The Dorsal Visual Pathway Represents Object-Centered Spatial Relations for Object Recognition

Abstract

Although there is mounting evidence that input from the dorsal visual pathway is crucial for object processes in the ventral pathway, the specific functional contributions of dorsal cortex to these processes remain poorly understood. Here, we hypothesized that dorsal cortex computes the spatial relations among an object's parts -a processes crucial for forming global shape perceptsand transmits this information to the ventral pathway to support object categorization. Using fMRI with human participants (females and males), we discovered regions in the intraparietal sulcus (IPS) that were selectively involved in computing object-centered part relations. These regions exhibited task-dependent functional and effective connectivity with ventral cortex, and were distinct from other dorsal regions, such as those representing allocentric relations, 3D shape, and tools. In a subsequent experiment, we found that the multivariate response of posterior IPS, defined on the basis of part-relations, could be used to decode object category at levels comparable to ventral object regions. Moreover, mediation and multivariate effective connectivity analyses further suggested that IPS may account for representations of part relations in the ventral pathway. Together, our results highlight specific contributions of the dorsal visual pathway to object recognition. We suggest that dorsal cortex is a crucial source of input to the ventral pathway and may support the ability to categorize objects on the basis of global shape.

Spatiotemporal neural dynamics of object recognition under uncertainty in humans

“…Accordingly, it is possible that the enhanced FCPN and DAN engagement during recognized trials reflect attention-related modulations that support object recognition 48,49 . Alternatively, given the increasing evidence that FCPN and DAN regions are actively involved in object recognition processing 11,12,50,51,52 , the enhanced FCPN and DAN engagement may be directly related to perceptual processing per se. For example, the early recognition-related responses in the FPCN and DAN may reflect an initial, fast analysis of noisy visual input in the dorsal visual stream which facilitates fine-grained analysis happening in the ventral stream 6,34,35 .…”

Temporal asymmetries and interactions between dorsal and ventral visual pathways during object recognition

“…By contrast, decoding in occipital cortex preceded the ventral pathway and occipital cortex was a significant predictor of the time-varying responses of the ventral pathway. Importantly, TMS and fMRI studies suggest that the coarse information transmitted by the magnocellular pathway is sufficient to compute an object’s global shape structure (Wang et al, 2022), and that this information can support decoding of object category in the dorsal pathway (Ayzenberg & Behrmann, 2022b). Furthermore, studies have shown that such structural information may then be transmitted to the ventral pathway to support object recognition (Ayzenberg & Behrmann, 2022b; Bar et al, 2006; Kveraga, Boshyan, et al, 2007).…”

“…Importantly, TMS and fMRI studies suggest that the coarse information transmitted by the magnocellular pathway is sufficient to compute an object’s global shape structure (Wang et al, 2022), and that this information can support decoding of object category in the dorsal pathway (Ayzenberg & Behrmann, 2022b). Furthermore, studies have shown that such structural information may then be transmitted to the ventral pathway to support object recognition (Ayzenberg & Behrmann, 2022b; Bar et al, 2006; Kveraga, Boshyan, et al, 2007). Thus, the earlier decoding of object category in the dorsal pathway may be explained by privileged magnocellular input.…”

“…The dorsal pathway may be ideally suited to compute such a representation given its well-known role in computing spatial relations more generally. Indeed, recent studies have found that regions in PPC were functionally selective for an object’s structure, independent of other properties represented by the dorsal pathway, such as tools (Ayzenberg & Behrmann, 2022b). These PPC regions were capable of decoding an object’s category and mediated representations of structure in the ventral pathway (Ayzenberg et al, 2022).…”

“…Moreover, the multivariate responses of dorsal regions were sufficient to decode an object's category across variations in the object's image-level properties and across variations among a category's exemplars (Bracci & Op de Beeck, 2016;Vaziri-Pashkam et al, 2019). Indeed, object classification accuracy in dorsal regions matched, and sometimes surpassed, classification accuracy of ventral object regions (Ayzenberg & Behrmann, 2022b;Jeong & Xu, 2016). Other studies have shown that applying transcranial magnetic stimulation (TMS) over the dorsal pathway impaired aspects of object perception, such as configural processing and global shape perception (Romei et al, 2011;Zachariou et al, 2017;Zaretskaya et al, 2013).…”