The cerebrum is the large upper area of the brain, which is physically divided at the midline into the right and left hemispheres. Within each hemisphere are five distinct regions, the insula, and the frontal, temporal, occipital and parietal lobes. Neurologists and neuroscientists have identified functional areas within the cerebrum dedicated to specific tasks. Damage to a given area of the brain causes predictable functional abnormalities.
Primary Motor Cortex
The primary motor cortex is located in the rear region of the right and left frontal lobes. These areas of the brain command voluntary movement, notes C. George Boeree, Ph.D., of Shippensburg University. Exceptionally large areas of the motor cortex are dedicated to motor control of the hands, head and facial structures compared to proportionately small areas committed to control of the trunk and upper arms.
Broca’s Area
Broca’s area is a region of the left frontal lobe that controls the muscular movements required for speech. Many muscles of the mouth, tongue and throat participate in the act of speaking. People with damage to Broca’s area typically present with a condition known as Broca’s aphasia. Language comprehension is generally preserved but the ability to speak is markedly limited, explains the National Aphasia Association. With severe Broca’s area damage, the capacity to speak may be lost entirely.
Primary Somatosensory Cortex
The primary somatosensory cortex lies next to the primary motor cortex within the right and left parietal lobes, notes the National Institute for Neurological Disorders and Stroke. These regions process physical sensations, including pressure, temperature, texture, vibration, itching and pain. As with the motor cortex, disproportionately large regions of the somatosensory cortex are dedicated to sensation in the hands, head and facial structures.
Auditory Cortex
The auditory cortex is located in right and left temporal lobes. These regions of the brain are committed to the reception and interpretation of sound. Damage to the right auditory cortex commonly leads to loss of the ability to interpret nonlanguage sounds such as the sounds of nature or music. Left-sided lesions disrupt the capacity to understand the spoken word, explains “The Merck Manual for Healthcare Professionals.”
Wernicke’s Area
Wernicke’s area is a region in the temporal lobe near the auditory cortex on the language-dominant side of the brain, which is the left side for most people. This region is important for language comprehension and choosing the words to speak. People with brain lesions in Wernicke’s area have a condition termed Wernicke’s aphasia, which is characterized by poor comprehension of the spoken and written word and nonsensical speech, notes the University of Florida College of Medicine.
References
- Shippensburg University: General Psychology, The Cerebrum
- Merck Manual for Healthcare Professionals: Function and Dysfunction of the Cerebral Lobes
- National Aphasia Association: Aphasia Facts
- University of Florida College of Medicine, Clinical Neurology: The Cerebral Cortex
- National Institute of Neurological Disorders and Stroke: Brain Basics
