Evidence for altered Fragile-X mental retardation protein expression in response to behavioral stimulation

Scott A. Irwin, Rodney A. Swain, Chariya A. Christmon, Aparna Chakravarti, Ivan Jeanne Weiler, William T. Greenough*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


The Fragile-X mental retardation protein, the protein absent in Fragile- X syndrome, is synthesized near synapses upon neurotransmitter activation. Humans and mice lacking this protein exhibit abnormal dendritic spine lengths and numbers. Here we investigated Fragile-X protein levels in animals exposed to behavioral paradigms that induce neuronal morphological change. Fragile-X protein immunoreactivity was examined in visual cortices of rats reared in a complex environment for 10 or 20 days, motor cortices of rats trained on motor-skill tasks for 3 or 7 days, and either visual or motor cortices of inactive controls. Rats exposed to a complex environment for 20 days or trained for 7 days on motor-skill tasks exhibited increased Fragile-X protein immunoreactivity in visual or motor cortices, respectively. These results provide the first evidence for a behaviorally induced alteration of Fragile-X protein expression and are compatible with previous findings suggesting synaptic regulation of its expression. These results also strengthen the association of Fragile-X mental retardation protein expression with the alteration of synaptic structure. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)87-93
Number of pages7
JournalNeurobiology of Learning and Memory
Issue number1
StatePublished - Jan 2000


  • Complex environment
  • Dendritic spines
  • Enriched environment
  • Fragile-X mental retardation protein (FMRP)
  • Fragile-X syndrome
  • Motor learning
  • Protein synthesis
  • Rat
  • Synaptic plasticity

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience


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