Abstract
There is extensive modification of the functional organization of the brain in the congenital blind human, although there is little understanding of the structural underpinnings of these changes. The visual system of macaque has been extensively characterized both anatomically and functionally. We have taken advantage of this to examine the influence of the congenital blindness in macaque resulting from the removal of the retina during in utero development. Developmental anophthalmia in macaque effectively removes the normal influence of the thalamus on cortical development leading to an induced hybrid cortex (HC) combining features of primary visual and extrastriate cortex. Here we show that retrograde tracers injected in early visual areas including hybrid cortex reveals a drastic reduction of cortical projections of the reduced lateral geniculate nucleus. In addition, there is an important expansion of projections from the pulvinar complex to the hybrid cortex, compared to the controls. These findings show that the functional consequences of congenital blindness need to be considered in terms of both modifications of the inter-areal cortical network and the ascending visual pathways.
Glossary
- AM
- anteromedial nucleus of the thalamus Amyg, amygdala
- Bsc
- brachium of superior colliculus
- Cau
- caudate nucleus
- CeM
- central medial nucleus of the thalamus
- CG
- central gray
- Cl
- Claustrum
- CL
- central lateral nucleus of the thalamus
- CM
- central median nucleus of the thalamus
- ctt
- cortico-tectal tract
- HbL
- lateral habenular nucleus
- HbM
- medial habenular nucleus
- hbt
- habenulopeduncular tract
- InC
- interstitial nucleus of Cajal
- ILN
- intralaminar nuclei
- LGN
- lateral geniculate nucleus
- MD
- mediodorsal nucleus of the thalamus
- MG
- medial geniculate complex
- mth
- mammillothalamic tract
- MV
- medioventral nucleus of the thalamus
- Pa
- paraventricular nuclei of the thalamus
- Pc
- paracentral nucleus of the thalamus
- Pf
- parafascicular nucleus of the thalamus
- PI
- inferior nucleus of the pulvinar
- Pi
- pineal gland
- PL
- lateral nucleus of the pulvinar
- PM
- medial nucleus of the pulvinar
- PrC
- Precomissural nucleus
- Prg
- pregeniculate nucleus
- Pul
- Pulvinar
- Rt
- reticular nucleus of the thalamus
- RN
- part of the red nucleus
- SC
- superior colliculus
- SG
- suprageniculate nucleus
- sm
- stria medullaris of the thalamus
- VAmc
- ventral anterior nucleus of thalamus, magnocellular division
- VLa
- ventral lateral anterior nucleus of thalamus
- VLp
- ventral lateral posterior nucleus of thalamus
- VPL
- ventral posterior lateral nucleus of thalamus
- VPM
- ventral posterior medial nucleus of thalamus
- ZIC
- zona incerta complex