The role of the ventral intraparietal area (VIP/pVIP) in the perception of object-motion and self-motion

David T Field,Nicolò Biagi,Laura A Inman

doi:10.1016/j.neuroimage.2020.116679

Abstract

Retinal image motion is a composite signal that contains information about two behaviourally significant factors: self-motion and the movement of environmental objects. It is thought that the brain separates the two relevant signals, and although multiple brain regions have been identified that respond selectively to the composite optic flow signal, which brain region(s) perform the parsing process remains unknown. Here, we present original evidence that the putative human ventral intraparietal area (pVIP), a region known to receive optic flow signals as well as independent self-motion signals from other sensory modalities, plays a critical role in the parsing process and acts to isolate object-motion. We localised pVIP using its multisensory response profile, and then tested its relative responses to simulated object-motion and self-motion stimuli; results indicated that responses were much stronger in pVIP to stimuli that specified object-motion. We report two further observations that will be significant for the future direction of research in this area; firstly, activation in pVIP was suppressed by distant stationary objects compared to the absence of objects or closer objects. Secondly, we describe several other brain regions that share with pVIP selectivity for visual object-motion over visual self-motion as well as a multisensory response.

Highlights

Visual motion provides the brain with behaviourally useful information about self-motion and object-motion
Brain areas surviving the three-way conjunction of visual motion, tactile motion, and auditory motion are presented in Fig. 3; only a very small activation cluster was found in the vicinity of the expected location of putative human ventral intraparietal area (pVIP) (5 voxels in the right ventral intraparietal sulcus centred on coordinates x 1⁄4 28, y 1⁄4 À47, z 1⁄4 46)
It shows that the activation peaks from our three-way conjunction were closer to those of Bremmer et al (2001) than to those of studies that localised ventral intraparietal area (VIP) using different methods; this suggests that our replication of Bremmer’s study was successful, this finding should be interpreted in the context of the weaker auditory activation in pVIP and the stronger multisensory activation we found elsewhere in the brain

Summary

Introduction

Visual motion provides the brain with behaviourally useful information about self-motion and object-motion. During self-motion through a static environment, the current heading direction and path curvature are both reflected systematically within the optic flow (Warren et al, 1991), and at the neural level it has been shown that multiple macaque brain regions contain neurons that are tuned to the necessary global patterns in optic flow as well as the location of the focus of expansion (FOE) in the flow field, which specifies the heading direction if gaze is fixed over time These include: MSTd, Duffy and Wurtz (1991); VIP, Schaafsma and Duysens (1996); area 7a, Siegel and Read (1997); Raffi et al (2002); and FEF, Gu et al (2016). A recent fMRI study of macaque brain activation in response to real objects placed in near extrapersonal space or far space found that VIP was part of the network preferentially activated for objects in near extrapersonal space (Clery et al, 2018)

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Conclusion