The brain is both neurocomputer and quantum computer.

A commentary defends the Penrose-Hameroff 'Orch OR' quantum computational model of consciousness against earlier criticism. Orch OR proposes that consciousness arises from quantum computations in microtubules inside neurons, particularly in dendrites connected by gap junctions called dendritic webs. These webs act as input layers in the brain's neurocomputational architecture, and consciousness is suggested to occur during gamma EEG-synchronized sequences of discrete quantum events within integration phases of neurocomputational integrate-and-fire cycles. The author argues that Orch OR is compatible with neurocomputation and questions whether neurocomputation alone can account for coherent gamma synchrony EEG, a candidate neural correlate of consciousness.

Study at a glance

Abstract

In their article, Is the Brain a Quantum Computer,? Litt, Eliasmith, Kroon, Weinstein, and Thagard (2006) criticize the Penrose-Hameroff "Orch OR" quantum computational model of consciousness, arguing instead for neurocomputation as an explanation for mental phenomena. Here I clarify and defend Orch OR, show how Orch OR and neurocomputation are compatible, and question whether neurocomputation alone can physiologically account for coherent gamma synchrony EEG, a candidate for the neural correlate of consciousness. Orch OR is based on quantum computation in microtubules within dendrites in cortex and other regions linked by dendritic-dendritic gap junctions ("dendritic webs") acting as laterally connected input layers of the brain's neurocomputational architecture. Within dendritic webs, consciousness is proposed to occur as gamma EEG-synchronized sequences of discrete quantum computational events acting in integration phases of neurocomputational "integrate-and-fire" cycles. Orch OR is a viable approach toward understanding how the brain produces consciousness.