Chapter 3.7 Cerebral Cortex

Question 1

What is the cerebrum?

Answer 1

Largest portion of the brain

-divides two halves: right and left cerebral hemispheres

Question 2

What is the corpus callosum?

Answer 2

• connects two hemispheres
• Thick band consisting of millions of neuronal axons travelling between the hemispheres
• considered the “information superhighway”

Question 3

What is the cerebral cortex?

Answer 3

Thin outer shell of grey matter of each hemisphere

The core is white matter

Question 4

Grey matter is organized into six well-defined layers, what are they? What type o cells are distributed at each layer?

Answer 4

1. Most superficial layer I (molecular layer) has few nerve cells
2. Layer II (external granular layer) - numerous,small densely packed neurons
3. Layer III (external pyramidal layer) and V (internal pyramidal layer) - pyramidal nerve cells
4. Layer IV (inner granular layer) - small, irregularly shaped nerve cells
5. Layer VI (multiform layer) - small polymorphic and fusiform nerve cells

Question 5

Layers of nerve cells are organized into functional vertical columns which___

Answer 5

address the same specific activity

Question 6

What are the 4 lobes of the cerebral cortex?

Answer 6

1. Occipital lobes
2. Temporal Lobes
3. Parietal Lobes
4. Frontal lobes

Question 7

What do the occipital lobes do?

Answer 7

House visual cortex

Question 8

What do the temporal lobes do?

Answer 8

House auditory cortex

Question 9

What do the parietal lobes do?

Answer 9

Receive and process somatosensory input

Question 10

What do the Frontal lobes do?

Answer 10

Voluntary motor activity, speaking, and elaboration of thought

Question 11

Wha does the primary motor cortex do?

Answer 11

Plan and execute movements?

Question 12

What does the motor homunculus do?

Answer 12

Depicts the location and relative amount o motor cortex devoted to output to thee muscles of each body part

Question 13

What are somesthetic sensations? (Parietal lobes)

Answer 13

• sensations from the surface of the body — temperature, touch, pain,
• transmit from PNS to somatosensory cortex

Question 14

What is the somatosensory cortex? (Parietal Lobes)

Answer 14

• anterior portion of each parietal lobe, posterior to central sulcus
• site of proprioceptive inputs

Question 15

What is sensory homunculus?

Answer 15

-the size of each body part indicates the relative proportion of the somatosensory cortex devoted to that area

Question 16

Primary motor cortex is not the only brain region controlling skeletal muscles, what are the other regions?

Answer 16

Lower Brain regions and spinal cord control involuntary muscle.
-primary motor cortex does not initiate voluntary movement

Question 17

What activates the motor cortex?

Answer 17

The readiness potential: a widespread pattern of neuronal discharge

• voluntary decision-making period

Question 18

Voluntary decision-making occur in 3 higher areas that command the primary motor cortex, what are they?

Answer 18

1. Supplementary motor area
2. Premotor cortex
3. Posterior parietal cortex

Question 19

What is the supplementary motor area?

Answer 19

Preparatory role in programming of complex sequences

Question 20

What is the premotor cortex?

Answer 20

Orienting body parts toward a specific target

Question 21

What is the posterior parietal cortex?

Answer 21

Guides premotor cortex by processing sensory input

Question 22

What role does the cerebellum have in regards to the motor cortex?

Answer 22

Assists in sending input t the motor cortex regarding planning, initiating and timing of certain movements

Question 23

What are electroencephalograms (EEG)

Answer 23

Represents epsp’s and ipsp’s in the cell bodies and dendrites located in the cortical layers

-records electrical activity during sleep and unconscious state of living brain

Question 24

What are three uses of EEG

Answer 24

• diagnosis of cerebral dysfunction eg abnormal EEG during epileptic seizures
• legal determination o brain death
• distinguish various stages of sleep