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Title: Multiple Postsynaptic Protein Levels in Adult Superior Colliculus Are Unaffected by Dark Rearing from Birth
Visual deprivation by dark rearing in kittens and monkeys delays visual pathway development and prolongs the critical period. In contrast, receptive fields (RFs) in superior colliculus (SC) of Syrian hamsters (Mesocricetus auratus) refine normally with spontaneous activity alone, requiring only brief juvenile visual experience to maintain refined RFs in adulthood (Carrasco et al., 2005). Extending dark rearing past puberty leads to lower GAD and GABA levels due to reduced BDNF-TrkB signaling, resulting in RF re-enlargement (Carrasco et al., 2011; Mudd et al., 2019). Previous studies in kittens and monkeys have reported that dark rearing is associated with changes in both GABA ligand and GABA-Areceptor levels. Given the reduced GABA levels in SC of dark reared adult hamsters, we asked if dark rearing also causes changes in GABAAreceptor levels. We examined expression of GABAAreceptor subunits, their anchoring protein gephyrin, and the cation-chloride co-transporters KCC2 and NKCC1 in dark reared hamsters. Surprisingly, we found that dark rearing from birth until puberty had no effect on the levels of any of these postsynaptic elements, revealing a new form of maladaptive, presynaptic only inhibitory plasticity in which, rather than extending the critical period as seen in kittens and monkeys, hamster receptive fields refine normally and then lose refinement in adulthood. These results suggest that attempts to increase plasticity in adulthood for rehabilitation or recovery from injury should consider the possibility of unintended negative consequences. In addition, our results demonstrate the interesting finding that changes in neurotransmitter levels are not necessarily coordinated with changes in postsynaptic components.  more » « less
Award ID(s):
2029980 1656838
PAR ID:
10656164
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
bioRxiv
Date Published:
Edition / Version:
3
Subject(s) / Keyword(s):
Keywords: rodent visual deprivation superior colliculus GABA adult plasticity visual refinement GABA-A receptor gephyrin chloride co-transporter
Format(s):
Medium: X Size: 1MB Other: .pdf
Size(s):
1MB
Institution:
Georgia State University, University of Massachusetts-Amherst
Sponsoring Org:
National Science Foundation
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