The Neural Substrates of Biological Motion Perception: an fMRI Study

Abstract

We used fMRI to identify the brain areas related to the perception of biological motion (4 T EPI; whole brain). In experiment 1, 10 subjects viewed biological motion (a human figure jumping up and down, composed of 21 dots), alternating with a control stimulus created by applying autoregressive models to the biological motion stimulus (such that the dots' speeds and amplitudes were preserved whereas their linking structure was not). The lengths of the stimulus bouts varied, and therefore the transitions between biological motion and control stimuli were unpredictable. Subjects had to indicate with a button press when each transition occurred. In a related biological motion task, subjects detected short (1 s) disturbances within these displays. We also examined the neural substrates of motion and shape perception, as well as motor imagery, to determine whether or not the cortical regions involved in these processes are also recruited during biological motion perception. Subjects viewed linear motion displays alternating with static dots and a series of common objects alternating with band-limited white noise patterns. Subjects also generated imagery of their own arm movements alternating with visual imagery of common objects. Biological motion specific BOLD signal was found within regions of the lingual gyrus at the cuneus border, showing little overlap with object recognition, linear motion or motion imagery areas. The lingual gyrus activation was replicated in a second experiment that also mapped retinotopic visual areas in three subjects. The results suggest that a region of the lingual gyrus within VP is involved in higher-order processing of motion information.

Structural encoding and recognition of biological motion: evidence from event-related potentials and source analysis

“…Such a discrimination of static displays would be based purely on geometrical cues and is clearly different from the discrimination based on the percept of a walking human figure which is only evoked by animated displays of biological motion. Moreover, we found sources of the ERP signal in the second component in brain areas which were reported to be selectively involved in biological motion perception in several imaging studies [11,[24][25][26][27]51,62] but were not reported to be activated by static displays consisting of a few dots which match joint positions.…”

“…The ANOVAs were conducted for the factors stimulus category (BM versus inverted BM versus scrambled motion), selected electrode locations (O1, O2 versus PO7, PO8 versus P7, P8 versus TP7, TP8) and recording side (right versus left). Electrode selection was based on the main areas of interest as suggested by previous functional imaging studies [11,[24][25][26][27]51,62]. Greenhouse-Geisser adjustments to the degrees of freedom were performed when appropriate.…”

“…From such point-light displays, observers can easily recognize a human walker, determine his/her gender [5,16,33,34,58], recognize various action patterns [18], identify individual persons [17] and even recognize themselves [6]. The evolutionary importance of the perception of animate motion patterns has led to the development of a specific neural machinery as shown by several brain imaging studies using fMRI and PET [11,[24][25][26][27]51,62]. These studies report selective activation of the superior temporal sulcus (STS) to visual stimuli consisting of BM.…”

“…These studies report selective activation of the superior temporal sulcus (STS) to visual stimuli consisting of BM. In addition to area STS, activation specific to BM has also been shown in the cerebellum [25,62], area VP [51], the amygdala [11] and the occipital and fusiform face area [27]. Activity in the STS-region is not induced by meaningful and coordinated non-biological motion such as the pendulum movements of a grandfather clock [44].…”

Autism and the development of face processing

“…The STS is more activated when subjects selectively attend to eye gaze than to face identity [1,2,9]. Regions in the STS also respond to a range of visual signals salient for social interaction, such as mutual gaze, emotional expression, speech, intentional limb movements, and biological motion in general [1,2,9,[36][37][38][39]. Grossman et al (2005) suggested that normal STS functioning is required for perception of biological motion, as repeated transcranial magnetic stimulation (rTMS) disrupted cortical activity in the posterior STS and reduced perceptual sensitivity to point-light animations in healthy adults [36].…”