Longitudinal callosal fascicle

Longitudinal callosal fascicles (or Probst bundles) are abnormal collections of brain cells characteristic of patients with Agenesis of the corpus callosum. Failure of the callosally-projecting neurons (mostly layer 2/3 pyramidal neurons) to extend axons across the midline and therefore form the corpus callosum results in anomalous collection of these axonal projections in both hemispheres. Longitudinal callosal fascicles were originally described by Moriz Probst in 1901 by gross anatomical observation.^[1] More recently, these anomalies are detected by Magnetic Resonance Imaging ^[2] or Diffusion Tensor Imaging.^[3]

References

1. Probst, M. (1901), "Über den Bau des vollständig balkenlosen Großhirns", Arch Psychiatr 34: 709–786, doi:10.1007/bf02680175
2. Barkovich, AJ.; Norman, D. (Jul 1988), "Anomalies of the corpus callosum: correlation with further anomalies of the brain.", AJR Am J Roentgenol 151 (1): 171–9, PMID 3259802
3. Lee, SK.; Mori, S.; Kim, DJ.; Kim, SY.; Kim, SY.; Kim, DI. (Jan 2004). "Diffusion tensor MR imaging visualizes the altered hemispheric fiber connection in callosal dysgenesis.". AJNR Am J Neuroradiol 25 (1): 25–8. PMID 14729523.