Using recently described quantitative techniques, we documented severe metabolic brain dysfunction far distant from surgically placed lesions in the association cortex of monkeys. Two (frontal and parietal) hemisensory neglect syndromes were documented using behavioral testing. Symptoms correlated in time with metabolic anatomically intact foci of glucose hypometabolism, not structural damage per se. Further, neglect animals' behavioral data point to moment-to-moment neural activity changes related to conditions of stimulus presentation. A definitive explanation for neglect symptoms is thus offered for the first time. We propose to further test and expand our original findings using methods previously validated in this laboratory, including 1) 14C-2-deoxyglucose autoradiography (2DG) to determine quantitative local cerebral glucose utilization (LGU), as an indicator of regional neural activity; 2) operative unilateral lesions that reproducibly induce neglect and other symptoms; 3) quantitative behavioral measures of neglect symptoms and their recovery. We will add computer assisted densitometry and image analysis to improve accuracy of the LGU measure and computer control of behavioral tests to allow a measurement of orienting efficiency. These methods will be used in experiments to 1) vary neglect symptoms vis-a-vis distant metabolic dysfunction in frontal and parietal animals. For example, neglect animals infused with 2DG while performing symmetrical motor activity will be sacrificed and the distribution of label compared with the distribution in previously studied non-performing operated animals. 2) Determine if other operative lesions outside frontal and parietal association cortex are accompanied by distant metabolic effects and if there are behavioral changes that correlate with them. For example, we will make unilateral superior colliculus (SC) lesions, and sacrifice with 2DG acutely, and after spontaneous recovery in resting alert monkeys. These primate model studies will advance understanding of the distant metabolic effects of focal cerebral damage, and will provide direct correlates for diagnosis and management of human stroke patients, in whom recovery is often impeded by neglect and other higher cortical function deficits.
| Deuel, R K; Farrar, C A (1993) Stimulus cancellation by macaques with unilateral frontal or parietal lesions. Neuropsychologia 31:29-38 |
| Deuel, R K (1992) The functional anatomy of manual motor behavior after unilateral frontal lobe lesions. Brain Res 580:249-54 |
| Deuel, R K; Regan, D J (1985) Parietal hemineglect and motor deficits in the monkey. Neuropsychologia 23:305-14 |
