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Shoham, A.

Publications and source records attributed to Shoham, A..

3 recordsLinked to original sources

The organization of high-level visual cortex is aligned with visual rather than abstract linguistic information

A fundamental question dominating the study of human visual cortex is whether it is organized along visual or semantic information. This question is unresolved, and the controversy has been rekindled by the recent report that surprisingly, revealed that the representations of textual description of images by linguistic artificial networks successfully predict the response of high-level visual cortex to visual images. These findings appear to support a linguistic, abstract, organizing principle of human visual cortex. Here, using iEEG recordings from high level visual cortex in patients, we contributed to this debate, by testing the hypothesis that this linguistic alignment is restricted to textual descriptions of the visual content of the images (visual text) and does not extend to abstract textual descriptions (abstract text). We selected images that depict familiar faces and places, as these images allow for the best dissociation between these two types of text and generated their visual and abstract (e.g., name and biography of a person) textual descriptions. We then predicted the relational structures of the iEEG response to the images using their textual representations based on a large language model and the image representation based on a convolutional neural network. Neural relational-structures in high-level visual cortex were similarly predicted by images and visual-text but not abstract-text representations. Abstract text best predicted responses of the fronto-parietal cortex to the images. These results demonstrate that visual-language alignment in high-level visual cortex is limited to visually grounded language.

neuroscience↗

Text-related functionality of visual human pre-frontal activations revealed through neural network convergence

The functional role of visual activations of human pre-frontal cortex remains a deeply debated question. Its significance extends to fundamental issues of functional localization and global theories of consciousness. Here we addressed this question by comparing, dynamically, the potential parallels between the relational structure of prefrontal visual activations and visual and textual-trained deep neural networks (DNNs). The frontal visual relational structures were revealed in intra-cranial recordings of human patients, conducted for clinical purposes, while the patients viewed familiar images of faces and places. Our results reveal that visual relational structures in frontal cortex were, surprisingly, predicted by text and not visual DNNs. Importantly, the temporal dynamics of these correlations showed striking differences, with a rapid decline over time for the visual component, but persistent dynamics including a significant image offset response for the text component. The results point to a dynamic text-related function of visual prefrontal responses in the human brain.

neuroscience↗

Deep learning algorithms reveal a new visual-semantic representation of familiar faces in human perception and memory

Recent studies show significant similarities between the representations humans and deep neural networks (DNNs) generate for faces. However, two critical aspects of human face recognition are overlooked by these networks. First, human face recognition is mostly concerned with familiar faces, which are encoded by visual and semantic information, while current DNNs solely rely on visual information. Second, humans represent familiar faces in memory, but representational similarities with DNNs were only investigated for human perception. To address this gap, we combined visual (VGG-16), visual-semantic (CLIP), and natural language processing (NLP) DNNs to predict human representations of familiar faces in perception and memory. The visual-semantic network substantially improved predictions beyond the visual network, revealing a new visual-semantic representation in human perception and memory. The NLP network further improved predictions of human representations in memory. Thus, a complete account of human face recognition should go beyond vision and incorporate visual-semantic, and semantic representations.

neuroscience↗