Regular articleThe left parietal and premotor cortices: motor attention and selection
Introduction
The premotor cortex has a central role in selecting movements while the parietal cortex is concerned with the preparation and redirection of movements and movement intentions Kalaska and Crammond, 1995, Rushworth et al., 2001a, Thoenissen et al., 2002. The same brain areas and cognitive processes must be discussed in any account of apraxia or motor recovery after stroke; apraxic patients' lesions cluster around the intraparietal sulcus and parts of the frontal lobe (Haaland et al., 2000) and new patterns of activation appear in such regions as patients recover movement skills after brain damage Johansen-Berg, 2002a, Johansen-Berg and Matthews, 2002.
Section snippets
The organization of attention systems within the parietal cortex
The involvement of the parietal cortex in coding space and in directing spatial attention is well established Bremmer et al., 2001a, Halligan et al., 2003. The firing rates of parietal neurons change in tandem with the direction of attention (Colby and Goldberg, 1999) and neuroimaging studies have identified signal modulations in the human parietal cortex in similar situations Corbetta and Shulman, 2002, Nobre, 2001. The ability to represent extrapersonal space and to direct attention within
Covert preparatory motor attention
Paradigms in which subjects covertly prepare for stimuli appearing in a certain part of the visual field are well established as ways of investigating oculomotor attention (Pashler, 1998). Reaction times (RTs) are quicker when subjects are able to prepare for a stimulus' appearance at a particular position. Although it may be possible to covertly orient attention in such paradigms without making an overt eye movement it is clear from both behavioral and neuroimaging experiments that the two
The left parietal cortex and covert motor attention
Before considering the evidence that links the left parietal cortex with motor attention it is worth recalling the evidence that relates covert orienting attention to other parietal areas. Two types of experiments have implicated the posterior parietal cortex, particularly in the right hemisphere, with the covert orienting of attention. First, neuroimaging experiments have shown that when subjects are covertly orienting to stimuli there is an increase in activation in the posterior parietal
Motor attention after left parietal lesions
Not only does TMS disrupt the redirection of motor attention, but lesions that include the same area have a similar effect Castiello and Paine, 2002, Rushworth et al., 1997c. Rushworth and colleagues compared performance on a motor attention redirection task in three groups of subjects: nine patients with lesions that included the left parietal cortex, nine patients with lesions that included the right parietal cortex, and a set of age-matched healthy controls. Patients performed the task with
Tool use and left parietal lesions
The updating of motor attention, if it is defined as the updating of the representation of the body and limbs, can also be invoked to help explain the role of the parietal cortex in tool use; when a person uses a tool the representation of the body plan must be updated to accommodate the tool. For example, a person using a hammer has a longer reach by virtue of the hammer's length. A failure to update the body representation appropriately would mean that the person attempting to hit a nail
The left premotor cortex and movement selection
While the parietal cortex may have a complex role in the preparation and redirection of movements and movement intentions, both single neuron recording and human neuroimaging studies indicate that the premotor cortex has a well-defined role in the selection of movements for execution Kalaska and Crammond, 1995, Thoenissen et al., 2002. Once again neuroimaging and TMS experiments indicate that the premotor cortex in the left hemisphere has the dominant role.
Different parts of the premotor cortex
The premotor cortex, motor impairment, and motor recovery after stroke
Disruption of such movement selection mechanisms may have some relevance for understanding the impairments of patients with lesions in the left hemisphere. Left hemisphere lesions have a particularly disruptive effect on the ability of patients to select between movements according to arbitrary rules (Rushworth et al., 1998). An impairment of such a mechanism may contribute to the difficulties that some apraxic patients with left hemisphere lesions have in selecting the appropriate movements in
Conclusions
While the premotor cortex is concerned with the selection of a movement for execution, parietal neurons are modulated when movements are prepared or redirected Kalaska and Crammond, 1995, Rushworth et al., 2001a, Thoenissen et al., 2002, a function that we have summarized with the term “motor attention.” In the cases of both the parietal and the premotor cortices of the human brain, the dominant role in motor attention and selection is played by areas in the left hemisphere. Some of the
Acknowledgements
This work was supported by core funding from the Medical Research Council, Medical Research Council grants (M.F.S.R., J.T.D.), the Wellcome Trust (H.J.-B.), Jesus College (S.M.G.), and the Royal Society (M.F.S.R.).
References (88)
Polymodal motion processing in posterior parietal and premotor cortexa human fMRI study strongly implies equivalencies between monkeys and humans
Neuron
(2001)- et al.
Heterogeneity of extrastriate visual areas and multiple parietal areas in the macaque monkey
Neuropsychologia
(1991) A common network of functional areas for attention and eye movements
Neuron
(1998)- et al.
Brain activation related to the representations of external space and body scheme in visuomotor control
NeuroImage
(2001) - et al.
Forward modeling allows feedback control for fast reaching movements
Trends Cognit. Sci.
(2000) - et al.
Saccade target selection and object recognitionevidence for a common attentional mechanism
Vision Res.
(1996) Anatomic constraints on cognitive theories of category specificity
NeuroImage
(2002)- et al.
The mental number line and the human angular gyrus
NeuroImage
(2001) - et al.
Crossmodal processing of object features in human anterior intraparietal cortexan fMRI study implies equivalencies between humans and monkeys
Neuron
(2002) - et al.
Hemispheric asymmetry of movement
Curr. Opin. Neurobiol.
(1996)
Spatial cognitionevidence from visual neglect
Trends Cognit. Sci.
Hemispheric specialization for motor sequencingabnormalities in levels of programming
Neuropsychologia
Ipsilesional deficits during fast diadochokinetic hand movements following unilateral brain damage
Neuropsychologia
Regional distribution of functions in parietal association area 7 of the monkey
Brain Res.
The attentive homunculusnow you see it, now you don't
Neurosci. Biobehav. Rev.
Covert visual spatial orienting and saccadesoverlapping neural systems
NeuroImage
Functional brain mapping of monkey tool use
NeuroImage
The left parietal cortex and motor attention
Neuropsychologia
The left hemisphere and the selection of learned actions
Neuropsychologia
Cerebral dominance for action in the human brainthe selection of actions
Neuropsychologia
Extrapersonal visual unilateral spatial neglect and its neuroanatomy
NeuroImage
Arbitrary associations between antecedents and actions
Trends Neurosci.
Intentional maps in posterior parietal cortex
Annu. Rev. Neurosci.
Functional organization of human intraparietal and frontal cortex for attending, looking, and pointing
J. Neurosci.
Human anterior intraparietal area subserves prehensiona combined lesion and functional MRI activation study
Neurology
A parieto-premotor network for object manipulationevidence from neuroimaging
Exp. Brain Res.
Neuronal activity in the lateral intraparietal area and spatial attention
Science
Attention versus intention in the primate premotor cortex
NeuroImage
Primate frontal cortexneuronal activity following attentional versus intentional cues
Exp. Brain Res.
Space coding in primate posterior parietal cortex
NeuroImage
Cerebral control of contralateral and ipsilateral arm, hand and finger movements in the split-brain rhesus monkey
Brain
Effects of left parietal injury on covert orienting of attention
J. Neurol. Neurosurg. Psychiatry
Space and attention in parietal cortex
Annu. Rev. Neurosci.
Control of goal-directed and stimulus-driven attention in the brain
Nat. Rev. Neurosci.
Methods of limb apraxia examination and their bearing on the interpretation of the disorder
Ideational apraxia
Brain
Imitating gesturesa quantitative approach to ideomotor apraxia
Arch. Neurol.
Cerebral structures participating in motor preparation in humansa positron emission tomography study
J. Neurophysiol.
Role of the posterior parietal cortex in updating reaching movements to a visual target
Nat. Neurosci.
Saccadic dysmetria in a patient with a right frontoparietal lesionthe importance of corollary discharge for accurate spatial behaviour
Brain
Functional neuroanatomy of the primate isocortical motor system
Anat. Embryol.
Separate visual representations in the planning and control of actions
Behav. Brain Sci.
Parietal activation during number comparison is not number-specific
J. Cognit. Neurosci.
Imitation and matching of hand and finger postures
NeuroImage
Cited by (422)
Aging alters functional connectivity of motor theta networks during sensorimotor reactions
2024, Clinical NeurophysiologyProbing intrahemispheric interactions with a novel dual-site TMS setup
2024, Clinical Neurophysiology