Neural Circuits and Systems Neuroscience
Author: Matias Mugnaini Mugnaini | email: matiasmugnaini@gmail.com
Matias Mugnaini 1°, Mariela Trinchero 2°, Alejandro Schinder 2°, Emilio Kropff 1°, Verónica Piatti 2°
1° Laboratorio de Fisiología y Algoritmos del Cerebro, Instituto Leloir (IIBBA)
2° Laboratorio de Plasticidad Neuronal, Instituto Leloir (IIBBA)
Adult hippocampal circuits undergo extensive remodeling by means of activity-dependent synaptic modification and by the generation of new dentate granule cells. While plasticity is fundamental for basic hippocampal functions such as learning, memory and spatial processing, the specific contributions of the distinct mechanisms of circuit modification remain unclear. To investigate the role of adult-born granule cells (aGCs) in spatial processing, we optogenetically stimulated cohorts of aGCs at 4 (young) or 8 weeks of age (mature) and recorded CA3 neural activity while mice freely foraged in an open field environment. Activation of young (but not mature) aGCs resulted in remapping of a substantial proportion of CA3 place cells despite the fact that they evoked CA3 activity in rare cases. Repetition of the protocol on subsequent days failed to induce further remapping, but a sharp increase in evoked activity similar to mature aGC levels was observed. These findings suggest that immature aGCs bear unique transient capabilities for synaptic transmission and spatial processing, granting them a potential for activity-dependent modification of CA3 spatial maps that decays with functional maturation.