Off-campus access
Using PhilPapers from home?
Click here to configure this browser for off-campus access.
- Scott Glover (2004). Separate Visual Representations in the Planning and Control of Action. Behavioral and Brain Sciences 27 (1):3-24.Evidence for a dichotomy between the planning of an action and its on-line control in humans is reviewed. This evidence suggests that planning and control each serve a specialized purpose utilizing distinct visual representations. Evidence from behavioral studies suggests that planning is influenced by a large array of visual and cognitive information, whereas control is influenced solely by the spatial characteristics of the target, including such things as its size, shape, orientation, and so forth. Evidence from brain imaging and neuropsychology suggests that planning and control are subserved by separate visual centers in the posterior parietal lobes, each constituting part of a larger network for planning and control. Planning appears to rely on phylogenetically newer regions in the inferior parietal lobe, along with the frontal lobes and basal ganglia, whereas control appears to rely on older regions in the superior parietal lobe, along with the cerebellum. Key Words: action; apraxia; control; illusions; optic ataxia; PET; planning; reaching;.
Similar books and articles
Evidence from optic ataxic patients with bilateral lesions to the superior parietal lobes does not support the view that there are separate planning and control mechanisms located in the IPL and SPL respectively. The aberrant reaches of patients with bilateral SPL damage towards extrafoveal targets seem to suggest a deficit in the selection of appropriate motor programmes rather than a deficit restricted to on-line control.
No categories
Very young children occasionally commit scale errors, which involve a dramatic dissociation between planning and control: A child's visual representation of the size of a miniature object is not used in planning an action on it, but is used in the control of the action. Glover's planning–control model offers a very useful framework for analyzing this newly documented phenomenon.
Glover proposes a planning–control model for the parietal lobe that contrasts with previous formulations that suggest independent mechanisms for perception and action. The planning–control model potentially solves practical functional problems with a proposed independence of perception and action, and offers some new directions for a study of human performance.
No categories
Glover postulates that the inferior parietal lobule (IPL), along with the frontal lobes and basal ganglia, mediates planning, while the superior parietal lobule (SPL), coupled with motor processes in the cerebellum, regulates the control process. We demonstrate that the control process extends beyond the cerebellum and SPL into regions hypothesized to represent planning.
The planning/control distinction is an important tool in the study of sensorimotor transformations. However, published data from our laboratories suggest that, contrary to what is predicted by the proposed model, (1) structures in the superior parietal lobe of both monkeys and humans can be involved in movement planning; and (2) fast pointing actions can be immune to visual illusions even if they are performed without visual feedback. The planning–control model as proposed by Glover is almost certainly too schematic.
No categories
Hommel et al. propose that high-level perception and action planning share a common representational domain, which facilitates the control of intentional actions. On the surface, this point of view appears quite different from an alternative account that suggests that “action” and “perception” are functionally and neurologically dissociable processes. But it is difficult to reconcile these apparently different perspectives, because Hommel et al. do not clearly specify what they mean by “perception” and “action planning.” With respect to the visual control of action, a distinction must be made between conscious visual perception and unconscious visuomotor processing. Hommel et al. must also distinguish between the what and how aspects of action planning, that is, planning what to do versus planning how to do it.
Glover suggests that representational systems for planning versus control are mapped exclusively to the inferior (IPL) versus superior (SPL) parietal lobules respectively. Yet, there is ample evidence that the IPL and SPL both contribute to action planning and control. Alternatively, I distinguish between the parietal-frontal systems involved in the representation of acquired manual skills versus nonskilled actions.
No categories
Several aspects of Glover's planning–control model (PCM) appear incompatible with existing data. Moreover, there is no logical reason to suppose that separate visual representations should be required for the “planning” and “control” of actions in the first place. Although intuitively appealing, the PCM appears to lack strong empirical support.
No categories
We address three issues that might be important in evaluating the validity of the planning–control model: (1) It could be artificial to distinguish between control and planning when control involves the re-planning of a new corrective submovement that overlaps with the initial response; (2) experiments involving illusions are not totally compelling; (3) selectively implicating the superior parietal lobe in movement control and the basal ganglia in movement planning, appears questionable.
Consistent with the planning–control model, recent fMRI data reveal that the inferior parietal lobe, the frontal lobes, and the basal ganglia are involved in motor planning. Inconsistent with the planning–control model, however, recent behavioral data reveal a spatial repulsion effect, indicating that the visual context surrounding the target can sometimes influence the on-line control of goal-directed action.
Discussion of Scott Glover, Separate visual representations in the planning and control of action
|
|
There are no threads in this forum |
Nothing in this forum yet.

