Temporal Lobe Dysfunction in Childhood Autism: A PET Study

Abstract

PET and voxel-based image analysis revealed a localized dysfunction of the temporal lobes in school-aged children with idiopathic autism. Further studies will clarify the relationships between these temporal abnormalities and the perceptive, cognitive, and emotional developmental abnormalities characteristic of this disorder.

PET Scan Perfusion Imaging in the Prader–Willi Syndrome: New Insights into the Psychiatric and Social Disturbances

“…Interestingly, abnormalities in these two regions, the anterior cingulum and the superior temporal lobe, have been also described in autism (Boddaert et al, 2004;Haznedar et al, 2000;Kennedy and Courchesne, 2008;Zilbovicius et al, 2000).…”

L’autisme : vers une nécessaire révolution culturelle

“…Les études en imagerie fonctionnelle cérébrale révèlent une hypoactivité dans certaines régions du cerveau (lobe frontal, préfrontal ou gyrus cingulaire). Dans une étude française utilisant la tomographie par émission de positons (TEP), une hypoperfusion temporale a été constatée dans 76% des cas étudiés [20]. Lorsque l'imagerie par résonance magnétique (IRM) est pratiquée au cours d'une activation auditive ou visuelle, des anomalies sont constatées, notamment dans le cas de la perception des visages: des zones habituellement impliquées dans la reconnaissance des objets inanimés sont anormalement activées [21].…”

Magnesium in the Central Nervous System

“…In children who received methylphenidate, a significant increase (6%) in plasma Mg concentrations was found depending on the dosage of the drug, showing a relationship between improvement of hyperactivity and Mg metabolism (Schmidt et al, 1994(Tolbert et al, 1993. More recently, in autistic children with behavioural disorders and hyperactivity (Zilbovicius et al, 2000;Schmidt and Taylor, 1988;Chakraborti et al, 2002), positive emission tomography (PET) has shown a significant decrease in cerebral blood flow localized at the temporal lobe level in 76% of the children examined. Taken together with the fact that intra--erythrocyte free Mg 2+ is associated with increased blood pressure (Zilbovicius et al, 2000) and that brain from rats fed with low Mg diets are more susceptible to permanent brain focal ischemia (Gervais et al, 2004), we can hypothesize that intracellular Mg 2+ deficiency could be responsible, at least in part, of some central activity disorders observed in these children.…”

“…More recently, in autistic children with behavioural disorders and hyperactivity (Zilbovicius et al, 2000;Schmidt and Taylor, 1988;Chakraborti et al, 2002), positive emission tomography (PET) has shown a significant decrease in cerebral blood flow localized at the temporal lobe level in 76% of the children examined. Taken together with the fact that intra--erythrocyte free Mg 2+ is associated with increased blood pressure (Zilbovicius et al, 2000) and that brain from rats fed with low Mg diets are more susceptible to permanent brain focal ischemia (Gervais et al, 2004), we can hypothesize that intracellular Mg 2+ deficiency could be responsible, at least in part, of some central activity disorders observed in these children. The duration of the treatment necessary to get significant improvement seems to be about 8 weeks.…”

“…Similarly, brain ischaemia caused a decline in intracellular free Mg 2+ concentrations (Basso et al, 2000) and Mg salt administration improves motor outcome in this situation (Ebel and Gunther, 2005). One of its most important modes of action is to inhibit the glutamate N--methyl--D--aspartate (NMDA) channel (Zilbovicius et al, 2000). The activity of this channel generates an influx of calcium and, in turn, leads to excitotoxic cell death and apoptosis (Borella et al, 1993).…”