Morphological differences in the commissural connections of the forebrain in white outbred mice and BALB/C mice

Abstract

BACKGROUND: The study of the mechanisms of interaction of paired structures of the mammalian brain is a fundamental problem of modern neuroscience, which is of great applied importance. Even mild underdevelopment of the corpus callosum in humans can lead to autism. It is known that the intensity of intraspecific interactions in BALB/c mice is lower than in white outbred ones, while some BALB/c substrains are characterized by underdevelopment of the corpus callosum.

AIM: To compare the morphological parameters of the large brain commissures in white outbred mice and BALB/c mice grown in the Rappolovo nursery (Leningrad region).

MATERIALS AND METHODS: The morphology of the corpus callosum was studied in 13 male white outbred mice and 7 male BALB/c mice at the age of 8 months.

RESULTS: In mice of both subpopulations, the area of the anterior commissure of the left hemisphere was smaller than that of the right hemisphere (p < 0.05). There were no differences between subpopulations in this parameter. The area of the left section of the corpus callosum trunkus in outbred mice was larger than the right one (p < 0.001), while in BALB/c mice the areas of the left and right slices did not differ. Despite the absence of significant differences in the area of the anterior part (rostrum et genu) of the corpus callosum the density of the location of oligodendrocytes in this brain structure in the mice of the two subpopulations was different. The number of oligodendrocytes in 0.01 mm² on the left section of the anterior part of the corpus callosum in BALB/c mice was greater than in white outbred mice (p < 0.05). A similar trend was revealed when comparing slices of the right hemisphere (p = 0.065).

CONCLUSIONS: The large area of the right parasagittal slice of the anterior commissure suggests that some of its constituent fibers do not cross the midline, but end within the same hemisphere, which may be the morphological basis for the functional dominance of the temporal cortex of the left hemisphere in mice of both subpopulations. The corpus callosum in BALB/c mice is developed symmetrically, and in white outbred ones – asymmetrically. This feature may be the morphological basis for the functional dominance of the parietal cortex of the right hemisphere in outbred animals.

Keywords

corpus callosum / commissural connections / white outbred mice / BALB/c mice

References

[1] Alikhanov AA. The phenotype of disturbance of corpus callosum structures: the data of neurovisualization (Lection). Russian Journal of Child Neurology. 2010;5(4):17–28. (In Russ.)

[2] Алиханов А.А. Фенотипы нарушений структуры мозолистого тела: данные нейровизуализации (лекция) // Русский журнал детской неврологии. 2010. Т. 5, № 4. С. 17–28.

[3] Zykin PA, Yalfimov AN, Alexandrov TA, et al. The features of development of corpus callosum of children’s brain. Pediatrician. 2018;9(1):37–48. (In Russ.). DOI: 10.17816/PED9137-48

[4] Зыкин П.А., Ялфимов А.Н., Александров Т.А. и др. Особенности развития мозолистого тела мозга детей по данным МРТ // Педиатр. 2018. Т. 9, № 1. С. 37–48. DOI: 10.17816/PED9137-48

[5] Hardan AY, Pabalan M, Gupta N, et al. Corpus callosum volume in children with autism. Psychiatry Res. 2009;174(1):57–61. DOI: 10.1016/j.pscychresns.2009.03.005

[6] Hardan A.Y., Pabalan M., Gupta N. et al. Corpus callosum volume in children with autism // Psychiatry Res. 2009. Vol. 174, No. 1. P. 57–61. DOI: 10.1016/j.pscychresns.2009.03.005

[7] Mikheev VV, Shabanov PD. Pharmacological asymmetry of the brain. Saint Petersburg; 2007. (In Russ.)

[8] Михеев В.В., Шабанов П.Д. Фармакологическая асимметрия мозга. Санкт-Петербург, 2007.

[9] Wahlsten D, Bishop KM, Ozaki HS. Recombinant inbreeding in mice reveals thresholds in embryonic corpus callosum development. Genes Brain Behav. 2006;5(2):170–188. DOI: 10.1111/j.1601-183X.2005.00153.x

[10] Wahlsten D., Bishop K.M., Ozaki H.S. Recombinant inbreeding in mice reveals thresholds in embryonic corpus callosum development // Genes. Brain Behav. 2006. Vol. 5, No. 2. P. 170–188. DOI: 10.1111/j.1601-183X.2005.00153.x

[11] Lefkowitz M, Durand D, Smith G, Silver J. Electrical properties of axons within probst bundles of acallosal mice and callosi that have reformed upon glial-coated polymer implants. Exp Neurol. 1991;113(3):306–313. DOI: 10.1016/0014-4886(91)90020-d

[12] Lefkowitz M., Durand D., Smith G., Silver J. Electrical properties of axons within probst bundles of acallosal mice and callosi that have reformed upon glial-coated polymer implants // Exp. Neurol. 1991. Vol. 113, No. 3. P. 306–313. DOI: 10.1016/0014-4886(91)90020-d

[13] Fairless AH, Dow HC, Toledo MM, et al. Low sociability is associated with reduced size of the corpus callosum in the BALB/cJ inbred mouse strain. Brain Res. 2008;1230:211–217. DOI: 10.1016/j.brainres.2008.07.025

[14] Fairless A.H., Dow H.C., Toledo M.M. et al. Low sociability is associated with reduced size of the corpus callosum in the BALB/cJ inbred mouse strain // Brain Res. 2008. Vol. 1230. P. 211–217. DOI: 10.1016/j.brainres.2008.07.025

[15] Krasnostchekova EI. Modular organization of nerve centers. Saint Petersburg; 2007. (In Russ.)

[16] Краснощекова Е.И. Модульная организация нервных центров. Санкт-Петербург, 2007.

RIGHTS & PERMISSIONS

Karpova I.V., Popkovsky N.A., Proshin S.N., Bychkov E.R., Tissen I.Y., Droblenkov A.V.