Cross‐sectional area of the posterior hippocampus in autistic patients with cerebellar and corpus callosum abnormalitiGs

Abstract

Using MRI methods previously shown to optimize visualization of cytoarchitectonic details in the body of the hippocampal formation caudal to the pes hippocampi, we imaged and quantified the hippocampus proper including the subiculum and the dentate gyrus in 33 autistic patients between the ages of 6 and 42 years and in 23 age-matched normal healthy volunteers. Measures of these structures in autistic patients and normal healthy volunteers differed nonsignificantly, by less than 1.4%, regardless of whether or not the autistic patients were retarded or had a history of seizure episodes. By contrast, measures of vermian lobules VI and VII and the posterior portion of the corpus callosum in these same autistic and normal volunteers differed significantly, by more than 9.9%. The lack of a significant difference in the cross-sectional size of the posterior hippocampal formation between autistic and normal 6- to 42-year-olds is discrepant with predictions based on some, but not all, autopsy studies. This suggests that there is a need for additional quantitative autopsy study of the hippocampal formation and quantitative MRI study of rostral hippocampal regions that we did not explore in the present report. Also, quantitative autopsy and MRI studies have yet to examine hippocampal development in autistic patients younger than 6 years of age; whether early stages of growth are normal or not is unknown.

Theory of Mind disruption and recruitment of the right hemisphere during narrative comprehension in autism

“…It is believed that genu fibers can be mapped to prefrontal cortical areas (Witelson, 1989). Our results are in good agreement with the literature (Courchesne, Press, & YeungCourchesne, 1993;Hardan, Minshew, & Keshavan, 2000;Manes et al, 1999;Piven, Bailey, Ranson, & Arndt, 1997;Saitoh, Courchesne, Egaas, Lincoln, & Schreibman, 1995), and they were obtained in the context of lowered functional connectivity in the autism group.…”

A Review on the Cognitive Neuroscience of Autism

“…Studies investigating CC anomalies in autism have employed structural MRI to find reductions in area on the midsagittal plane as well as in volumetric measures. Results include overall decreases in midsagittal area (Boger-Megiddo et al, 2006;Manes et al, 1999;Vidal et al, 2006), and subregional decreases in in the anterior (Hardan, Minshew, & Keshavan, 2000;Just, Cherkassky, Keller, Kana, & Minshew, 2006;Vidal et al, 2006), middle Piven, Bailey, Ranson, & Arndt, 1997), and posterior (Just et al, 2006;Saitoh, Courchesne, Egaas, Lincoln, & Schreibman, 1995;Waiter et al, 2005) portions of the CC. The majority of nonstatistically significant results from these studies also showed a trend towards a decrease in area in all subregions.…”

“…The combined findings of ten structural MRI studies yield no consistent pattern, with a near equal distribution of increased, decreased, and non-significant differences in hippocampal volumes. The first five stu- Schumann et al (2004) employed HFA, LFA, and AS subgroups; Saitoh et al (1995) and Saitoh et al (2001) employed partial LFA subgroup.…”

“…A summary of these studies is shown in Figure 5. All results are of volumetric measurements except for Saitoh et al (1995) and (2001), which measured crosssectional area.…”

Atualização sobre comorbidade entre transtorno do déficit de atenção e hiperatividade (TDAH) e transtornos invasivos do desenvolvimento (TID)

“…Em oposição ao que se observa no TDAH, pacientes autistas apresentam aumento do volume total do cérebro e também específico de regiões como o cerebelo, o caudado e o globo pálido (Piven et al, 1996). Ambos, entretanto, apresentam diminuição do corpo caloso (Saitoh et al, 1995). Em estudos de neuroimagem funcional, o achado que sobressai é a reduzida ativação das regiões frontotemporais em autistas (Baron-Cohen et al, 1999), o que também ocorre em pacientes com TDAH.…”