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Sprague effect

AI overview

The Sprague effect is the phenomenon where homonymous hemianopia, caused by damage to the visual cortex, gets slightly better when the contralesional superior colliculus is destroyed.

Key points
  • The effect is named after James Sprague, who discovered it in 1966 using a cat model.
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    named for its discoverer, James Sprague, who observed this phenomenon in 1966 using a cat model
  • A proposed mechanism is mutual inhibition between the two brain hemispheres.
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    mutual inhibition between the two brain hemispheres
  • Damaging the substantia nigra, such as with ibotenic acid, can produce the same improvement due to inhibition of an inhibitory structure.
    source quote
    damaging the substantia nigra, for instance by using ibotenic acid , can also cause the same improvement
Symptoms
  • The condition addressed by the Sprague effect is homonymous hemianopia caused by visual cortex damage.
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    homonymous hemianopia , caused by damage to the visual cortex
Treatment
  • Destroying the contralesional superior colliculus can slightly improve homonymous hemianopia.
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    contralesional superior colliculus is destroyed
  • Damaging the substantia nigra, for example with ibotenic acid, can also cause improvement.
    source quote
    damaging the substantia nigra, for instance by using ibotenic acid , can also cause the same improvement
Prognosis

Homonymous hemianopia gets slightly better when the contralesional superior colliculus is destroyed.

AI-synthesized from the Wikipedia article “Sprague effect”. Not medical advice. Verify source →

The Sprague effect is the phenomenon where homonymous hemianopia, caused by damage to the visual cortex, gets slightly better when the contralesional superior colliculus is destroyed.[1][2] The effect is named for its discoverer, James Sprague, who observed this phenomenon in 1966 using a cat model.[3] Several reasons have been thought of for this happening, including mutual inhibition between the two brain hemispheres.[4] For similar reasons of inhibiting an inhibitory structure, damaging the substantia nigra, for instance by using ibotenic acid, can also cause the same improvement.[5]

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  1. ↑ Weddell, Rodger A. (August 2004). "Subcortical modulation of spatial attention including evidence that the Sprague effect extends to man". Brain and Cognition. 55 (3): 497–506. doi:10.1016/j.bandc.2004.02.075. PMID 15223196.
  2. ↑ Lomber, Stephen G.; Malhotra, Shveta; Sprague, James M. (2007-02-01). "Restoration of Acoustic Orienting Into a Cortically Deaf Hemifield by Reversible Deactivation of the Contralesional Superior Colliculus: The Acoustic "Sprague Effect"". Journal of Neurophysiology. 97 (2). United States: Journal of Applied Physiology: 979–993. doi:10.1152/jn.00767.2006. PMID 17151228.
  3. ↑ Sprague, James M. (1966-09-23). "Interaction of Cortex and Superior Colliculus in Mediation of Visually Guided Behavior in the Cat". Science. 153 (3743): 1544–1547. Bibcode:1966Sci...153.1544S. doi:10.1126/science.153.3743.1544. PMID 5917786.
  4. ↑ Hilgetag, Claus C. (2000-06-01). "Spatial neglect and paradoxical lesion effects in the cat — A model based on midbrain connectivity". Neurocomputing. 32–33: 793–799. doi:10.1016/S0925-2312(00)00246-0.
  5. ↑ Wallace, Steven F.; Rosenquist, Alan C.; Sprague, James M. (1990). "Ibotenic acid lesions of the lateral substantia nigra restore visual orientation behavior in the hemianopic cat". The Journal of Comparative Neurology. 296 (2). Wiley-Blackwell: 222–252. doi:10.1002/cne.902960204. PMID 2358533.