It's the holiday season and you've been given a gift in a neatly wrapped box. You pick the box up, shake it, and judge its weight, but you can't figure out what's inside. Your curiosity peaked, you eagerly unwrap the gift. You feel like a kid again.
This sense of anticipation and discovery may make holiday gift exchange fun, but it is also critically important for neurological rehabilitation and recovery. In order for me, cross-eyed since infancy, to develop stereovision or for an individual to regain function after a stroke or other injury, brain circuits have to change. Some synapses, barely effective before the disorder or injury, must become stronger, others weaker, and many of these changes occur in the cerebral cortex. A sense of anticipation and discovery promotes synaptic changes because these feelings are accompanied by excitation of neurons in neuromodulatory areas of the brainstem and basal forebrain. These cells make connections onto cortical neurons where they liberate several different neurotransmitters or neuromodulators including dopamine, noradrenaline, serotonin, and acetylcholine. Release of these chemical messengers triggers and facilitates the synaptic changes among cortical neurons necessary for learning and recovery.
When I first began to see in 3D, all I wanted was to be left alone to explore. Everything from sink faucets to tree limbs looked different and captivating. I went on hunts for new sights to greenhouses, gardens, and city streets. Neurons in the neuromodulatory areas of my brain must have been firing away with vigor, thus triggering synaptic changes that led to further visual improvements. No wonder the transformation in my vision made me feel like I had been given a great gift.
A baby's brain is more malleable than that of an adult. One reason may be that everything is new and intriguing to a very young person. The neuromodulatory areas of his or her brain must be continually active, thus facilitating rapid learning and development. For a very young child, each day may bring novel sights and discoveries. Each day may be a little bit like Christmas.