The Nervous System

The Nervous System & Neurodivergence
🧠 THE NERVOUS SYSTEM
Your brain’s electrical wiring, emergency department & slightly overenthusiastic security system
Your nervous system is one enormous communication network connecting your brain to pretty much everything else.
It helps you:
move
think
feel
process sensory information
regulate temperature
digest food
sleep
respond to danger
concentrate
remember things
control automatic body functions
interact with the world around you
And it does most of this without asking you first.
Which is probably just as well.
Imagine having to manually remember to keep your heart beating.
⚡ THE BASIC SETUP
Your nervous system can broadly be divided into two major parts:
🧠 Central Nervous System — CNS
This is your:
brain + spinal cord
Think of it as the main processing and command centre.
The brain processes information, makes decisions, stores memories and coordinates responses.
The spinal cord acts as a major communication pathway between the brain and the rest of the body.
🕸️ Peripheral Nervous System — PNS
This includes nerves outside the brain and spinal cord.
It carries information to and from the central nervous system.
Your skin gets touched?
Information travels inward.
You decide to move your hand?
Instructions travel outward.
Basically:
BODY → BRAIN → DECISION → BODY
All day.
Every day.
Without a courier service.
🚦 THE AUTONOMIC NERVOUS SYSTEM
Part of the peripheral nervous system controls many automatic functions.
This is the autonomic nervous system (ANS).
It helps regulate things such as:
❤️ heart rate
🫁 breathing patterns
🍽️ digestion
🌡️ temperature regulation
💧 sweating
👁️ pupil size
⚡ stress responses
Two major branches are:
⚡ Sympathetic nervous system
Generally increases physiological arousal and prepares the body for action.
Fight, flight and getting-ready-to-do-something mode.
Heart rate can increase.
Breathing changes.
Muscles become more prepared.
Attention becomes focused on what might require action.
Useful when you’re escaping an actual threat.
Less useful when your brain decides that someone saying “Can we talk?” means your life is about to end.
🌿 Parasympathetic nervous system
Supports rest, digestion and recovery.
It’s involved in helping the body return toward a calmer physiological state.
Basically:
“The emergency is over. Please stop behaving like we’re being chased by a tiger.”
🧠 THE BRAIN DOESN’T JUST REACT — IT PREDICTS
One of the really interesting things about the nervous system is that the brain doesn’t simply wait for information and then react.
It is constantly making predictions about what is happening.
It uses previous experiences, sensory information and internal body signals to help determine:
What’s happening?
Is it safe?
What happens next?
What should I do?
This predictive system is incredibly useful.
It also explains why two people can experience exactly the same situation and have completely different nervous-system responses.
One person:
“Cool. A surprise party.”
Another:
“WHY ARE THERE TWENTY PEOPLE IN MY HOUSE?”
👂 SENSORY PROCESSING
Before the brain can respond appropriately, it has to process information coming from the environment and the body.
This includes:
👁️ vision
👂 hearing
👃 smell
👅 taste
✋ touch
⚖️ balance and movement
🧍 body position
🫀 internal body sensations
That last category is called interoception — the ability to sense internal physiological signals such as hunger, thirst, heartbeat, temperature and the need to use the bathroom.
And yes…
Sometimes the brain can apparently receive:
“URGENTLY NEED THE TOILET.”
and respond:
“Interesting. We’ll process that information in approximately 47 minutes.”
🧩 NEURODIVERGENCE & THE NERVOUS SYSTEM
Neurodivergence isn’t one single nervous-system condition.
ADHD, autism, dyslexia, Tourette syndrome and other forms of neurodivergence involve different neurological profiles.
But differences in sensory processing, attention, arousal, executive functioning and regulation can be particularly important.
For some neurodivergent people, ordinary environments can require considerably more neurological processing.
A busy shopping centre isn’t simply:
people + lights + music.
It can be:
people
voices
background conversations
music
fluorescent lighting
movement
smells
temperature changes
touch
visual clutter
decisions
social expectations
navigation
working memory
and approximately 900 things nobody else appears to notice.
Your nervous system:
“WE HAVE RECEIVED THE ENTIRE INTERNET.”
🎚️ AROUSAL: TOO LITTLE, TOO MUCH OR JUST RIGHT
The brain generally functions best within an individual’s workable range of arousal.
Too little stimulation can produce:
😴 boredom
😑 under-engagement
🧠 mind wandering
restlessness
difficulty initiating tasks
Too much stimulation can produce:
😵 overwhelm
irritability
anxiety
shutdown
meltdown
difficulty thinking
difficulty communicating
And somewhere between the two is the magical zone where the brain says:
“Okay. Now we’re cooking.”
This is one reason some neurodivergent people actively seek stimulation.
Music.
Movement.
Fidgeting.
Chewing.
Tapping.
Rocking.
Spinning.
Deep pressure.
Background noise.
Certain textures.
Repetitive activities.
These behaviours aren’t necessarily meaningless.
They can sometimes help regulate arousal and sensory input.
🔁 STIMMING
Stimming — short for self-stimulatory behaviour — refers to repetitive movements, sounds or sensory behaviours.
Examples include:
rocking
hand movements
tapping
pacing
humming
repeating sounds
hair twirling
touching textures
bouncing a leg
repeating phrases
spinning objects
Stimming can serve different purposes.
It may provide sensory input.
Help maintain attention.
Reduce boredom.
Express excitement.
Provide predictability.
Or help regulate overwhelming emotions.
So the next time somebody says:
“Stop doing that.”
the nervous system might reasonably respond:
“Counterproposal: absolutely not.”
Of course, context matters. Some stims can cause injury or interfere with daily functioning, and those may need safer alternatives.
🚨 TRAUMA CHANGES THE PICTURE
Neurodivergence and trauma are not the same thing.
But they can interact.
A neurodivergent child who repeatedly experiences bullying, sensory overwhelm, punishment for behaviours they cannot easily control, social rejection, chronic misunderstanding or an unpredictable environment may experience significant stress.
Trauma can also independently affect the nervous system.
Repeated or overwhelming stress can influence:
threat detection
emotional regulation
attention
memory
sleep
autonomic arousal
sensory sensitivity
pain processing
behaviour
This creates an important distinction:
Neurodevelopmental difference ≠ trauma.
But:
Neurodevelopmental difference + chronic stress/trauma can create a complicated nervous-system cocktail.
And nobody ordered the cocktail.
🧠 HYPERVIGILANCE
Trauma can make the nervous system highly alert to possible danger.
The brain starts monitoring:
facial expressions
tone of voice
body language
silence
footsteps
changes in behaviour
environmental cues
This is called hypervigilance.
In some circumstances, increased threat detection can be adaptive.
But when the danger has passed and the system remains permanently switched to:
🔴 MAXIMUM SECURITY
life becomes exhausting.
You’re not relaxing.
You’re analysing.
You’re not hearing someone sigh.
You’re calculating the probability that the sigh means something.
Your nervous system:
“I have reviewed the sigh. Something is definitely happening.”
🧊 FIGHT, FLIGHT, FREEZE & OTHER RESPONSES
When the nervous system detects threat, people can respond in different ways.
Fight
Confront the threat.
Flight
Escape or avoid it.
Freeze
Become unable to act or respond normally.
Fawn
A term commonly used to describe attempts to maintain safety through appeasing or accommodating others.
People can also experience dissociation, emotional numbing or other protective responses.
These aren’t personality defects.
They’re ways the nervous system can respond to overwhelming situations.
And humans are wonderfully complicated creatures, so one person may respond differently depending on the situation.
🔋 EXECUTIVE FUNCTIONING & NERVOUS-SYSTEM LOAD
Executive functioning includes abilities such as:
working memory
planning
inhibition
task switching
organisation
prioritising
initiating tasks
These abilities require significant brain resources.
When someone is overloaded, sleep-deprived, chronically stressed or emotionally overwhelmed, executive functioning can become more difficult.
This is especially relevant when trying to understand neurodivergent experiences.
Someone can genuinely know exactly what they need to do…
…and still be unable to initiate it.
That’s not necessarily laziness.
Sometimes the instruction has arrived.
The brain has simply put it in the queue behind:
“Stare at the wall for 17 minutes.”
🧠 CAN THE NERVOUS SYSTEM HEAL?
The nervous system is adaptable.
The brain changes in response to experience, learning and environmental demands.
This capacity is called neuroplasticity.
That doesn’t mean:
“Just think positive and rewire your brain.”
If only neuroscience were that easy.
Recovery from trauma generally involves reducing ongoing threat and helping the brain and body develop more effective ways of responding to stress.
Depending on the person, useful strategies can include:
🌱 Predictability
Routines and clear expectations can reduce unnecessary cognitive load.
😴 Sleep
Sleep supports memory, emotional regulation and physiological recovery.
🚶 Movement
Physical activity can support overall brain and nervous-system health.
🎧 Sensory regulation
Reducing overwhelming sensory input — or deliberately adding useful sensory input — can help some people regulate.
🧑‍🤝‍🧑 Safe relationships
Supportive relationships can provide social safety and reduce isolation.
🧠 Trauma-focused therapy
Evidence-based psychological treatments can help people process trauma and develop healthier responses to triggers.
🧘 Regulation skills
Breathing, grounding, mindfulness and other techniques can help some people manage physiological arousal.
The trick is discovering what actually works for your nervous system.
Because unfortunately…
there is no universal USB cable for humans.
🌱 THE IMPORTANT BIT
Your nervous system is not broken simply because it works differently.
Neurodivergence isn’t a synonym for damaged.
A nervous system can be:
different without being defective.
And a nervous system affected by trauma isn’t necessarily permanently damaged either.
Brains change.
Bodies adapt.
Patterns can change.
Responses can change.
People can learn new ways of regulating themselves.
Sometimes professional support is needed.
Sometimes environmental changes make a massive difference.
Sometimes the first step is simply understanding what’s happening.
🧠 KNOWING YOUR NERVOUS SYSTEM
Start noticing the patterns.
What overwhelms you?
What calms you?
What makes you restless?
What helps you concentrate?
What sensory input do you seek?
What sensory input do you avoid?
What happens when you’re tired?
What happens when you’re stressed?
What happens when you feel safe?
Your nervous system is constantly giving you information.
You just have to learn its language.
Because your brain isn’t trying to make your life difficult.
It’s trying to keep you alive.
Sometimes it just has a rather questionable definition of what constitutes an emergency.
Welcome to being human. 🧠🖤