About the Brain

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The nervous system is your body's decision and communication center. The central nervous system (CNS) is made of the brain and the spinal cord and the peripheral nervous system (PNS) is made of nerves. Together they control every part of your daily life, from breathing and blinking to helping you memorize facts for a test. Nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Sensory nerves gather information from the environment, send that info to the spinal cord, which then speed the message to the brain. The brain then makes sense of that message and fires off a response. Motor neurons deliver the instructions from the brain to the rest of your body. The spinal cord, made of a bundle of nerves running up and down the spine, is similar to a superhighway, speeding messages to and from the brain at every second.

The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system). The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem.

Understanding the Anatomy and Various Parts of the Brain

Frontal Lobe
The frontal lobe links and integrates all components of behavior at the highest level. Emotion and social adjustment and impulse control are also localized here. Injury to parts of the frontal lobe may cause an inability to move part of the body or the whole side of the body. Speech may become halting, disorganized or be stopped except for single explosive words. Personality may change. Social rules of behavior may be disregarded.

The executive functions, planning, abstract reasoning, impulse control, sustained attention and insight are all located here. The frontal lobe is highly susceptible to injury.

Parietal Lobes
The Parietal Lobe of the cortex is bounded by the central fissure, the Sylvian fissure, the cingulate gyrus, and the parietal-occipital sulcus. The anterior (front) portion of the Parietal Lobes is concerned primarily with somatic (touch, pressure, pain, temperature) sensations and perceptions, while the posterior (back) portion of the Parietal Lobes is concerned primarily with integrating visual and somatic input.

Injuries to the Parietal Lobes can result in disorders of tactile (touch) function, visual or tactile agnosia (an inability to recognize objects, even though the are clearly "seen" or "felt".), apraxia (an inability to carry out specific purposeful movements, not due to paralysis or weakness), alexia (inability to read), agraphia (inability to write), acalculia (inability to perform mathematical calculations), anosagnosia (inability to recognize one's cognitive or perceptual deficits), contralateral neglect (attentional neglect of the perceptual world on the opposite side of the lesion), disorders of body image, right-left confusion, disorders of spatial ability, and defects in eye movement.

Occipital Lobe
The occipital lobe is located at the back of the brain above the cerebellum. The primary concern of the occipital lobe is visual perception, recognition of printed words and colors.

Injury to this area usually results in "blindness" to part or all of the visual field. Usually people experience "holes" or "blind spots" in what they see. There may be problems picking things out of space or they may misperceive pictures or objects. Recognition of colors may also be disturbed.

Temporal Lobe
The temporal lobe perceives and recognizes verbal material. It is among the most frequently injured parts of the brain during head injury. A person may have difficulty screening out distractions. Left temporal area includes production of speech, naming and verbal memory. Right temporal area includes musical abilities, foreign languages, visual memory and comprehension of environment.

Cerebellum
The cerebellum is located just above the brain stem and toward the back of the brain. (Behind the mesencephalon and above the pons, forming the roof of the fourth ventricle.) It is involved in the coordination of voluntary motor movement, balance, equilibrium and muscle tone. The cerebellum learns and executes instructions for movements and ensures coordination of force, extent and duration of the contractions of the muscles. One hypothesis suggests that an essential role of cerebellum is to "learn" and store motor patterns. Injury to the cerebellum may result in:

Brainstem
The brainstem consists of the midbrain, medulla oblongata, and the pons. It is located at the juncture of the cerebrum and the spinal column. All information to and from our body passes through the brain stem on the way to or from the brain.

Functions mediated by the brainstem include: Alertness, Arousal, Breathing, Blood Pressure, Digestion, Heart Rate, and other autonomic functions. The brainstem contains most of the crainal nerves.