Synaptic Pruning: How Your Brain Tidies Up (And How To Keep What Matters)

Today the blog is about something that we have all experienced and even spoken about, but rarely understand and couldn't put a name to - Synaptic pruning.

If you have ever cleared a cupboard before moving house, you will know the odd mix of relief and discomfort that comes with sorting. You keep the mug you use every morning. You finally let go of the cable that once belonged to something important, although you have no idea what it was for. Your brain does its own version of this. It is called synaptic pruning. It sounds technical, yet it quietly shapes how you learn, how you regulate emotions, how you repair in relationships, and how thinking changes with age.

As a clinician, I see pruning as the brain’s housekeeping. A bit like pruning in the garden, it trims what is not earning its keep and nourishes what is regularly used. Pathways you practise become easier to access. Pathways you neglect fade into the background. That is not necessarily failure. It is efficiency. But it can be problematic if too many routes fall out of use, the skills and cognitive power you once relied on can atrophy, and everyday stresses start to feel bigger than they need to.  Left unattended, disuse and dysregulated pruning can thin the very networks that keep thinking sharp, or for you to be able to see the positives in life. A good reason to keep practising what you want your brain to keep.

In childhood and adolescence pruning is particularly busy, but it never fully stops. It continues in adulthood as your roles, routines and priorities change. Ever wondered why you suddenly care a little less as you get older?. New habits lay fresh tracks. Old ones grow over. If you have shifted jobs, become a parent, moved country, entered perimenopause or poured your energy into caring for someone, your brain has been reorganising around that reality. Sometimes that feels like clarity. Sometimes it feels like you have lost a part of yourself.

Pruning is not a fault or failure; it is a feature of brain functioning. So lets walk through what synaptic pruning is, and how to work with it. The invitation is to work with it on purpose. You can teach your brain what to keep by what you repeat, and you can gently let go of what no longer serves you. Small daily choices add up. With a little attention, you can keep the mug that matters and recycle the dusty cables, in your mind as well as your cupboards.

What Synaptic Pruning Actually Is

Neurons chat with one another along tiny pathways and meet at junctions called synapses. These synapses join up areas of our brain for us to learn and perform. In infancy there is a building boom. The brain lays down far more synapses than it will ever need because every sight, sound, cuddle and babble invites new wiring. That overbuild is your early superpower. It gives a baby the flexibility to learn any language, adapt to any set of social rules and make sense of whatever world they land in.

Then the system edits. Synaptic pruning is the tidy-up crew. It trims connections that are weak or rarely used and strengthens the ones that are used and rewarded. Think of it as smart resource management. Energy and materials go to the circuits that help you navigate school, friendships, work, and the habits you practise. Sleep, attention, and repetition quietly vote on what stays.

The result is a brain that becomes sleeker and more efficient. Signals travel with less clutter and less noise, which means quicker decisions and smoother skills. Whilst pruning is efficient, it is also unforgiving. If a child rarely gets chances to use a pathway, the brain quietly reallocates those resources elsewhere. That might be a second language that fades after nursery, musical talent that never quite develops because there was no instrument at home, or social confidence that shrinks when play is limited and adults feel unpredictable. The message is not that a child is broken. It is that the environment did not feed certain circuits often enough for them to become sturdy.  You lose options you never use, and you gain speed and reliability in the ones you do.

Two simple lines capture it. Neurons that fire together wire together. Connections that do not fire get retired. It is not damage, it is maintenance. Less clutter, faster signal, better alignment with the life you actually live.

The Biology Under The Bonnet

Anyone who reads my blogs knows I like to explain what is happening in the brain at a neurochemical / psychological level as I believe understanding the biology helps the process feel real and hopeful.

• Microglia are the brain’s gardeners. They sense which synapses are quiet and tag them for removal.

• The complement system, particularly proteins like C1q and C3, acts like a highlighter on synapses that are not pulling their weight.

• Oligodendrocytes wrap active axons in myelin, which speeds the signals you use most. Pruning and myelination often travel together.

• Excitation and inhibition need balance. The brain trims to keep networks stable. Too many weak connections can create noisy circuits that feel like scatter and overwhelm.

• Sleep is a nightly clean-up shift. Deep sleep helps consolidate memories and trim noise, which is why sleep is so important. Poor sleep blunts this housekeeping, which is one reason everything feels harder after a run of late nights.

• Reward chemistry matters. Dopamine flags what was valuable and likely to be valuable again. That tag encourages the brain to keep the relevant route.

• Inflammation changes pruning. Long stress, illness, or chronic inflammation can push the system to trim in unhelpful ways. This is one reason that sustained stress can alter attention, mood, and patience.

You do not need to memorise any of this. The take-home is simple. The brain saves what you activate and reward, especially when you sleep and recover well.

A Tour of Pruning Across the Lifespan

Pruning shifts as our needs change. In one season the brain trims for play and language, in another for judgement and close relationships, and later for the habits and values we live by, keeping what helps and letting the rest fade.  Let’s take a quick look.

Infancy and childhood

The brain builds an exuberant tangle of connections. Experience sculpts this into efficient maps. Speak two languages to a toddler and both sound maps stay alive. If one language is not used, the unused map can thin. The system is not cruel. It is thrifty.

The middle childhood years

School-age brains become more efficient at the skills that get repeated and praised. Reading, number sense, motor skills, and the social rules of the playground all become faster. Children who practise naming feelings, negotiating turn-taking, and repairing after bumps develop those routes early. The tone of the home and classroom matters because repetition writes code.

Adolescence

Teenagers are not broken. They are under renovation. There is a second wave of pruning, especially in the prefrontal cortex that supports planning, inhibition, and perspective taking. Networks for motivation and reward are highly sensitive. This is a powerful window for habit formation and identity experiments. It can be baffling too. On Monday your teenager is a philosopher. On Tuesday they cannot find their shoes. Both are normal for a brain mid-upgrade.

Early adulthood through midlife

Pruning continues. It becomes more targeted. By your mid-20s the prefrontal systems that handle planning, values, and long-term goals are coming online with more efficiency. Pruning trims weaker connections and strengthens the ones you use often. Socially, that looks like clearer preferences, less patience for relationships that drain you, and a stronger pull toward people and environments that fit who you are becoming rather than who you were.  Your job, your friendships, your stress patterns, and your hobbies all feed the algorithm. If you problem-solve every day under time pressure, those rapid triage circuits get strong. If you switch careers, the brain will quietly let go of tools you no longer use and build new ones. What looks like personality is often a history of practice, reward, and context.

Midlife and ageing

Efficiency becomes the theme. Many people report that they care less about impressing the wrong crowd and more about a small set of values. Part of that is perspective. Part of it is pruning. Networks that are not rewarded reduce their claim on energy. This can feel like clarity. It can also trigger grief if you have relied on old ways of being. The encouraging news is that plasticity persists. Brains can learn at any age with repetition, sleep, and meaningful reward.

Pruning is Experience Dependent.

So, what determines pruning – there are three ingredients that are a reliable indicator.

1. Use keeps. Repetition strengthens and stabilises synapses.

2. Reward seals the deal. When an action leads to something that feels useful or safe, the brain marks that circuit as valuable.

3. Context writes the story. High threat environments push the brain to keep scanning routes. Safe, warm environments give approach and play networks a chance to grow.

This is why early caregiving has such a long echo. Consistent care lays down maps for trust and co-regulation. Unreliable care teaches different maps. Neither story is fate. The brain remains adjustable. It is simply that an early path gets a head start.

The Pruning Behind Habits, Mental Health, Emotions, Attention, and Identity

Imagine a field. Every route you walk turns into a path. After a while you forget you are choosing it at all you just go that way. That is how habits feel in the brain. Pruning touches mental health because it keeps what is rehearsed. Anxiety circuits become efficient if life often cues threat and there is little chance to settle. If your nervous system often surges into high alert, the alarm routes stay clear and quick to access. Rumination becomes swift if you practise looping on problems without resolution.

The opposite is also true. If you repeatedly practise grounding, naming feelings, and taking perspective, those stabilising routes become the easier walk. Small daily repetitions of soothing skills, healthy connection, and problem solving teach the brain to keep calm, flexible pathways. It is not willpower alone. It is training.  Over time this feels like personality. Underneath, it is learned patterning shaped by pruning.

Memory also depends on this housekeeping. When you revisit useful information, the links between related ideas are strengthened and distracting links are trimmed. That is why spaced practice, sleep, and retrieval make learning stick. Chronic stress can interfere with this process. High stress narrows attention to what feels risky and can disrupt the consolidation that happens during deep sleep. If most evenings end with overstimulating screens, your brain keeps the fast-skim pathways and sheds some of the slower ones that support deep recall.

Attention is also sculpted by what you reward. If your day constantly pulls you into alerts, quick replies, and multitasking, your attention stays jumpy and shallow. If you protect blocks of single-task focus, pause before reacting, and close tasks properly, your brain keeps the networks for steadier concentration. Boundaries are not only about time. They are a way of telling your brain which paths to maintain.

The practical takeaway here is kind and simple. What you repeat, you keep. If you want less reactivity, rehearse small acts of settling several times a day. It is why in therapy, your therapist might encourage daily practice of being calm and soothing or being mindful. If you want better memory, sleep on it, return to it, and recall it out loud. If you want stronger attention, design one part of each day for undivided focus and treat that time as non-negotiable. The brain listens to what you do most, then prunes the rest.

Hormones, Stress, and Health

Hormones help decide what the brain keeps. Oestrogen, progesterone, testosterone, thyroid hormones and cortisol change how sensitive synapses are to experience, so pruning adjusts with your hormonal state and time of life. During puberty, pregnancy, the weeks after birth, and perimenopause, the brain reshapes.  We even talk about baby brain or brain fog to note the changes we notice during these times without understanding what is happening.  It is common to notice shifts in memory, social drive, sexual desire, sleep and mood. Some of this comes from the hormones themselves. Some comes from pruning updating the wiring to fit your changing body and life.

Stress also steers the system. When pressure stays high, your attention and memory lock onto what feels urgent. The brain becomes very good at scanning for risk and less practised at curiosity and reflection. As safety returns, and routines become steadier, pruning starts to favour learning, play and connection again.

Sleep is non-negotiable. So is nutrition that keeps blood sugar stable and inflammation low. Good sleep helps the brain store what matters and clear what does not. Regular meals that keep blood sugar steady and reduce inflammation support clear thinking. Movement raises brain-derived neurotrophic factor, which makes it easier to learn and keep new skills. These are not empty lifestyle tips. They are practical ways to influence what is trimmed and what is strengthened, so your brain stays aligned with the life you want.

How Pruning Shapes Relationships

Here the theory becomes very practical. Pruning keeps the shortcuts you and your partner, child, friend, or colleague use most. That includes how you greet each other, how you raise concerns, and how you repair after a wobble.

If closeness has usually been safe, the brain keeps approach, curiosity, and soothing routes. If closeness has been unpredictable or costly, it may favour scanning, controlling, or withdrawing. Day to day this shows up as how quickly you assume good intent, how you ask for reassurance, or how easily you shut down. These are trained networks. They can be updated.

Many couples fall into a pursue–withdraw loop. One raises the issue. The other feels flooded and takes space. The more the loop runs, the slicker it gets. Pruning does not judge. It simply optimises. The task of change is to rehearse a different loop long enough for it to become the easier route. For example, agree one signal for a short pause, return within twenty minutes, and start again with a validation before problem solving. Repeat this enough and the brain keeps it.

Some people instinctively reach out after conflict. Others go quiet to lower arousal. Both were useful once. If you practise small, timely repairs and reward them with warmth, those reconnection circuits stay vivid. If conflict usually ends in silence or scorekeeping, avoidance becomes the default.

Shared rituals keep shared maps alive. Without them, the brain quietly trims the sense of us. People wake up and feel like strangers not because anything dramatic happened, but because the old rituals lapsed and the synapses for micro-connection were not being used. The antidote is not a grand gesture once a year. It is frequent, tiny points of contact that are easy to repeat.

Parenting and friendship

Children borrow our nervous systems. If we model naming feelings, tolerating pauses, and repairing after sharp moments, they learn those routes. In friendship, consistency beats intensity. A brief monthly call maintains more neural warmth than a long message once a year followed by silence.

Teams prune too. If criticism is the only reliable feedback at work, brains keep defensive routes. If small wins are noticed and safety to ask for help is normalised, learning routes stay open. The meetings you repeat will decide whether your team keeps problem solving or theatre.

Neurodiversity and Pruning

ADHD, autism, dyspraxia, dyslexia, and related profiles come with different rhythms of attention, reward, and sensory processing. In ADHD, novelty and immediacy often drive dopamine more than distant goals. That changes which synapses are maintained. In autism, perceptual weighting can prioritise detail and predictability, which can make social uncertainty costly. None of this is a flaw. It is a different set of defaults. The same principles apply. Design the environment so the right repetitions are possible, valued, and rewarded. Reduce unnecessary sensory load. Break tasks into visible steps. Celebrate consistency. The brain will keep what is reinforced.

Trauma and Pruning

Trauma teaches the brain to survive. It keeps hypervigilance, avoidance, and shutdown because those routes worked. The brain is doing its best accounting with the information it has. Therapy provides new data. Safety, gentle exposure, and experiences of mastery allow the system to keep connection and curiosity again. There is nothing weak about needing help to do this. Pruning needs the right conditions to feel safe enough to change its priorities.

Many adults learned strategies like people-pleasing, perfectionism, or making themselves small. These were clever solutions in context. You can thank those circuits for their service and begin to practise alternatives. Boundaries, honest requests, and self-compassion will feel strange at first. That is not a sign you are doing it wrong. It is unfamiliar wiring. Repetition and safe relationships will make it feel possible, then natural.

Pruning and Online Activities

Here is the simple truth about heavy internet use and doom scrolling: it trains the brain to prefer short, fast, emotionally loaded snippets. Pruning keeps what you repeat, so if most of your attention goes to rapid swipes, hot takes and constant alerts, the brain keeps the quick-switch pathways and lets some of the slower, reflective ones fade. Over time this makes deep thinking feel harder to start and easier to abandon.  I had noticed this myself recently so have significantly reduced my online use.

Memory takes a hit for similar reasons. When you skim, you rarely encode information deeply enough for it to stick. Frequent task-switching also overloads working memory, so less makes it into long-term storage. Add late-night scrolling and you disrupt the sleep cycles that consolidate learning. The result is a sense of knowing a little about a lot, while struggling to recall anything with detail when you need it.

Doom scrolling also amplifies stress. The variable rewards of feeds and the steady stream of threat-coloured headlines keep your nervous system in a low hum of vigilance. Under sustained stress, pruning favours scanning and drops curiosity. That is why you can feel wired and flat at the same time.

Two quick signals that the cost is showing up:

• Reading long articles or books feels unusually effortful, and you catch yourself checking your phone mid-paragraph.

• You recognise headlines but cannot explain the idea without looking it up.

None of this means you must quit the internet. It means using it on purpose. If you want to protect thinking, memory and steady attention, give your brain daily practice in the slower routes, and keep the high-stimulus feeds in defined, short windows rather than as the background to your whole day.

Pruning in Older Age and Cognitive Decline

Pruning does not stop; it changes pace and purpose. In later life the brain still trims and tidies, but there’s less new growth to balance the cuts, so what you use and revisit matters more than ever. When days become more repetitive, senses are under-stimulated (for example, from untreated hearing or vision loss), or stress and poor sleep linger, the system quietly lets rarely used routes fade. That can look like slower word-finding, reduced mental flexibility, and a smaller “attentional spotlight.”

This is normal ageing, not automatically disease. In Alzheimer’s and other dementias there is extra, pathological loss, protein build-up, inflammation, vascular changes, which accelerates synapse failure and neuron death. But even then, the principle holds: brains keep what they can still practise. That is why “cognitive reserve” helps. Years of varied learning, rich social contact, and movement create more alternative routes, so the same biological damage causes fewer day-to-day problems, for longer.

The practical message is hopeful: you can still bias pruning. Give your brain reasons to keep the circuits you care about with novel, meaningful, repeated reasons. Learn new skills that stretch you (an instrument, a language, dancing, complex crafts). Read long pieces, recall them out loud, and teach someone else. Protect sleep so consolidation can do its job.

Move most days, aerobic activity and some strength work support blood flow, growth factors and plasticity. Mind your “inputs”: treat hearing and vision problems, manage cardiovascular risks with your GP, and keep inflammation down with decent diet and daylight. Stay socially engaged; conversation demands memory, attention, word retrieval and empathy all at once.

Ageing prunes. Your routines decide where the shears land.

Over-pruning Versus Under-stimulation

Pruning is meant to be a tidy editor, but it can be pushed in unhelpful directions when the brain is starved of good input or overwhelmed by the wrong kind. Emotional deprivation, chronic inflammation, untreated hearing or vision loss, and long-term stress all nudge the system to keep scanning and survival routes while letting curiosity, memory, and social ease thin from lack of practice.

A quiet house with little conversation, months of poor sleep, or straining to hear every sentence each day can look to the brain like, “This pathway is not needed.” The hopeful part is that causes can be treated. Restoring sensory input with hearing aids or proper glasses, treating inflammation with medical care and lifestyle changes, and reintroducing warm, predictable contact give the nervous system richer signals. With better input and repeated use, those pruned networks can stabilise again.

Repair and Relearning (a concrete example)

A few years after stopping Spanish lessons, you realise your confidence has faded. Rather than waiting for motivation to strike, you set up a tiny, repeatable routine that teaches your brain, “Keep this.” On Mondays, Wednesdays and Fridays you read one short news paragraph aloud, close the page, and say out loud what it was about in your own words. The next session you start by recalling yesterday’s key sentence before reading anything new. At the end of the week, you message a friend two lines in Spanish about your day. The sessions are brief, slightly effortful, and spaced out, so they strengthen retrieval rather than just recognition. Sleep does some quiet consolidation. After four weeks you can explain a short article without peeking, which feels like identity returning.

The same approach works for music: choose one piece, play it slowly most days for five minutes, stop while it is going well, and every third session begin from memory before touching the score. The mix of spacing, retrieval, and small wins tells the editor to keep the pathway, so the skill stops feeling fragile and starts feeling like home again.

• So, is pruning good or bad.

• It is both and neither. Pruning is a mechanism. It keeps what you use and trims what you do not. If you choose repetitions that fit your values, pruning will feel like clarity.

• Can I rebuild something I let slide?

• Yes. With repetition, rest, and meaningful reward you can revive pathways. It may be slower than you hope and faster than you fear.

• How long does change take?

• There is no magic number. Daily practice for a month is a good start. Many social changes need many dozens of reps in varied contexts. Keep the steps tiny.

Closing Thought

Synaptic pruning is your brain’s way of honouring what you actually do, not what you hope you might do one day. It is steady, efficient and, at times, a little ruthless. That can feel confronting when you notice a skill has faded or an old coping style is still running the show. It is also hopeful, because pruning listens. It updates itself in response to repetition, reward and context.

You can talk to it through your choices.

Psychology helps by turning this from a vague idea into a plan you can live. A therapist is essentially a coach for your neural editor. We help you choose which pages to keep, which ones to recycle, and how to create the conditions for the “keepers” to win.

Ask yourself two questions: what do I want my brain to keep, and what tiny behaviour proves it today. Vague wishes rarely survive competing demands. Clear behaviours do. If you want steadier attention, your proof might be eight minutes of single-task work with your phone in another room. If you want kinder self-talk, it might be one written sentence that reframes a harsh thought. If you want stronger relationships, it might be a two-minute repair text after a wobble. Small acts send strong signals when they are repeated.

Expect lapses and plan for them. Pruning honours frequency, not heroics. If you miss a day, shrink the target and show up. One sentence, one scale, one message. This maintains identity: “I am the sort of person who returns.” When motivation dips, review your cues and make the first step easier to start. If a skill keeps sliding, look for friction points: too late in the day, too hard, too lonely, too dull. Adjust one variable at a time.

Remember the old adage – what you don’t use, you lose.  It has basis in reality.  So, if you want to keep that brain function, if you want to think positively not negatively, prune what doesn’t work for you and expand on what does,

As always until next time

Carla