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BUTTER, C. M. Perseveration in extinction and in discrimination reversal tasks /bllowing selective frontal ablations in Macaca mulatta. PHYSIOL. BEHAV. 4 (2) 163-171, 1969.-In order to determine whether the perseverative syndrome exhibited by monkeys with frontal lobe lesions can be fractionated by partial frontal lesions, monkeys with dorsolateral frontal(More)
Simple reaction times to lateralized visual (Experiment 1) or auditory (Experiment 2) targets were studied in normal subjects. The targets were preceded by a visual or auditory cue located on the same (valid cue), or opposite (invalid cue) side as the subsequent target, or on both sides (neutral cue), with one of four cue target intervals. The validity of(More)
Patients with stable, homonymous hemianopia due to unilateral occipital infarcts and control subjects performed a task in which they judged whether or not an arrow was pointing at one of the dots in a pattern of dots they had recently seen in free vision, but was no longer visible. This task, as shown in prior studies as well as in the present one, involves(More)
Monkeys with orbital frontal ablation, compared with sham-operated controls, showed enhancement of oral tendencies toward nonfood items. Further, unlike the controls, they persistently performed an instrumental response for one of these nonfood items. On the other hand, the lesioned monkeys did not show altered preferences for food versus nonfood items.(More)
Rhesus monkeys were trained to fixate a central stimulus and to detect and localize a 50 msec light flash presented 6-80 degrees on either side of the central stimulus. Following large lesions of the superior colliculus, they showed persistent deficits in localizing flashes presented 43-80 degrees from the fixation stimulus. However, they were not(More)
We recorded eye movements to and away from visual stimuli from a patient with left-sided neglect following a right frontal infarct in order to determine (a) whether and to what extent his neglect was due to sensory inattention and directional motor neglect and (b) whether he had difficulty suppressing inappropriate eye movements to visual stimuli ("release"(More)
Normal subjects performed simple reaction time responses to lateralized visual target stimuli (Experiment 1) and lateralized tactile target stimuli (Experiment 2). In each experiment, the lateralized targets were preceded at one of four intervals by a visual or tactile cue located on the same (valid cue), or opposite (invalid cue) side, or on both sides(More)
A 43 year-old man with presumed progressive multifocal leukoencephalopathy developed difficulty recognizing objects and faces in the presence of adequate visual acuity and visual fields. His copying and matching of line drawings was intact, suggesting that his agnosia was associative. However, he had difficulty perceiving overlapping forms and drawings of(More)
Monkeys with thermocoagulation or kainic acid lesions of the pulvinar and unoperated control monkeys were tested in two tasks: pattern discrimination retention and color discrimination learning in which the stimuli were located at the response sites or were separated spatially from them (S-R separation). The monkeys with kainic acid pulvinar lesions were(More)