Human fMRI Reveals That Delayed Action Re-Recruits Visual Perception

Abstract

Behavioral and neuropsychological research suggests that delayed actions rely on different neural substrates than immediate actions; however, the specific brain areas implicated in the two types of actions remain unknown. We used functional magnetic resonance imaging (fMRI) to measure human brain activation during delayed grasping and reaching. Specifically, we examined activation during visual stimulation and action execution separated by a 18-s delay interval in which subjects had to remember an intended action toward the remembered object. The long delay interval enabled us to unambiguously distinguish visual, memory-related, and action responses. Most strikingly, we observed reactivation of the lateral occipital complex (LOC), a ventral-stream area implicated in visual object recognition, and early visual cortex (EVC) at the time of action. Importantly this reactivation was observed even though participants remained in complete darkness with no visual stimulation at the time of the action. Moreover, within EVC, higher activation was observed for grasping than reaching during both vision and action execution. Areas in the dorsal visual stream were activated during action execution as expected and, for some, also during vision. Several areas, including the anterior intraparietal sulcus (aIPS), dorsal premotor cortex (PMd), primary motor cortex (M1) and the supplementary motor area (SMA), showed sustained activation during the delay phase. We propose that during delayed actions, dorsal-stream areas plan and maintain coarse action goals; however, at the time of execution, motor programming requires re-recruitment of detailed visual information about the object through reactivation of (1) ventral-stream areas involved in object perception and (2) early visual areas that contain richly detailed visual representations, particularly for grasping.

Studying the neural bases of prism adaptation using fMRI: A technical and design challenge

“…In contrast, head movements for at least some participants are likely to exceed this amount in studies such as the current one that involve naïve older controls, patients, and a task that requires arm movements. Nonetheless, the amount of movement that we have reported is comparable to other studies that involve arm (or leg) movements within the scanner (Gallivan, McLean, Flanagan, et al, 2013;Singhal, Monaco, Kaufman, & Culham, 2013) and is within the limits of what could reasonably be corrected by motion correction algorithms.…”

The Müller-Lyer illusion affects visuomotor updating in the dorsal visual stream

“…A memory-guided grasping experiment without illusions, performed in an fMRI scanner, showed that LOC was active during the presentation of the stimulus, but also at the time of action. This suggests that the ventral stream is re-activated to provide relevant information about object properties to guide the dorsal stream in performing the action (Singhal et al, 2013). Given these findings, the effects that we see in the IPS may be the result of direct interactions with LOC.…”

Through the forest of motor representations

“…Accordingly, (at least some) detection of action possibilities is not only dorsal, but results from an interstream interaction for off-line visual processing. Accordingly, we know that dorsal perception encodes action possibilities (unconsciously), whereas ventral perception does this consciously (Young, 2006), following object semantic categorization (Gallese, 2007: 3) -for an important analysis of how dorsal and ventral vision interact in vision-for-action, especially in the case of delayed grasping with respect to action guided by memory-stored information see (Singhal, Culham, Chinellato, & Goodale, 2007;Singhal, Monaco, Kaufman, & Culham, 2013; concerning interaction in attention see Adamo & Ferber, 2009; cfr. with my Section 5.3).…”