Biographical Memoirs Volume 89 (2007) / Chapter Skim
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JAMES MATHER SPRAGUE
JAMES MATHER SPRAGUE
Pages 306-323
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From page 307... ...
The Great Depression hit Jim's family hard, ending the bucolic, idyllic summer stays on Mackinac Island, but Jim continued his study of nature through the Boy Scouts and other public opportunities. He "tramped" the Missouri River bottoms, 307
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From page 308... ...
Jim described those days as very fortunate for his continued education, because his teachers at Kansas City Junior College, while perhaps not qualified for university positions, turned out to be wonderful educators, and provided a necessary bridge in his education toward an academic career. At this time a new building was being constructed in the center of town and during the excavation, fossils were found in large numbers.
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From page 309... ...
His job entailed field work to obtain new fossils for the museum collection and teaching various courses in comparative anatomy, evolution, and ecology. Some of Jim's colleagues at the museum, like Jim, went on to distinguished careers in comparative zoology and paleontology.
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From page 310... ...
It seems that Jim and his future mentor were both proud Kansas alumni, and this happy coincidence cemented a relationship that had much to do with Professor Romer's offer of a position at Harvard and an opportunity for Jim's Ph.D. Jim initially intended to train himself as a future museum curator, and Professor Romer was an early model for him.
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From page 311... ...
Jim's colleagues at Johns Hopkins included some of the great neuroscientists of the day: Bill Strauss, Marion Hines, Louis Flexner, Vernon Mountcastle, Jerzy Rose, Reginald Bromiley, and Clinton Woolsey. Soon after arriving at Johns Hopkins, Jim developed his deep fascination with the brain that was to endure for the remainder of his days.
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From page 312... ...
William Windle and in collaboration with Bill Chambers and John Liu, Jim continued his studies of the spinocerebellar tracts and the structure and function of the cerebellum. Using the newly devised silver degeneration techniques of Walle Nauta and his collaborators, Jim, Chambers, and Liu expanded on the earlier studies of Jan Jansen and Alf Brodal on the efferent projections of the cerebellar cortex and deep nuclei.
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From page 313... ...
To address the functional questions concerning the cerebellum, Jim and Chambers placed cerebellar lesions or stimulating electrodes into each of the three mediolateral cerebellar zones of the cat, and showed that the vermis and fastigal nucleus are involved with gross postural tone, equilibrium, and locomotion of the entire body. They further showed that the intermediate zone is involved with skilled movements and tone of the ipsilateral limbs, and that the lateral zone (lateral cerebellar cortex and dentate nucleus)
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From page 314... ...
The background to this was a controversy as to whether the 1a dorsal root afferents made monosynaptic, inhibitory connections onto ipsilateral antagonist muscle motoneurons or whether they affected their inhibition on these motoneurons via local, inhibitory interneurons. The importance of this question is linked to a key hypothesis that still endures: a single neuron must produce the same transmitter(s)
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From page 315... ...
. Then, in 1966 Jim published a seminal paper in Science that described a remarkable visual recovery phenomenon in the cat that has since been called the "Sprague effect." Jim had shown that a large unilateral visual cortical lesion produces an enduring hemianopia (i.e., blindness in half the visual field)
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From page 316... ...
Indeed, Jim's interpretation of the Sprague effect is as follows. There is a large ipsilateral projection from the visual cortex to the superior colliculus, and the result of the first cortical lesion removes this input, leaving a depressed colliculus; this depression is largely subserved by the remaining fibers coursing through the collicular commissure, and the second lesion of the other colliculus or transaction of the commissure removes this depressing input, releasing the untouched colliculus for action.
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From page 317... ...
exerts a controlling influence on nigral neurons which project to the superior colliculus by way of a nigrotectal tract. The nigrotectal path is a tonically active GABAergic tract that suppresses firing of the orienting neurons in the colliculus; these nigral neurons are phasically inhibited by GABAergic activity in the striatonigral path, thus releasing the colliculus to trigger contralateral orienting responses.
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From page 318... ...
from 1968 to 1975. Both authors of this memoir were students and later colleagues of Jim Sprague and both of us greatly lament his loss of a role model, mentor, and close personal friend.
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From page 319... ...
103:105-129. 1958 The distribution of dorsal root fibres on motor cells in the lum bosacral spinal cord of the cat, and the site of excitatory and inhibitory terminals in monosynaptic pathways.
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From page 320... ...
Rizzolatti. Unit responses to visual stimuli in the superior colliculus of the unanesthetized, mid-pon tine cat.
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From page 321... ...
87:1134-1138. 1991 The role of the superior colliculus in facilitating visual attention and form perception.
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From page 322... ...
Orientation discrimination in the cat: Its cortical locus II. Extrastriate cortical areas.
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