Last month's column introduced the concept of our working brain, the set of emotion/attention systems that identify and focus on current challenges. Our working brain must differentiate between what's currently more and less important (foreground and background), focus on the foreground, and monitor the background in case something important occurs there.

Our working brain is thus quite limited in the amount of information it can process at a given time, and in the length of time it can hold the information. Its content might involve such things as the magazine page you're reading, the TV show you're watching, the phone conversation you're having, or the pizza you're eating. Our brain and environment are vast storehouses of information, but our working brain is very selective. Think of all the information your computer contains and can access via the Internet, and then think of what's currently on the screen as analogous to the content of your working brain.

Massively Interconnected

Our modular brain's 100 billion neurons are arranged into hundreds of highly interconnected systems that process specific tasks. For example, our visual system encompasses some thirty separate subsystems that process such phenomena as color, shape, location, and movement. Our motor cortex contains separate subsystems for each joint in our body. Our working brain (centered principally in our frontal lobes) is interconnected to all brain processing systems.

Communication within both an individual neuron and a complex neuronal system requires input, information processing, and output functions. At the micro level, information enters a neuron via the cell body's many short dendrite extensions. This incoming neuronal information is consolidated into a response within the cell body, and the response is chemically delivered to other neurons via an axon extension. Similarly, at the macro level, our entire brain contains a sensory system input function, an emotion/attention/problem-solving processing function, and a behavior/motor system output function.

Scientists aren't certain what neuronal information is, but it's apparently at least partially a function of the 60 different kinds of neurotransmitter molecules that our brain synthesizes within neurons, transports down their tubular axons, and distributes across the narrow synaptic gap that connects the axon of a sending neuron and the dendrites of receiving neurons.

The proper synthesis of neurotransmitters and the robustness of the connecting pathways are thus key elements in efficient neuronal communication. Our genes and life experiences combine to develop these systems – and it's obvious that neurotransmitter over/under-production and/or poorly developed neuronal pathways will compromise the efficiency of our brain's functions.