Effects of lesions to area V6A in monkeys

Battaglini, Piero Paolo; Muzur, Amir; Galletti, Claudio; Škrap, Miran; Brovelli, Andrea; Fattori, Patrizia

doi:10.1007/s00221-002-1099-4

Cited by 89 publications

(74 citation statements)

References 7 publications

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“…Therefore, although AIP is crucial to control distal movements such as those required for grasping and manipulating objects, V6A is likely involved in the control of both reaching and grasping phases, that is the entire act of prehension. This hypothesis is supported by lesion studies in monkeys: selective, bilateral ablation of area V6A evoked misreaching but also misgrasping and incorrect wrist orientation (Battaglini et al, 2002).…”

Section: The Dorsomedial Parieto-frontal Circuit Is Involved In Graspingmentioning

confidence: 67%

The Dorsomedial Pathway Is Not Just for Reaching: Grasping Neurons in the Medial Parieto-Occipital Cortex of the Macaque Monkey

Fattori¹,

Raos²,

Breveglieri³

et al. 2010

J. Neurosci.

176

151

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Brain control of prehension is thought to rely on two specific brain circuits: a dorsomedial one (involving the areas of the superior parietal lobule and the dorsal premotor cortex) involved in the transport of the hand toward the object and a dorsolateral one (involving the inferior parietal lobule and the ventral premotor cortex) dealing with the preshaping of the hand according to the features of the object. The present study aimed at testing whether a pivotal component of the dorsomedial pathway (area V6A) is involved also in hand preshaping and grip formation to grasp objects of different shapes.Two macaque monkeys were trained to reach and grasp different objects. For each object, animals used a different grip: whole-hand prehension, finger prehension, hook grip, primitive precision grip, and advanced precision grip. Almost half of 235 neurons recorded from V6A displayed selectivity for a grip or a group of grips. Several experimental controls were used to ensure that neural modulation was attributable to grip only.Thesefindings,inconcertwithpreviousstudiesdemonstratingthatV6Aneuronsaremodulatedbyreachdirectionandwristorientation,that lesion of V6A evokes reaching and grasping deficits, and that dorsal premotor cortex contains both reaching and grasping neurons, indicate that the dorsomedial parieto-frontal circuit may play a central role in all phases of reach-to-grasp action. Our data suggest new directions for the modeling of prehension movements and testable predictions for new brain imaging and neuropsychological experiments.

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Section: The Dorsomedial Parieto-frontal Circuit Is Involved In Graspingmentioning

confidence: 67%

The Dorsomedial Pathway Is Not Just for Reaching: Grasping Neurons in the Medial Parieto-Occipital Cortex of the Macaque Monkey

Fattori¹,

Raos²,

Breveglieri³

et al. 2010

J. Neurosci.

176

151

View full text Add to dashboard Cite

show abstract

“…One way to do this is with reversible lesions. A previous study found that permanent V6a lesions produce deficits specific to the contralateral limb, including increases in reach RT (Battaglini et al, 2002). In contrast, another study reported that permanent bilateral lesions in areas 5, 7b, and MIP produce incorrect reaching in the dark, but have little effect on visually guided reaching (Rushworth et al, 1997).…”

Section: Potential Roles Of the Activity On Ipsilateral-limb Trialsmentioning

confidence: 98%

Limb-Specific Representation for Reaching in the Posterior Parietal Cortex

Chang¹,

Dickinson²,

Snyder³

2008

Journal of Neuroscience

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To reach for something we see, the brain must integrate the target location with the limb to be used for reaching. Neuronal activity in the parietal reach region (PRR) located in the posterior parietal cortex represents targets for reaching. Does this representation depend on the limb to be used? We found a continuum of limb-dependent and limb-independent responses: some neurons represented targets for movements of either limb, whereas others represented only contralateral-limb targets. Only a few cells represented ipsilateral-limb targets. Furthermore, these representations were not dependent on preferred direction. Additional experiments provide evidence that the PRR is specifically involved in contralateral-limb movements: firing rates are correlated with contralateral-but not ipsilateral-limb reaction times. The current study therefore provides novel evidence that the PRR operates as a limb-dependent stage that lies further along the sensory-motor transformation for visually guided reaching than previously expected.

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“…V6A neurons also respond during visual and nonvisual goaldirected reaching (Galletti et al, 1997;Fattori et al, 2001Fattori et al, , 2005 and are modulated by somatosensory stimulation of the arm and shoulder (Breveglieri et al, 2002). Selective lesions to macaque V6A produce deficits in both reaching and grasping (Battaglini et al, 2002). V6A sends strong output to dorsal premotor cortex (Galletti et al, 1999).…”

Section: Spoc In Macaques and Humansmentioning

confidence: 99%

Is That within Reach? fMRI Reveals That the Human Superior Parieto-Occipital Cortex Encodes Objects Reachable by the Hand

Gallivan¹,

Cavina-Pratesi²,

Culham³

2009

J. Neurosci.

193

173

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Macaque neurophysiology and human neuropsychology results suggest that parietal cortex encodes a unique representation of space within reach of the arm. Here, we used slow event-related functional magnetic resonance imaging (fMRI) to investigate whether human brain areas involved in reaching are more activated by objects within reach versus beyond reach. In experiment 1, graspable objects were placed at three possible locations on a platform: two reachable locations and one beyond reach. On some trials, participants reached to touch or grasp objects at the reachable location; on other trials participants passively viewed objects at one of the three locations. A reach-related area in the superior parieto-occipital cortex (SPOC) was more activated for targets within reach than beyond. In experiment 2, we investigated whether this SPOC response occurred when visual and motor confounds were controlled and whether it was modulated when a tool extended the effective range of the arm. On some trials, participants performed grasping and reaching actions to a reachable object location using either the hand alone or a tool; on other trials, participants passively viewed reachable and unreachable object locations. SPOC was significantly more active for passively viewed objects within reach of the hand versus beyond reach, regardless of whether or not a tool was available. Interestingly, these findings suggest that neural responses within brain areas coding actions (such as SPOC for reaching) may reflect automatic processing of motor affordances (such as reachability with the hand).

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Effects of lesions to area V6A in monkeys

Cited by 89 publications

References 7 publications

The Dorsomedial Pathway Is Not Just for Reaching: Grasping Neurons in the Medial Parieto-Occipital Cortex of the Macaque Monkey

The Dorsomedial Pathway Is Not Just for Reaching: Grasping Neurons in the Medial Parieto-Occipital Cortex of the Macaque Monkey

Limb-Specific Representation for Reaching in the Posterior Parietal Cortex

Is That within Reach? fMRI Reveals That the Human Superior Parieto-Occipital Cortex Encodes Objects Reachable by the Hand

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