22
Mnesic Imbalance and the Neuroanatomy of Autism Spectrum Disorders
Hospital Psiquiátrico "Dr. Samuel Ramírez Moreno”, Secretaría de Salud México 1. Introduction
Currently, the diagnostic and statistical manual of the American Psychiatric Association (APA) defines autistic disorder together with Rett syndrome, childhood disintegrative disorder, Asperger syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) as Pervasive Developmental Disorders (APA, 2000). This term implies disorders that vary in several ways but the term Autism Spectrum Disorders (ASD), which excludes Rett syndrome and childhood disintegrative disorder, implies that there are shared clinical and etiological factors among diagnoses (Gabis et …ver más…

1).

Fig. 1. Progressive reduction of reaction time during repeated sequence was an index of procedural learning, while the frequency of words remembered was an index of declarative learning. The standard error of measurement is also represented. (From Quintero-Gallego et al., 2006). It is also important to note that there are neurobiological changes that occur with the development of memories in healthy human individuals. For instance, it is now accepted that neurogenesis occurs in the adult human hippocampus and it has been surmised that adding new neurons helps in acquiring new knowledge without disrupting knowledge that has already been stored (Appleby et al., 2011), whereas neurogenesis occurs in the human

Mnesic Imbalance and the Neuroanatomy of Autism Spectrum Disorders

427

cerebellum mainly before the end of the first postnatal year, but its cytoarchitectonical development is completed subsequently (Ábrahám et al., 2001; Rakic & Sidman, 1970). On the other hand, a postmortem study of persons who had developed a complex declarative memory showed significant