Fig 1.
One cycle of the visual / motor task.
Including their instruction screens, two motor conditions alternated with a visual condition; this sequence repeated for a total of six cycles. Motor conditions were accompanied by a metronome ticking at two beats per sec for pacing finger movements.
Fig 2.
Independence of activation and connectivity analysis.
(A) Predicted patterns of BOLD activation (top, blue), and connectivity from the left and right hippocampal seeds (bottom, green and red, respectively). (B) BOLD activity observed at the SMC connectivity maximum (black) compared with activity predicted from the sum of the activity from the left and right hippocampal seeds (purple). (C) BOLD activity observed at the SMC activation maximum (black) compared to the predicted pattern for activation (top, blue), the sum of activity from left and right hippocampal seeds (middle, purple), and the sum of activation plus hippocampal activity (bottom, orange).
Fig 3.
Rehearsal effects on motor performance during sequence learning and repetitive tapping.
(A) Changes in stimulus-response asynchrony across rehearsals. Negative values for asynchrony represent anticipatory responses, which developed across rehearsals for all motor conditions; variability represents standard deviations for 4-note groupings among individuals. Colored encircled asterisks indicate a significant difference from the first to last pair of repetitions during a task; a plain black asterisk at the beginning or end of rehearsals indicates a significant difference between task conditions (p<0.05). (B) A change in intertap intervals was observed across rehearsals only in the sequence learning task, accompanied by a decrease in variability. (C) A change in precision was observed across rehearsals only in the sequence learning task.
Table 1.
Group rehearsal effects during sequence learning and repetitive tapping.
Table 2.
Individual variability during sequence learning and repetitive tapping.
Fig 4.
Sensorimotor activation during performance of motor tasks.
(A) Group analysis (top) showed unilateral activation in left sensorimotor cortex during performance of the unimanual sequence learning task, and bilateral activation during the bimanual repetitive tapping task. Global analysis for the group expanded the area of demonstrable activation; in this analysis, subthreshold activation revealed through global analysis is shown in cyan, with overlap between global and individual task activation shown in orange. Individual analysis (subjects 308–309) verified bilateral activation for both tasks. (B) Task activation with a smaller (6mm) smoothing kernel used for connectivity analysis. The area of activation was reduced in both tasks, with the area of detectable activation during repetitive tapping limited to the right SMC. Direct task comparisons revealed greater left SMC activation during sequence learning and greater right SMC activation during repetitive tapping. Threshold for both individual and group activation was p = 0.05 with FWE correction for multiple comparisons. Results in this and subsequent figures are displayed using the neurological convention (left display = left side of brain).
Table 3.
Location of group sensorimotor cortical activation.
Fig 5.
Sensorimotor connectivity of structural and functional seeds during sequential learning.
(A) Negative connectivity with the left SMC was generated from three structural seeds (A2, B1, and B2) and a functional seed selected from each motor task; positive connectivity with the right SMC was generated from an anterior functional seed (left column, memseed+). Connectivity from the left hippocampus was more prevalent than from the right (right column). (B) Beta values for connectivity (left) and the total number of SMC voxels with significant connectivity generated from seeds in each hemisphere (right) indicate a role for both the left and right hippocampus. Connectivity from global analysis of both could be greater than connectivity from the left or right hippocampus by itself.
Table 4.
Connectivity clusters within sensorimotor cortex during group analysis.
Fig 6.
Sensorimotor connectivity of structural and functional seeds during paced repetitive tapping.
(A) Negative connectivity generated from structural and functional seeds was observed in the right SMC, almost exclusively from global analysis of the left and right hippocampus. (B) Structural seeds showed greater negative connectivity in the right SMC during repetitive tapping, whereas functional seeds showed greater negative connectivity in the left SMC (light blue) and positive connectivity in the right SMC (magenta) during sequence learning. (C) Beta values indicated equal contributions from the left and right hippocampus (left), with global analysis required to demonstrate most connectivity effects (right).
Table 5.
Selectivity of task-dependent connectivity for the hand representation.