Critical Windows in Neurodevelopment

Why the First 3 Weeks Matter More Than Most People Realise

At Emerald Park Border Collies, I often say that I am not simply raising puppies, I am shaping nervous systems.

The earliest weeks of life are not a passive waiting period before “real learning” begins. They are a neurobiological construction phase, when the brain is wiring itself in response to the environment.

What happens in this window lays the foundation for stress tolerance, emotional regulation, learning capacity, and resilience for the rest of the dog’s life.

The first critical window: Birth to three weeks

From birth to around three weeks of age, puppies move through the neonatal and early transitional stages of development.

During this time:

• The nervous system is forming its primary sensory pathways

• The stress response system (HPA axis) is being calibrated

• Neural connections are rapidly created and pruned

• The brain is learning what is “normal,” safe, and predictable

This is known as experience-dependent development. The brain requires input from the environment to finish building itself.

In simple terms:

the brain is waiting for instructions.

Sensory input is not optional

Even before their eyes and ears open, puppies are learning through three key systems:

Tactile input (touch)

Warmth, gentle handling, pressure, different textures, and the mother’s contact stimulate the somatosensory system. This input helps organise the nervous system and improves stress resilience later in life.

Olfactory input (smell)

Scent is the earliest functioning sense. Puppies learn the smell of their mother, littermates, humans, and their environment long before they see them. This begins the process of social recognition and environmental familiarity.

Vestibular input (movement)

Being repositioned, carried, gently rocked, and moved activates the balance and spatial systems of the brain. This improves coordination, confidence, and adaptability.

Each of these inputs strengthens specific neural pathways.When those pathways are used, they grow stronger.When they are not, they are pruned away.

This is how early experience literally shapes the brain.

Maternal care is brain architecture

A calm, responsive dam does more than nourish her puppies; she regulates their nervous systems.

Her licking, nursing rhythms, warmth, and responsiveness help calibrate each puppy’s stress-response system. High-quality maternal care has been shown to:

• Lower baseline cortisol

• Improve emotional stability

• Increase learning capacity

• Improve stress recovery later in life

This is not just behaviour. It is epigenetics — experience influencing gene expression.

The dam’s presence becomes the puppy’s first nervous system.

Why this matters for Border Collies

Border Collies are neurologically sensitive, fast-processing dogs. This gives them their remarkable intelligence — but it also makes them more vulnerable to poor early wiring.

Early experiences influence:

• frustration tolerance

• emotional recovery after arousal

• resilience under pressure

• confidence in new environments

You cannot train around a poorly regulated nervous system. But you can build a strong one from the start.

What this means at Emerald Park Border Collies

These early weeks are not left to chance.

I carefully manage:

• calm handling

• safe, gentle sensory exposure

• stable maternal environments

• low-stress routines

Every choice is made with one goal: to support the development of a stable, adaptable nervous system.

Because regulation is not taught later —it is built first.

At Emerald Park Border Collies, I believe that the foundation of a great dog is not obedience, drive, or appearance.

It is a well-wired nervous system.

And that work begins from day one.