It remains unclear if interplays between sensory experience and alterations to spine density and morphology take place over adolescent brain development in sensory regions in female animals, as they have been shown to in males. A caveat of many of these studies is that they included male animals only. Sensory deprivation experiments demonstrate that sensory cues are required for normal patterning of dendritic spines over neurodevelopment, including reduction in dendritic spine number observed over the adolescent period 27. Long-term potentiation has been shown to precipitate spine head enlargement 28, 29, 30, whereas long-term depression precipitates spine shrinkage 29, 31. Ca 2+ signaling in activated spines leads to activity-dependent actin remodeling and altered spine morphology 27. In vivo calcium imaging experiments reveal that visual and auditory cues evoke Ca 2+ signaling cascades in individual dendritic spines in first-order sensory areas including primary visual and primary auditory cortices 25, 26. Sensory cortex adapts as diverse sensory stimuli shape perception and motor planning 24. Spine formation and morphology are altered as a result of sensory experience. To our knowledge, there is yet no existing published data providing evidence for sex differences in morphology or DSD in mouse auditory and visual sensory regions. DSD was recently reported to be increased on apical dendrites in medial prefrontal cortex in female mice 16. DSD is significantly lower in female rats in two regions of the hypothalamus, the preoptic area and the ventromedial nucleus 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23. DSD is significantly increased in female rats in the posterodorsal medial amygdala, nucleus accumbens, CA1 hippocampus (during proestrus), arcuate nucleus of the hypothalamus and medial prefrontal cortex. Sex differences in DSD in adult animals have so far been reported in subcortical brain regions and medial prefrontal cortex. Sex is an important biological variable that has recently become an important priority in biomedical research 7. Such plasticity and structural remodeling generate substantial diversity in spine number and morphology through a myriad of context- and activity-dependent mediators 3, 4, 5, 6.Ī growing body-of-work has established that dendritic spine density (DSD) significantly differs based on sex. The number of dendritic spines on a neuron and the morphology of single spines are altered via actin remodeling as a consequence of synaptic plasticity and circuit refinement that occur during neurodevelopment or as a result of sensory experience. This spine contacts a single pre-synaptic axon terminal and contains the constitutive molecular machinery, receptors, channels and signaling molecules, required for transmitting incoming glutamatergic signals to the dendritic shaft. The canonical dendritic spine is a mushroom-shaped structure protruding from the shaft of a dendrite, supported by a dynamic actin cytoskeleton, with a narrow neck and large, bulbous head. In the 85 years between Ramón y Cajal’s death and the present day, we have learned a great deal about these micron-sized dendritic protrusions. Neuroscience pioneer Santiago Ramón y Cajal discovered dendritic spines in 1890 1, 2. Together these data support the possibility of developmental sex differences in DSD in visual and auditory regions and provide evidence of layer-specific refinement of DSD over adolescent brain development.ĭendritic spines are the predominant postsynaptic sites of excitatory input onto pyramidal cells in the cerebral cortex. We found striking layer-specific patterns including a significant age by layer interaction and significantly decreased DSD in layer 4 from P28 to P84. We analyzed dendritic spines in 4-week-old (P28) and 12-week-old (P84) male and female mice and found that DSD is lower in female mice due in part to fewer short stubby, long stubby and short mushroom spines. It is largely unknown if sex differences in DSD exist in auditory and visual brain regions and if there are sex-specific changes in DSD in these regions that occur during adolescent development. Dendritic spine density (DSD) is significantly different based on sex in subcortical brain regions associated with the generation of sex-specific behaviors. Dendritic spine number and morphology are altered as a consequence of synaptic plasticity and circuit refinement during adolescence. Dendritic spines are small protrusions on dendrites that endow neurons with the ability to receive and transform synaptic input.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |