Frontoparietal cortex and cerebellum contribution to the update of actual and mental motor performance during the day

Abstract

Actual and imagined movement speed increases from early morning until mid-afternoon. Here, we investigated the neural correlates of these daily changes. Fifteen subjects performed actual and imagined right finger opposition movement sequences at 8 am and 2 pm. Both actual and imagined movements were significantly faster at 2 pm than 8 am. In the morning, actual movements significantly activated the left primary somatosensory and motor areas, and bilaterally the cerebellum; in the afternoon activations were similar but reduced. Contrast analysis revealed greater activity in the cerebellum, the left primary sensorimotor cortex and parietal lobe in the morning than in the afternoon. Imagined movements in the morning significantly activated the parietal association cortices bilaterally, the left supplementary and premotor areas, and the right orbitofrontal cortex and cerebellum. In the afternoon, the frontal lobe was significantly activated with the right cerebellum. Contrast analysis revealed increased activity in the left parietal lobe in the morning than in the afternoon. For both tasks, speed in the morning was significantly related to the BOLD signal in the brain areas resulted more active. These findings suggest that motor performance is continuously updated on a daily basis with a predominant role of the frontoparietal cortex and cerebellum.

Figure 1. Durations of the two task conditions (PE = physical execution, MI = motor imagery) in the two sessions (AM = 8 am, PM = 2 pm).

The error bars represent the SD. *Indicates significant difference at 2 pm compared to the respective value at 8 am.

Figure 2

Group activation blobs displayed on a rendering surface for the physical execution (PE) condition (height threshold p < 0.05 FWE-corrected; extent threshold k = 50 voxels): (a) morning (AM) and afternoon (PM) sessions pooled together (see Table 1 for details), (b) AM in red, PM in green (see Table 2 for details). Yellow represents the superposition of the blobs obtained in the two sessions.

Figure 3

Group activation blobs displayed on a rendering surface for the motor imagery (MI) condition (height threshold p < 0.05 FWE-corrected; extent threshold k = 50 voxels): (a) morning (AM) and afternoon (PM) sessions pooled together (see Table 1 for details), (b) AM in red, PM in green (see Table 2 for details). Yellow represents the superposition of the blobs obtained in the two sessions.

Figure 4

Linear relationships during the morning session between task duration and the 1^st eigenvariate of the BOLD signal in: (a) cluster I–PE, (b) cluster II–PE, (c) cluster I–MI.