Prominent facilitation at beta and gamma frequency range revealed with physiological calcium concentration in adult mouse piriform cortex in vitro.
PLoS ONE. 2017-08-18; 12(8): e0183246
DOI: 10.1371/journal.pone.0183246
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Gleizes M(1)(2), Perrier SP(1)(2), Fonta C(1)(2), Nowak LG(1)(2).
Author information:
(1)Centre de Recherche Cerveau et Cognition, Université de Toulouse, Toulouse, France.
(2)Unité Mixte de Recherche 5549, Centre National de la Recherche Scientifique, Toulouse, France.
Neuronal activity is characterized by a diversity of oscillatory phenomena that
are associated with multiple behavioral and cognitive processes, yet the
functional consequences of these oscillations are not fully understood. Our aim
was to determine whether and how these different oscillatory activities affect
short-term synaptic plasticity (STP), using the olfactory system as a model. In
response to odorant stimuli, the olfactory bulb displays a slow breathing rhythm
as well as beta and gamma oscillations. Since the firing of olfactory bulb
projecting neurons is phase-locked with beta and gamma oscillations, structures
downstream from the olfactory bulb should be driven preferentially at these
frequencies. We examined STP exhibited by olfactory bulb inputs in slices of
adult mouse piriform cortex maintained in vitro in an in vivo-like ACSF (calcium
concentration: 1.1 mM). We replaced the presynaptic neuronal firing rate by
repeated electrical stimulation (frequency between 3.125 and 100 Hz) applied to
the lateral olfactory tract. Our results revealed a considerable enhancement of
postsynaptic response amplitude for stimulation frequencies in the beta and gamma
range. A phenomenological model of STP fitted to the data suggests that the
experimental results can be explained by the interplay between three mechanisms:
a short-term facilitation mechanism (time constant ≈160 msec), and two short-term
depression mechanisms (recovery time constants