Motor memory formation: what have we learned from longitudinal studies conducted at different time scales.

DELLA MAGGIORE V

CABA

Congreso; NEUROCOG; 2015

Neurocog

The consolidation hypothesis first proposed by Muller and Pilzeker in 1900, states that new information acquired through learning is initially stored in labile memory traces that stabilize with the passage of time, becoming resistant from degradation by new learning. In line with this seminal work, the time course of memory consolidation has often been inferred as the temporal gradient in memory resistance to retrograde interference. Although this behavioral approach has proved successful to study the time course of memory formation in declarative learning, it has yielded controversial results in motor learning. One hypothesis for the lack of a reproducible gradient in memory resistance when learning to adapt to two opposite perturbations is that anterograde interference between tasks masks the retrograde effect of interest at recall (Miall et. al., 2004). Here, we decided to explore this anterograde effect by having subjects learned two opposite motor tasks at different time intervals through a 24 h period. In agreement with previous reports, we found evidence for strong interference when the two tasks were learned very close in time. Yet, in contrast with previous studies we observed faster learning for the second task as the time interval became longer. Our results show that anterograde effects may either interfere or facilitate learning of conflicting information depending on the time scale, and draw attention on the use of behavioral paradigms to study memory consolidation.