Decoding Effector-Dependent and Effector-Independent Movement Intentions from Human Parieto-Frontal Brain Activity

Abstract

Our present understanding of the neural mechanisms and sensorimotor transformations that govern the planning of arm and eye movements predominantly come from invasive parieto-frontal neural recordings in nonhuman primates. While functional MRI (fMRI) has motivated investigations on much of these same issues in humans, the highly distributed and multiplexed organization of parietofrontal neurons necessarily constrain the types of intention-related signals that can be detected with traditional fMRI analysis techniques. Here we employed multivoxel pattern analysis (MVPA), a multivariate technique sensitive to spatially distributed fMRI patterns, to provide a more detailed understanding of how hand and eye movement plans are coded in human parieto-frontal cortex. Subjects performed an event-related delayed movement task requiring that a reach or saccade be planned and executed toward one of two spatial target positions. We show with MVPA that, even in the absence of signal amplitude differences, the fMRI spatial activity patterns preceding movement onset are predictive of upcoming reaches and saccades and their intended directions. Within certain parieto-frontal regions we show that these predictive activity patterns reflect a similar spatial target representation for the hand and eye. Within some of the same regions, we further demonstrate that these preparatory spatial signals can be discriminated from nonspatial, effector-specific signals. In contrast to the largely graded effector-and direction-related planning responses found with fMRI subtraction methods, these results reveal considerable consensus with the parieto-frontal network organization suggested from primate neurophysiology and specifically show how predictive spatial and nonspatial movement information coexists within single human parieto-frontal areas.

That's Near My Hand! Parietal and Premotor Coding of Hand-Centered Space Contributes to Localization and Self-Attribution of the Hand

“…This is in keeping with the known neurophysiological functions of the posterior parietal cortex and its role in supporting the body-schema representation (Head and Holmes, 1911;Kammers et al, 2009) and the planning of manual actions (Culham and Valyear, 2006;Gallivan et al, 2011). Neurons in area 5 of the macaque brain encode the hand position by integrating visual and proprioceptive signals (Graziano et al, 2000;Graziano and Botvinick, 2002).…”

Human posterior parietal cortex encodes the movement goal in a pro-/anti-reach task

“…Our results thus speak in favor of a stronger effector-and weaker target-specificity in PMd compared with PCu in the human brain. Although earlier studies on reach planning indicated that PMd is primarily modulated by the effector hand (Beurze et al 2007;Medendorp et al 2005) more recent work using multivariate decoding approaches on fMRI data also demonstrated target-selectivity in PMd (Gallivan et al 2011;Fabbri et al 2014). …”

Action Observation as a Visual Process: Different Classes of Actions Engage Distinct Regions of Human PPC

“…Some are easily dissociated from an observed action such as biological factors, e.g. age or gender, or motor aspects such as posture; but other more cognitive properties, such as intention or determination are more difficult to dissociate from the observed action, and are actually often attributed to the observed action (Gallivan et al, 2011;Palmer et al, 2016). Another extrinsic factor is the target of the action, which can be an object, a point in space, or a conspecific, depending on the action class.…”