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In the hippocampus, the brain region central to memory, the team focused on a classic pathway that helps store context-rich memories.<\/p>\n
A team led by Dr. Sangkyu Lee at the Institute for Basic Science (IBS<\/a>) built a tag-and-grab system that steered support cells toward chosen nerve fibers.<\/p>\n Three weeks later, excitatory synapses in the targeted zone had dropped by about 27 percent without obvious loss of neurons or nerve fibers.<\/p>\n That narrow change sharpened the paper\u2019s central claim, but it also raised a harder question about what exactly those remaining connections had become.<\/p>\n Controlled trimming in the brain<\/p>\n The new tool, called SynTrogo, lets scientists guide which connections in the brain get trimmed without damaging the rest.<\/p>\n It works by placing a simple \u201ctag\u201d on certain nerve cells<\/a> so nearby helper cells can recognize and attach to them.<\/p>\n When they connect, the helper cells<\/a> gently remove small pieces of those connections rather than tearing anything apart.<\/p>\n Because the system naturally shuts itself off after contact, the changes stay controlled instead of spreading too far.<\/p>\n Surviving links grow stronger<\/p>\n After the trimming, the connections left behind did not stay ordinary, and both sides of each remaining connection grew larger.<\/p>\n The sending side of the connection grew larger and packed in more of the tiny packets that carry signals.<\/p>\n On the receiving side, the contact area also expanded, giving the cell more space to catch and process those signals.<\/p>\n Those paired changes suggest the circuit did not merely endure the loss, but reorganized around the links that remained.<\/p>\n Signals with more punch<\/p>\n Electrical recordings showed fewer small background signals, which matched the lost synapses, but active responses still grew stronger.<\/p>\n That increase came from a larger reserve of chemical messengers at the remaining connections, ready to be released when needed.<\/p>\n Researchers also measured stronger long-term potentiation<\/a>, a lasting rise in synaptic strength after activity, in the edited pathway.<\/p>\n Even so, the change stayed local, because neighboring untargeted fibers did not show the same drop in synapse density.<\/p>\n Targeted remodeling of brain connections<\/p>\n High-resolution images captured astrocytes pressing tightly against nerve fibers, especially around release points where signals normally passed onward.<\/p>\n At those contact sites, membranes thickened and partly wrapped small nerve-fiber regions instead of triggering widespread degeneration.<\/p>\n Some enclosed pockets held signal packets and even mitochondria \u2013 the cell\u2019s energy producers \u2013 which pointed to very local remodeling.<\/p>\n Because the altered shapes stayed attached to parent nerve fibers, the pictures pointed to careful nibbling rather than severed fragments drifting away.<\/p>\n Better memory scores<\/p>\n Mice with edited hippocampal circuits<\/a> froze more during recall tests, a standard memory measure.<\/p>\n With mild training, that advantage appeared two days after learning and remained 23 days later, strengthening both recent and long-term memory.<\/p>\n With more intense training, the treated group held steady while controls faded, so the difference was not just a lucky one-off.<\/p>\n That behavioral edge mattered most because it linked microscopic remodeling to memory that lasted well beyond the training session.<\/p>\n Primed for learning<\/p>\n Before learning began, the edited synapses responded less through glutamate receptors<\/a>, proteins that carry excitatory signals.<\/p>\n After fear conditioning, those fast responses returned to control-like levels, showing that experience could rapidly refill the circuit\u2019s immediate strength.<\/p>\n That pattern fit a primed state, where structure was ready first and full functional power arrived when learning demanded it.<\/p>\n Rather than making memory rigid, the edited mice still learned to let the fear response fade, so stronger recall did not erase flexibility.<\/p>\n Selective loss of weak links<\/p>\n Brains normally remove some synapses over time, and synaptic pruning<\/a> \u2013 the selective loss of weaker links \u2013 helps refine circuits.<\/p>\n Earlier tools could excite or silence neurons, but they mostly worked on existing wiring instead of physically changing it.<\/p>\n \u201cThis is the first demonstration that brain circuits can be directly edited by engineering physical interactions between neurons and astrocytes, independent of neuronal activity,\u201d said Dr. Lee,<\/p>\n That clarity has limits, because the study cannot yet tell how much came from true pruning versus blocked formation of new synapses.<\/p>\n Medical promise and limitations <\/p>\n Abnormal synapse numbers<\/a> have been tied to conditions such as autism, schizophrenia, Alzheimer\u2019s disease, and some forms of brain injury.<\/p>\n SynTrogo could help researchers test whether correcting synapse counts also restores function. Human treatment is still distant, since this work relied on gene delivery in mice and focused on carefully chosen circuits.<\/p>\n For now, the tool looks most useful as an experimental handle on diseases where too many or too few synapses matter.<\/p>\n By letting scientists remove chosen connections and watch survivors adapt, SynTrogo reframes memory as a balance between number and quality.<\/p>\n \u201cIt opens the possibility of \u2018connectome editing\u2019 and provides a new platform for studying and reshaping the physical architecture of neural circuits,\u201d Lee said.<\/p>\n The study is published in the journal Nature Communications<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"New research shows that trimming specific synapses in a mouse brain circuit can strengthen memories and help them…\n","protected":false},"author":2,"featured_media":400235,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[163,85,46],"class_list":{"0":"post-400234","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-health","9":"tag-il","10":"tag-israel"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/400234","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=400234"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/400234\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/400235"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=400234"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=400234"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=400234"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}