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Biomedical subjects

R R Tasker

Publications and source records attributed to R R Tasker.

At least 55 records · Page 3Linked to original sources
PubMed1977

Computerized graphic display of results of subcortical stimulation during stereotactic surgery.

An on-line computer programme is described and illustrated which is capable of displaying graphically in the form of Woolsey-type figurine charts stimulation-induced responses obtained during stereotactic surgery. Not only can these data then be optimally utilized for lesion localization but also the programme includes facilities for a variety of types of analysis of the tape-stored data pooled from all patients studied.

Computers↗
PubMed1976

Computer mapping of brain-stem sensory centers in man.

A computer program is described for use on-line with a two--stage stereotaxic technique in man. It has four capabilities. It transposes coordinates between a brain atlas and a stereotaxic frame, simultaneously adjusting for variations in individual brain dimensions. Corrections for electrode trajectories, and for any irregularities of placement of the stereotaxic frame in the head are also made. It plots an operative template that shows electrode trajectories and the sites from which physiological data are collected appropriately oriented upon a sagittal diagram of the brain. It graphically displays physiological data in the form of a Woolsey-type figurine chart that indicates threshold in milliamperes and, through the use of coded symbols, the quality of response and certain other data. It stores all this data in a tape library together with the locations of any lesions made. This makes it possible to replot any individual patient's operative data at any time. It also permits scanning of the stored protocols from all patients for any particular type of data either by itself or in combination with other data. This retrieved information is plotted on appropriate sagittal brain diagrams corrected for individual variations in brain size. Illustrations of the capabilities of the program are presented particularly with reference to the primary afferent pathways of the upper brain stem.

Afferent Pathways↗
PubMed1975

Decorticate spasticity: a re-examination using quantitative assessment in the primate.

Decorticate spasticity in the squirrel monkey was chosen as a convenient laboratory model of spasticity capable of quantitative assessment upon which to evaluate various currently popular clinical spasmolytic measures. The effects of a wide variety of cortical lesions were studied involving primary and supplementary motor, premotor and parietal cortex unilaterally and bilaterally, measuring muscle tone with the evoked integrated E.M.G. technique. Measurable spasticity resulted only if primary motor cortex was ablated bilaterally usually but not always preferentially involving biceps brachii and quadriceps. Resulting postures were variable offering no justification for the term "decorticate posture". The integrated evoked E.M.G. was proportional to rate of stretch and chiefly phasic in type as in hemiplegic man. Stereotactic dentatectomy resulted in profound ipsilateral reduction in this spasticity, but was without effect in intercollicular or anemic decerebrate cats. The mechanism of the spasticity and of the cerebellar effects are discussed.

Animals↗
PubMed1975

Neurological concepts of pain management in head and neck cancer.

The physiological basis, historical evolution, and our own practice of stereotactic surgery for the relief of cancer pain are briefly described. Thirty-nine procedures have been performed on 33 patients, 27 for pain due to cancer. Lesions have been made both in the specific neospinothalamic pathway of midbrain and thalamus and in the non-specific reticulothalamic system with an overall five per cent mortality and five per cent morbidity. Initial pain relief was achieved in 90 per cent of patients with relief till death in 74 per cent. Lesions were more successful in releiving pain when the specific pain system was involved but only if the analgesia produced by the lesion "covered" the patient's pain. On the other hand, dysesthesia occurred only with lesions of the specific system, especially if they involved the thalamus.

Brain↗