Consciousness is a person’s awareness of
oneself and one’s context. This subjective state is studied scientifically by
searching for brain activity correlated with the experience of consciousness.
Clinically, consciousness is experienced in
terms of the common cognitive-behavioral triad (Affective, Behavior, Cognition
or ABC) and two contexts. The internal context of physiological processes and
the external context of social space and time. Briefly, consciousness includes
thoughts, feelings, and action patterns contextualized by physiological
processes of which we are sometimes aware and an external social space-time
context such as where and when an experience occurs and who and what were
prominent features in that context. These components of the psychological self are
summarized elsewhere in the SCOPES model of functioning.
Consciousness is an emergent property of
brains. Researchers have looked for the Neuronal Correlates of Consciousness
(NCCs). The entire brain is an NCC but we do not appear to be aware of the
basic processes that capture audio or visual stimuli. Brain imagery research suggests
the proximal source of consciousness lies within the posterior part of the
cortex called the hot zone. Electrical stimulation of cortical tissue in
the hot zone elicits reports of flashing lights, shapes, distorted faces,
feelings, urges, and hallucinations. The removal of parts of the posterior
cortex has resulted in losses of selective consciousness such as an awareness
of motion, color, or space.
Measurement
A technique called zap and zip
allows neuroscientists to send a pulse of energy to the brain and measure
activity using EEG sensors. The results were zipped like a computer zip file.
Analysis yielded an index (perturbational complexity index) that has
distinguished between consciousness in patients unable to communicate and those
who were unconscious—a vegetative state.
Two Approaches to Understanding
Consciousness
Global Neuronal Workspace (GNW)
GNW is associated with the work of
psychologist Bernard J. Baars and neuroscientists Stanislas Dehaene and
Jean-Pierre Changeaux. The idea is that when our brains process a stimulus,
many of the brain’s cognitive subsystems access the information. Theoretically,
a neural network in the frontal and parietal lobes is activated and the
information enters consciousness. In contrast, unconscious processes occur when
people carry out automatic behavior like walking while talking on their mobile
phones.
Integrated Information Theory (IIT)
IIT was developed by Giulio Tononi and
others. The focus is on the processing of whole experience scenarios analogous
to a video clip. Consciousness of experience is quantified from zero as unconscious
with higher numbers representing a more complex integration of information. The
quantitative index is phi. The zap-zip meter estimates phi.
Status of Theories
At this point there is no acceptable theory
explaining consciousness. This may be in part because of the subjectivity of
the experience we call consciousness. Schurger et al. (2022) offer a critique
of extant theories, which they view as descriptions of activity rather than an
explanation. These authors suggest Attention Schema Theory (AST) as a possible
candidate for a scientific theory. AST has been criticized as not explaining
consciousness. A quote from the authors may help:
Consciousness,
according to AST, is a special kind of percept that arises due to the workings
of a hypothetical mechanism called an ‘attention schema’. The attention schema
helps to guide, stabilize, and control selective attention, and having an
attention scheme can lead to an adamant belief in an ineffable something extra
that we might call qualia.
References
Koch,
C. (2018, May 9). What is consciousness? Nature. Retrieved from https://www.nature.com/articles/d41586-018-05097-x
Neuroscience
News (2023, May 20). Unlocking the mind: The neuroscience behind our conscious
reality. Neuroscience News. Retrieved from https://neurosciencenews.com/consciousness-neuroscience-23299/
Schurger,
A. & Graziano, M. (2022). Consciousness explained or described?, Neuroscience
of Consciousness, 1, niac001, https://doi.org/10.1093/nc/niac001
Geoffrey W. Sutton, PhD is Emeritus Professor of Psychology. He retired from a clinical practice and was credentialed in clinical neuropsychology and psychopharmacology. His website is www.suttong.com
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2 comments:
Thanks Geoff for these insightful remarks.
You are welcome. There's so much to learn.
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