Optic flow selectivity in the macaque parieto-occipital sulcus

Abstract

In humans, several neuroimaging studies have demonstrated that passive viewing of optic flow stimuli activates higher-level motion areas, like V6 and the cingulate sulcus visual area (CSv). In macaque, there are few studies on the sensitivity of V6 and CSv to egomotion compatible optic flow. The only fMRI study on this issue revealed selectivity to egomotion compatible optic flow in macaque CSv but not in V6 (Cotterau et al, 2017, but see Fan et al. 2015). Yet, it is unknown whether monkey visual motion areas MT+ and V6 display any distinctive fMRI functional profile relative to the optic flow stimulation, as it is the case for the homologous human areas (Pitzalis et al., 2010). Here, we described the sensitivity of the monkey brain to two motion stimuli (Radial Rings and Flow Fields) originally used in humans to functionally map the motion middle temporal area MT+ (Tootell et al. 1995a,b) and the motion medial parietal area V6 (Pitzalis et al. 2010), respectively. In both animals, we found regions responding only to optic flow or Radial Rings stimulation, and regions responding to both stimuli. A region in the parieto occipital sulcus (likely including V6) was one of the most highly selective area for coherently moving fields of dots, further demonstrating the power of this type of stimulation to activate V6 in both humans and monkeys. We did not find any evidence that putative macaque CSv responds to Flow Fields.

The Role of Optic Flow and Gaze Direction on Postural Control

“…Thus, the human brain needs a large cortical network to encode self-motion perception. This network includes the homologues of area MST [38][39][40], area VIP [41], area PEc [42], the parieto-insular vestibular cortex [43,44] and area V6 in the parieto-occipital sulcus [45,46]. It has to be noted that the laboratory studies performed on monkeys required the animals to orient the gaze toward a fixation point with the restrained head (database search using "freely viewing monkey AND optic flow" retrieved no results).…”

Neural sensitivity to translational self‐ and object‐motion velocities

“…In monkeys, an optic flow stimulation that is compatible with self-motion is able to activate a series of higher-level motion areas, such as the ventral intraparietal area (VIP; Bremmer et al, 2001;Duhamel et al, 1998), the middle superior temporal area (MST; Duffy, 1998), and the caudal portion of the posterior parietal cortex (PEc; Raffi et al, 2002). In addition, we recently revealed in a fMRI study on macaque monkeys (Pitzalis et al, 2021) that also the medial motion area V6 (Galletti et al, 1996(Galletti et al, , 1999 is responsive to flow fields. In humans, recent human neuroimaging studies revealed the existence of a wider network of higher-level multisensory cortical regions (called egomotion regions) that are sensitive to optic processing, that is, the V6 complex (or V6+, involving the two retinotopic regions V6 and V6Av; Pitzalis et al, 2006Pitzalis et al, , 2010Tosoni et al, 2015;Serra et al, 2019; see also Sulpizio et al, 2023 for a recent review) in the parietal occipital sulcus, the MT complex (or MT+; Morrone et al, 2000;Pitzalis, Bozzacchi, et al, 2013;Sulpizio et al, 2022;Tootell et al, 1995) in the lateral temporo-occipital cortex, area V3A (Orban et al, 2003;Pitzalis et al, 2010;Serra et al, 2019;Sulpizio et al, 2020;Sunaert et al, 1999;Tootell et al, 1997) in the transverse occipital sulcus, the putative human homolog of area VIP in the intraparietal sulcus (IPSmot; Bremmer et al, 2001, Cardin & Smith, 2010, Pitzalis, Sdoia, et al, 2013, the cingulate sulcus areas (CSv and pCi; Serra et al, 2019;Wall & Smith, 2008), the adjacent precuneus (PEc; Pitzalis et al, 2019), and the posterior insular cortex (PIC; Frank et al, 2014).…”

Common and specific activations supporting optic flow processing and navigation as revealed by a meta-analysis of neuroimaging studies

“…Neurophysiological evidence on monkeys revealed the crucial role of a series of cortical nodes in the analysis of optic flow. For instance, passive viewing of optic flow stimuli activates the parieto-occipital sulcus, likely including V6 (Pitzalis et al 2021 ) and area PEc in the anterior precuneus (pCu) (Raffi et al 2002 , 2011 ). Additionally, the achievement of a robust perception of self-motion has been ascribed to a set of multisensory regions as the dorsal portion of medial superior temporal area (MSTd), the ventral intraparietal area (VIP), the visual posterior sylvian area (VPS) that are particularly implicated in the multimodal estimate of heading by combining visual and vestibular cues to self-motion direction (Duffy 1998 ; Bremmer et al 1999 ; Schlack et al 2002 ; Gu 2018 ; DeAngelis and Angelaki 2012 ).…”