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Biomedical subjects

B Milner

Publications and source records attributed to B Milner.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of frontal or temporal lobectomy on the use of advance information in a choice reaction time task.

The ability to make use of directional cues presented to subjects before they are asked to make a specific response was studied in 69 patients who had undergone a unilateral frontal or temporal lobe excision, and in 24 normal control subjects. Choice reaction time was measured in two conditions: (1) informative, where a centrally presented cue indicated in advance the target's location, and (2) neutral, where the cue was a symbol carrying no directional information. Patients with excisions from the left or right frontal lobe did not benefit from the available information to the same extent as patients with either left or right temporal lobe excisions or normal control subjects.

Adult↗
PubMed1989

Right hippocampal impairment in the recall of spatial location: encoding deficit or rapid forgetting?

The recall of spatial location in patients with left or right temporal-lobe lesions was studied in two experiments, in which recall was tested either immediately after presentation of an array of objects, or after an intervening verbal task, a spatial task or an unfilled interval. Deficits were found only in patients with right temporal-lobe lesions that included extensive removal of the hippocampal region, and only when recall was tested after a delay. The presence of an intervening task in the delay interval did not accentuate the deficit. The results show that, despite a normal ability to encode location, patients with large right hippocampal lesions demonstrate an abnormally rapid forgetting of such information.

Adolescent↗
PubMed1988

Performance on unimanual and bimanual tapping tasks by patients with lesions of the frontal or temporal lobe.

The performance of 151 patients with unilateral excisions from either the frontal or the temporal cortex and 60 normal subjects was examined on three motor tasks: (1) simple unimanual tapping; (2) spatially ordered unimanual tapping; and (3) bimanual tapping in which the movements of the two hands were out-of-phase. All patient groups were impaired with both hands on spatially ordered unimanual tapping. In contrast, only those patients with either left or right frontal-lobe lesions performed poorly on the bimanual tapping task. Our findings demonstrate that the frontal cortex plays a critical role in the co-ordination of arm and hand movements, particularly when different movements have to be performed simultaneously.

Adolescent↗
PubMed1988

Estimation of frequency of occurrence of abstract designs after frontal or temporal lobectomy.

Patients with unilateral frontal- or temporal-lobe excisions and normal control subjects were shown a series of abstract designs. Within the series, the designs differed in the number of times that they appeared. The frontal-lobe groups (right more so than left) were impaired in recalling the frequency of occurrence of the designs. Recognition deficits were found only in the patients with right temporal-lobe lesions. The impairment in frequency estimation may reflect a disorderly search process in memory, or a deficit in cognitive estimation, or both.

Form Perception↗
PubMed1988

Residual impairment in handgrip strength after unilateral frontal-lobe lesions.

The handgrip strength of 65 normal control subjects and 166 patients with unilateral frontal- or temporal-lobe excisions was assessed. Because of the known sex differences in strength, the results for the men and women were analysed separately. The grip strength of men with left frontal-lobe lesions was found to be within the normal range, but women with comparable excisions from the left frontal lobe had a residual impairment in strength on both hands. The men with right frontal-lobe lesions had a significant reduction in the strength of only the left hand, and the women in this group displayed a similar tendency. The deficits were interpreted in terms of a loss or disruption of input from the premotor area to the primary motor cortex.

Adolescent↗
PubMed1985

Cognitive risk-taking after frontal or temporal lobectomy--II. The synthesis of phonemic and semantic information.

Patients with unilateral cerebral excisions and control subjects performed two tasks in which target words had to be guessed on the basis of either phonemic or semantic partial-information clues. Each cumulatively provided clue was assigned successively lower point-value, these points being risked whenever the subject responded. Patients with frontal-lobe excisions chose to make a guess after seeing only one clue more often than did a combined group of subjects without frontal-lobe damage, but this guessing-score was also related to extent of right temporal-lobe removal. Patients with left temporal-lobe or left frontal-lobe lesions had difficulty solving the verbal clues, occasionally failing to recognize that a response generated in the context of one clue satisfied all the clues.

Adolescent↗
PubMed1985

Performance of complex arm movements and facial-movement sequences after cerebral commissurotomy.

Two patients with presumed complete midline section of the interhemispheric commissures and two patients with partial section were asked to copy complex arm movements and facial-movement sequences. Their performance was compared with our previously published findings on these tasks for patients with unilateral removals from the frontal, temporal or parietal region. On the arm-movement task, the commissurotomized patients were impaired equally with either the left or right arm and were as poor at performing this task as patients with excisions of left parietal cortex. On the face-movement task, commissurotomized patients performed very poorly, scoring significantly lower than all excision groups. There was no significant difference on either task between the performance of the patients with partial and those with complete sections.

Adult↗
PubMed1985

Frontal lobes and the temporal organization of memory.

Evidence for a major involvement of the frontal cortex in various aspects of the temporal organization of memory has emerged from the study of patients who had sustained a unilateral frontal- or temporal-lobe excision for the control of cerebral seizures. It has now been established that the frontal cortex participates in judgements of the temporal order of recent events and of their frequency of occurrence, as well as in the planning and monitoring of the execution of self-determined sequences of responses. Some differential effects related to the side of the lesion were observed, these depending both on the nature of the stimulus material used and on the special demands of the task.

Discrimination, Psychological↗
PubMed1984

Differential effects of frontal-lobe lesions on cognitive estimation and spatial memory.

Patients with unilateral frontal- or temporal-lobe excisions and normal control subjects were tested on the recall of objects and of their location in an array. An incidental-learning situation was used, in which the task was presented as a test of the ability to estimate the prices of the objects. Patients with right frontal-lobe lesions were the only group impaired on price estimation, but a correlation was obtained between error-score in price estimation and lesion-size for the left frontal-lobe group. In contrast to patients with extensive right hippocampal excisions, both frontal-lobe groups were accurate on location-recall when tested immediately and again 24 hr later.

Adolescent↗
PubMed1983

Handwriting posture as related to cerebral speech lateralization, sex, and writing hand.

The claim that handwriting posture can provide clues to the cerebral lateralization of language was investigated in a sample of 131 patients undergoing preoperative intracarotid injections of sodium amobarbital to determine the side of speech representation. More males than females inverted the left hand when writing, but no consistent relationship was found between speech lateralization and handwriting posture. These results suggest that perceptual asymmetries correlated with hand posture vary independently of cerebral dominance for speech.

Female↗
PubMed1982

Some cognitive effects of frontal-lobe lesions in man.

The study of patients undergoing unilateral frontal-lobe excisions for the relief of focal epilepsy has revealed specific cognitive disorders that appear against a background of normal functioning on many intellectual, perceptual and memory tasks. Lesions that invade the frontal eye field cause subtle impairments of voluntary oculomotor control, which reveal themselves as an inability to suppress an initial glance at a potentially distracting stimulus. After frontal lobectomy in either hemisphere, deficits are found quite consistently on motor-differentiation tasks (Konorski 1972) in which the subject must learn to produce different responses to different, randomly presented, environmental signals. More directly related to the concept of planning are those sequential tasks in which the subject is free to choose his own order of responding, but must not make the same response twice. Here the left frontal lobe plays the major role, a finding consistent with the notion of left-hemisphere dominance for the programming of voluntary actions. In contrast, the right frontal lobe appears to be more critically involved in monitoring the temporal sequence of externally ordered events, although the verbal or non-verbal nature of the stimuli remains a relevant factor.

Adult↗
PubMed1982

Deficits on subject-ordered tasks after frontal- and temporal-lobe lesions in man.

Seventy-nine patients with unilateral frontal- or temporal-lobe excisions and 18 normal control subjects were tested on four self-ordered tasks requiring the organization of a sequence of pointing responses. There were two verbal and two nonverbal tasks. Patients wih excisions from the left frontal lobe exhibited significant impairments on all four tasks, whilst patients with excisions from the right frontal lobe showed deficits only on the two nonverbal tasks. Patients with temporal-love lesions not extending posteriorly, on the medial side, beyond the pes of the hippocampus were unimpaired on all tasks, whereas those with more radical hippocampal excisions exhibited material-specific deficits that varied with the side of the lesion.

Adolescent↗