CEREBRAL CORTEX

Module 1.4b-7

Learning Target: Describe the four lobes that make up the cerebral cortex and explain the functions of the motor cortex, somatosensory cortex, and association areas

Thin outer layer of interconnected neurons that are responsible for higher level thinking & skills

The Evolving Brain

• Different animal species have many structures in common, including a cerebellum and cortex.
• The cortex is much larger in mammals than in species that evolved earlier, such as fish and amphibians.
• The cross section of the human brain shows how the cerebral cortex has developed around and above more primitive brain structures.

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When it comes to Cortex…�Size DOES Matter

• If flattened, a human cortex would cover about four pages of your textbook.
• A chimpanzee's would cover one page
• a monkey's a postcard
• a rat's a postage stamp.
• From Scientific American, October 1994, p. 102.

Forebrain Structures

Largest Brain Region with the most complex structures.

What separates us from the beasts.

2 hemispheres are�divided into 4 lobes

Frontal Lobe

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• Important in judgment, planning and sequencing
• Controls emotional center of the brain (limbic system)
• Contains Broca’s area for speech & primary motor cortex for movement
• Prefrontal area for working memory (Short-Term Memory)
• Helps you remember what you just did so you know what to do next (sequencing)

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Temporal Lobe

• Contains primary auditory cortex – interprets hearing info
• Helps with Recognition
• speech recognition
• word recognition
• memory formation
• face recognition (Fusiform Gyrus)

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Occipital Lobe

• Contains primary visual cortex
• Makes sense of visual info it receives from the optic nerve

Parietal Lobe

• MAIN FUNCTION: Contains primary somatosensory cortex
• “skin” sense of touch and temperature.
• Processes body position
• Plays a role in sending info to Frontal lobe to help in:
• hand-eye coordination
• eye movements
• attention

Lobes of the Cortex�Review

• Frontal lobe - largest lobe, involved in thinking, planning, emotional control, voluntary muscle movements
• Temporal lobe - auditory information, recognition
• Occipital lobe - visual information
• Parietal lobe - sensory information from your body & muscles

Motor & Somatosensory Cortex

Motor Cortex: Located at the back of the Frontal Lobe.

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The more precise movements, the more motor cortex the body part uses.

Sensory Cortex:

Located at the front of the Parietal Lobe.

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The more sensitive the area, the more sensory cortex it uses.

Cognitive Neural Prosthetics is using this map to “read” the brain and help paralyzed people move again. (3 min video)

Association Areas of the Cortex

• More intelligent animals have increased "uncommitted" or association areas of the cortex.
• These areas used for integrating and acting on information received and processed by sensory areas.
• Allows for learning, thinking, memory & adaptability

Language Results from Association Areas

• Broca’s area—plays role in speech production
• Wernicke’s area—plays role in understanding and producing meaningful speech

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• Aphasia—partial or complete inability to articulate ideas or understand language because of brain injury or damage

Broca’s Aphasia

• Damage to Broca’s Area causes a person to struggle formulating words while still being able to comprehend speech.
• frequently speak in short, meaningful phrases that are produced with great effort
• Example: Broca first discovered this area when he had a patient with damage to this area who could only say “tan”
• Example:  Affected people often omit small words such as “is,” “and,” and “the.” For example, a person with Broca’s aphasia may say, “Walk dog” meaning, “I will take the dog for a walk.” The same sentence could also mean “You take the dog for a walk,” or “The dog walked out of the yard,” depending on the circumstances.
• Click HERE for a video example of Broca’s Aphasia

Wernicke’s Aphasia

• Damage to Wernicke’s Area would cause a person only to be able to speak in meaningless words.
• Example: Asked to describe a picture of two boys stealing cookies from behind a woman’s back, a patient responded:
• “Mother is away her working her work to get her better, but when she’s looking the two boys looking the other part. She’s working another time.”
• Example: Someone with Wernicke’s aphasia may say, “You know that smoodle pinkered and that I want to get him round and take care of him like you want before,” meaning “The dog needs to go out so I will take him for a walk.”
• Individuals with Wernicke’s aphasia usually have great difficulty understanding speech and are therefore often unaware of their mistakes.
• Click HERE for a video example
• Mnemonic to remember: You can't understand Wernicke's words and Broca's breaks up your speech.

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Association Areas are used when doing complex tasks as information is passed from one area to another which results from

Functional Connectivity.