Ephaptic coupling, a mechanism for spontaneous neural propagation in the brain (conference abstract)

" It is well documented that synapses play a significant role in the transmission of information between neurons in the brain. However, in the absence of synaptic transmission, neural activity has been observed to continue to propagate. Several experimental results have shown that propagation of epileptiform activity in rodent hippocampi propagates at a speed of ∼0.1 m/s. This observed activity in the 4-AP model propagates independently of synaptic transmission and gap junctions, and is outside the range of ionic diffusion and axonal conduction speeds. Compartment modeling of pyramidal neurons indicate that ephaptic coupling, or endogenous electric fields, could be responsible for this propagation of neural activity in pathological conditions such as epilepsy. Recent studies suggest electric fields can activate neighboring neurons, thereby generating a self-propagating wave.

... By blocking propagation we are able to show that ephaptic coupling is a necessary mechanism for propagation of spontaneous activity. Finally, since electric fields propagate as volume conductors, we test if activity can propagate through a complete physical cut of the tissue, thereby eliminating all other forms of close cell-to-cell communication and showing that electric fields alone are sufficient to mediate non-synaptic propagation.

... Furthermore, endogenous electric fields could play an important role in brain function and could provide an explanation for unresolved mechanisms of deep brain stimulation or transcranial direct current stimulation (tDCS)."

Last modified on 30-Jan-19

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