Correction and suppression of reaching movements in the cerebral cortex: Physiological and neuropsychological aspects

Abstract

Modification or suppression of reaches occurs in everyday life. We argue that a common modular architecture, based on similar neural structures and principles of kinematic and kinetic control, is used for both direct reaches and for their on-line corrections. When a reach is corrected, both the pattern of neural activity in parietal, premotor and motor cortex and the muscle synergies associated with the first movement can be smoothly blended or sharply substituted into those associated with the second one. Premotor cortex provides the early signaling for trajectory updating, while parietal and motor cortex provide the fine-grained encoding of hand kinematics necessary to reshape the motor plan. The cortical contribution to the inhibitory control of reaching is supported by the activity of a network of frontal areas. Premotor cortex has been proposed as a key structure for reaching suppression. Consistent with this, lesions in different nodes of this network result in different forms of motor deficits, such as Optic Ataxia in parietal patients, and commission errors in frontal ones.

Event-Based Data Acquisition and Reconstruction—Mathematical Background

“…Refractoriness in humans is associated with a-modal response selection rather than sensory processing or motor execution (Pashler and Johnston, 1998). This function suggests plausible locations within premotor regions and within the slow striatalprefrontal gating loops (Jiang and Kanwisher, 2003;Dux, Ivanoff, Asplund, and Marois, 2006;Houk, Bastianen, Fansler, Fishbach, Fraser, Reber, Roy, and Simo, 2007;Seidler, 2010;Battaglia-Mayer, Buiatti, Caminiti, Ferraina, Lacquaniti, and Shallice, 2014;.…”

Timing and communication of parietal cortex for visuomotor control

“…No special classes of parietal cells are recruited in this process by the change in target location, which instead is encoded through a graded utilization of the kinematics variables encoded by parietal neurons. The same applies to PMd and M1, suggesting that a common mechanism underlies trajectory formation and correction in the cerebral cortex [17]. Within this network, premotor cortex first provides the higher-order signal about the change of target location, thus calling for the specification of a new reach goal.…”

“…As an example, the effective connection strength between areas can be increased, if the timing of firing of cortical projecting neurons with small axon diameter, therefore slow conduction velocity, leads the activation of neurons with large axon diameter and faster conduction velocity. Studies of the temporal dynamics of parieto-frontal interactions indicates that while parietal and premotor cortex oscillate in-phase in the beta band (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), partial spike-field coherence in parietal cortex is asynchronous with oscillations in premotor cortex during periods of attentive fixation and motor planning [8 ], probably down-modulating parieto-frontal communication. Using a population partial spike-field coherence approach to study temporal interactions between parietal areas 2/5 and motor cortex (MI), only a weak parietal influence was found on MI during reach planning, but a strong one during reach movement [9 ], with parietal cortex influencing encoding of movement direction in primary motor cortex.…”

“…The causal role of areas PE/PEc in the online control is shown by their reversible bilateral inactivation [20 ], which results in the impaired online control of hand trajectory (for a review see [17]), as also observed in patients with optic ataxia (OA). The deficit in trajectory correction is in part dependent on a delayed saccade to the second target location, which is coherent with the combined influence of eye-hand signals on SPL neural activity, as well as with the eye movement disorders of OA patients [21].…”

Response Inhibition

“…However, despite numerous studies demonstrating reachrelated neuronal activities in cortical regions, few show unambiguous evidence for activities that inhibit reaching. As recently reviewed (Battaglia-Mayer et al, 2014), lesioning of the dorsal premotor cortex (PMd) results in an increased frequency of impulsive and uncontrolled reaching movements (Moll & Kuypers, 1977). The injection of GABA-A antagonists in the PMd reduces the ability of monkeys to withhold movements (Sawaguchi et al, 1996).…”