Understanding stroke requires a knowledge of basic brain anatomy. Symptoms vary depending on which parts of the brain are affected by strokes. While a stroke in the frontal lobe may affect behavior or emotion, a stroke in the brain stem may affect breathing.
The Three Main Parts of the Brain
Brain anatomy recognizes three main parts of the brain: the cerebrum, the cerebellum, and the brain stem. Each area is responsible for different brain functions, although there is often some overlap.
The Cerebrum: Emotion, Behavior, and More
The cerebrum is the largest area of the brain. The cerebrum can be anatomically divided into two parts; the right and left hemispheres. The right hemisphere controls the left side of the body, and the left hemisphere controls the right side. This aspect of brain anatomy explains why stroke symptoms often only affect one side of the body.
Four distinct lobes make up the cerebrum: the frontal lobe, the parietal lobe, the occipital lobe, and the temporal lobe. Each of these parts of the brain has different functions. Some of these functions may overlap: for instance, the frontal and temporal lobes are both important for language and speech.
Frontal Lobe: The frontal lobe is responsible for speech, emotion, behavior, movement, and planning. A stroke in the frontal lobe may leave a person unable to talk, or may affect behavior. For example, an affected person may experience emotional lability in the form of sudden mood swings and uncontrolled crying.
Temporal Lobe: The temporal lobe controls memory, personality, and language. The temporal lobe also allows us to distinguish smells and sounds.
Parietal Lobe: The parietal lobe allows us to process pain, pressure, and other physical sensations. It is also the area of the brain that allows us to identify objects.
Occipital Lobe: The occipital lobe processes visual stimuli and allows the brain to process light and objects.
The cerebellum is located behind the brain stem. While the frontal lobe controls movement, the cerebellum “fine-tunes” movement. This area of the brain controls fine motor movement, balance, and our brain’s ability to determine limb position. A stroke in the cerebellum can lead to paralysis or “jerky” muscle movements.
The Brain Stem: Breathing and Autonomic Responses
The brain stem is sometimes referred to as one of the “primitive” parts of the brain. Located at the top of the spinal column, the brain stem controls breathing, heart rate, blood pressure, and alertness. Brain stem strokes can disrupt breathing, causing sudden death.
American Association of Neurological Surgeons. (1999). Anatomy of the brain. Retrieved February 11, 2004, from www.neurosurgery.org/health/patient/answers.asp?DisorderID=51.
American Medical Association. (1998). Atlas of the body: The brain â€” Effects of stroke. Retrieved February 11, 2004, from www.medem.com/MedLB/article_detaillb.cfm?article_ID=ZZZ0ZFP46JC