Activity In Superior Temporal Sulcus Research Articles

Grasping the Intentions of Others: The Perceived Intentionality of an Action Influences Activity in the Superior Temporal Sulcus during Social Perception

An explication of the neural substrates for social perception is an important component in the emerging field of social cognitive neuroscience and is relevant to the field of cognitive neuroscience as a whole. Prior studies from our laboratory have demonstrated that passive viewing of biological motion (Pelphrey, Mitchell, et al., 2003; Puce et al., 1998) activates the posterior superior temporal sulcus (STS ) region. Furthermore, recent evidence has shown that the perceived context of observed gaze shifts (Pelphrey, Singerman, et al., 2003; Pelphrey et al., 2004) modulates STS activity. Here, using event-related functional magnetic resonance imaging at 4 T, we investigated brain activity in response to passive viewing of goal- and nongoal-directed reaching-to-grasp movements. Participants viewed an animated character making reaching-to-grasp movements either toward (correct) or away (incorrect) from a blinking dial. Both conditions evoked significant posterior STS activity that was strongly right lateralized. By examining the time course of the blood oxygenation level-dependent response from areas of activation, we observed a functional dissociation. Incorrect trials evoked significantly greater activity in the STS than did correct trials, while an area posterior and inferior to the STS (likely corresponding to the MT/ V5 complex) responded equally to correct and incorrect movements. Parietal cortical regions, including the superior parietal lobule and the anterior intraparietal sulcus, also responded equally to correct and incorrect movements, but showed evidence for differential responding based on the hand and arm (left or right) of the animated character used to make the reaching-to-grasp movement. The results of this study further suggest that a region of the right posterior STS is involved in analyzing the intentions of other people's actions and that activity in this region is sensitive to the context of observed biological motions.

Is voice processing species-specific in human auditory cortex? An fMRI study

Recent studies suggested a sensitivity of regions of the human superior temporal sulcus (STS) to the sound of the human voice. However, the question of the species specificity of this response is still open. Healthy adult volunteers were scanned in an event-related fMRI design to compare responses in the STS to human and animal vocalizations, as well as to control nonvocal sounds (e.g., musical instruments). Bilateral activation of anterior STS was observed for human vocalizations, when contrasted with both nonvocal sounds and animal vocalizations. Animal vocalizations, compared to nonvocal sounds, elicited a more restricted left STS activation, although this region responded even more strongly to human vocalizations. This study provides the first evidence suggesting a species specificity in STS responses to vocalizations in humans.

When strangers pass: processing of mutual and averted social gaze in the superior temporal sulcus.

Using functional magnetic resonance imaging (fMRI), we investigated brain activity evoked by mutual and averted gaze in a compelling and commonly experienced social encounter. Through virtual-reality goggles, subjects viewed a man who walked toward them and shifted his neutral gaze either toward (mutual gaze) or away (averted gaze) from them. Robust activity was evoked in the superior temporal sulcus (STS) and fusiform gyrus (FFG). For both conditions, STS activity was strongly right lateralized. Mutual gaze evoked greater activity in the STS than did averted gaze, whereas the FFG responded equivalently to mutual and averted gaze. Thus, we show that the STS is involved in processing social information conveyed by shifts in gaze within an overtly social context. This study extends understanding of the role of the STS in social cognition and social perception by demonstrating that it is highly sensitive to the context in which a human action occurs.

Here's Looking at You, Kid

Children with fragile X syndrome (fraX) are at risk for manifesting abnormalities in social function that overlap with features of autism and social anxiety disorder. In this study, we analyzed brain activation in response to face and gaze stimuli to better understand neural functioning associated with social perception in fraX. Eleven female subjects with fraX, aged 10 to 22 years, were compared with age-matched female control subjects. Photographs of forward-facing and angled faces, each having direct and averted gaze (4 types of stimuli), were presented in an event-related design during functional magnetic resonance imaging. Subjects were instructed to determine the direction of gaze for each photograph. Activation in brain regions known to respond to face and gaze stimuli, the fusiform gyrus (FG) and superior temporal sulcus (STS), were compared between groups to isolate neural abnormalities in the perception of directed social stimuli. The fraX subjects had decreased accuracy in determining the direction of gaze compared with controls. Region of interest analysis of the FG revealed a significant interaction between diagnostic group and face orientation. Specifically, control subjects had greater FG activation to forward than to angled faces, whereas fraX subjects had no difference in FG activation to forward and angled faces. Controls showed greater left STS activation to all stimuli compared with fraX subjects. Our results suggest that gaze aversion in fraX subjects is related to decreased specialization of the FG in the perception of face orientation. Decreased STS activation in fraX suggests aberrant processing of gaze. These data suggest that gaze aversion in fraX may be related to dysfunction of neural systems underlying both face and gaze processing.

Brain Activity Evoked by the Perception of Human Walking: Controlling for Meaningful Coherent Motion

Many functional neuroimaging studies of biological motion have used as stimuli point-light displays of walking figures and compared the resulting activations with those evoked by the same display elements moving in a random or noncoherent manner. Although these studies have established that biological motion activates the superior temporal sulcus (STS), the use of random motion controls has left open the possibility that coordinated and meaningful nonbiological motion might activate these same brain regions and thus call into question their specificity for processing biological motion. Here we used functional magnetic resonance imaging and an anatomical region-of-interest approach to test a hierarchy of three questions regarding activity within the STS. First, by comparing responses in the STS with animations of human and robot walking figures, we determined (1) that the STS is sensitive to biological motion itself, not merely to the superficial characteristics of the stimulus. Then we determined that the STS responds more strongly to biological motion (as conveyed by the walking robot) than to (2) a nonmeaningful but complex nonbiological motion (a disjointed mechanical figure) and (3) a complex and meaningful nonbiological motion (the movements of a grandfather clock). In subsequent whole-brain voxel-based analyses, we confirmed robust STS activity that was strongly right lateralized. In addition, we observed significant deactivations in the STS that differentiated biological and nonbiological motion. These voxel-based analyses also revealed regions of motion-related positive activity in other brain regions, including MT or V5, fusiform gyri, right premotor cortex, and the intraparietal sulci.