Complexmotor function in humans: validating and extending the postulates pf Alexandr R. Luria

Bhimani AA, Hlustik P, Small SL, Solodkin A. Cog Behav Neurol 2006; 19:11-20.

The authors use functional imaging to elaborate the neural circuitry of 3 of Luria's motor tests, modified for convenience with fMRI. The fist-palm-edge test, modified to fist, scissors, gun test, activated M1, S1 and the Supplementary motor area. The hand imitation task activated the right more than the left IFC (inferior frontal cortex) , as well as S1 and PL. The piano key task activated the SMA, pre SMA and LPMCd (lateral premotor cortex).

In the discussion the authors noted the contralateral M! activated without fail during movement, but ipsilateral activation was seen for simple movements. The paino key task had LESS ipsilateral M! activation than did fist-scissors-gun. (Familiarity diminished activation, and all subjects had typing experience per authors). However all 3 tasks had some ipsilateral activation. S1 activation was thought necessary to the requirement for proprioception activation. PL (parietal lobe) was extensively activated for the hand imitation task, as in other studies the area is shown tobe important for visuomotor transformation (Luria, Higher Cortical Functions), mental imagery rotation (Bonda et al. J Neurophysiol, 1996), and mechanisms of imitation (Iacoboni M et al. Science 1999; 286:2526-2528).
HI task is thought by Rizolatti to be part of the continuum of learning language through imitation (Trends in Neurosci 1998). The deficit was for static not dynamic HI which may be separately affected. Left preference was not seen, unlike cases in literature (Poizner et al.) nor in PK task perhaps due to familiarity. The piano key task had more activation of the pre SMA, perhaps due to self pacing.

The cerebellar cortex was crucially activated in all 3 tasks. Activation however, was generally ipsilateral.