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LIT-965: Evolution of consciousness: Phylogeny, ontogeny, and emergence from general anesthesia

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StatusActive — read 2026-10-14 (NOTE-797) in full; worth reading as a clear statement of the case for animal consciousness from anaesthesia and comparative anatomy: the return of a response to command after anaesthesia correlates mainly with brainstem, thalamus and anterior cingulate, so ancient conserved structures with limited recurrent cortex are taken to suffice, and early mammals and birds are taken to be phenomenally conscious. Read it knowing that it is a perspective with no data of its own, that its marker of returning consciousness is an access marker (which it concedes), and that the step to other species is by homology, not by anaesthesia evidence from them. No THEORY was filed from it; THEORY-091 holds the limit it illustrates.
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Tagsconsciousness, neuroscience
Cited as “paper” byNOTE-797 — Mashour & Alkire — Evolution of consciousness and emergence from anesthesia

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George A. Mashour and Michael T. Alkire (2013), Proceedings of the National Academy of Sciences 110 (Suppl. 2): 10357–10364.

Key takeaways

From the reading, NOTE-797.

  • A proposed model, not a study. Emergence from anaesthesia runs from breathing to arousal to following a command to higher cognition, and can be watched “in real time over the course of hours”. The authors propose it as a model of the evolution of consciousness.
  • The cited core. In Långsjö et al. (2012), the return of a response to command correlated “primarily with activity of the brainstem (locus coeruleus), hypothalamus, thalamus, and anterior cingulate”, with “limited neocortical involvement”. The authors grant that this may reflect “an arousal-related response to the test stimulus itself”.
  • Access contaminates the model. The model needs phenomenal and access consciousness “closely juxtaposed or collapsed” at emergence, and the authors concede “the contamination of access consciousness, because language is involved in assessing return”.
  • The step to animals is by homology. Birds and mammals share brainstem, thalamus and a pallium or cortex “capable of recurrent processing”. So the authors “postulate that early mammals and birds … are capable of phenomenal consciousness”, along “two independent lineages” from the amniote radiation about 315 million years ago.
  • Human richness. It is put down to frontal interconnectivity and a dominant anterior-to-posterior information flow. The authors call the role of that flow “unclear at this time”.

Standing in the record

Filed on 2026-10-12 for QUESTION-048, and read on 2026-10-14 in NOTE-797. For that question it is a worked example of recovery evidence pressed into service for experience. Its marker is an access marker, and it assumes access and experience collapse at emergence. That is the limit THEORY-091 states for deficits, here conceded in the authors’ own words. Its transfer to animals without a human cortex rests on anatomy and behaviour, not on anaesthesia data from them. That is the architectural route THEORY-023 questions, and THEORY-100 holds the bird evidence more directly. The cited emergence data fit THEORY-090’s subcortical clause, but the paper keeps limited recurrent cortex in the core and uses command-following as its marker, so it is not a second source for “without cortex”. No THEORY was filed. The paper has no data of its own, and its primary source, Långsjö et al. (2012), is not held.

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