What’s the secret behind the flexibility of young brains? It’s not about

growing new cells – in fact, the number of brain cells is the same in

children and adults. Instead, ★the secret lies in how those cells are

connected.

The human brain’s ability to shape itself to the world into

which it’s born has allowed our species to take over every

ecosystem on the planet and begin our move into the solar

system.

When a synapse successfully

participates in a circuit, it is strengthened; in contrast, synapses

weaken if they aren’t useful, and eventually they are eliminated.

In a sense, the process of becoming who you are is defined by

carving back the possibilities that were already present. You become

who you are not because of what grows in your brain, but because of

what is removed. ???

Throughout our childhoods, our local environments refine our

brain, taking the jungle of possibilities and shaping it back to

correspond to what we’re exposed to. Our brains form fewer but stronger connections.

★stimulation 刺激 啟發(fā)

In 1966, to increase the population and the work force,Romanian president Nicolae

?Ceau?escu banned contraception and abortion. State gynecologists known as

“menstrual police” examined women of childbearing age to ensure they were producing?

enough offspring. A “celibacy tax” was levied on families who had fewer than five

children. The birth rate skyrocketed.

Without an environment with emotional care and cognitive

stimulation, the human brain cannot develop normally.

the brain can often recover, to varying degrees, once the children are

removed to a safe and loving environment.

We are exquisitely強(qiáng)烈地 sensitive to our surroundings. Because

of the wire-on-the-fly strategy of the human brain, who we are

depends heavily on where we’ve been.

who we are as a teenager is not simply the result

of a choice or an attitude; it is the product of a period of intense and

inevitable neural change.

★In adulthood our brains continue to change.

Something that can be shaped – and can hold that

shape – is what we describe as plastic. And so it is with the brain, even

in adulthood: experience changes it, and it retains the change.

Although most

of the changes are too small to detect with the naked eye, everything

you’ve experienced has altered the physical structure of your brain –

from the expression of genes to the positions of molecules分子學(xué) to the

architecture of neurons.?

less dramatic changes in your brain

can alter the fabric of who you are. Consider the ingestion of drugs or alcohol.

Your neurons operate in a dynamic matrix of shifting relationships,?

and heavy demand is continually placed on them to wire with others.

Each new event needs to establish new

relationships among a finite number of neurons. The surprise is that a

faded memory doesn’t seem faded to you. You feel, or at least assume,

that the full picture is there.

★Not only was it possible to implant false new memories in the

brain, but people embraced and embellished修飾 them, unknowingly

weaving fantasy into the fabric組織/構(gòu)造 of their identity.

Our past is not a faithful record. Instead it’s a reconstruction, and

sometimes it can border on mythology.?

Your memory of who you were at fifteen is different to

who you actually were at fifteen; moreover, you’ll have different

memories that relate back to the same events.

The enemy of memory isn’t time; it’s other memories.

Keeping a busy lifestyle into old age benefits the brain.

Having brain tissue that was being riddled(充斥) with the ravages(毀壞后的痕跡) of Alzheimer’s?

disease didn’t necessarily mean a person would experience cognitive problems.

★★★Specifically, cognitive exercise – that is,

activity that keeps the brain active, like crosswords(填字游戲), reading, driving,

learning new skills, and having responsibilities – was protective. So

were social activity, social networks and interactions, and physical

activity.

★★★negative psychological factors like

loneliness, anxiety, depression, and proneness to psychological

distress were related to more rapid cognitive decline.

★★★Positive traits性格 like conscientiousness, purpose in life, and keeping busy were

protective.

As areas of brain tissue have degenerated, other areas have been well

exercised, and therefore have compensated補(bǔ)償 or taken over those

functions. The more we keep our brains cognitively fit – typically by

challenging them with difficult and novel tasks, including social

interaction – the more the neural networks build new roadways to get

from A to B.

even if many pathways degenerate because of disease, the brain can retrieve other

solutions.

We can’t stop the process of aging,? but by practicing all?

the skills in our cognitive toolbox, we may be able to slow it down.

The brain is just as active at night as during the day. During sleep,?

neurons simply coordinate with one another differently, entering a more

synchronized, rhythmic state.

who you are at any given moment depends on the detailed rhythms of your neuronal firing.

tease out 梳理？

imagine that those pigments on a cloth are arranged into a pattern of a national?

flag. Almost certainly that sight will trigger something for you – but the?

specific meaning is unique to your history of experiences. ★You don’t perceive?

objects as they are. You perceive them as you are.

Each of us is on our own trajectory – steered by our genes and our

experiences – and as a result every brain has a different internal life.

Brains are as unique as snowflakes.