R. Espert et Jf. Navarro, BIOLOGICAL BASIS OF INFANTILE-AUTISM - II - NEUROPATHOLOGICAL, NEUROPHYSIOLOGICAL AND NEUROPSYCHOLOGICAL ASPECTS, Psicologia conductual, 6(2), 1998, pp. 391-409
In the second part of this review paper on biological basis of infanti
le autism we describe the main neuropathological, neurophysiological a
nd neuropsychological investigations carried out in this disease. Nume
rous neuropathological ''postmorten'' studies as well as neuroanatomic
al studies using neuroimaging techniques have demonstrated the existen
ce of a broad variety of structural and functional abnormalities in au
tistic patients. Although results are not entirely consistent, the mai
n changes in autism have been located in limbic system (medial tempora
l robe), cerebellum and cerebral cortex, Likewise, it has been propose
d that some cases of autism might be provoked by an injury at the time
of closure of the neural tube. On the other hand, we examine the main
neurophysiological studies in autistic subjects, emphasizing investig
ations with evoked potentials. In this context, several authors have s
uggested that in autism exists a disordered functioning in brainstem a
nd thalamic systems which mediate arousal, attention and information-p
rocessing. The third part of this paper focuses on neuropsychological
studies realized in autistic patients. It is a well-known fact that th
ese subjects exhibit neuropsychological disorders in a wide range of d
omains, a fact that suggests that autism probably involves a dysfuncti
on of multiple regions rather than of only one brain region. Most stud
ies reveal large individual differences in certain neuropsychological
domains. Whereas most autistic patients have frontal lobe impairments,
great variability exists in the areas of language and memory. This re
view concludes with a brief description of several neurofunctional int
egrative models of autism (Bachevalier, 1994; Morton and Frith, 1995;
Couchesne, Townsend and Chase, 1995, and Waterhouse, Fein and Modahl,
1996).