blocking

1. Obstructing; arresting of passage, conduction, or transmission. 2. In psychoanalysis, a sudden break in free association occurring when a painful subject or repressed complex is touched. 3. Sudden cessation of thoughts and speech, which may indicate the presence of a severe thought disorder or a psychosis.

- alpha b. the attenuation of the occipital alpha rhythm (8–14 Hz brain waves as seen on an electroencephalogram), produced by opening the eyes or by intense mental concentration.

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block·ing 'bläk-iŋ n interruption of a trend of associative thought by the arousal of an opposing trend or through the welling up into consciousness of a complex of unpleasant ideas compare BLOCKAGE (b)

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n. (in psychiatry)

1. a sudden halting of the flow of thought or speech. Blocking of thought, accompanied by the sensation of thoughts being removed from the mind, is a symptom of schizophrenia. Blocking of speech may be a consequence of thought block or a result of a mechanical impediment in speech, such as stammering.

2. the failure to recall a specific event, or to explore a specific train of thought, because of its unpleasant associations.

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block·ing (blokґing) 1. interfering with afferent nerve impulses; see regional anesthesia, under anesthesia. 2. sudden cessation of the train of thought or speech, such as may occur in a period of extreme emotion or when a repressed painful thought is approached. Called also thought b. or deprivation. 3. casting of tissue blocks in an embedding medium such as paraffin wax so that sections can be cut with a microtome.