By Farah Bader
If you ever want to see my face light up, then gift me with box of newly – sharpened, fresh Crayola crayons. Indigo, burnt sienna, mahogany, magenta, lavender, electric lime- the assortment of colors I have at my disposal does not matter. Now, hand me a crisp neuro-anatomy coloring book from my college years. Observe as my grin widens and my face beams.
Watch carefully as I excitedly flip the pages, eager to color in each part of the nervous system. First, I slowly fill in the long, slender spinal cord with its bundle of nerves extending from the base of the brain to the lower back. I imagine the neuronal firing needed to ferry the information and communication signals on sensation and movement between the brain and the body. I color upwards from the spinal cord, shading in the medulla, the part of the brainstem involved in controlling involuntary functions, such as respiration, blood pressure, swallowing, and digestion. I proceed to color in the pons, a relay center that transmits movement related information from the cerebral hemispheres to the cerebellum. I take pause to muse on the pons’ involvement in sleep, arousal, and autonomic functions. Tucked over the pons, I find the cerebellum, a lobed structure known for maintaining body balance, posture, fine head/eye movements. It also receives sensory input from the spinal cord and motor information from the cortex (Kandel et. al, 2000).
My brainstem-coloring expedition then takes me to the midbrain, the tiniest region of the brain and the section of tissue between the forebrain and hindbrain. As I color, I think to myself, how can this small structure be responsible for voluntary motor control, auditory and visual reflexes, and eye movement (Kandel et. al, 2000)?
I select a new Crayola and embark on the diencephalon, a structure comprising of the thalamus and hypothalamus. Commonly considered the dispatch station to the cortex, the thalamus takes sensory information (auditory, visual, tactile) from the body periphery and feeds it to the sensory processing parts of the cerebral cortex with the intent to make us consciously aware of sensations. Motor input is also integrated from the midbrain and the cerebellum to the cortex by various neuronal cell bodies in the thalamus. Right underneath the thalamus, I spot the hypothalamus. I relish the opportunity to use a new Crayola to add pigment to the structure that controls growth, eating, drinking, maternal behavior, and reproduction-related behaviors (Kandel et. al, 2000).
Once more, I turn the page and see the two cerebral hemispheres and the four distinct lobes. I see the wrinkled appearance of the frontal lobes and as I color within the lines, I contemplate its role in decision making, future planning, goal-directed movement and executive function. I consider my body huddled over a lap desk, happily coloring away and think about the parietal lobe in its involvement in somatic sensation and positioning the body in space. I admire the hues that I have chosen and imagine the firing in the visual centers of the occipital lobe. The intelligible murmurs of housemates talking in the kitchen remind me of the temporal lobe which is involved in hearing.
As I attempt to decipher what my housemate are muttering about, I find that I’m about to fill in Wernicke’s area, the region in the temporal lobe responsible for understanding speech. After glancing up and chiming in the conversation, I color in Broca’s area, the region associated with producing speech (Kandel et. al, 2000).
I wonder if I will remember this delightful coloring episode. Like clockwork, my thoughts drift to the hippocampus, the seahorse shaped bundle of tissue in the deep part of the brain involved in memory storage and learning (Kandel et. al, 2000).
I hear a dog bark in the background and my heart races a little. Dogs make me nervous and panicky. It is no coincidence that my coloring has now taken me to the almond shaped amygdala. It governs the involuntary nervous system activity and endocrine responses linked to the expression of various high-intensity emotions, most notably fear/anxiety and aggression (Kandel et. al, 2000).
As I ponder on my childhood days where I first learned the motor skills involved in coloring, I shade the various nuclei of the basal ganglia (BG). This extensive network of nuclei deep within the brain are implicated in voluntary motor control, learning that involves a step-wise process, and in deciding which behavior to undertake at any one given time (action selection). The BG are also at the forefront of modulating inhibition of the motor systems through “behavioral switching”(http://en.wikipedia.org/wiki/Basal_ganglia).
With a sense of deep contentment, I finish the last of my coloring and gently close the book. I lay my Crayolas to rest in their yellow and green cardboard box and let out an elated sigh. As always, my visual voyage through the nervous system has been highly satisfying so not surprisingly enough, I look already forward to a re-visitation!
Kandel, E., Schwartz, J., Jessell. (2000) Principles of Neural Science. John Butler, Harriet Lebowitz (Eds.). New York, NY: McGraw-Hill.
Basal Ganglia (n.d.). In Wikipedia. Retrieved June 3, 2014, from http://en.wikipedia.org/wiki/Basal_ganglia