Projects per year
Lesions of striate cortex (V1) trigger massive retrograde degeneration of neurons in the LGN. In primates, these lesions also lead to scotomas, within which conscious vision is abolished. Mediation of residual visual capacity within these regions (blindsight) has been traditionally attributed to an indirect visual pathway to the extrastriate cortex, which involves the superior colliculus and pulvinar complex. However, recent studies have suggested that preservation of the LGN is critical for behavioral evidence of blindsight, raising the question of what type of visual information is channeled by remaining neurons in this structure. A possible contribution of LGN neurons to blindsight is predicated on two conditions: that the neurons that survive degeneration remain visually responsive, and that their receptive fields continue to represent the region of the visual field inside the scotoma. We tested these conditions in male and female marmoset monkeys (Callithrix jacchus) with partial V1 lesions at three developmental stages (early postnatal life, young adulthood, old age), followed by long recovery periods. In all cases, recordings from the degenerated LGN revealed neurons with well-formed receptive fields throughout the scotoma. The responses were consistent and robust, and followed the expected eye dominance and retinotopy observed in the normal LGN. The responses had short latencies and preceded those of neurons recorded in the extrastriate middle temporal area. These findings suggest that the pathway that links LGN neurons to the extrastriate cortex is physiologically viable and can support residual vision in animals with V1 lesions incurred at various ages.
- 3 Finished
Yu, H., Rosa, M., Morris, A. & Triesch, J.
1/01/17 → 31/12/19
Egan, G., Rosa, M., Lowery, A., Stuart, G., Arabzadeh, E., Skafidas, E., Ibbotson, M., Petrou, S., Paxinos, G., Mattingley, J., Garrido, M., Sah, P., Robinson, P. A., Martin, P., Grunert, U., Tanaka, K., Mitra, P., Johnson, G., Diamond, M., Margrie, T., Leopold, D., Movshon, J., Markram, H., Victor, J., Hill, S. & Jirsa, V.
Australian National University (ANU), ETH Zurich, Australian Research Council (ARC), Karolinska Institute, QIMR Berghofer Medical Research Institute, Ecole Polytechnique Federale de Lausanne (Swiss Federal Institute of Technology in Lausanne) , Monash University, University of Melbourne, University of New South Wales, University of Queensland , University of Sydney, Monash University – Internal University Contribution, National Institutes of Health (United States), Cornell University, New York University, MRC National Institute for Medical Research, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Duke University, Cold Spring Harbor Laboratory, RIKEN
25/06/14 → 31/12/21
1/02/14 → 10/09/18