Asymmetries of the Left and Right Temporal Lobes

Abstract

SUMMARY: Anatomical brain asymmetries are subtle and still little studied in humans. Among all the animals, humans have the most asymmetric brains Crow (2004). The language faculty and handedness are localized on the left side. The objective this paper is to verify whether the temporal lobes are anatomically different. Our sample was composed of 40 post mortem adult brains of both sexes, which were investigated at the Human Anatomy Laboratory of the Nove de Julho University Center in São Paulo, Brazil. The brains were fixed in a solution of 5% paraformaldehyde. Three different measurements were taken using a pachimeter (Mitutoyo) and a goniometer (Carci) on both hemispheres: M1 -the length of the lateral sulcus; M2 -the distance from the lateral sulcus to the inferior margin of the inferior temporal gyrus, and M3 -the angle formed between the lines of the collateral sulcus and the inferior margin of the inferior temporal gyrus. Results were submitted to a statistical analysis (ANOVA) and demonstrated that M1 was larger in the left hemisphere, by contrast with the data obtained for M2 and M3, which were larger in the right hemisphere. The measurements taken showed differences between the right and left temporal lobes.

Anatomical Variations in the Pseudosylvian Fissure Morphology of Brachy‐, Dolicho‐, and Mesaticephalic Dogs

“…The results obtained allows us to sort in ascending order the Psfl as dolicho‐(D), mesati‐ (M), and brachycephalic (B) in both hemispheres, with no statistically significant differences among each brain side, contrary to what was registered between the groups. Consequently, the results obtained suggest that the presence of a significant asymmetry between the right and the left Psf characteristic of humans is not seen in dogs (Tan and Caliskan, ; Heilbroner and Holloway, ; Witelson and Kigar, ; Tan and Kutlu, ; Pilcher et al, ; Boni et al, ; Lui and Kimberley, ) similar to what is describe in some other primates and cats (Yeni‐Komshian and Benson, ; Falk et al, ; Hopkins et al, ; Boni et al, ). Our study demonstrates that although no statistically significant differences were found, it is possible to conclude that the left Psf is bigger than the right one, being this, a common feature in dogs regardless of the type of skull considered.…”

Morphometric analysis of the main brain sulci and clinical implications: Radiological and cadaveric study

“…have reported that the distance from the terminal point of the LS to the inferior margin of the ITG in the right hemisphere is 46.86 mm (medium number), and that in the left hemisphere is 44.28 mm (5.95% higher in the right hemisphere). 14 In our study, the distance from the terminal point of the LS to the inferior margin of the ITG was measured as 3.93 ± 0.4300 (mean ± SD) and 4.02 ± 0.4023 cm on the right and left sides, respectively.…”

Gyral folding pattern analysis via surface profiling

“…For example, the frontal lobe has more 3-hinge and 4-hinge gyri than any other lobes, possibly indicating the more complicated gyrification process in the later stage of neurodevelopment (Brown et al, 2002). Another interesting observation is the left hemisphere shows more foldings than the right hemisphere, both for 3-hinge gyri and 4-hinge gyri, which may indicate more complicated gyrification and functional specification process in the left hemisphere (Sun and Walsh, 2006; Boni et al, 2007). This result reflects the asymmetry of the human brain from a gyral folding perspective.…”