Sensory Experience, Behavioral Therapy, and Neural Plasticity:
Implications for Autism Remediation
Autism is
characterized by impairments in social interaction, disordered communication,
repetitive behavior, and stereotyped interests. We propose that these symptoms
lead to a form of isolation that disrupts the development of normal brain
responses and in turn hinders the acquisition of critical language skills.
Anatomical studies have established that even mild isolation during development
can lead to significant weakening of cortical circuits. Although behavioral
therapy and auditory training appear to improve language skills in autistic
children, the neural basis of these improvements is not known. We have recently
demonstrated that early sensory enrichment in rats leads to a profound increase
in the sensitivity, frequency selectivity, response strength, and processing
speed of neurons in primary auditory cortex. Similar brain plasticity may
explain training-induced improvements of language function in autistic
children. To better understand how plasticity can be used to treat autism we
will 1) more completely characterize what specific aspects of an enriched
environment strengthen cortical circuits, 2) document how daily behavioral
training improves cortical processing, 3) establish the time course of
developmental plasticity, and 4) determine how dysfunction in the central
cholinergic system affects auditory cortex maturation. Our preliminary findings
indicate that during development cortical circuits are highly susceptible to
degradation, and that targeted sensory enrichment can be extremely effective at
restoring these circuits to normal performance. Results from the
these experiments will significantly influence the development of
behavioral and pharmacological treatments for autism.