Beck-Eccles’s Quantum Processes in the Synapse

Sir John Eccles, Nobel laureate for his seminal work on the synapse, the small space between neurons across which neurochemicals flow to excite or inhibit contiguous neurons, was a pioneer in early efforts to construct a “quantum neurobiological” theory of consciousness. In their formulation, Beck and Eccles applied concrete quantum mechanical features to describe how, in the cerebral cortex, incoming nerve impulses cause the emission of transmitter molecules in presynaptic neurons (i.e., exocytosis) via information transfer and “quantal selection” with a direct relationship with consciousness (i.e., influenced by mental actions) (Beck and Eccles, 1992).

Quantum Synapse Model

Beck and Eccles propose that “the quantum state reduction, or selection of amplitudes, offers a doorway for a new logic, the quantum logic, with its unpredictability for a single event.” Because conscious action (e.g., intention) is a dynamical process which forms temporal patterns in relevant areas of the brain (cerebral cortex), they propose how regulating the myriad synaptic switches between innumerable neurons in those relevant areas can be regulated effectively by a quantum trigger (based on an electron transfer process in the synaptic membrane). Thus, they conclude, “conscious action is essentially related to quantum state reduction” (Beck and Eccles, 1998).

Support and Implications

Stapp supports the hypothesis that quantum effects are important in brain dynamics in connection with cerebral exocytosis. Exocytosis is instigated by a neuronal action potential pulse that triggers an influx of calcium ions through ion channels into a nerve terminal, such that, due to the very small diameter of the ion channel, the quantum wave packet that describes the location of the ion spreads out to a size much larger than the trigger site. This means that “one must retain both the possibility that the ion activates the trigger, and exocytosis occurs, and also the possibility that the ion misses the trigger site, and exocytosis does not occur” (Stapp, 2006).

As Beck and Eccles hypothesize, “the mental intention (the volition) becomes neurally effective by momentarily increasing the probability of exocytosis in selected cortical areas” (Beck and Eccles, 1992). If so, this fundamental indeterminism of the nature of each specific quantum state collapse is said to open opportunity for mental powers to affect brain states, with supposed implications for conscious intervention and even for free will.