Consciousness without cortex.

Area of Science:

• Neuroscience
• Evolutionary Biology
• Comparative Psychology

Background:

• Sensory consciousness, the ability to report subjective experiences, is a complex trait of biological nervous systems.
• The mammalian cerebral cortex, with its unique cell types and layered structure, has been traditionally associated with the emergence of consciousness.
• Understanding the evolutionary origins and neural substrates of consciousness across diverse species is a key challenge in neuroscience.

Purpose of the Study:

• To investigate the neural correlates of consciousness in non-mammalian vertebrates.
• To determine if consciousness can emerge from brain structures other than the mammalian cerebral cortex.
• To explore the evolutionary principles underlying the emergence of consciousness across different vertebrate lineages.

Main Methods:

• Review of existing neurophysiological recordings in crows.
• Comparative analysis of brain structures and cellular architecture between mammals and birds.
• Examination of the embryonic origins and evolutionary history of pallial territories.

Main Results:

• Neurophysiological recordings reveal a neuronal correlate of consciousness in the pallial endbrain of crows.
• Bird pallial endbrain structures, unlike the cerebral cortex, lack a layered architecture and possess independently evolved cell types.
• These findings challenge the notion that a mammalian-like cerebral cortex is essential for consciousness.

Conclusions:

• The mammalian cerebral cortex is not a prerequisite for the emergence of consciousness in all vertebrates.
• The anatomical and physiological principles of the telencephalic pallium provide a substrate for consciousness to evolve independently.
• Consciousness may arise from diverse neural architectures across vertebrate phylogeny.