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Brain Struct Funct. 2017 Sep;222(7):3283-3293. doi: 10.1007/s00429-017-1404-4. Epub 2017 Mar 22.

Neuronal degeneration in the dorsal lateral geniculate nucleus following lesions of primary visual cortex: comparison of young adult and geriatric marmoset monkeys.

Atapour N1,2,3, Worthy KH4,5, Lui LL4,6,5, Yu HH4,6,5, Rosa MGP4,6,5.

Author information

1
Neuroscience Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia. nafiseh.atapour@monash.edu.
2
Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Melbourne, VIC, Australia. nafiseh.atapour@monash.edu.
3
Department of Physiology, Monash University, Clayton, Melbourne, VIC, 3800, Australia. nafiseh.atapour@monash.edu.
4
Neuroscience Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia.
5
Department of Physiology, Monash University, Clayton, Melbourne, VIC, 3800, Australia.
6
Australian Research Council, Centre of Excellence for Integrative Brain Function, Monash University Node, Melbourne, VIC, Australia.

Abstract

Neuronal loss in the lateral geniculate nucleus (LGN) is a consequence of lesions of the primary visual cortex (V1). Despite the importance of this phenomenon in understanding the residual capacities of the primate visual system following V1 damage, few quantitative studies are available, and the effect of age at the time of lesion remains unknown. We compared the volume, neuronal number, and neuronal density in the LGN, 6-21 months after unilateral V1 lesions in marmoset monkeys. Stereological sampling techniques and neuronal nuclei (NeuN) staining were used to assess the effects of similar-sized lesions in adult (2-4 years) and geriatric (10-14 years) animals. We found that lesions involving the opercular and caudal calcarine parts of V1 caused robust loss of neurons in topographically corresponding regions of the ipsilateral LGN (lesion projection zones), concomitant with a substantial reduction in the volume of this nucleus. Neuronal density was markedly reduced in the lesion projection zones, relative to the corresponding regions of the contralateral LGN, or the LGN in non-lesioned animals. Moreover, the percentage decrease in neuronal density within the lesion projection zones was significantly greater in the geriatric group, compared with the adult groups. The volume and neuronal density in the contralateral LGN of lesioned adult and geriatric marmosets were similar to those in non-lesioned animals. These results show that the primate LGN becomes more vulnerable to degeneration with advancing age. However, even in geriatric primates there is a population of LGN neurons which survives degeneration, and which could play a role in blindsight.

KEYWORDS:

Blindsight; Callithrix jacchus; Degeneration; Lateral geniculate nucleus; Neuronal loss; Primary visual cortex

PMID:
28331974
DOI:
10.1007/s00429-017-1404-4
[Indexed for MEDLINE]

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