Adolescent pruning and stabilization of dendritic spines on cortical layer 5 pyramidal neurons do not depend on gonadal hormones. (April 2018)

• Record Type: Journal Article
• Authors: Boivin, Josiah R.; Piekarski, David J.; Thomas, A. Wren; Wilbrecht, Linda
• Is Part Of: Developmental cognitive neuroscience. Volume 30(2018)
• Page Start: 100
• Page End: 107
• Publication Date: 2018-04
• Subjects: Adolescence -- Puberty -- Gonadal hormones -- Dendritic spines -- Pruning -- Structural plasticity; Cognitive neuroscience -- Periodicals; Developmental neurobiology -- Periodicals; Neuropsychology -- Periodicals; Neuropsychiatry -- Periodicals; 612.8233
• DOI: 10.1016/j.dcn.2018.01.007
• Languages: English
• ISSNs: 1878-9293

Abstract

Highlights: Spines in frontal cortex of female mice are pruned and stabilized during adolescence. Pre-pubertal hormone exposure does not accelerate spine pruning and stabilization. Pre-pubertal gonadectomy does not prevent spine pruning and stabilization. Pre-pubertal hormone exposure and gonadectomy do impact spine morphology. Abstract: Pyramidal neurons in the neocortex receive a majority of their synapses on dendritic spines, whose growth, gain, and loss regulate the strength and identity of neural connections. Juvenile brains typically show higher spine density and turnover compared to adult brains, potentially enabling greater capacity for experience-dependent circuit 'rewiring'. Although spine pruning and stabilization in frontal cortex overlap with pubertal milestones, it is unclear if gonadal hormones drive these processes. To address this question, we used hormone manipulations and in vivo 2-photon microscopy to test for a causal relationship between pubertal hormones and spine pruning and stabilization in layer 5 neurons in the frontal cortex of female mice. We found that spine density, gains, and losses decreased from P27 to P60 and that these measures were not affected by pre-pubertal hormone injections or ovariectomy. Further analyses of spine morphology after manipulation of gonadal hormones suggest that gonadal hormones may play a role in morphological maturation and dynamics. Our data help to segregate hormone-sensitive and hormone-insensitive maturational processes that occur simultaneously in dorsomedial frontal cortex. These data provide more specific insight into adolescent development and may have implications for understanding the neurodevelopmental effects of changes in pubertal timing in humans.