A strong relationship exists between the structure, maintenance and function of dendritic spines and activity-dependent spine remodeling is believed to underlie physiological processes such as synaptic transmission and plasticity.Consequently, structural and/or functional changes at the level of dendritic spines will be sensed by, and affect, all the local neuronal networks, and ultimately, behavior such as learning and memory.A broad variety of psychiatric and neurologic disorders are accompanied by patterns of altered spine.Therefore, the molecular mechanisms that control spine morphology and pathology have been studied for many years.We have focused our studies on Scribblel, which is a crucial regulator of spine development, as well as structural and functional plasticity.Our data suggested that the circletail mutant, a mouse model for planar cell polarity (PCP) defects, might be a model for studying synaptic dysfunction and human psychiatric disorders such as autism syndrome disorders.