g., 8 × 6 = 48 dot products, in the case of G2). Second, the best-matching grasp-related versus ICMS-derived pair was defined to be the one with the highest dot product. The second-best match was the one with the highest dot product among the remaining (Ngrasp – 1) × (Nicms – 1) synergy pairs (7 × 5 = 35 for G2), and so on. This process continued until there were no more unpaired

synergies left in one set Selleck Compound C (min(8,6) = 6 iterations for G2; Tresch et al., 1999). The significance of each matched pair was determined by Monte Carlo simulation. For each monkey, the greedy search procedure was run 10,000 times, each time after randomly shuffling muscle identity. Then the dot product of the best-matched pair of actual grasp-related and ICMS-derived synergies was compared with the distribution of dot products from the 10,000 best-matched pairs of shuffled synergies—or more precisely, with the 95th percentile of this distribution, as this defined a threshold for significant similarity at p < 0.05. The process was then repeated for the second-best pair of actual synergies versus the 10,000 second-best pairs of shuffled synergies, and so on. These procedures were also used to compare ICMS-derived synergies between G1 and G2, after first restricting the synergies to the 12 channels common to both animals

( Figure 3D). Each animal’s cortical topography of ICMS-derived muscle synergies (Figure 4) was tested for nonuniformity Nutlin3a as follows. First, the degree to which a given synergy n   was represented at a given ICMS location l   was taken to be the mean coefficient Wicms(n  ,t  ,l  ) over t   = 1,…,7 ICMS trains delivered at the site, i.e., Wicms(n,:,l)¯. (The Wicms(n,:,l)¯ values are indicated in Figure 4 by the width of each circle.) For each ICMS location l  , 10,000 vectors each of 33 (G1) or 13 (G2) values were randomly

taken from a uniform distribution with the same mean and SD as the observed Wicms(n,:,l)¯. Second, the 95th percentile of the 10,000 maximum values from each vector was selected. Any observed Wicms(n,:,l)¯ values in excess either of this threshold were deemed to reflect significant nonuniformity in the cortical representation of synergy n, peaking around cortical location(s) l (p < 0.05, Bonferroni-corrected for the number of synergies and the number of locations). This project was supported by NIH (NINDS) grant NS44393 to E.B. and a Dystonia Medical Research Foundation fellowship to S.A.O. We thank M. Cantor, C. Potak, J. Roh, S. Szczepanowski, and F. Zaheer for their assistance. "
“Much of our adult behavior reflects the neural circuits actively refined by sensory experience in infancy and early childhood. Mounting evidence suggests that aberrant synaptic connections underlie many forms of neurodevelopmental disorders of human cognition (Zoghbi, 2003; Chahrour and Zoghbi, 2007).