INVESTIGADORES
MONGIAT lucas Alberto
congresos y reuniones científicas
Título:
Immature neurons are preferentially activated in the dentate gyrus of adult mice
Autor/es:
MONGIAT LA; PARDI MB; MARIN-BURGIN A ; SCHINDER AF
Lugar:
Washington DC
Reunión:
Congreso; 2011 Society for Neurosciences Annual Meeting; 2011
Institución organizadora:
Society for Neurosciences
Resumen:
Adult
neurogenesis provides a continuous pool of new granule cells (GCs) to the
dentate gyrus (DG) of the hippocampus. Immature GCs exhibit elevated
excitability and increased synaptic plasticity at their input synapses. These
properties led us to investigate whether immature GCs are differently activated
by entorhinal inputs, as compared to preexistent mature neurons in the DG. For this purpose, we performed experiments to
determine the network recruitment of immature (four weeks old) vs. mature (>
eight weeks old) GCs. Briefly, adult-born neurons were labeled by retroviral
injections and mice were euthanized at 4 (immature) or >8 weeks (mature)
after injection, and hippocampal slices were obtained and maintained in ACSF. Loose-patch
voltage clamp recordings were performed in fluorescently labeled GCs to assess
spiking probability elicited by perforant path stimulation. We found that
four-week-old GCs evoked spikes at a range of low stimulus intensities, whereas
higher stimulation amplitudes were needed to activate mature neurons. Moreover,
application of the GABAA antagonist picrotoxin (100µM) induced a shift in
the recruitment of mature GCs towards weaker stimulus intensities, in a way
that resembled the activation profile of immature neurons. Interestingly, the
four-week-old GC population resulted insensitive to picrotoxin. These results
indicate that immature neurons are preferentially activated due to a weaker inhibitory
control. We are currently investigating the
precise contribution of excitatory and inhibitory afferents to young and mature
GCs.