Causal Connectivity between the Human Anterior Intraparietal Area and Premotor Cortex during Grasp

Abstract

SummaryThe cortical visuomotor grasping circuit, comprising the anterior intraparietal area (AIP), ventral premotor (PMv), and primary motor cortex (M1) allows transformation of an object's physical properties into a suitable motor command for grasp [1–9]. However, little is known about how AIP contributes to the processing of grasp-related information conveyed through the cortical grasping circuit. We addressed this by studying the consequences of AIP “virtual lesions” on physiological interactions between PMv and M1 at rest or during preparation to grasp objects with either a precision grip or a whole-hand grasp. We used a conditioning-test transcranial magnetic stimulation (TMS) paradigm to test how PMv-M1 interactions [10–12] were modified by disrupting AIP function with theta-burst TMS (cTBS) [13]. At rest, AIP virtual lesions did not modify PMv-M1 interactions. In contrast, the usual muscle-specific PMv-M1 interactions that appeared during grasp preparation were significantly reduced following AIP cTBS without directly modifying corticospinal excitability. Behaviorally, disruption of AIP was also associated with a relative loss of the grasp-specific pattern of digit muscle activity. These findings suggest that grasp-related and muscle-specific PMv-M1 interactions are driven by information about object properties provided by AIP.

The dorsal premotor cortex exerts a powerful and specific inhibitory effect on the ipsilateral corticofacial system: a dual-coil transcranial magnetic stimulation study

“…The temporal specificity is consistent with corticocortical connections. In fact, other studies exploring corticocortical connections between areas the distances between which are similar to that between the PMCd and the mouthM1 have found interactions at ISIs around 6 ms. (Baumer et al 2009;Cattaneo and Barchiesi 2011;Davare et al 2008Davare et al , 2009Davare et al , 2010. It should be noted that the physical distance between the dorsal premotor cortex and the mouthM1 is of around 6 cm, entirely compatible with a direct corticocortical connection.…”

“…We provide evidence for a specific short-latency inhibitory effect of the The connectivity between the PMC and the ipsilateral M1 in humans is largely hypothesized by analogy with the non-human primates. Still, direct evidence for it has been obtained by means of the dual-coil paradigm of transcranial magnetic stimulation (TMS) (Baumer et al 2009;Cattaneo and Barchiesi 2011;Civardi et al 2001;Davare et al 2008Davare et al , 2009Davare et al , 2010Koch et al 2006;Mars et al 2009). This protocol involves the use of two magnetic stimulators connected to two distinct coils, both of which are used simultaneously on the participant's scalp.…”

Probing the reaching–grasping network in humans through multivoxel pattern decoding

“…Crucially, the precise nature, in terms of timing and direction (causality—Davare et al. 2010; Grol et al. 2007) of the relations between the involved brain areas remains to be clarified by future studies.…”

Functional connectivity associated with hand shape generation: Imitating novel hand postures and pantomiming tool grips challenge different nodes of a shared neural network

“…Their function has been interpreted in terms of goaldirected planning, planning of hand movements, and adequate sequencing of motor commands respectively (Buxbaum et al, 2006;Davare et al, 2010;Grafton et al, 1998;Lewis, 2006;Makuuchi et al, 2012;Meister et al, 2009;Vingerhoets et al, 2013). The focus of vPMC of matching hand posture configurations in accordance to visual demands is nicely demonstrated by its close correspondence with inferior parietal and extrastriate regions, whereas the focus of DLPFC and dPMC on the planning of motor control is underlined by its strong reciprocal connections (see Figure 4B).…”