There may be more to reaching than meets the eye: Re-thinking optic ataxia

Jackson, Stephen R.; Newport, Roger; Husain, Masud; Fowlie, Jane; O’Donoghue, Michael; Bajaj, Nin

doi:10.1016/j.neuropsychologia.2009.01.035

Cited by 49 publications

(43 citation statements)

References 48 publications

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“…Whereas saccade planning is thought to occur in eye-centered coordinates, both eye-and body-related reference frames are probably used for limb movement planning (Pesaran et al, 2006;Chang and Snyder, 2007;Marzocchi et al, 2008;Chang et al, 2009;Ferraina et al, 2009;McGuire and Sabes, 2009;Bernier and Grafton, 2010;Chang and Snyder, 2010;Pesaran et al, 2010). The PPC, and especially the SPL, has been suggested to play a major role in the estimation of the current limb positions using proprioceptive and visual information (Graziano et al, 2000;Shadmehr and Krakauer, 2008;Jackson et al, 2009), implicated, for example, by patients suffering from optic ataxia (Karnath and Perenin, 2005). In monkeys, area 5 neurons integrate vision and proprioception to represent limb posture (Graziano et al, 2000), and neurons in area PEc code for complex body postures involving not only hands and arms, but also legs and feet (Breveglieri et al, 2006.…”

Section: Discussionmentioning

confidence: 99%

Functional Rather than Effector-Specific Organization of Human Posterior Parietal Cortex

Heed¹,

Beurze²,

Toni³

et al. 2011

J. Neurosci.

116

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Neurophysiological and neuroimaging studies have shown that the posterior parietal cortex (PPC) distinguishes between the planning of eye and hand movements. This distinction has usually been interpreted as evidence for a modular, effector-specific organization of this cerebral region. However, the eyes differ markedly from other body parts both in terms of their functional purpose and with regard to the spatial transformations required to plan goal-directed movements. PPC may therefore provide specialized subregions for eye movements, but distinguish less for other effectors. Using functional magnetic resonance imaging, we compared activity during memoryguided eye, hand, and foot movements in human participants. The results did not reveal any significant activation differences during the planning of hand and foot movements, except in the most anterior part of PPC [Brodmann's area (BA) 5], marginally extending into anterior BA 7/40. This region showed a lateral-to-medial gradient for hand versus foot movement planning. The limb-unspecific PPC regions were functionally connected with hand and foot motor regions. In contrast, a gradient-like organization was found for all of PPC for the planning of eye versus hand and foot movements. Although planning-related activity across the three effectors considerably overlapped, saccade planning activated occipitoparietal regions more than limb movements, whereas limb movements activated anterior regions of the superior parietal lobule more than saccades. We infer that PPC does not follow a strict effector-specific organization. Rather, the large-scale organization of this region might reflect the different computational constraints that need to be satisfied when planning eye and limb movements.

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Section: Discussionmentioning

confidence: 99%

Functional Rather than Effector-Specific Organization of Human Posterior Parietal Cortex

Heed¹,

Beurze²,

Toni³

et al. 2011

J. Neurosci.

116

View full text Add to dashboard Cite

show abstract

“…In fact, the basic premise of the present paradigm is based on the interpretation by Jackson et al (2009) of the deficits in nonfoveal OA patients. In OA, the disorder of visually guided reaching movements cannot be attributed to a basic motor or sensory deficit (Bálint 1909;Perenin and Vighetto 1988;Rizzo and Vecera 2002), but seems a higher-level impairment in spatial integration of information from both vision and proprioception (Blangero et al 2007(Blangero et al , 2009Khan et al 2005a,b;Pisella et al 2009).…”

Section: Relation To Previous Workmentioning

confidence: 99%

“…In OA, the disorder of visually guided reaching movements cannot be attributed to a basic motor or sensory deficit (Bálint 1909;Perenin and Vighetto 1988;Rizzo and Vecera 2002), but seems a higher-level impairment in spatial integration of information from both vision and proprioception (Blangero et al 2007(Blangero et al , 2009Khan et al 2005a,b;Pisella et al 2009). According to Jackson et al (2009), these deficits result from an impaired ability to simultaneously represent multiple spatial locations that must be directly compared with one another. In our study, in the case of a peripheral target, gaze direction and target location had to be represented simultaneously, whereas for a reach to a central target, these directions matched.…”

Section: Relation To Previous Workmentioning

confidence: 99%

“…Buneo et al (2002) showed that position of the hand relative to gaze modulated the neuronal activity in area 5 of the posterior parietal cortex (PPC), whereas Pesaran et al (2006) discovered that reach-related activity in neurons in the dorsal premotor cortex depends on hand, eye, and target positions. Finally, unilateral and bilateral optic ataxia patients with damage in the PPC show reach deficits that reflect the use of gaze-centered coordinates (Blangero et al 2007(Blangero et al , 2009(Blangero et al , 2010Coslett 1997, 1998;Jackson et al 2009;Khan et al 2005a,b;Pisella et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…We hypothesized that brain areas that compute a difference vector in gaze coordinates respond more strongly when target and hand are both at peripheral coordinates in the gaze frame than when either of these is at the origin of the gaze-centered coordinate frame (Jackson et al 2009). The motivation for this hypothesis is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Reference Frames for Reach Planning in Human Parietofrontal Cortex

Beurze

Toni

Pisella

et al. 2010

Journal of Neurophysiology

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To plan a reaching movement, the brain must integrate information about the spatial goal of the reach with positional information about the selected hand. Recent monkey neurophysiological evidence suggests that a mixture of reference frames is involved in this process. Here, using 3T functional magnetic resonance imaging (fMRI), we tested the role of gaze-centered and bodycentered reference frames in reach planning in the human brain. Fourteen human subjects planned and executed arm movements to memorized visual targets, while hand starting position and gaze direction were monitored and varied on a trial-by-trial basis. We further introduced a variable delay between target presentation and movement onset to dissociate cerebral preparatory activity from stimulusand movement-related responses. By varying the position of the target and hand relative to the gaze line, we distinguished cerebral responses that increased for those movements requiring the integration of peripheral target and hand positions in a gaze-centered frame. Posterior parietal and dorsal premotor areas showed such gaze-centered integration effects. In regions closer to the primary motor cortex, bodycentered hand position effects were found. These results suggest that, in humans, spatially contiguous neuronal populations operate in different frames of reference, supporting sensorimotor transformations according to gaze-centered or body-centered coordinates. The former appears suited for calculating a difference vector between target and hand location, whereas the latter may be related to the implementation of a joint-based motor command.

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Subcortical electrostimulation to identify network subserving motor control

Schucht

Moritz‐Gasser

Herbet

et al. 2012

Human Brain Mapping

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The diverse interferences with motor function resulting in inhibition and acceleration imply a modulatory influence of the detected fiber network. The subcortical stimulation sites were distributed veil-like, anterior to the primary motor fibers, suggesting descending pathways originating from premotor areas known for negative motor response characteristics. Further stimulation sites in the parietal white matter as well as in the anterior arm of the internal capsule indicate a large-scale fronto-parietal motor control network.

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There may be more to reaching than meets the eye: Re-thinking optic ataxia

Cited by 49 publications

References 48 publications

Functional Rather than Effector-Specific Organization of Human Posterior Parietal Cortex

Functional Rather than Effector-Specific Organization of Human Posterior Parietal Cortex

Reference Frames for Reach Planning in Human Parietofrontal Cortex

Subcortical electrostimulation to identify network subserving motor control

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