucleus of the inferior pulvinar (PIp), medial nucleus of the inferior pulvinar (PIm), and central medial nucleus of the inferior pulvinar (PIcm), projecting to dorsal stream visual areas for visually directed actions. In primates, both cortical streams are highly dependent on visual information distributed from primary visual cortex (V1). This area is so vital to vision that patients with V1 lesions are considered “cortically blind”. When the V1 inputs to dorsal stream area middle temporal visual area (MT) are absent, other dorsal stream areas receive visual information relayed from the superior colliculus via PIp and PIcm, thereby preserving some dorsal stream functions, a phenomenon called “blind sight”. Non-primate mammals do not have a dorsal stream area MT with V1 inputs, but superior colliculus inputs to temporal cortex can be more significant and more visual functions are preserved when V1 input is disrupted. The current review will discuss how the different visual streams, especially the dorsal stream, have changed during primate evolution and we propose which features are retained from the common ancestor of primates and their close relatives.

Neuronal Activity in the Rat Pulvinar Correlates with Multiple Higher-Order Cognitive Functions

“…There were no differences between these two areas in proportions of allocentric cells. Our findings are in line with the notion that the medial pulvinar may be more involved in ventral visual stream functions and the lateral pulvinar may be more involved in dorsal visual stream functions, as has been suggested for the primate brain [36]. Future research is needed to understand how these subregional differences in the rat pulvinar map onto subregional differences in the primate pulvinar.…”

Hierarchical Organization of Corticothalamic Projections to the Pulvinar

“…Should the organization of CT projections be built upon that of cortico-cortical ones, one may also expect to find, within the pulvinar, an internal organization that would reflect the existence of dorsal and ventral functional pathways. In the macaque, evidence suggests that the anatomical connectivity pattern of specific subnuclei of the pulvinar show a bias toward areas of the ventral or dorsal stream ( Kaas and Lyon 2007 ; Kaas and Baldwin 2019 ), an organization which may also be present in the mouse ( Bennett et al. 2019 ) further strengthening the emerging view that fundamental units of CT computations are not individual thalamic nuclei but more precise thalamic networks linking functionally related cortical areas ( Shipp 2003 ; Halassa and Kastner 2017 ).…”

Laminar distribution of cortical projection neurons to the pulvinar: A comparative study in cats and mice

“…The primate pulvinar consists of distinct subregions projecting to several areas from the associative, somatosensory, and visual cortices (Kaas & Lyon, 2007; Stepniewska, 2003). The visual part of the pulvinar is composed of its lateral and inferior subdivisions which are extensively connected with almost all visual cortical areas (Arcaro et al, 2015; Barron et al, 2015; Casanova, 2004; Chalfin et al, 2007; Kaas & Baldwin, 2019; Leh et al, 2008). In carnivores and rodents, the lateral posterior (LP) nucleus is thought to be the homolog of the primate visual pulvinar (Kaas & Lyon, 2007; Nakamura et al, 2015; Raczkowski & Rosenquist, 1983).…”