Autism memory

Bachevaher J (1991) An animal model for childhood autism memory loss and sodoemotional disturbances following neonatal damage to the limbic system in monkeys. In Advances in neuropsychiatry and psychopharmacology, volume 1 Schizophrenia research (Tamminga CA, Schulz SC, eds), pp. 129-140. New York Raven Press. 

This chapter is concerned with the neurochemical basis of developmental disability which is considered here in two forms the globally delayed or halted development seen in mental retardation, and the more circumscribed pattern of disordered development of autism. A range of deficits of important key aspects of consciousness are apparent in both conditions. Of particular relevance to consciousness are the cognitive and behavioural impairments in attention, concentration, memory, information processing and social behaviour which are commonly present. Consideration of aberrant neurotransmitter activities in these developmental deficits may provide insights into the role of neurotransmitters in consciousness. 

The peptide, melatonin, has been implicated in autism. Excess melatonin is thought to decrease learning, memory, attention, emotionality, motivation and pain responses (reviewed Chamberlain Herman, 1990)—all behaviours that are abnormal in autism. Melatonin, released from the pineal gland, is implicated in controlling serotonin and POMC (proopiomelanocortin) peptides, such as beta-endorphin, and an elevation may contribute to, or cause, the serotonin and opioid abnormalities (Chamberlain Herman, 1990). 

The dorsal and ventral hippocampus is involved in the formation of social memory (van Wimersma Greidanus and Maigret, 1996). Neonatal ablations of hippocampal regions can lead to decreased and abnormal social behavior in rhesus monkeys that is reminiscent of severe neuropsychiatric disorders in humans such as autism and schizophrenia (Bachevalier et ah, 1999). These monkeys are often withdrawn socially and will develop locomotoric stereotypies a pattern similar to that found in autistic children. 

Serotonin involvement. There is substantial evidence supporting abnormal 5-HT function in autism, particularly with regard to both the social deficit and repetitive behavior dimensions of this disorder. Many studies of the neurobiology of autism have focused on 5-HT, which is implicated in the regulation of many functions relevant to autism, such as learning, memory. 

Oxytocin is a neuropeptide synthesized in the paraventricular and supraoptic nucleus of the hypothalamus. Oxytocin is released from axon terminals of the posterior pituitary into the bloodstream. It is also distributed to the central nervous system and oxytocin binding sites are found throughout, especially in the limbic system (Insel and Young, 2000). Oxytocin has been linked to afifiliative behavior, social memory, and behavior, all of which are impaired in autism (Insel et al., 1999). It has been hypothesized that dysfunction of oxytocin and vasopresin contributes to social impairment in autism (Waterhouse et al., 1996). 

Combined use of ChEI with neuroleptic and antidepressant medication Although the successes of most pharmacological treatments for autistic adults are limited, combining medications may prove to be more effective. A study by Wang et al., 2007 examined the synergistic effect of risperidone and galantamine on the phencyclidine-induced mouse model of schizophrenia. Similar to autism, schizophrenic patients suffer from cognitive defects and impaired memory function. 

Luna B, Minshew NJ, Garver KE, Lazar NA, Thulborn KR, Eddy WF, Sweeney JA (2002) Neocortical system abnormalities in autism an fMRI study of spatial working memory. Neurology 59 834-840. 

Yoo JH, Valdovinos MG, Williams DC (2007) Relevance of donepezil in enhancing learning and memory in special populations a review of the literature. J Autism Dev Disord 37 1883-1901. 

Beversdorf DQ, Smith BW, Cmdan GP, Anderson JM, KeUlor JM, Barrett AM, Hughes JD, Eelopulos GJ, Bauman ML, Nadeau SE, HeUman KM (2000) Increased discrimination of false memories in autism spectrum disorder. Proc Natl Acad Sci USA 97 8734—8737. 

HUlier A, Campbell H, Keillor J, Philhps N, Beversdorf DQ (2007) Decreased false memory for visually presented shapes and symbols among adults on the autism spectrum. J Clin Exp Neuropsychol 29 610-616. 

Minshew NJ, Goldstein G (2001) The pattern of intact and impaired memory functions in autism. J Child Psychol Psychiatry 42 1095-1101. 

---