Planning Functional Grasps of Simple Tools Invokes the Hand-independent Praxis Representation Network: An fMRI Study (original) (raw)
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The neural underpinnings of haptically guided functional grasping of tools: An fMRI study
NeuroImage, 2019
The neural bases of haptically guided interactions with tools are largely unknown. Whereas in the visual domain there is clear evidence for left lateralization of the networks underlying the guidance of actions involving tools, comparable evidence in haptic modality is missing. Therefore, we examined whether the temporo-parieto-frontal networks responsive to interactions with tools also support haptically guided functional grasping. We used event-related functional magnetic resonance imaging (fMRI) to measure brain activity while, in the absence of vision, 21 right-handed participants performed the following tasks with either their dominant or non-dominant hands: haptic exploration of real 3-D tools or size-matched control objects, subsequent planning of functionally appropriate grasps of tools and most convenient grasps of non-tools, and the resulting grasp execution. As predicted, haptic exploration of tools (vs. non-tools) was associated with significant asymmetrical/left-lateralized increases of activity in temporo-parieto-frontal networks. While grasp planning did not reveal differences between tools and control objects, the execution of functional grasping of tools (as compared to control grasps) re-recruited mainly dorsal cortical regions engaged earlier during the exploration phase. These results demonstrate that haptically guided grasping of tools invokes only subsets of cortical regions typically associated with tool-directed actions. They also call for a re-interpretation of what we assumed would be happening during the exploration phase, as this early stage of processing most likely included preliminary grasp planning. After all, the requisite integration of structural and conceptual tool features, as well as relevant action knowledge mediated at the neuronal level by the temporo-parietal projections in the early stage of processing, is not then critical for the execution of the preprogrammed functional grasp.
Perception meets action: fMRI and behavioural investigations of human tool use
Tool use is essential and culturally universal to human life, common to huntergatherer and modern advanced societies alike. Although the neuroscience of simpler visuomotor behaviours like reaching and grasping have been studied extensively, relatively little is known about the brain mechanisms underlying learned tool use.
Does tool-related fMRI activity within the intraparietal sulcus reflect the plan to grasp?
NeuroImage, 2007
Neuroimaging investigations reliably describe a left-lateralized network of areas as underlying the representations of knowledge about familiar tools. Among the critical 'nodes' of the network, an area centered within the left intraparietal sulcus (IPS) is thought to be related to the motoric representations associated with familiar tools and their usage. This area is in the vicinity of an area implicated in the control of object-directed grasping actions: the anterior intraparietal area, AIP. The current study aimed to evaluate whether this toolrelated intraparietal activity could be accounted for by the graspable nature of tools or whether it was due to additional factors such as the functionality of tools. First, we found that during a naming task activation within a discrete region of the left anterior intraparietal cortex was higher for tools than for graspable objects, but did not differ between graspable and non-graspable objects. In addition, the peak activity associated with tool naming was found to be largely distinct and consistently posterior to that associated with real object grasping. A separate region, anterior to the tool-selective focus and possibly overlapping with AIP, demonstrated weak selectivity for both tools and graspable objects relative to non-graspable objects.
Journal of Cognitive Neuroscience, 2010
■ Humans display a remarkable capacity to use tools instead of their biological effectors. Yet, little is known about the mechanisms that support these behaviors. Here, participants learned to grasp objects, appearing in a variety of orientations, with a novel, handheld mechanical tool. Following training, psychophysical functions relating grip preferences (i.e., pronated vs. supinated) to stimulus orientations indicate a reliance on distinct, effectorspecific internal representations when planning grasping actions on the basis of the tool versus the hands. Accompanying f MRI data show that grip planning in both hand and tool conditions was associated with similar increases in activity within the same regions of the anterior intraparietal and caudal ventral premotor cortices, a putative homologue of the macaque anterior intraparietalventral premotor (area F5) "grasp circuit." These findings suggest that tool use is supported by effector-specific representations of grasping with the tool that are functionally independent of previously existing representations of the hand and yet occur within the same parieto-frontal regions involved in manual prehension. These levels of representation are critical for accurate planning and execution of actions in a manner that is sensitive to the respective properties of these effectors. These effector-specific representations likely coexist with effector-independent representations. The latter were recently reported in macaque F5 [Umiltà, M. A., Escola, L., Intskirveli, I., Grammont, F., Rochat, M., Caruana, F., et al. When pliers become fingers in the monkey motor system. ] and appear to be established by tool use training through modification of existing representations of grasping with the hand. These more abstract levels of representation may facilitate the transfer of skills between hand and tool. ■
2016
Although facilitation of the corticospinal system during action observation is widely accepted, it remains controversial whether this facilitation reflects a replica of the observed movements or the goal of the observed motor acts. In the present study, we asked whether, when an object is grasped by using a tool, corticospinal facilitation represents 1) the movements of the hand, 2) the movements of the tool, or 3) the distal goal of the action. To address this question, we recorded motor-evoked potentials (MEPs) to transcranial magnetic stimulation while participants observed a hand reaching and grasping a mothball by using 3 types of pliers, requiring different hand--tool movements to achieve the same goal (grasping the object). We found that MEPs recorded from the opponens pollicis and from the first dorsal interosseous reflected the observed hand movements rather than the movements of the tool or the distal goal of the action. These results suggest that during observation of too...