RT Journal Article
SR Electronic
T1 Normal CA1 place fields but discoordinated network discharge in a Fmr1-null mouse model of fragile X syndrome
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 152462
DO 10.1101/152462
A1 Fraser Todd Sparks
A1 Zoe Nicole Talbot
A1 Dino Dvorak
A1 Bridget Mary Curran
A1 Juan Marcos Alarcon
A1 André Antonio Fenton
YR 2017
UL http://biorxiv.org/content/early/2017/06/20/152462.abstract
AB Silence of FMR1 causes loss of fragile X mental retardation protein (FMRP) and dysregulated translation at synapses, resulting in the intellectual disability and autistic symptoms of Fragile X Syndrome (FXS). Synaptic dysfunction hypotheses for how intellectual disabilities like cognitive inflexibility arise in FXS, predict impaired neural coding in the absence of FMRP. We tested the prediction by comparing hippocampus place cells in wild-type and FXS-model mice. Experience-driven CA1 synaptic function and synaptic plasticity changes are excessive in Fmr1-null mice, but CA1 place fields are normal. However, Fmr1-null discharge relationships to local field potential oscillations are abnormally weak, stereotyped, and homogeneous; also discharge coordination within Fmr1-null place cell networks is weaker and less reliable than wild-type. Rather than disruption of single-cell neural codes, these findings point to invariant tuning of single-cell responses and inadequate discharge coordination within neural ensembles as a pathophysiological basis of cognitive inflexibility in FXS.