Present address: Wolfson Brain Imaging Centre, Box 65, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
The role of the medial temporal lobe in autistic spectrum disorders
Article first published online: 11 AUG 2005
European Journal of Neuroscience
Volume 22, Issue 3, pages 764–772, August 2005
How to Cite
Salmond, C. H., Ashburner, J., Connelly, A., Friston, K. J., Gadian, D. G. and Vargha-Khadem, F. (2005), The role of the medial temporal lobe in autistic spectrum disorders. European Journal of Neuroscience, 22: 764–772. doi: 10.1111/j.1460-9568.2005.04217.x
- Issue published online: 11 AUG 2005
- Article first published online: 11 AUG 2005
- Received 5 November 2004, revised 4 May 2005, accepted 11 May 2005
- episodic memory;
- magnetic resonance imaging
The neural basis of autistic spectrum disorders (ASDs) is poorly understood. Studies of mnemonic function in ASD suggest a profile of impaired episodic memory with relative preservation of semantic memory (at least in high-functioning individuals). Such a pattern is consistent with developmental hippocampal abnormality. However, imaging evidence for abnormality of the hippocampal formation in ASD is inconsistent. These inconsistencies led us to examine the memory profile of children with ASD and the relationship to structural abnormalities. A cohort of high-functioning individuals with ASD and matched controls completed a comprehensive neuropsychological memory battery and underwent magnetic resonance imaging for the purpose of voxel-based morphometric analyses. Correlations between cognitive/behavioural test scores and quantified results of brain scans were also carried out to further examine the role of the medial temporal lobe in ASD. A selective deficit in episodic memory with relative preservation of semantic memory was found. Voxel-based morphometry revealed bilateral abnormalities in several areas implicated in ASD including the hippocampal formation. A significant correlation was found between parental ratings reflecting autistic symptomatology and the measure of grey matter density in the junction area involving the amygdala, hippocampus and entorhinal cortex. The data reveal a pattern of impaired and relatively preserved mnemonic function that is consistent with a hippocampal abnormality of developmental origin. The structural imaging data highlight abnormalities in several brain regions previously implicated in ASD, including the medial temporal lobes.