Scientific reports
May 8, 2024
Annika Hense, Antje Peters, Maximilian Bruchmann et al.
Sustained visual awareness is associated with a negative event-related potential (ERP) that persists for the entire duration a stimulus is consciously perceived. In a visual task, participants viewed line stimuli presented for 500 or 1000 milliseconds. Some participants were informed that the lines sometimes contained a face, enabling them to see the face through visual one-shot learning, while uninformed participants did not perceive the face. Comparing brain activity between groups showed an enhanced negativity over occipitotemporal electrodes that lasted as long as the stimulus was presented. This sustained visual awareness negativity (SVAN) indicates that awareness-related brain signals correspond to the duration of a conscious percept, not just a transient onset response.
Scientific reports
December 19, 2023
Antje Peters, Maximilian Bruchmann, Torge Dellert et al.
Inattentional numbness, the somatosensory equivalent of inattentional blindness or deafness, was studied with fMRI in 44 participants who received weak electrical stimulation on the left hand while performing a demanding visual task. Half were told the tactile stimuli would be above detection threshold, half below. Ten participants did not consciously perceive the stimuli. Prior information did not significantly affect awareness. Awareness of stimuli increased activation in the contralateral secondary somatosensory cortex but not in the primary somatosensory cortex or frontoparietal areas. The results suggest that somatosensory awareness relies on higher somatosensory cortex areas and does not require strong activation in extended anterior or posterior networks seen when stimuli are task-relevant.
NeuroImage
December 1, 2022
Torge Dellert, Sophie Krebs, Maximilian Bruchmann et al.
The P3b brain wave, long thought to be a signature of conscious perception, may instead reflect decision-making processes. In a study of 38 participants using a modified attentional blink paradigm—where seeing a first image briefly impairs awareness of a second—the early visual awareness negativity (VAN) appeared for seen versus unseen targets, but no enhanced P3b did, even when the second target was made distinct from distractors. The findings challenge the P3b as a neural correlate of consciousness and support the view that awareness arises during early sensory processing rather than later stages.
Annika Hense, Antje Peters, Torge Dellert et al.
Conscious visual experience ranges from basic features to integrated percepts like faces, but it is unclear whether brain signals linked to consciousness reflect only low-level features or also higher-order content. Using an inattentional blindness design with 85 participants, the study measured brain activity while people perceived either no stimulus, only low-level lines, or a high-level face. Low-level perception produced an early occipital negativity, while face perception additionally recruited a right-lateralized occipitotemporal negativity and later medial posterior positivities. These results suggest that distinct spatiotemporal brain patterns correspond to different representational levels of conscious perception, independent of task-related processes.