fMR-adaptation reveals invariant coding of biological motion on human STS

Abstract

Neuroimaging studies of biological motion perception have found a network of coordinated brain areas, the hub of which appears to be the human posterior superior temporal sulcus (STSp). Understanding the functional role of the STSp requires characterizing the response tuning of neuronal populations underlying the BOLD response. Thus far our understanding of these response properties comes from single-unit studies of the monkey anterior STS, which has individual neurons tuned to body actions, with a small population invariant to changes in viewpoint, position and size of the action being viewed. To measure for homologous functional properties on the human STS, we used fMR-adaptation to investigate action, position and size invariance. Observers viewed pairs of point-light animations depicting human actions that were either identical, differed in the action depicted, locally scrambled, or differed in the viewing perspective, the position or the size. While extrastriate hMT+ had neural signals indicative of viewpoint specificity, the human STS adapted for all of these changes, as compared to viewing two different actions. Similar findings were observed in more posterior brain areas also implicated in action recognition. Our findings are evidence for viewpoint invariance in the human STS and related brain areas, with the implication that actions are abstracted into object-centered representations during visual analysis.

The Application of kNN and SVM in the Decoding of fMRI Data

“…The study indicated that both EBA and pSTS could represent motion information and they were indeed involved in the motion recognition task. This was consistent with previous investigations using the paradigm of fMRI adaptation [4,6]. No previous studies has used the method of classification to investigate human movement recognition.…”

“…EBA was defined by the activation cluster in the posterior inferior temporal sulcus, in which headless bodies evoked stronger compared to chairs [3]. pSTS was defined as the activation cluster in the superior temporal sulcus using the contrast between point-light biological motion and the scrambled versions [4].…”

Effects of TMS over Premotor and Superior Temporal Cortices on Biological Motion Perception

“…If processing in PMC is disrupted, and the match-to-body process is impacted, subjects could exhibit reduced sensitivity for biological motion. It is possible that, in processing these stimuli, the pSTS broadly categorizes movements as biological (Grossman, Jardine, & Pyles, 2011) and works in concert with PMC to further refine the computations, perhaps via a template matching strategy (Lange, Georg, & Lappe, 2006).…”

Ventral aspect of the visual form pathway is not critical for the perception of biological motion

“…To do so, for each patient we carefully delineated the lesion, assessed the magnitude of the damage, and situated the lesion relative to regions in the ventral, lateral, and middle temporal cortex that are standardly associated with biological motion processing, including body parts and visual motion-sensitive regions (e.g., refs. 13,14,20,[31][32][33].…”