Cerebral Cortex, Vol. 10, No. 10, 1005-1013,
October 2000
© 2000 Oxford University Press
Connectivity of Ectopic Neurons in the Molecular Layer of the Somatosensory Cortex in Autoimmune Mice
1 Dyslexia Research Laboratory and Charles A. Dana Research Institute, Beth Israel Deaconess Medical Center; Division of Behavioral Neurology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 and , 2 Program of Neuroscience Harvard Medical School, Boston, MA 02115, USA
Approximately 50% of New Zealand Black mice (NZB/BINJ) and 80% of NXSM-D/EiJ mice prenatally develop neocortical layer I ectopias, mostly in somatosensory cortices. These cortical anomalies are similar to those seen in the brains of individuals with dyslexia. Neurofilament staining revealed a radial column of tightly packed fiber bundles in the layers underlying ectopias. This suggested that the connectivity of the ectopic neurons was aberrant. The present study used the tracers 1,1'-dioctadecyl- 3,3,3',3'-tetramethylindo- carbocyanine perchlorate (DiI) and biotinylated dextran amine (BDA) to more thoroughly explore the cortical and thalamic connectivity of the ectopias. DiI placement into ectopias again revealed a distinct bundle of fibers extending from the ectopic neurons to the deep cortical layers. This bundle split in the white matter with some fibers traveling to the corpus callosum and others to the internal capsule. Thalamic connections were concentrated in the ventrobasal com- plex (VB) and posterior thalamic nucleus group (Po). Injections of BDA into VB revealed reciprocal connections between VB and the ectopic cortical neurons. Ipsilateral corticocortical projections were seen between ectopias in primary somatosensory and motor and secondary somatosensory cortices, but no contralateral connections of the ectopic neurons were seen. These findings confirm the notion that layer I ectopias are anomalously connected by comparison to neurons in homologous cortex, which may underlie widespread dysfunction of brains containing ectopias.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  L. A. Gabel and J. J. LoTurco Layer I Ectopias and Increased Excitability in Murine Neocortex J Neurophysiol, May 1, 2002; 87(5): 2471 - 2479. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. A. Gabel and J. J. LoTurco Electrophysiological and Morphological Characterization of Neurons Within Neocortical Ectopias J Neurophysiol, February 1, 2001; 85(2): 495 - 505. [Abstract] [Full Text] [PDF]
|
|