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Letrou, A.

Publications and source records attributed to Letrou, A..

2 recordsLinked to original sources

Enhanced processing of cartoons in infant visual cortex

Developing sensory systems may have heightened sensitivity to exaggerated features that emphasize diagnostic information, as shown by the benefits of infant-directed speech for language acquisition. Here, we examine this sensory exaggeration hypothesis in the visual domain by testing whether cartoons elicit stronger and more consistent neural representations than realistic movies in human infants. We collected fMRI data while 24 awake infants (4-15 months) watched the same 3-minute clip of the opening sequence from the original animated version of The Lion King (1994) and its shot-for-shot remake with photorealistic CGI (2019). A computer vision model confirmed that the movies differed in low-level features while depicting similar high-level content. Consistent with sensory exaggeration, the animated version yielded more reliable neural responses and better decoding of visual features than the CGI version throughout occipital cortex. This effect was not observed in adults nor in higher-order regions in infants and could not be explained by differential head motion or looking time. These results suggest that the developing visual system may be attuned to diagnostic features and that cartoons may (unwittingly) exploit this early neural preference.

neuroscience↗

Hippocampal Codes for Real-World Human Navigation

As animals move through the world, the hippocampus represents their location, direction, and speed. Parallel studies in humans have been mostly limited to virtual navigation because of physical constraints of suitable neural recording technologies. However, there are known differences between real-world and virtual navigation, leaving open the question of how the hippocampus supports real-world navigation in humans. Here we report evidence from ambulatory patients with chronic brain implants that the location, direction, and speed of humans walking along a linear track are represented in local field potentials from the hippocampus. We further show in a subset of patients who were tested twice after long delays that these representations can be reliable over time. These findings provide the first demonstration of multiple, stable neural codes for real-world navigation in the human hippocampus.

neuroscience↗