The Latest: The most detailed synaptic map record - the change of synapse from birth to aging.

Learn about the latest advances in neuroscience ● click on the blue word to focus on us ● synapses connect neurons together to form a neural loop, which is also a key part of transmitting information.proteomic studies show that the molecular composition of synapses is highly complex, and the terminal structures of presynaptic and postsynaptic terminals have highly organized molecular systems of protein networks.how complex are synapses? There are more than 1000 proteins in excitatory postsynaptic structure, which can cause more than 130 kinds of brain diseases (1,2).Second, there are 29800 synapses per neuron in the cerebral cortex, so there are 36 trillion synapses in the cortex alone (3).just ask if it is complicated.the third picture is quoted from: scientists never stop their pace of exploring synaptic mysteries. On June 13, 2020, Seth G.N. grant team from the clinical brain science center of University of Edinburgh revealed the morphological structure and molecular changes of synapses in the brain from the time dimension (4).the researchers used transgenic mice labeled synapses to map the molecular and spatial maps of excitatory synapses in the brain of mice from birth to old age at a single synaptic level, which is called the life span synaptome Architecture (LSA), and what's more touching is that they open up all the data and analysis tools available in theGet.cited in refs. 4. The synaptic density of the large brain was analyzed at 1 day after birth, 1 week after birth, 2 weeks after birth, 3 weeks after birth, 3 weeks after birth, 3 months after birth, 6 months after birth, 12 months after birth and 18 months after birth (covering the whole life cycle), the results showed that the changes of synaptic density in different brain regions were different Density peaked before the brain reached its peak, which may reflect the need for brain stem function in the early postnatal period.although the structure of synapses changes in all ages, the development of synapses can be divided into three stages according to the distribution of synaptic trajectories: lsa-i, when it is found that the density of synapses increases rapidly in the first month; the density of lsa-ii maintains a steady state in adulthood (from one month to six months); and at lsa-iii, the density decreases gradually in old age.according to the molecular and morphological characteristics of synapses, the researchers further divided them into 37 subtypes, and found several characteristics: first, the molecular composition of synapses is changing throughout the life cycle, not limited to lsa-i stage; second, all brain area synaptic subtypes show rapid initial growth to peak in the first three weeks after birth, and then the diversity of synapses has always been It declined until 3 months old, and then kept dynamic balance.the cortex, hippocampus and striatum, which are responsible for higher cognitive function, continue to increase after birth. The diversity of synaptic subtypes reaches its peak at 2 months old, while the midbrain, medulla oblongata and other brain regions with basic neurophysiological functions reach the peak at 3 weeks.these results strongly confirm that subtypes of excitatory synapses are selectively acquired or lost with age, and reveal how brain regions age in different ways.interestingly, the synaptic structure of the aged mice brain is similar to that of adolescent mice, which can explain the "old children"? In general, LSA reveals the way in which synaptic diversity is produced and the differences in brain regions are more conducive to understanding the pathogenesis of brain diseases.for example, changes in the composition of synapses may reveal the cause of susceptibility to genetic diseases at different ages - changing gene expression will change the distribution of synaptic types in specific neural circuits, resulting in behavioral phenotypes.References: 1. Emes R D, grant s g n. evolution of synapse complexity and diversity [J]. Annual review of neuroscience, 2012, 35 (1): 111-131.2. Bay é s, lex, van, et al. Characterization of the protein, diseases and evolution of the human postsynaptic density. [J]. Nature Neuroscience, 2011.3. Rockland, K.S. (2002) Non-uniformity of extrinsic connections and columnar organization. J. Neurocytol. 31, 247–2534. A brain-wide atlas of synapses across the mouse lifespan，Cizeron et al., Science 10.1126/ science.aba3163(2020).