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Beck et al. reinterpret Osborne et al.'s experiments stating it is more likely that sensory estimation in this task is suboptimal (thereby amplifying variability due to external and internal noise) than that the internal noise in perceptual and motor systems is vastly different.

Osborne et al. modeled performance of monkeys in a visual smooth pursuit task. According to their model, variability in this task is due mostly to estimation errors and not due to motor errors.

Beck et al. acknowledge that the task in Osborne et al.'s experiments was very artificial and the brain circuits involved in smooth pursuit are probably optimized for more natural tasks.

People with lesions of the parieto-occipital cortex (POJ) are impaired in reaching and grasping objects in their peripheral visual field (an effect called 'optic ataxia').

Himmelbach et al. studied one patient in a visuo-haptic grasping task and found that she had a healthy-like ability to adapt her grip online to changes of object size when it was in the central viewing field. This indicates that the problem for patients with lesions of parieto-occipital cortex (POJ) is not an inability to adapt online, but more likely the connection between visuomotor pathways and pathways necessary for grasping.

The SC is involved in the transformation of multisensory signals into motor commands.

The motmap algorithm uses reinforcement learning to organize behavior in a two-dimensional map.

Optimal solutions to many computational tasks in perception and action have high computational complexity (in the complexity theory sense).

Open-loop control (in biological sensorimotor modeling) is a simplification because most motions are not ballistic.

Cost terms that are routinely minimized in sensorimotor control are

  • Metabolic (muscular) energy consumption
  • smoothness cost (time-derivative of acceleration)
  • variance (of execution; usually assuming motor noise is control dependent)

Cost functions including multiple cost terms must be tuned by weighting, which is often arbitrarily done by the modeler.