Role of Quantum Mechanics in the Brain

Quantum mechanics is a physical science that describes the behavior of matter and energy in their atomic and subatomic levels and the forces they interact with. It explains simple things like how the position of momentum changes with time. It deals with the particles at different scales, small or big, and how they relate to changing energy and temperature. “Quantum mechanics” was first coined in 1924 by Max Born.

Early physicists who have no idea of modern neurobiology assume that the quantum world is irrelevant to brain functions and consciousness and therefore, did not bother to study the concept. The knowledge of modern neurology sheds light on it. The rise of quantum biology as a borderline between life-sciences and quantum physics insinuate that quantum events play a consequential role in neuronal cells. The modern physicist believes that Quantum mechanics can explain consciousness and some brain functions.

The brain is a system of non-linear dynamic complexes. I.e. the brain is like a machine that process input-output computation, and response to stimuli with the network of nerve cells and other connecting cells which consist of atoms.

The brain has 10¹⁰ and 10¹¹ nerve cells that can be in two states each–firing or quiescent. The brain receives input through the peripheral nervous system by the consistent firing of sensory neurons, which is caused by the changes in the system of the external world. The output is by the actions of motor neurons that cause a contraction in muscles that follow a particular pattern. There is a massive complex wiring diagram in between, but, a non-sensory neuron fires in response to the firing of other neurons connected to it. The human brain does not function as an input-output machine alone but, it also processes direct information, has awareness, and it has direct knowledge. The complex non-linear system of the brain gives it high sensitivity to fluctuations

The nervous system which is also a system with a non-linear dynamical complex has much feedback loop. In a complex and advanced system, the microscopic fluctuations can be amplified and as a result, affect the behavior of the system and probably amplify the microscopic effect of quantum. The consequential quantum effect speeds up the computation process of organisms at the microscopic level.

Matthew Fisher a physicist of the University of California at Santa Barbara in the study he published in 2015 argued that the brain probably has molecules that are capable of sustaining big quantum superposition. He thinks that the nuclei of phosphorus specifically have this ability. Phosphorus atom can be found everywhere in the cell of a living organism. Most of the cell's energy is stored in the ATP molecule. ATP molecule contains a wrap of three phosphate groups that is joined to an organic molecule. Energy is released for the cell to use when one of the phosphates is cut free. Fisher inferred a process in which two phosphate ions could be placed in a special superposition called “entangled state”.

The “spin” which is the quantum property of phosphorus nuclei makes them little magnets with poles that point in a particular direction. One phosphorus nuclei spin is dependent on the spin of the other nucleus in an entangled state. The entangled states are the superposition state that involves more than one particle. Fisher assumes that the mechanical behavior of the quantum of these nuclear spins might resist the coherence of human activities. Fisher said he was not looking for a quantum explanation when he studied how Lithium drugs work in treating bipolar disorder. He said they work, but nobody truly knows how. He realized that the nuclei of different lithium's atoms spin differently. This spin, which is a quantum property, affects the way lithium works. E.g. if lithium is substituted for calcium in Posner molecules, the lithium spin interferes with the entanglement of a phosphorus atom. Aaron Posner noticed an odd cluster of calcium and in his x-rays of bone, He draw the structure of the clusters: six phosphorus and nine calcium atoms called “Posner molecules”. Fisher assumes the Posner molecule could be a natural qubit in the brain.

Neurological assembly process is needed to make the encoded content accessible consciously. This process is initiated by external stimuli. The memory will be unused if the assembly is not activated. Umezawa insinuates that the assembly of neurons correlated to such memory in that state is called "vacuum states". The excited state is reached when the assembly is activated and it enables a conscious remembrance of the encoded content in the ground states.

Freeman and Vitiello (2006-2010) studied the neurobiology of electric and magnetic field amplitudes and the concentration of neurotransmitters. They discovered evidence for non-equilibrium phase analogs transitions (Vitiello) and the distribution of power-law of spectral energy of electrocorticograms. ( Quian Quiroga- 2013, Freeman and Vitiello-2010) . Power-law distributions are closely related to dissipative quantum coherent states.

Penrose and Hameroff claimed that quantum theory is highly effective in the quantum study but the process is complex. The basic acts of consciousness that are not superposition states are in microtubule.

Quantum concepts such as entanglement, dispersive state, and non-Boolean logic are interrelated with mental processes. An accurate quantum approach to brain and mental functions uses formal features that are also employed in quantum physics.

David Bohm explained the relationship between matter and consciousness. He collaborated with Karl Pribram’s holonomic brain theory as the basis of quantum consciousness. Philosopher Paavo Pyikkanen opined that Bohm's suggestion "leads to the assumption that the physical example of the logical thinking process is at a classical stage of the brain, while the fundamental thinking process can be described using quantum theory.

The coherence of Quantum mechanics has been demonstrated at the microscopic or atomic level although it has not been proved. Hameroff and Penrose(2014)'s quantum brain proposal which focuses on explaining consciousness require large scale coherent quantum wave longer than those found so far. The quantum mechanism has been adopted by Scott Aaronson in his “freebit” theory which postulates that the complex dynamics in the brain have a direct effect of amplifying freebit at a microscopic level.