Action Categories in Lateral Occipitotemporal Cortex Are Organized Along Sociality and Transitivity

Abstract

How neural specificity for distinct conceptual knowledge categories arises is central for understanding the organization of semantic memory in the human brain. Although there is a large body of research on the neural processing of distinct object categories, the organization of action categories remains largely unknown. In particular, it is unknown whether different action categories follow a specific topographical organization on the cortical surface analogously to the category-specific organization of object knowledge. Here, we tested whether the neural representation of action knowledge is organized in terms of nonsocial versus social and object-unrelated versus object-related actions (sociality and transitivity, respectively, hereafter). We hypothesized a major distinction of sociality and transitivity along dorsal and ventral lateral occipitotemporal cortex (LOTC), respectively. Using fMRI-based multivoxel pattern analysis, we identified neural representations of action information associated with sociality and transitivity in bilateral LOTC. Representational similarity analysis revealed a dissociation between dorsal and ventral LOTC. We found that action representations in dorsal LOTC are segregated along features of sociality, whereas action representations in ventral LOTC are segregated along features of transitivity. In addition, representations of sociality and transitivity features were found more anteriorly in LOTC than representations of specific subtypes of actions, suggesting a posterior-anterior gradient from concrete to abstract action features. These findings elucidate how the neural representations of perceptually and conceptually diverse actions are organized in distinct subsystems in the LOTC.

The role of putative human anterior intraparietal sulcus area in observed manipulative action discrimination

“…Yet premotor activation was observed in experiment 2, and the psychophysical control experiment using brief static-probe stimuli makes it unlikely that this premotor activation reflects the static cues available at the start of the OA. The PCS activation in experiment 2, in which the two OMAS also differed with respect to the effector is consistent with our view (Orban, 2018) 2016;Wurm & Lingnau, 2015;Wurm et al, 2017). While we agree with the notion of the representation of action components in LOTC, we suggest that the single neuron data indicate that the identity of observed actions is represented at the parietal level.…”

Action Observation as a Visual Process: Different Classes of Actions Engage Distinct Regions of Human PPC

“…While the two lowest levels of description were readily recognized from the onset (Rizzolatti et al, 1987;Gallese et al, 1996), the notion of observed action class was recognized only very recently (Abdollahi et al, 2013). It should be distinguished from the semantic action categories that describe actions at a more abstract, conceptual level (Wurm et al, 2016). The present notion of action classes is directly related to sensorimotor transformations and behavioral repertoire, reminiscent of the work of Graziano and Aflalo (2007), Kaas and Stepniewska (2016).…”

Sociality and Interaction Envelope Organize Visual Action Representations

“…Much previous work on the nature of action representation in the brain has focused on the end-stages of this process; for example, attempting to localize the more abstract and conceptual aspects of action representation (e.g., Nelissen et al, 2005;Bedny et al, 2011;van Elk et al, 2013;Watson & Buxbaum, 2014;Wurm & Caramazza, 2019). However, recent research has begun to examine action-related processing from a more perceptual angle, asking how regions involved in high-level vision are organized to support action observation (Lingnau & Downing, 2015;Wurm & Caramazza, 2017). The present work follows this latter approach, leveraging an encoding analytical framework to characterize action responses in the visual system (Mitchell et al, 2008;Huth et al, 2012;Lescroart et al, 2015).…”

“…A related consideration is how best to depict these actions in order to probe underlying neural responses at a meaningful level of abstraction. Historically, researchers have relied on highly-controlled action stimuli (Jastorff et al, 2010;, often sampling primarily from hand actions such as reaching or hammering (Watson & Buxbaum, 2014;Fabbri et al, 2016;Wurm et al, 2017). However, these welldesigned and controlled stimuli are fundamentally limited in the range of actions they depict, which in turn constrains researchers' ability to discover joints in the broader domain of action perception.…”

“…Therefore, it is critical to consider more widespread action responses across broad swathes of occipitotemporal and parietal cortices (e.g. Hafri et al, 2017;Wurm & Caramazza, 2017). Given this, we used a novel method to identify voxels that reliably differentiate among different actions (Tarhan & Konkle, under review), rather than constraining our analyses to specific regions of interest emphasized in the literature.…”