Frontiers in psychology
January 1, 2015
Valdas Noreika, Andrés Canales-Johnson, Justin Koh et al.
During the transition from relaxation to drowsiness, people often experience hypnagogic phenomena such as perceptual imagery or linguistic intrusions—sudden, unpredictable anomalies in inner speech. In a single participant across 10 EEG sessions, drowsiness depth (measured by Hori stages) increased in the 20 seconds before reporting such an experience, and EEG Dimension of Activation values decreased, indicating rapid changes in brain predictability. Linguistic intrusions were associated with higher alpha and gamma power over the left hemisphere, while perceptual imagery corresponded to higher beta power over the right hemisphere. These results suggest that the modality and incongruence of hypnagogic experiences have distinct EEG signatures, and sleep onset offers a way to study the neural basis of consciousness fragmentation in healthy individuals.
Frontiers in psychology
January 1, 2014
Kristjan Loorits
The hard problem of consciousness, often considered unsolvable by empirical science, can be addressed through a structuralist framework in neuroscience. Qualia, or qualitative properties of experience, are argued to be compositional with internal structures that determine their nature, and these structures can be identified with specific neural patterns. Consciousness is understood as a complex neural pattern that misperceives some of its own structural properties as monadic and qualitative. This approach analyzes consciousness in fully structural terms, thereby claiming to solve the hard problem.
Frontiers in psychology
January 1, 2013
Ralf-Peter Behrendt
Unitary conscious experience can be defined as a symbolic representation of the pattern of hippocampal neuronal firing that encodes an event memory. At each cycle of the θ rhythm, the hippocampus rapidly forms event codes that integrate object information from the ventral visual stream and orbitofrontal cortex, contextual emotional information from the anterior insula, and spatial environmental information from the dorsal visual stream. These event codes, formed in the CA3-dentate network for memorization, are allocentric representations, similar to conscious experiences of events in a seemingly objective framework of phenomenal space and time. Conscious perception is evolutionarily related to autobiographical memory recall, mental imagery, dreaming, and hallucinations, and evidence for hippocampal contributions to these phenomena is reviewed.