Effects of left parietal injury on covert orienting of attention.
OBJECTIVE
To assess the effects of left parietal injury on covert visual attention during a detection task and a pointing task.


METHODS
The Posner's paradigm was given to a patient who was found at the age of 74 to have spent all his life without the left parietal lobe as a result of a congenital perinatal insult and to a control subject. In one session subjects were required to provide an arbitrary response at stimulus appearance (key press). In another session subjects were required to point to the stimulus.


RESULTS
The patient was able to disengage covert attention from a cued position when the task was to provide an arbitrary key press response in a similar fashion to a control subject with no neurological deficits. By contrast, he was impaired in disengaging attention from a cued position when the task was to reprogramme an overt pointing action.


CONCLUSIONS
Response to cued information is differentially available depending on task. It is suggested that mechanisms concerned with the attention for action systems are located within the left parietal lobe.
Castiello
U
U
Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK. ucastiello@rhul.ac.uk
Paine
M
M
D000368:Aged; D001288:Attention / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D006423:Hemianopsia / Q000151:congenital / Q000503:physiopathology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology*; D010296:Parietal Lobe / Q000002:abnormalities* / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014057:Tomography, X-Ray Computed; D058609:Visual Field Tests