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Hirschhorn, R.

Publications and source records attributed to Hirschhorn, R..

2 recordsLinked to original sources

Clutter does not affect the spatial tuning of * category representations in human object-selective cortex *

Natural vision is frequently impaired when the visual field is crowded with multiple competing objects. One common interpretation of this clutter interference is that large receptive fields in high-level visual cortex make it hard to separate objects from their surround. This view predicts less interference for spatially localized representations; therefore, classifiers trained under clutter might rely more on such localized representations. Here we tested this by measuring participants brain signals with fMRI while they viewed objects presented either alone or within cluttered arrays. Consistent with prior work, category decoding accuracy was significantly reduced in clutter. However, classifiers trained directly on cluttered displays were not spatially more localized. Instead, they generalized robustly across spatial positions, comparable to classifiers trained on isolated objects. This finding challenges the idea that clutter preferentially disrupts position-tolerant representations.

neuroscience↗

An adversarial collaboration to critically evaluate theories of consciousness

Different theories explain how subjective experience arises from brain activity1,2. These theories have independently accrued evidence, yet, confirmation bias and dependence on design choices hamper progress in the field3. Here, we present an open science adversarial collaboration which directly juxtaposes Integrated Information Theory (IIT)4,5 and Global Neuronal Workspace Theory (GNWT)6-10, employing a theory-neutral consortium approach11,12. We investigate neural correlates of the content and duration of visual experience. The theory proponents and the consortium developed and preregistered the experimental design, divergent predictions, expected outcomes, and their interpretation12. 256 human subjects viewed suprathreshold stimuli for variable durations while neural activity was measured with functional magnetic resonance imaging, magnetoencephalography, and electrocorticography. We find information about conscious content in visual, ventro-temporal and inferior frontal cortex, with sustained responses in occipital and lateral temporal cortex reflecting stimulus duration, and content-specific synchronization between frontal and early visual areas. These results confirm some predictions of IIT and GNWT, while substantially challenging both theories: for IIT, a lack of sustained synchronization within posterior cortex contradicts the claim that network connectivity specifies consciousness. GNWT is challenged by the general lack of ignition at stimulus offset and limited representation of certain conscious dimensions in prefrontal cortex. Beyond challenging the theories themselves, we present an alternative approach to advance cognitive neuroscience through a principled, theory-driven, collaborative effort. We highlight the challenges to change peoples mind 13 and the need for a quantitative framework integrating evidence for systematic theory testing and building.

neuroscience↗