alien limb syndrome

a neurological disorder characterized by unintended hand, arm, or leg movements, often accompanied by a feeling that one has no control over the limb. The individual may not even recognize the limb as his or her own. The syndrome may be associated with lesions to the supplementary motor area or the motor regions of the corpus callosum.

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Psychology term of the day

November 18th 2024

center–surround antagonism

a characteristic of the receptive fields of many visual and somatosensory neurons in which stimulation in the center of the receptive field evokes opposite responses to stimulation in the periphery. Thus, some neurons depolarize with center stimulation and hyperpolarize when the same stimulus appears in the surrounding region of the receptive field, whereas other neurons have the opposite pattern of responses. Center–surround antagonism greatly increases the sensitivity of the nervous system to contrast. See also off response; on response; simple cell.