Exploratory Movement

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The ability of the brain to control movement depends on the descending cortical and brainstem pathways to the spinal cord. Each hemisphere has both direct and indirect connections with dorsolateral and ventromedial parts of the intermediate zone and to motorneurons of distal extremity muscles contralaterally, while mainly to the ventromedial parts of the intermediate zone ipsilaterally. Research on cat and findings from Lawrence and Kuypers suggests that pathways to the ventromedial part of the intermediate zone is especially concerned with steering axial and proximal limb movements, while those to the dorsolateral part provides the capacity for individual movements of the distal extremities. Based on implications from previous findings,…show more content…
Both contralateral and ipsilateral arm were able to pick up pieces of food from either table top or forceps, and either hand retrieved it with relatively independent hand and finger movements. However, the independent movements in the ipsilateral hand seemed to only occur after making physical contact with the food. The exploratory movements suggest that the ipsilateral hand relies on somatosensory pathways to recruit full motor control of the nonseeing half of the brain which decussate below pontine levels, thus remains undamaged by splitbrain…show more content…
On the other hand, the ipsilateral hand was brought to the proper place on the board through the reaching movement of the arm, but the hand and fingers were unable to pick the food out as if it was blind. Furthermore, when large food pellets that protruded above the surface of the board were used, either hands were able to retrieve it. Note that the ipsilateral hand to the open eye still required contact with food to perform independent movement of hand and fingers. Finally, the subjects were blindfolded; independent hand and fingers explored the board surface and were able to retrieve the large food pellets, but they were unable to retrieve small food pellets. The results suggest that visual guidance is necessary for the retrieval of small food
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