INVESTIGADORES
MONGIAT lucas Alberto
congresos y reuniones científicas
Título:
Spatio-temporal pattern of efferent connectivity of adult-born dentate granule cells
Autor/es:
SILVIO GABRIEL TEMPRANA ; LUCAS A MONGIAT; ALEJANDRO F SCHINDER
Lugar:
Huerta Grande - Cordoba
Reunión:
Congreso; Reunión Anual Sociedad Argentina de Investigación en Neurociencia; 2011
Institución organizadora:
Sociedad Argentina de Investigación en Neurociencia
Resumen:
Adult neurogenesis provides a continuous pool of new dentate granule
cells (DGCs) to the hippocampus. The maturation process of adult-born DGCs
takes from six to eight weeks. Whereas the development of afferents to new DGCs
has been extensively characterized, the pattern of efferent connectivity
remains poorly understood. In the adult hippocampus, mossy fibers grow through
the hilus to reach pyramidal cells in the CA3 region. This led us to
hypothesize that mossy fibers of immature DGCs primarily innervate proximal
GABAergic interneurons and lately they synapse on pyramidal cells. To test this
hypothesis we retrovirally transduced adult-born DGCs to express channelrhodopsin-2
(ChR2). Newborn DGCs were stimulated by flashes of blue light in order to
characterize their connectivity by recording on putative postsynaptic targets
in acute slices. Preliminary recordings on pyramidal neurons suggest that 6 to
8-week-old DGCs project functional monosynaptic contacts as evidenced by evoked
glutamatergic EPSCs. Moreover, light stimulation also evoked disynaptic IPSCs
on pyramidal neurons. These results suggest that adult-born DGCs perform
functional synaptic connections on CA3 neurons by 6 weeks. We are currently
investigating the functional output connectivity of younger DGCs.