Architectural organisation of neuronal activity-associated magnetic fields: a hypothesis for memory

Astroglial Isopotentiality and Calcium-Associated Biomagnetic Field Effects on Cortical Neuronal Coupling

Synaptic neurotransmission is necessary but does not sufficiently explain superior cognitive faculties. Growing evidence has shown that neuron-astroglial chemical crosstalk plays a critical role in the processing of information, computation, and memory. In addition to chemical and electrical communication among neurons and between neurons and astrocytes, other nonsynaptic mechanisms called ephaptic interactions can contribute to the neuronal synchronization from different brain regions involved in the processing of information. New research on brain astrocytes has clearly shown that the membrane potential of these cells remains very stable among neighboring and distant astrocytes due to the marked bioelectric coupling between them through gap junctions. This finding raises the possibility that the neocortical astroglial network exerts a guiding template modulating the excitability and synchronization of trillions of neurons by astroglial Ca²⁺-associated bioelectromagnetic interactions. We propose that bioelectric and biomagnetic fields of the astroglial network equalize extracellular local field potentials (LFPs) and associated local magnetic field potentials (LMFPs) in the cortical layers of the brain areas involved in the processing of information, contributing to the adequate and coherent integration of external and internal signals. This article reviews the current knowledge of ephaptic interactions in the cerebral cortex and proposes that the isopotentiality of cortical astrocytes is a prerequisite for the maintenance of the bioelectromagnetic crosstalk between neurons and astrocytes in the neocortex.

Neuromagnetic dialogue between neuronal minicolumns and astroglial network: A new approach for memory and cerebral computation

Rapidly accumulating experimental data over the past two decades discloses extremely complex neuro-glial interactions and provides new insights regarding novel roles of glial cells, particularly astrocytes, in complex functions. Widespread astrocytic processes, interconnected by gap junctions, form an extremely large physiological syncytium. This structure in conjunction with neuronal activity, very likely contributes to cognitive functions. Based on electrophysiological and neuroanatomical data, the present hypothesis proposes a self-organised, iterative and reciprocal magnetic interaction between neurones and astrocytes to explain neurocomputation, including memory processing, in the human neocortex.

Magnetic storage of information in the human cerebral cortex: a hypothesis for memory

The diversity of memory phenomena argues against a single place or anatomical structure for memory in the nervous system. Moreover, molecular mechanisms of information storage and synaptic transmission seem insufficient to support contextual recall and other very complex human memory processes. Here, we propose a new physical model for memory based on the magnetic fields associated with neuronal activity and its possible interaction with the adjacent astroglial network. The hypothesis emphasizes the architectural organization of the human cerebral cortex because the close geometrical relationships between neuronal minicolums and astroglial network acquire transcendental importance.