Time course of structural plasticity induced by visuomotor adaptation

VALDÉS-SOSA PEDRO; HIDALGO-MARQUES MARCIA RENATA; LERNER GONZALO; ARMONY JORGE; DOYON JULIEN; JACOBACCI FLORENCIA; DELLA MAGGIORE VALERIA; AMARO EDSON; JOVICICH JORGE

Buenos Aires

Congreso; 2nd LABMAN Meeting; 2017

Learning is a major inducer of adaptive plasticity: the nervous system translates new knowledge into long-lasting plastic changes that lead to the formation of memories. However, the timescale of structural remodeling that accompanies functional neuroplasticity is largely unknown. There is wide evidence of changes in grey and in white matter structure in the healthy human adult brain following extensive training (more than one week) in the acquisition of a new motor skill (Dragansky et al., 2004; Landi et al., 2011; Scholz et al., 2009). Yet, little is known as to what happens structurally when the brain needs to modify preexisting internal representations or adopt new ones within minutes or hours. Experiments in nonhuman animals suggest that structural remodeling due to motor learning is a rapid, dynamic process that can be detected over much shorter timescales (2-3 hours; Fu and Zuo, 2011; Xiao et al., 2016). Evidence in humans has detected structural changes associated with learning a spatial memory task within only 30 minutes post training (Sagi at al. 2012). Neuroimaging provides us with a window into this structural change in humans. Here, we will present the results from an MRI study aimed at identifying the time course of structural plasticity in two different motor learning tasks: visuomotor adaptation and sequence learning. Subjects were scanned before, 30 min and 24 hours post training using diffusion weighted imaging (DWI). DWI, in particular mean difussivity is a sensitive measure that reflects, among other things, the level of astrocytic hypertrophy, a well characterized marker of structural plasticity in the brain (Sagi et al., 2012). The results will allow disinguishing the neural substrates undergoing plastic changes in both tasks and to unveil the time course of this process within a short time interval.