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V1/V2

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Adversarial testing of global neuronal workspace and ... - Nature nature.com Nature Apr 30, 2025 19 facts

procedureMEG cortical time-series analysis (N=65) extracted signals from cortical parcels in V1/V2, Prefrontal Cortex (PFC), and fusiform regions of interest, with category-selective signals obtained via a category-selective Generalized Eigenvalue Decomposition (GED) filter on fusiform activity.

measurementBayesian analysis of connectivity between face-selective electrodes and V1/V2 in iEEG recordings resulted in a BF01 of 1.3, favoring the null hypothesis.

claimFunctional MRI analysis found no selective increase in interareal connectivity between object-selective nodes and the prefrontal cortex or V1/V2, even when separating task conditions.

measurementThe study population had sparse sampling of V1/V2, with only 12 electrodes localized to V1/V2 compared with 472 electrodes in the prefrontal cortex (PFC).

claimRegarding interareal connectivity during conscious perception, Integrated Information Theory (IIT) predicts sustained short-range connectivity within the posterior cortex, linking low-level sensory areas like V1/V2 with high-level category-selective areas, whereas Global Neuronal Workspace Theory (GNWT) predicts long-range connectivity between high-level category-selective areas and the prefrontal cortex (PFC).

claimIn V1/V2 regions of interest, iEEG Pairwise phase consistency (PPC) analysis shows faces elicit stronger connectivity than objects for face-selective electrodes, and objects elicit stronger connectivity than faces for object-selective electrodes.

claimExploratory dynamic functional connectivity (DFC) results in iEEG were consistent with Global Neuronal Workspace Theory (GNWT) predictions while challenging Integrated Information Theory (IIT) predictions, as connectivity with V1/V2 was not sustained.

measurementMEG DFC analysis of task-irrelevant trials without removing the evoked response reveals significant content-selective synchrony between the face-selective GED filter node and both V1/V2 and PFC regions, characterized by an increase in low-frequency connectivity (< 25 Hz) and a decrease in high-frequency connectivity (25–100 Hz).

measurementIntracranial EEG (iEEG) recordings showed significant connectivity between object-selective electrodes and V1/V2 spanning multiple frequency bands, with the gamma band being the most predominant, though the connectivity was brief, which contradicts Integrated Information Theory (IIT) predictions.

measurementiEEG DFC analysis of task-irrelevant trials without removing the evoked response reveals significant content-selective connectivity between object-selective electrodes and V1/V2 electrodes, reflected as a broadband (25–125 Hz) decrease in the change in DFC.

claimIntracranial EEG data analysis revealed task-independent, selective directed functional connectivity (face stimuli greater than object stimuli) for face-selective electrodes in both the inferior frontal gyrus and V1/V2.

claimiEEG Pairwise phase consistency (PPC) analysis of task-irrelevant trials reveals significant content-selective synchrony in V1/V2 regions of interest, but not in Prefrontal Cortex (PFC) regions of interest.

measurementMagnetoencephalography (MEG) recordings showed selective synchronization between face-selective areas and both V1/V2 and prefrontal cortex (PFC) that was early, restricted to low frequencies (2–25 Hz), and mostly explained by stimulus-evoked responses, with Bayesian analysis supporting the null hypothesis for gamma-band synchronization (BF01 > 3).

measurementMEG PPC analysis of task-irrelevant trials with a sample size of 65 reveals significant category-selective synchrony below 25 Hz for face-selective GED filters in both V1/V2 and PFC regions of interest, and for object-selective synchrony in the PFC region of interest only.

claimThe fusiform face area showed content-selective connectivity (face stimuli greater than object stimuli) with V1/V2, the inferior frontal gyrus, and the intraparietal sulcus, which is consistent with predictions from both Global Neuronal Workspace theory and Integrated Information Theory.

measurementMagnetoencephalography (MEG) recordings showed brief dynamic functional connectivity (DFC) in the alpha–beta frequency bands between face-selective nodes and both the prefrontal cortex (PFC) and V1/V2.

referenceIntegrated Information Theory (IIT) predicts sustained gamma-band connectivity within the posterior cortex, specifically between high-level and low-level sensory areas (V1/V2), throughout any conscious visual experience.

claimCommon significant regions showing task-related connectivity in task-irrelevant, task-relevant, and combined conditions include V1/V2, the right intraparietal sulcus (IPS), and the right inferior frontal gyrus (IFG).

measurementThe study observed increased category-selective synchrony between category-selective and V1/V2 electrodes that was early, brief (less than 0.75 seconds), and restricted to low frequencies (2–25 Hz), with the synchrony mostly explained by stimulus-evoked responses.