Lifestyle and the Aging Brain

Your Cortex

Cortex is a word that translates to mean “bark of a tree” and refers to the outer covering of your brain. It is one part of your brain and is responsible for your most complicated thinking abilities. Your memory, language, personality, intentional motor skills, spatial ability, and visual perception are all controlled by your Cortex.

Your entire brain weighs between 2 and 4 pounds, is made up of nearly 60% fat, and demands 25% of the blood from each heart beat (how is that for market share!). Millions of brain cells (called neurons) function in your Cortex to relay information electrically that result in your ability to think, move, and emote.

The Cortex evolved from the back to the front which means the front part of your brain is the youngest and most sophisticated part of you. We now believe the Cortex has the ability to generate new brain cells in the area known as the “Hippocampus”. The Cortex actually grew over time through its convolutions, grooves, and valleys.

There is no greater or more complicated system than the human brain!

Medial Section of Your Brain

Your brain has both an outer shell and a middle (medial or mesial) part. The inner structures of the brain tend to be older and more primitive. They are responsible for controlling drives, impulses, fears, instincts, emotions, reflexes, subconscious processes, and automatic behaviors.

The deeper brain structures are referred to as “Subcortex” or under the Cortex. While this region of the brain is distinct from the Cortex, it has multiple connections to and from the Cortex. This permits a smooth integration of information processing in the brain.

Four Lobes of the Brain

Your brain has four distinct regions referred to as “lobes.” Please note that you have two lobes for each region distributed in your left and right hemispheres. Each of the lobes is related to distinct behaviors and regions where overlapping responsibilities occur are referred to as “association areas.”

Frontal Lobe: Your frontal lobe is the youngest and largest region of your brain sitting just behind your forehead. Your frontal lobe is a highly complex and specialized region that helps to control many different and important skills: These include:

Organization
Concept Formation
Mental Flexibility
Personality
Execution of behavior (Frontal Lobe is referred to as Executive System)
Abstract Reasoning
Problem Solving
Planning
Judgment
Ethical Behavior
Inhibition
Expressive Language
Affect
Attention

Temporal Lobe: Your Temporal Lobe sits just under each temple on the sides of your head. This is an important region of your brain that helps with many critical skills including:

Memory and new learning
Language comprehension
Auditory processing
Spatial processing
Attention
Spirituality
Emotion

Your Temporal Lobe is vulnerable to seizures though we do not know why. There is an actual condition known as Temporal Lobe Epilepsy to refer to this condition.

Parietal Lobe: Your Parietal Lobe sits just above your Temporal Lobe and behind your Frontal Lobe. Your Parietal Lobe is an example of “association area” as it serves as a type of meeting site for multiple inputs from the different lobes. As a result your Parietal Lobe helps to coordinate complex behaviors that include:

Reading
Calculation
Attention
Short Term Memory
Cross Modal Processing (e.g. listening, writing, reading notes)
Spatial navigation
Visual perception and discrimination

Occipital Lobe: Your Occipital Lobe sits in the rear of your brain just under the back of your skull. You actually see, perceive and differentiate what you see because of your Occipital Lobe. Vision is such a complex process and the visual pathway is a highly important one for humans. Your Occipital Lobes helps you with:

Visual Processing
Visually Perceive
Visual Discrimination
Visual Spatial Skill
Facial Discrimination

Two Hemispheres

Your Brain is divided into two sides or hemispheres (left and right). Each of the hemispheres is connected by a bridge of white matter known as the “Corpus Callosum”. This bridge facilitates communication and information processing between the two hemispheres. The Corpus Callosum is actually larger in females relative to male brains.

Your two hemispheres help to coordinate and process different types of information generally categorized as “Verbal or Non-Verbal.” While this is not a perfect differentiation you may consider the hemisphere that processes verbal information primarily as your “Dominant Hemisphere” and the hemisphere that processes non-verbal information as “Non-Dominant.” We use the term dominant to highlight how important language is to your brain and being.

Interestingly, the vast majority of right handed people and many left handed people have language distributed primarily in their left hemisphere (their brains are considered “left dominant”). Left handed persons may have a higher probability of having functions distributed more equally across the two hemispheres or to have more ambidextrous brains. This is also true for female brains relative to male brains. Left handed people who have a parent who is also left handed have a higher probability of having language distributed in the right hemisphere (they would be considered “right hemisphere dominant”). This latter example is rare.

The Dominant Hemisphere helps with the following behaviors or skills:

Verbal Processing
Language
Analysis of information or analytic processing
Attention to detail
Ability to sequence information
Ability to be task oriented
Academics

Our entire western civilization is based around the Dominant Hemisphere. Consider our architecture typically uses vertical and horizontal with less emphasis on round or circular patterns. Take a look at the buildings in our cities. Our curriculum in the classroom is predominantly verbal and the classroom is typically set up in rows and columns. It is not uncommon to see neighborhood streets lined with trees. Signage is typically verbal. These are but a few examples of our culture’s dependency on the dominant hemisphere.
Your Non-Dominant Hemisphere helps you process stimuli that are not highly verbal. This includes processing of the following:

Shapes
Sizes
Contours
Space around you
Faces
Sounds
Melodies
Tones
Emotions, Affect, and “reading between the lines”
Your position relative to others or other things
Depth and Breadth

As noted above female brains tend to be pretty efficient at processing both types of information while males tend to have more unilateral dominant or verbal processing brains.

Hippocampus

Your Hippocampus sits in the middle part of each Temporal Lobe and is a critical part of your being. Your Hippocampus helps you learn new information and also helps to transition new learning to permanent storage sites in the Cortex. Your Hippocampus also helps you with spatial processing.

Your Hippocampus has the ability to generate new brain cells (neurogenesis), a highly adaptive process. Neurogenesis is likely a result of persistent exposure to an enriched environment that is provided from five major areas:

1. Physical Activity
2. Mental Stimulation
3. Nutrition
4. Socialization
5. Spirituality

Research has demonstrated specific activities within each of these five domains that you can do to promote your brain health. Dr. Nussbaum has published a Brain Health Lifestyle (see www.paulnussbaum.com) to help guide you towards your own brain healthy lifestyle.

Interestingly, animals exposed to chronic stress demonstrate structural damage to their hippocampus with memory problems. Your Hippocampus appears to have a very sensitive and important relationship to environmental input. Positive, loving, and stimulating input leads to positive changes in the Hippocampus. Negative, damaging, and traumatic input relates to potential structural damage and memory problems in the Hippocampus.

The Neuron or Brain Cell

Your brain has millions if not trillions of brain cells with two major types referred to as Neurons and Glial cells. Glial cells are considered supportive and nurturing cells that help Neurons function at peak performance. Neurons are the brain cells that conduct and produce the emotions, motion, and thoughts on a daily basis. These behaviors are the result of neurons communicating with other neurons electrically and chemically. A neurochemical is sometimes referred to as a “neurotransmitter”.

A typical Neuron or brain cell is composed of:

1. Cell Body or Soma
2. Axon
3. Dendrite

The Cell Body contains much of the energy producing and maintenance duties of the cell. Information travels to the cell body from the dendrite and away from the cell body with the Axon.

The Axon is a long tract insulated with glial cells that takes information away from the cell body in search of communication with a surrounding neuron. Interestingly, brain cells never touch each other. They communicate with each other via a chemical marriage referred to as a “Synapse.” The more synaptic connections you have the healthier your brain may be. This is referred to as “Synaptic Density” that helps to build your “Brain Reserve” over the course of your lifetime. Having more Brain Reserve is thought to help your brain delay the onset of neurodegenerative diseases such as Alzheimer’s. (to learn how to build your brain reserve see Dr. Nussbaum’s new book “Your Brain Health Lifestyle…”).

Your Dendrites are branch like figures at the end of the cell body opposite the axon. The dendrite serves to seek information from the environment pulling it back to the cell body. Research indicates that the human brain has the potential to generate new brain cells (called “Neurogenesis”) in the Hippocampus located in the temporal lobe. The Hippocampus is important for memory and new learning and spatial processing. It is thought that an enriched environment including novel and complex stimuli on a daily basis promotes brain health.

This little introduction to the basics of Your Brain will help you understand how brilliant your Brain is and why it is important to care for your Brain across your lifespan. Brain Health is an ongoing process. Your goal should be to engage in the novel and complex, enjoy enriched environments and build up as much Brain Reserve as possible. You want to preserve your Lifestory!!!

Illustrations by Visual Anatomy Medical Illustration (www.visualanatomy.com).