Effects of dark rearing on the development of visual callosal connections

1989 ◽  
Vol 78 (1) ◽  
Author(s):  
D.O. Frost ◽  
Y.P. Moy
Keyword(s):  
Callosal Connections ◽  
Dark Rearing

The effects of dark-rearing on visual callosal connections of cats

1979 ◽  
Vol 167 (1) ◽  
pp. 172-175 ◽  
Author(s):  
R.D. Lund ◽  
D.E. Mitchell
Keyword(s):  
Callosal Connections ◽  
Dark Rearing

scholarly journals Functional Expansion of Sensorimotor Representation and Structural Reorganization of Callosal Connections in Lower Limb Amputees

2012 ◽  
Vol 32 (9) ◽  
pp. 3211-3220 ◽  
Author(s):  
E. L. Simoes ◽  
I. Bramati ◽  
E. Rodrigues ◽  
A. Franzoi ◽  
J. Moll ◽  
...  
Keyword(s):  
Lower Limb ◽  
Structural Reorganization ◽  
Callosal Connections ◽  
Functional Expansion ◽  
Lower Limb Amputees

Development of visual callosal connections in neonatally enucleated rats

1987 ◽  
Vol 260 (3) ◽  
pp. 321-348 ◽  
Author(s):  
Jaime Olavarria ◽  
Rafael Malach ◽  
Richard C. Van sluyters
Keyword(s):  
Callosal Connections

Effect of longer periods of dark rearing on NMDA receptors in cat visual cortex

1994 ◽  
Vol 72 (3) ◽  
pp. 1220-1226 ◽  
Author(s):  
D. Czepita ◽  
S. N. Reid ◽  
N. W. Daw
Keyword(s):  
Visual Cortex ◽  
Nmda Receptor ◽  
Firing Rate ◽  
Spontaneous Activity ◽  
Visual Response ◽  
Visual Responses ◽  
Level Of Activity ◽  
Direction Of Movement ◽  
Excitatory Drive ◽  
Dark Rearing

1. Cats were reared in the dark to 3, 5, and 11 mo. We studied the N-methyl-D-aspartate (NMDA) receptor contribution to the visual response in the cortex, defined as the percentage reduction in visual response after application of 2-amino-5-phosphonovaleric acid (APV). We also studied the firing rate in response to the optimal visual stimulus and the spontaneous activity. We made comparisons of all these properties between light-reared and dark-reared animals. 2. The NMDA receptor contribution to the visual response in layers IV, V, and VI of dark-reared animals was substantially above that in light-reared animals at all ages tested. 3. The specificity of receptive field properties in dark-reared animals showed some degeneration between 6 wk and 3 mo of age. At > or = 3 mo, almost no cells were specific for orientation and direction of movement. 4. Firing rate was lower in dark-reared animals at all ages, suggesting a decrease in excitatory drive to the visual cortex. 5. Spontaneous activity was equal in dark- and light-reared animals, suggesting that the overall level of activity (including visual responses as well as spontaneous activity) in light-reared animals is higher than in dark-reared animals. This should tend to upregulate glutamate receptors in general in dark-reared animals.

scholarly journals Retino-thalamo-cortical and callosal connections visualized with manganese-enhanced magnetic resonance imaging and validated with tract tracing techniques

2020 ◽  
Author(s):  
Robyn J. Laing ◽  
Donna J Cross ◽  
Jaime Olavarria
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Longitudinal Studies ◽  
Ocular Dominance ◽  
Surface Coil ◽  
Resonance Imaging ◽  
Adult Rats ◽  
Callosal Connections ◽  
Plastic Changes

Ocular dominance columns correlate with patchy callosal connections in Long Evans rats (Laing et al., 2015). We explored in vivo manganese-enhanced magnetic resonance imaging (MEMRI) as a possible strategy for longitudinal studies of plastic changes in the retino-thalamo-cortical and callosal pathways. MnCl 2 was injected either intraocularly or intracortically to label these pathways, respectively. The transport of the paramagnetic ion Mn 2+ was evaluated by comparing images acquired both before and 36 or 12 hours after intraocular or cortical injections, respectively. Images were acquired on a 3T magnet (Philips Achieva, Philips Healthcare, Andover, MA), using a custom surface coil and a T1-weighted MPRAGE image sequence (TR/TE = 23/11 ms; Ti=1000 ms; FA= 10 deg acquired matrix 432x432 mm over 118 slices, voxel size 0.11x0.11x0.2 mm 3 ). To validate the transport of Mn 2+ , each animal also received either an intraocular injection of the transneuronal tracer WGA-HRP, or cortical injections of HRP. Following monocular injections of MnCl 2 , MRI images showed significant, bilateral accumulations of Mn 2+ in regions of the SC, LGN and visual cortex that corresponded with regions labeled with HRP. In adult rats monocularly enucleated at birth, we injected MnCl 2 in the hemisphere contralateral to the remaining eye in an attempt to detect anomalies reported previously in the callosal pattern ipsilateral to the remaining eye. After the scans, the hemisphere injected with MnCl 2 was injected with HRP. MRI images revealed Mn 2+ patterns that closely resembled the callosal patterns demonstrated with HRP in the same animal. Our results suggest that both transneuronal retino-thalamo-cortical, as well as cortico-cortical transport of Mn 2+ provide potentially useful strategies for longitudinal studies of plastic changes in these pathways.

Cerebrocortical Microdysgenesis with Anomalous Callosal Connections: A Case Study in the Rat

1989 ◽  
Vol 47 (3-4) ◽  
pp. 237-247 ◽  
Author(s):  
Glenn D. Rosen ◽  
Albert M. Galaburda ◽  
Gordon F. Sherman
Keyword(s):  
Callosal Connections
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