PT  - JOURNAL ARTICLE
AU  - Mariska van Lier
AU  - M. Hadi Saiepour
AU  - Koen Kole
AU  - Juliette E. Cheyne
AU  - Nawal Zabouri
AU  - Thomas Blok
AU  - Yi Qin
AU  - Emma Ruimschotel
AU  - J. Alexander Heimel
AU  - Christian Lohmann
AU  - Christiaan N. Levelt
TI  - Disruption of Critical Period Plasticity in a Mouse Model of Neurofibromatosis Type 1
AID  - 10.1523/JNEUROSCI.2235-19.2020
DP  - 2020 Jul 08
TA  - The Journal of Neuroscience
PG  - 5495--5509
VI  - 40
IP  - 28
4099  - http://www.jneurosci.org/content/40/28/5495.short
4100  - http://www.jneurosci.org/content/40/28/5495.full
SO  - J. Neurosci.2020 Jul 08; 40
AB  - Neurofibromatosis type 1 (NF1) is a common monogenic neurodevelopmental disorder associated with physical and cognitive problems. The cognitive issues are thought to arise from increased release of the neurotransmitter GABA. Modulating the signaling pathways causing increased GABA release in a mouse model of NF1 reverts deficits in hippocampal learning. However, clinical trials based on these approaches have so far been unsuccessful. We therefore used a combination of slice electrophysiology, in vivo two-photon calcium imaging, and optical imaging of intrinsic signal in a mouse model of NF1 to investigate whether cortical development is affected in NF1, possibly causing lifelong consequences that cannot be rescued by reducing inhibition later in life. We find that, in NF1 mice of both sexes, inhibition increases strongly during the development of the visual cortex and remains high. While this increase in cortical inhibition does not affect spontaneous cortical activity patterns during early cortical development, the critical period for ocular dominance plasticity is shortened in NF1 mice due to its early closure but unaltered onset. Notably, after environmental enrichment, differences in inhibitory innervation and ocular dominance plasticity between NF1 mice and WT littermates disappear. These results provide the first evidence for critical period dysregulation in NF1 and suggest that treatments aimed at normalizing levels of inhibition will need to start at early stages of development.SIGNIFICANCE STATEMENT Neurofibromatosis type 1 is associated with cognitive problems for which no treatment is currently available. This study shows that, in a mouse model of neurofibromatosis type 1, cortical inhibition is increased during development and critical period regulation is disturbed. Rearing the mice in an environment that stimulates cognitive function overcomes these deficits. These results uncover critical period dysregulation as a novel mechanism in the pathogenesis of neurofibromatosis type 1. This suggests that targeting the affected signaling pathways in neurofibromatosis type 1 for the treatment of cognitive disabilities may have to start at a much younger age than has so far been tested in clinical trials.