Fragile X Syndrome Research Today is a free monthly online journal that collates and summarizes the latest research about Fragile X Syndrome, including details on symptoms, treatment, heritability, diagnosis.

Savings and Extinction of Conditioned Eyeblink Responses in Fragile X Syndrome.

Smit AE, van der Geest JN, Vellema M, Koekkoek B, Willemsen R, Govaerts LC, Oostra BA, De Zeeuw CI, Vanderwerf F

Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.

The fragile X syndrome is the most widespread heritable form of mental retardation caused by the lack of expression of the fragile X mental retardation protein. This lack has been related to deficits in cerebellum-mediated acquisition of conditioned eyelid responses in individuals with fragile X syndrome. In the current behavioral study long term effects of deficiency of fragile X mental retardation protein were investigated, by examining the acquisition, savings and extinction of delay eyeblink conditioning in male individuals with fragile X syndrome. In the acquisition experiment fragile X syndrome subjects displayed a significantly poor performance compared to control subjects. In the savings experiment performed at least 6 months later, fragile X syndrome and control subjects showed similar levels of savings of conditioned responses. Subsequently, extinction was faster in fragile X syndrome than in control subjects. These findings confirm that absence of the fragile X mental retardation protein affects cerebellar motor learning. The normal performance in the savings experiment and aberrant performance in the acquisition and extinction experiments of individuals with fragile X syndrome suggests that different mechanisms underlie acquisition, savings and extinction of cerebellar motor learning.

Published 11 July 2008 in Genes Brain Behav.
Full-text of this article is available online (may require subscription).

© 2005-2008 Fragile X Syndrome Research Today. All Rights Reserved.