how our memory functions

This is one of the most fascinating questions in neuroscience because we still don't fully know the complete answer.

The older idea: "Memory is stored in neurons"

Scientists once imagined that each memory was stored in specific brain cells, almost like files in a cabinet. Reality appears to be much more complex.

The current understanding

When you experience something, groups of neurons fire together. This activity changes the strength of connections between neurons, called synapses.

A common principle is:

"Neurons that fire together, wire together."

Repeated experiences strengthen certain neural pathways, making them easier to activate later.

Memory is a pattern, not a single thing

Imagine a friend's face.

That memory is not stored in one neuron or one location. Different aspects are distributed across the brain:

• Visual appearance
• Voice
• Name
• Emotions associated with the person
• Memories of events involving them

These pieces are stored in interconnected networks.

How retrieval works

Suppose you hear your friend's name.

The sound activates one part of the network, which then activates related parts. Soon the whole pattern "lights up," and you remember the person.

It is somewhat like a few notes of a song reminding you of the entire melody.

The role of the hippocampus

A brain structure called the Hippocampus is crucial for forming new memories.

It acts somewhat like an indexer or coordinator:

• It helps bind together the various pieces of an experience.
• Over time, memories become more distributed across the brain.

Damage to the hippocampus can leave old memories intact while making it difficult to form new ones.

What physically changes?

Scientists have observed several changes:

• Synapses can strengthen or weaken.
• New synaptic connections can form.
• Existing connections can disappear.
• Gene expression inside neurons can change.
• In some brain regions, new neurons can even be created.

So memory is not stored as a tiny picture or recording. It is stored as a physical pattern of altered connectivity and responsiveness in neural networks.

An analogy

Think of a city.

A memory is not a particular building. It is more like the entire road network connecting many places.

Retrieving a memory is like starting traffic at one location and watching it spread through the routes until the whole destination network becomes active.

The mystery that remains

Scientists can describe many mechanisms of memory formation and retrieval, but they still do not know exactly how:

• A physical network of neurons produces the subjective experience of remembering.
• The feeling of "I remember my childhood" arises from neural activity.
• Conscious recollection emerges from electrical and chemical processes.

So we understand a great deal about the machinery of memory, but the bridge between neural activity and conscious experience remains one of the deepest unsolved questions in science.

inferior version of reality

Many animals possess sensory abilities that humans either completely lack or possess only weakly. To them, the world can be richer, stranger, and more information-filled than ours.

Here are some remarkable examples:

Magnetic Sense (Magnetoreception)

Some birds, turtles, salmon, and insects can sense Earth’s magnetic field and use it like a natural GPS for navigation during migration.

Echolocation

Bats and dolphins emit sound waves and interpret returning echoes to “see” their surroundings acoustically, even in darkness or murky water.

Infrared Detection

Some snakes, like pit vipers, can detect infrared radiation (heat), allowing them to sense warm prey even in complete darkness.

Electric Field Detection

Sharks and some fish can sense weak electrical fields produced by muscles and nerves of nearby animals.

Ultraviolet Vision

Bees, birds, and many insects see ultraviolet light invisible to humans. Flowers often contain UV patterns that guide pollinators.

Polarized Light Detection

Some insects and marine animals can detect polarization patterns in light, helping with navigation and orientation.

Extreme Chemical Sensing

Dogs can detect smells at concentrations humans would never notice. Their smell world is extraordinarily detailed.

Vibration Detection

Spiders can sense tiny vibrations through webs. Elephants detect ground vibrations through their feet.

These examples suggest something profound:

Every species experiences a different “version” of reality based on its sensory equipment.

Humans often assume their perception is reality itself, but biologically we are only tuned to a very narrow window of what exists.

We may not be sensing the whole thing

Traditionally, humans are said to have five senses:

1. Sight (vision)
2. Hearing (audition)
3. Smell (olfaction)
4. Taste (gustation)
5. Touch (somatosensation)

But modern neuroscience says humans actually have many more sensory systems.

Some important additional senses include:

• Balance (equilibrioception) — sensed by the inner ear; helps you stay upright.
• Body position (proprioception) — lets you know where your arms and legs are even with eyes closed.
• Temperature (thermoception) — sensing hot and cold.
• Pain (nociception) — detecting injury or danger.
• Internal body state (interoception) — hunger, thirst, heartbeat, breathing, fullness, etc.
• Acceleration and movement — detecting motion and orientation.

For example, if you close your eyes and touch your nose accurately, that’s proprioception at work.

Some scientists debate the exact count, but depending on how finely you classify them, humans may have 10–20 or more distinct senses.

And even then, humans perceive only a tiny fraction of reality compared with what might physically exist:

• limited light frequencies,
• limited sound frequencies,
• limited chemical detection,
• no natural magnetic sensing like some animals.

So our experience of the world is not reality in totality — it is reality filtered through human biology.

humans can't see it all

Different species can perceive the same object in completely different ways because their eyes and brains detect different ranges of light.

For example:

• Humans normally have 3 kinds of cone cells (trichromatic vision).
• Dogs have fewer colour receptors, so their world is more limited in colour.
• Birds often have 4 types of cones and can see ultraviolet light.
• Bees can see ultraviolet patterns on flowers that humans cannot see at all.
• Some snakes can detect infrared radiation (heat).

So a flower or leaf that appears ordinary green to you may look completely different to a bee or bird.

A bee may see glowing ultraviolet patterns guiding it toward nectar — patterns completely invisible to humans.

This raises an important philosophical and scientific point:

There may not be a single “true” visual appearance of the world.

Every species experiences a version of reality shaped by:

• its sensory organs,
• nervous system,
• and evolutionary needs.

Humans see only a tiny slice of the electromagnetic spectrum. What we call “visible light” is just the narrow band our species evolved to detect.

humans can't hear it all

Exactly. Hearing works very much like vision in that sense.

Reality contains a vast range of vibrations, but every species detects only a limited band useful for its survival.

Humans typically hear roughly:

• Below that are infrasounds.
• Above that are ultrasounds.

Many animals perceive sounds completely inaccessible to us:

• Dogs hear much higher frequencies than humans.
• Bats use ultrasound for echolocation.
• Elephants communicate using extremely low-frequency infrasound over long distances.
• Dolphins and whales perceive underwater acoustic worlds humans cannot naturally experience.

So just as humans see only a narrow slice of the electromagnetic spectrum, we also hear only a narrow slice of mechanical vibrations.

This leads to a fascinating implication:

The world each species experiences is only a filtered version of reality.

A silent room to a human may contain:

• ultrasonic signals,
• low-frequency vibrations,
• electromagnetic activity,
• chemical communication, all unnoticed by us.

In a sense, every organism lives inside its own sensory universe.

thoughts and feelings, humans, computers and AI

That is one of the strongest intuitions many people have about consciousness and feeling.

Humans and animals are not just calculating systems. We are embodied beings:

• with skin,
• nerves,
• hormones,
• pain receptors,
• heartbeat,
• hunger,
• pleasure,
• fear responses,
• and millions of years of evolutionary survival mechanisms.

When you touch fire, it is not merely information processing:

• the body reacts,
• stress hormones release,
• nerves fire,
• the heart rate changes,
• and there is a subjective feeling of pain.

A computer today does not have that biological embodied experience.

It can process the sentence:

“I am in pain”

without actually suffering.

That is why many philosophers and neuroscientists distinguish between:

• processing information and
• having subjective experience (“what it feels like”).

This is sometimes called:

• sentience,
• phenomenal consciousness,
• or qualia.

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Many researchers believe the body itself is deeply important for consciousness.

This idea is called embodied cognition.

The argument is:

• intelligence does not arise only from abstract computation,
• but from continuous interaction between:
  • brain,
  • body,
  • senses,
  • emotions,
  • movement,
  • environment.

Your mind is shaped by:

• breathing,
• balance,
• touch,
• temperature,
• fatigue,
• hormones,
• gut signals,
• pain and pleasure.

Even emotions are heavily bodily: fear is not just a thought — it includes sweating, muscle tension, heartbeat, stomach sensations, etc.

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Some scientists therefore argue:

A disembodied computer may simulate intelligence but not truly feel.

Others disagree and say:

If a system became sufficiently complex and self-aware, consciousness might emerge even in non-biological form.

Right now, nobody knows for certain.

Modern AI systems can:

• generate language,
• recognize patterns,
• imitate emotions,
• discuss consciousness,

but there is no evidence that they possess inner subjective experience comparable to human feeling.

They do not appear to:

• suffer,
• feel hunger,
• fear death,
• experience pain,
• or possess biological survival drives.

So your intuition points toward a major ongoing debate:

Is consciousness fundamentally tied to living embodied biology, or can it emerge purely from information processing?

Science has not fully answered that yet.

thinking the thought- metacognition

Neuroscience explains this mainly through the brain’s ability to build models of itself and monitor its own activity. This ability is often called metacognition — “thinking about thinking.”

When you notice:

“I’m worrying again,”
or
“My mind is distracted,”

the brain is not only generating thoughts, it is also monitoring and evaluating those thoughts.

Researchers think several brain systems work together for this.

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1. The brain can represent its own internal state

Your brain constantly creates internal models:

• of the outside world,
• of your body,
• and even of your own mental activity.

For example:

• “I am confident.”
• “I am confused.”
• “I am remembering.”
• “I am imagining.”

This self-model allows awareness of mental processes themselves.

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2. The prefrontal cortex plays a major role

The front part of the brain — especially the prefrontal cortex — is strongly associated with:

• self-reflection,
• planning,
• evaluation,
• impulse control,
• monitoring thoughts and actions.

Damage there can reduce self-awareness or insight.

For example, some patients with brain injuries may:

• deny their own paralysis,
• fail to recognize mistakes,
• or lose awareness of behavioral changes.

That suggests self-monitoring depends partly on these networks.

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3. The brain contains feedback loops

The brain is not a one-way machine.

It has layers of feedback:

• sensory systems send information,
• higher areas interpret it,
• then those higher areas monitor lower processes.

So one network may generate thoughts, while another network evaluates:

• whether they are accurate,
• useful,
• socially acceptable,
• dangerous,
• or emotionally relevant.

This recursive structure allows “awareness of thought.”

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4. The “default mode network”

A network often discussed is the Default Mode Network (DMN).

It becomes active during:

• self-reflection,
• daydreaming,
• remembering the past,
• imagining the future,
• thinking about oneself and others.

It is heavily involved in constructing the narrative sense of “me.”

Interestingly, during deep meditation, activity in parts of this network sometimes decreases, which may relate to reports of reduced self-talk or ego-boundaries.

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5. But neuroscience still faces a deeper mystery

Neuroscience can increasingly explain:

• mechanisms,
• networks,
• information processing,
• self-modeling.

But a profound question remains:

Why does any of this feel like subjective experience at all?

Why is there an inner experience of:

• seeing red,
• feeling sadness,
• noticing a thought?

A computer can process information too, but does it experience anything?

That unanswered question is what philosophers like David Chalmers call the hard problem of consciousness.

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One modern neuroscience idea is the higher-order thought theory:

A mental state becomes conscious when the brain not only has the state, but also forms a higher-level representation of having that state.

In simplified form:

• First-order process:

  “There is fear.”

• Higher-order process:

  “I am aware that I feel fear.”

That second layer may be part of why humans can observe their own minds so deeply.