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Module 1.4b

Structure of the Cortex
If you opened a human skull, exposing the brain, you would see a wrinkled organ, shaped TEACH 1.4-7
somewhat like an oversized walnut. Without these wrinkles, a flattened cerebral cortex
would require triple the area — roughly that of a large pizza. The brain’s left and right hemi- Teaching Tip
spheres are filled mainly with axons connecting the cortex to the brain’s other regions. The
cerebral cortex — that thin surface layer — contains some 20 to 23 billion of the brain’s nerve To help students remember the loca-
cells and 300 trillion synaptic connections (de Courten-Myers, 2005). Being human takes a tion and function of the four lobes of
lot of nerve. the cortex, use the following:
Each hemisphere’s cortex is subdivided into four lobes, separated by prominent
fissures, or folds (Figure 1.4-12). Starting at the front of your brain and moving over the
top, there are the frontal lobes (behind your forehead), the parietal lobes (at the top • Frontal lobes control thinking
and to the rear), and the occipital lobes (at the back of your head). Reversing direc- and judgment, so have students
tion and moving forward, just above your ears, you find the temporal lobes. Each of tap their foreheads like they
the four lobes carries out many functions, and many functions require the interplay of
several lobes. are thinking through a difficult
decision.
• Temporal lobes control hearing,
Figure 1.4-12
The brain has left and and they are located just beside
right hemispheres The cortex and its basic
subdivisions the ears.
Distributed by Bedford, Freeman & Worth Publishers. Not for redistribution.
• Occipital lobes control vision,
Frontal lobe Parietal lobe so have students recall a time
when they were hit in the back
Copyright © Bedford, Freeman & Worth Publishers.
Temporal lobe
of the head and “saw stars.”
This happens because the visual
frontal lobes the portion of
Occipital lobe the cerebral cortex lying just system is momentarily impaired.
behind the forehead. They
enable linguistic processing, • Parietal lobes control touch and
muscle movements, higher- sensory processing and are
order thinking, and executive
functioning (such as making located at the top of the brain.
plans and judgments).
parietal [puh-RYE-uh-tuhl]
lobes the portion of the TEACH 1.4-7
cerebral cortex lying at the top of
the head and toward the rear; it Teaching Tip
receives sensory input for touch
Functions of the Cortex and body position. Help students avoid a common pitfall
More than a century ago, surgeons found damaged cortical areas during autopsies of people occipital [ahk-SIP-uh-tuhl] by emphasizing that the lobes of the
who had been partially paralyzed or speechless. This rather crude evidence did not prove lobes the portion of the brain are plural—there are two of each
that specific parts of the cortex control complex functions like movement or speech. A lap- cerebral cortex lying at the back
of the head; it includes areas that
top with a broken power cord might go dead, but we would be fooling ourselves if we receive information from the lobe, one for each hemisphere. Often,
thought we had “localized” the internet in the cord. visual fields. students will talk about the “frontal
temporal lobes the portion of lobe” and forget that there are actually
Motor Functions the cerebral cortex lying roughly
Scientists had better luck in localizing simpler brain functions. For example, in 1870, German above the ears; it includes the two of each of the following: frontal,
physicians Gustav Fritsch and Eduard Hitzig made an important discovery: Mild electrical auditory areas, each of which parietal, occipital, and temporal lobes.
receives information primarily
stimulation to parts of an animal’s cortex made parts of its body move. The effects were from the opposite ear. They also
selective: Stimulation caused movement only when applied to an arch-shaped region at the enable language processing. TEACH 1.4-7
back of the frontal lobe, running roughly ear-to-ear across the top of the brain. Moreover,
Active Learning
The Brain: Brain Regions and Structures Module 1.4b 71
(10 minutes) Before moving on to the
functions of the cortex, allow students
to practice what each lobe is respon-
TEACH 1.4-7
15/12/23 9:23 AM
03_myersAPpsychology4e_28116_ch01_002_163.indd 71 • The temporal lobes are bordered on the sible for. Give them a scenario (for
Enrichment top by the lateral fissure, a long gyrus example, talking on the phone), and
running horizontally from front to back. ask them to indicate how each lobe is
Explain to your students that the lobes of the • The two hemispheres are separated by engaged during that scenario. You can
brain are demarcated by major gyri on the the longitudinal fissure, the largest of the have them do this activity in pairs or
cortex: individually, in class or for homework.
gyri. This deep fissure separates the two
• The frontal lobes are bordered in the rear hemispheres almost completely down to Remember: Take time to address any
by the central fissure, a long gyrus going the corpus callosum. misinformation that comes up during
vertically down the center of the cortex. the activity.
This gyrus is more prominent on the left
side.

The Brain: Brain Regions and Structures Module 1.4b 71

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