Thursday, January 27, 2005

New Autism Spectrum Disorder Research

The causes of autism have long remained amystery, but new research from Columbia University Medical Center hasidentified, for the first time, how a cellular defect may be involvedin the often crippling neurological disorder. The research, which is published in today's issue of Science,examines how a defect in neuroligin genes may contribute to autism.Neuroligins are components of synapses, which connect individualneurons in the brain. The researchers found that the loss ofneuroligins perturbs the formation of neuronal connections andresults in an imbalance of neuronal function. This imbalance providesan explanation for the neurodevelopmental defects in autisticchildren. "Understanding the cellular defects that may underlieautism-spectrum disorders represents an important step towards thegoal of providing therapies," said Peter Scheiffele, Ph.D., assistantprofessor of physiology and cellular biophysics at Columbia UniversityMedical Center, and principal investigator on the study. A defect in the neuroligin genes had previously been observed inautistic patients, but its functional significance was not yetunderstood. Scheiffele's study showed that in rat neurons without anyneuroligin, connections between neurons are altered in a way that isstrikingly similar to those found in autistic children. Each neuron in the brain receives many different inputs – some areexcitatory and signal the neuron to fire, and some are inhibitory andsignal the neuron to stop firing. Scheiffele's research team foundthat neuroligin genes are responsible for regulating the balancebetween excitatory and inhibitory synaptic function. A defect inneuroligin leads to a selective loss in inhibitory function andthereby impairs the fine-tuning of neuronal connectivity, aneurological problem that is understood to play a role in autism. "There is much we still don't know about how neurons connect to eachother, but our findings have provided unique insights into what may begoing wrong on a cellular level in autistic patients," said Dr.Scheiffele.