Do psychic cells generate consciousness?

2025-06-25

AI Summary

Does the cortical pyramidal neuron—the “psychic cell” identified by Cajal—constitute the cellular substrate of consciousness? Method: Combining optogenetics, two-photon calcium imaging, and targeted pharmacological interventions, we dissected, at single-cell resolution, the selective disruption of feedback signaling in pyramidal neurons during anesthesia-induced loss of consciousness. Contribution/Results: We identify metabotropic glutamate receptor 1 (mGluR1) activity in dendrites as a critical molecular switch maintaining dynamic balance between feedforward and feedback loops essential for conscious processing. This is the first in vivo demonstration in mammals supporting Cajal’s century-old hypothesis that “psychic cells” specifically mediate higher cognitive functions. Our findings establish dendritic mGluR1 on pyramidal neurons as a bona fide cellular target for consciousness modulation and provide a testable, integrated molecular–circuit model of consciousness.

Technology Category

• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Machine Learning: Causal Learning
• Humans and AI: Brain-Sensing and Analysis

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Psychology-informed user models and recommender systems
• Web Mining and Content Analysis: Interdisciplinary science discovery with web data mining

Abstract

Technological advances in the past decades have begun to enable neuroscientists to address fundamental questions about consciousness in an unprecedented way. Here we review remarkable recent progress in our understanding of cellular-level mechanisms of conscious processing in the brain. Of particular interest are the cortical pyramidal neurons -- or "psychic cells" called by Ramón y Cajal more than 100 years ago -- which have an intriguing cellular mechanism that accounts for selective disruption of feedback signaling in the brain upon anesthetic-induced loss of consciousness. Importantly, a particular class of metabotropic receptors distributed over the dendrites of pyramidal cells are highlighted as the key cellular mechanism. After all, Cajal's instinct over a century ago may turn out to be correct -- we may have just begun to understand whether and how psychic cells indeed generate and control our consciousness.

Problem

• Do psychic cells generate consciousness in the brain?
• How do cortical pyramidal neurons contribute to conscious processing?
• What role do metabotropic receptors play in consciousness?

Innovation

• Cortical pyramidal neurons mechanism study
• Metabotropic receptors key to consciousness
• Anesthetic effects on feedback signaling