One of the basic elements of brain functioning lies in the
synapse. This is the point where electrical signals from one
neuron generate electrical effects in another.
The initiation of an action potential, for example, that which
allows transmitting nerve impulses, and which is the basis
of brain functioning at the level of the neuron, requires the
opening of sodium ion channels in the mound of the axon
hillock of the neuron.
At this level, the phenomena depend on physical and
chemical properties and on the characteristics of the
biological structures at play.
To unleash an action potential, a certain trigger threshold
must be overcome thanks to the action of graduated
potentials that are added temporally and spatially, provided
by the connections with other neurons. In order for activity
to occur in the latter, the same phenomena must occur.