Corticocortical Systems Underlying High-Order Motor Control

Abstract

Cortical networks are characterized by the origin, destination, and reciprocity of their connections, as well as by the diameter, conduction velocity, and synaptic efficacy of their axons. The network formed by parietal and frontal areas lies at the core of cognitive-motor control because the outflow of parietofrontal signaling is conveyed to the subcortical centers and spinal cord through different parallel pathways, whose orchestration determines, not only when and how movements will be generated, but also the nature of forthcoming actions. Despite intensive studies over the last 50 years, the role of corticocortical connections in motor control and the principles whereby selected cortical networks are recruited by different task demands remain elusive. Furthermore, the synaptic integration of different cortical signals, their modulation by transthalamic loops, and the effects of conduction delays remain challenging questions that must be tackled to understand the dynamical aspects of parietofrontal operations. In this article, we evaluate results from nonhuman primate and selected rodent experiments to offer a viewpoint on how corticocortical systems contribute to learning and producing skilled actions. Addressing this subject is not only of scientific interest but also essential for interpreting the devastating consequences for motor control of lesions at different nodes of this integrated circuit. In humans, the study of corticocortical motor networks is currently based on MRI-related methods, such as resting-state connectivity and diffusion tract-tracing, which both need to be contrasted with histological studies in nonhuman primates.

Spatial frequency tuning of motor responses reveals differential contribution of dorsal and ventral systems to action comprehension

“…These results fit well with neurophysiological evidence from neural recordings in monkeys showing that activity in the ventral PFC encodes object identity for action goal selection in a context-dependent manner (15,16). Furthermore, the PFC exhibits dense connectivity with premotor regions, the inferotemporal cortex and orbitofrontal areas supporting the existence of different routes for processing actions in context beyond the classical AON (e.g., prefrontal-premotor route) (16,17). Altogether, these studies provide functional and anatomical evidence for the existence of different routes impacting on action processing, carrying semantic information about objects in context that is further transformed into motor representations of potential actions afforded by them.…”

“…Future studies are needed to disentangle whether these prediction signals would modulate AON activity via a dorsal-dorsal route (i.e., prefrontal-premotor connection) or indirectly through a dorsal-ventral-dorsal network (i.e., prefrontal-temporal-premotor connections). While evidence from monkey studies (15,17) seems to support the first possibility, its existence in humans awaits direct testing.…”

Spatiotemporal transformations for gaze control

“…To guide appropriate behavior, the information about target location needs to be gated to the appropriate memory and motor circuitry to meet the requirements of the task. Such a gating mechanism can be implemented by the corticocortical and cortico‐striato‐thalamic loops, and subcortical circuits through the basal ganglia (Battaglia‐Mayer & Caminiti, 2019; Coe et al, 2019; Krauzlis et al., 2013; Lynch & Tian, 2006; O'Reilly & Frank, 2006). These circuits can integrate various sensory information with learned associations to transfer the spotlight of attention onto relevant locations.…”

Characteristics of Kinematic Parameters in Decoding Intended Reaching Movements Using Electroencephalography (EEG)

“…Since the frontal area is also involved in movement planning (Pobric and Hamilton, 2006; Andersen and Cui, 2009), this area may play a different role than the parietal or occipital cortices (Connolly et al, 2007), necessitating additional studies to determine how other areas are involved in classification or decoding during movement preparation. In addition to an independent area, the contribution of multiple areas, such as the network of parietal and frontal areas, may be involved in the motor control of reaching movement (Battaglia-Mayer et al, 2014; Battaglia-Mayer and Caminiti, 2019); therefore, functional connectivity of the prefrontal cortex and dorsal premotor cortex (Mattia et al, 2010) could be considered. In participant 7, the top ICs were not related to the parietal and occipital areas as in other participants (Figures 10, 11).…”