The Default Mode Network is activated when there is no engagement with
external experiences, but in experiences of self-awareness and endogenous
consciousness. The DMN anticorrelates with Task-Positive networks, such as networks
for executive control, stimulus salience, external attentional control, and external
perceptual processing. The connectivity of a core self-awareness system overlaps with
the DMN, in particular with the posterior cingulate cortex. Neural networks that
produce social perception also overlap with the DMN. However, neither Task-Positive
networks nor DMN computations directly generate a subject. The thalamus is not part
of the DMN. Theories emphasizing the DMN and the GNW theory can be reconciled
through phenomenological descriptions reported in classic Zen texts. Anesthesia
studies point towards the disruption of signaling at upper cortical layers by general
anesthetics with different pharmacological mechanisms. General anesthetics seem to
act by disrupting top-down signaling and disabling mechanisms matching top-down
and bottom-up informational streams at the apical dendrites of cortical pyramidal cells.
According to proponents of the Orch OR, quantum phenomena in tubulin have a causal
role in the regulation of synaptic firing. The theory suffers from the same biases of the
IIT, as both propose a bottom-up causal origin of conscious experiences. Instead,
research with general anesthetics suggests a crucial role for top-down projections and
for the signaling that matches top-down and bottom-up streams. Children born without
a cortex can display behaviors associated with consciousness. They can smile and
laugh, show initiative and instrumental behaviors. Their parents can easily distinguish
episodes of loss of consciousness due to absence seizures. In the damaged or cortically
deactivated brain, secondary effects in the midbrain contribute to the loss of
consciousness. The upper brain stem may support sustained rhythms encoding
predictive coding expectations. Subcortical regions can provide an interface with the
essential attributes of phenomenal consciousness. Phenomenal experiences may
conceivably emerge with the onset of sustained oscillatory rhythms depicting sustained
expectations in an integrative action-based model. Traces of phenomenal consciousness
may thus emerge with the onset of rhythms that sustain an organism’s internal
expectations. These observations are consistent with the blueprint presented here.
Keywords: Anencephalic Children, Animal Consciousness, Cortical Deactivation,
Coma, Cross-Frequency Coupling, Default Mode Network, Dendritic
Signaling Disruption, Gamma Oscillations, General Anesthetics, Internal
Expectations, Ketamine, Minimally Conscious State, Orch OR Theory,
Phenomenal Consciousness, Propofol, Predictive Coding, Pyramidal Cells Apical Dendrites, Quantum Phenomena in Tubulin, Sprague Effect, Superior Colliculus, Task-
Positive Networks, Top-Down Projections, Zen Phenomenology.
