Neuroelectric Tuning of Cortical Oscillations by Apical Dendrites in Loop Circuits.

Bundles of relatively long apical dendrites dominate the neurons that make up the thickness of the cerebral cortex. It is proposed that a major function of the apical dendrite is to produce sustained oscillations at a specific frequency that can serve as a common timing unit for the processing of information in circuits connected to that apical dendrite. Many layer 5 and 6 pyramidal neurons are connected to thalamic neurons in loop circuits.

The cognitive significance of resonating neurons in the cerebral cortex.

Most neural fibers of the cerebral cortex engage in electric signaling, but one particular fiber, the apical dendrite of the pyramidal neuron, specializes in electric resonating. This dendrite extends upward from somas of pyramidal neurons, the most numerous neurons of the cortex. The apical dendrite is embedded in a recurrent corticothalamic circuit that induces surges of electric current to move repeatedly down the dendrite.

Theory of electric resonance in the neocortical apical dendrite.

Pyramidal neurons of the neocortex display a wide range of synchronous EEG rhythms, which arise from electric activity along the apical dendrites of neocortical pyramidal neurons. Here we present a theoretical description of oscillation frequency profiles along apical dendrites which exhibit resonance frequencies in the range of 10 to 100 Hz. The apical dendrite is modeled as a leaky coaxial cable coated with a dielectric, in which a series of compartments act as coupled electric circuits that gradually narrow the resonance profile.

[Capacity to act on its life and inflexion of biographical lines: the point of view of homeless women.].

To think of homelessness as a process opens the path to two questions. How can one prevent this disqualification process to arrive at its ultimate end? (the fact of being on the street with an identity of a homeless person)? One then thinks of prevention. How can one (re)store a reversed process allowing to modify the condition of homelessness? The issue of (re)integration or (re)affiliation is then raised.

[The police and mental health services.].

Access to mental health services for people referred by the police represent an important stake to prevent the criminalization of minor infractions. The police play an essential role in the choice of the answer given to these situations. When informal measures cannot be retained or when health services are not accessible or when a person refuses, criminalization often appears as the only way to solve the problem and potentially, obtain care for the person.