Objective (Real-world) Motion Responses in Scene Responsive Regions

We perceive scenes as stable even when eye movements induce retinal motion, for example during pursuit of a moving object. Mechanisms mediating perceptual stability have primarily been examined in motion regions of the dorsal visual pathway. Here we examined whether motion responses in human scene regions are encoded in eye- or world centered reference frames. We recorded brain responses in human participants using fMRI while they performed a well-controlled visual pursuit paradigm previously used to examine dorsal motion regions. In addition, we examined effects of content by using either natural scenes or their Fourier scrambles. We found that parahippocampal place area (PPA) responded to motion only in world- but not in eye-centered coordinates, regardless of scene content. The occipital place area (OPA) responded to both, objective and retinal motion equally, and retrosplenial cortex (RSC) had no motion responses but responded to pursuit. Only PPA’s objective motion responses were higher during scenes than scrambled images, although there was a similar trend in OPA. These results indicate a special role of PPA in representing its content in real-world coordinates. Our results question a strict subdivision of dorsal “what” and ventral “where” streams, and suggest a role of PPA in contributing to perceptual stability

Motion responses in scene-selective regions

The vast majority of studies on scene processing were conducted using stationary scenes. However, during natural vision, scene views change dynamically due to self-induced eye-, head-, and body-motion, and these dynamic changes are crucial for other higher-level functions such as navigation, self-motion perception, and spatial updating. Yet, we do not know whether or how scene selective regions are modulated by visual motion and to which degree their motion response depends on scene content. In this study, we used fMRI to examine both questions using a 2 × 2 factorial design with the factors 2D planar motion (motion versus static) and scene content (natural scenes versus their Fourier scrambles). We found that among independently localized scene-responsive regions, parahippocampal place area (PPA) and transverse occipital sulcus (TOS), also referred to as occipital place area (OPA), were significantly motion responsive, whereas retrosplenial cortex (RSC) was not. Additionally, PPA showed an interaction between motion and scene in that it responded more to motion in context of scenes than scramble, with similar trends in TOS and RSC. These results provide a novel functional dissociation between motion-responsive PPA and TOS/OPA versus motion-unresponsive RSC and suggest a strong role for PPA in integrating motion and scene content

Real-world Motion Responses in Scene Responsive Regions

We perceive scenes as stable even when eye movements induce retinal motion, for example during pursuit of a moving object. Mechanisms mediating perceptual stability have primarily been examined in motion regions of the dorsal visual pathway. Here we examined whether motion responses in human scene regions are encoded in eye- or world centered reference frames. We recorded brain responses in human participants using fMRI while they performed a well-controlled visual pursuit paradigm previously used to examine dorsal motion regions. In addition, we examined effects of content by using either natural scenes or their Fourier scrambles. We found that parahippocampal place area (PPA) responded to motion only in world- but not in eye-centered coordinates, regardless of scene content. The occipital place area (OPA) responded to both, objective and retinal motion equally, and retrosplenial cortex (RSC) had no motion responses but responded to pursuit. Only PPA’s objective motion responses were higher during scenes than scrambled images, although there was a similar trend in OPA. These results indicate a special role of PPA in representing its content in real-world coordinates. Our results question a strict subdivision of dorsal “what” and ventral “where” streams, and suggest a role of PPA in contributing to perceptual stability