During cardiac arrest and cardiopulmonary resuscitation (CPR), some patients show signs of consciousness and cognitive activity, including brain activity on EEG that resembles normal waking patterns despite severe oxygen deprivation. In a study of 567 in-hospital cardiac arrests, 11 of 28 survivors interviewed reported memories or perceptions suggesting consciousness during CPR. Four categories of experiences emerged: CPR-induced consciousness, post-resuscitation awareness, dream-like experiences, and transcendent recalled experience of death (RED). A separate group of 126 community survivors reinforced these categories and added delusions. Normal EEG activity (delta, theta, alpha) appeared for up to 35–60 minutes into CPR even with low cerebral oxygenation, suggesting that a network-level cognitive activity and lucidity may occur during cardiac arrest.
The representational geometry of color qualia differs between AI vision models and the human brain. Using fMRI with a no-report paradigm, the study compared neural activity during pure perception versus task-modulated perception against diverse vision models. Most models aligned better with pure perception, indicating current feedforward architectures do not capture cognitive processes during task execution. Training paradigm and architecture interact critically: Contrastive Language-Image Pre-training (CLIP) improved brain-alignment for a vision transformer but worsened it for a ConvNet. The work provides a new benchmark for color qualia, revealing fundamental divergence in inductive biases between artificial and biological vision systems.
People who more frequently recall their dreams have less cortical volume in the medial portion of the right fusiform gyrus and parahippocampal gyrus, as well as lower fractional anisotropy in the white matter fibers connected to those regions. These relationships were not affected by regular sleep. The findings provide direct evidence that brain structure is linked to individual differences in dream recall frequency.
Dream recall frequency and REM sleep percentage are linked to different brain functional networks. In 43 healthy adults, resting-state fMRI and polysomnography showed that both measures negatively correlated with multiple networks. Dream recall frequency was mainly associated with connectivity in the lateral visual network and thalamus, while REM sleep percentage was mainly associated with connectivity in frontoparietal networks and cerebellum. A time-of-day effect emerged: dream recall frequency had stronger coupling with the lateral visual network at night, and REM sleep percentage had stronger coupling with the cerebellum in the morning. The findings indicate that the neural substrates for dream recall and REM sleep are distinct.