The Anatomical and Functional Organization of the Human Visual Pulvinar

Abstract

The pulvinar is the largest nucleus in the primate thalamus and contains extensive, reciprocal connections with visual cortex. Although the anatomical and functional organization of the pulvinar has been extensively studied in old and new world monkeys, little is known about the organization of the human pulvinar. Using high-resolution functional magnetic resonance imaging at 3 T, we identified two visual field maps within the ventral pulvinar, referred to as vPul1 and vPul2. Both maps contain an inversion of contralateral visual space with the upper visual field represented ventrally and the lower visual field represented dorsally. vPul1 and vPul2 border each other at the vertical meridian and share a representation of foveal space with iso-eccentricity lines extending across areal borders. Additional, coarse representations of contralateral visual space were identified within ventral medial and dorsal lateral portions of the pulvinar. Connectivity analyses on functional and diffusion imaging data revealed a strong distinction in thalamocortical connectivity between the dorsal and ventral pulvinar. The two maps in the ventral pulvinar were most strongly connected with early and extrastriate visual areas. Given the shared eccentricity representation and similarity in cortical connectivity, we propose that these two maps form a distinct visual field map cluster and perform related functions. The dorsal pulvinar was most strongly connected with parietal and frontal areas. The functional and anatomical organization observed within the human pulvinar was similar to the organization of the pulvinar in other primate species.

Population Receptive Field Estimation Reveals New Retinotopic Maps in Human Subcortex

“…The LP and IP have a similar polar angle representation where the upper vertical meridian is represented inferior and lateral while the lower vertical meridian is represented more superior and medial. The orientations of our pRF maps correspond well with previous imaging experiments in the human pulvinar (Cotton and Smith, 2007;Smith et al, 2009;Schneider, 2011;Arcaro et al, 2015). We also found that the IP shares a foveal representation with the LP and a positive relationship between pRF size and eccentricity in both nuclei.…”

“…For example, the subcortical visual system, including the lateral geniculate nucleus (LGN) and pulvinar nuclei in the thalamus and the superior colliculus (SC) in the brainstem, contains important hubs that regulate the flow of visual information from the retina to cortex and are implicated in visual attention (O'Connor et al, 2002;Schneider and Kastner, 2009;Schneider, 2011;Arcaro et al, 2015). However, the human subcortical visual system remains poorly understood.…”

The HCP 7T Retinotopy Dataset: Description and pRF Analysis

“…The subcortical 11 fMRI data were aligned using FNIRT nonlinear volume registration based on T1-weighted image 12 intensities (Glasser et al, 2013). Several subcortical nuclei have retinotopic maps that have been 13 previously measured using fMRI (Schneider et al, 2004;Schneider and Kastner, 2005; Cotton and Smith, 14 2007; Katyal et al, 2010;Arcaro et al, 2015;DeSimone et al, 2015). In contrast to cortex, subcortical 15 structures are not easily represented as 2D surfaces, and hence it is more difficult to visualize complete 16 maps.…”

Brain bases of the automaticity via visual search task

“…The pulvinar nucleus is the largest thalamic nucleus in the primate brain (Saalmann and Kastner, 2011;Arcaro, Pinsk and Kastner 2015). In terms of visual perception, four areas have been distinguished: lateral and ventral pulvinar with retinotopic organization, and ventromedial and dorsal areas without topographic organization (Saalmann and Kastner, 2011).…”

“…In terms of visual perception, four areas have been distinguished: lateral and ventral pulvinar with retinotopic organization, and ventromedial and dorsal areas without topographic organization (Saalmann and Kastner, 2011). The pulvinar has cortical and cortico-thalamo-cortical afferences and efferences, and because of its location, is thought to regulate corticocortical communications (Sherman and Guillery, 2006;Arcaro et al, 2015). The pulvinar has diverse representations of the contralateral visual field and, there have been at least two identified maps of the space in the lateral aspect of the ventral pulvinar (Arcaro et al, 2015).…”