Brain On Fire: My Month of Madness

by Susannah Cahalan

The healthy brain is a symphony of 100 billion neurons, the actions of each individual brain cell harmonizing into a whole that enables thoughts, movements, memories, or even just a sneeze. But it takes only one dissonant instrument to mar the cohesion of a symphony. When neurons begin to play nonstop, out of tune, and all at once because of disease, trauma, tumor, lack of sleep, or even alcohol withdrawal, the cacophonous result can be a seizure.

We are, in the end, a sum of our parts, and when the body fails, all the virtues we hold dear go with it.

The mind is like a circuit of Christmas tree lights. When the brain works well, all of the lights twinkle brilliantly, and it’s adaptable enough that, often, even if one bulb goes out, the rest will still shine on. But depending on where the damage is, sometimes that one blown bulb can make the whole strand go dark.

My short-term memory had been obliterated, a problem usually rooted in the hippocampus, which is like a way station for new memories. The hippocampus briefly “stores” the patterns of neurons that make up a memory before passing them along to the parts of the brain responsible for preserving them long term. Memories are maintained by the areas of the brain responsible for the initial perception: a visual memory is saved by the visual cortex in the occipital lobe, an auditory memory by the auditory cortex of the temporal lobe, and so forth.

To understand how important the hippocampus is to the circuitry of the brain, all you have to do is consider what happens when it is removed, as in the famous case of the patient who became known to the medical world as H.M. In 1933, a bicycle struck seven-year-old Henry Gustav Molaison

The healthy brain enables vision through a complex process involving both hemispheres. First, certain receptors are activated in the retina, and information passes through the eye and visual pathways until it reaches the primary visual cortex, located at the back of the brain, where it becomes one single perception, which the parietal and temporal lobes then process. The parietal lobes provide the person with the “where and when” of the image, situating us in time and space. The temporal lobe supplies the “who, what, and why,” governing our ability to recognize names, feelings, and memories. But in a broken brain, where one hemisphere isn’t working properly and the flow of information is obstructed, the visual world becomes lopsided.