Cortex Somatosensory

Question 1

What are the 6 layers of the cortex from outer to inner?

Answer 1

• Molecular
• External granular
• External pyramidal
• Internal granular
• Internal pyramidal
• Multiform

Question 2

What types of fibers enter the external granular layer?

Answer 2

Long associative fibers

Question 3

What types of fibers are found throughout the external granular layer?

Answer 3

• Short associative fibers

Question 4

What types of fibers exit the external pyramidal layer?

Answer 4

Long associative

Question 5

What types of fibers are found within the external pyramidal layer?

Answer 5

• Short associative

- Commissural

Question 6

What types of fibers are found within the internal granular layer?

Answer 6

• Corticalpetal (go everywhere)

- Thalamocortical radiations

Question 7

What types are found in the internal pyramidal layer?

Answer 7

Corticofugal fibers from:

• Striatum
• Brainstem
• Spinal cord

Question 8

What layer has reciprocal connections to the thalamus?

Answer 8

Multiform

Question 9

What gyrus makes up the Sensory cortex?

Answer 9

Postcentral gyrus

Question 10

Is the sensory cortex hetero or homotypical?

Answer 10

Hetero

Question 11

What are the 4 portions of the sensory cortex from anterior to posterior

Answer 11

3a, 3b, 1, 2

Question 12

From what structure do 3a and 3b receive most of their projections?

Answer 12

Thalamus

Question 13

What types of fibers does 3b receive? What sensory information do they carry?

Answer 13

Fast and slow adapting cutaneous receptors (texture, and size and shape of objects)

Question 14

What types of fibers does 3a receive?

Answer 14

Proprioception

Question 15

What areas do 3a and 3b project to?

Answer 15

Areas 1 and 2

Question 16

What are the 5 largest areas of the sensory homunculus?

Answer 16

• Lips
• Tongue
• Feet
• Hand
• Face

Question 17

How are individual modalities of S1 arranged within the cortex?

Answer 17

In columns (one for fast adapting, one for slow adapting fibers)

Question 18

What are the 2 pathways of S1?

Answer 18

• What

- Where

Question 19

Which pathway sends information to S2?

Answer 19

What

Question 20

Which pathway works with the posterior parietal cortex?

Answer 20

Where

Question 21

What structures does the What pathway connect with?

Answer 21

• Insula
• Parietal operculum
• S2

Question 22

What areas make up the Where pathway?

Answer 22

5, 6, 7

Question 23

Which pathway can recognize objects with visual aid?

Answer 23

What

Question 24

Which pathway can determine where an object is in space?

Answer 24

Where

Question 25

What will a lesion to 3b cause?

Answer 25

Loss of discrimination of texture, shape, and size

Question 26

What will a lesion to 1 cause?

Answer 26

Inability to assess texture

Question 27

What will a lesion to 2 cause?

Answer 27

Inability to assess shape and size

Question 28

Why are pain, temperature, and crude touch not affected by a lesion to S1?

Answer 28

The LSTT negates the loss

Question 29

How does S2 connect with S1?

Answer 29

Via the Treanscallosal Connection

Question 30

What are the 5 functions of S2?

Answer 30

- Bimanual coordination - Rapid transfer of acquired tactile skills - Texture and shape discrimination - Acute pain - Localizes

Question 31

What 2 effects will a lesion of S2 cause?

Answer 31

- Severe impairment of discernment of shape and texture | - Inability to learn tactile discrimination based on shape

Question 32

Is the associative somatosensory cortex homotypical or heterotypical?

Answer 32

Homotypical (most common)

Question 33

What complex plays a large role in the Associative cortex?

Answer 33

Posterior parietal complex

Question 34

What 3 functions does the posterior parietal complex perform?

Answer 34

- Perception and intrepretation of spatial relationships - Accurate body image - Learning tasks related to coordination of bod yin psace

Question 35

What function does Area 5 perform in the Associative cortex?

Answer 35

Integrates tractile info from mechanoreceptors in skin and prorioception from muscles and joints

Question 36

What sensory information does area 7 of the associative cortex integrate?

Answer 36

- Vision - Tactile information - Propriocpetive information Aligns body coordinate system with the environment

Question 37

What 5 strange disorders result from lesions to the Associative cortex?

Answer 37

- Tactile agnosia - Astereognosia - Amorphognosia - Ahylognosia - Neglect syndrome

Question 38

What is tactile agnosia?

Answer 38

- Can't recognize objects, but can describe them through touch

Question 39

What is astereognosia?

Answer 39

Can't recognize object through feel

Question 40

What is amorphognosia?

Answer 40

Can't recognize object through form

Question 41

What is ahylognosia?

Answer 41

Can't feel: weight, texture, or density

Question 42

What is neglect syndrome?

Answer 42

- Ignore portion of body or world

Question 43

Is the motor cortex granular or agranular?

Answer 43

Agranular

Question 44

Is the motor cortex heterotypical or homotypical?

Answer 44

Heterotypical

Question 45

What functions does the insula perform?

Answer 45

- Determines quality and intensity of stimulus - Affective aspects of pain - Deals with homeostasis

Question 46

What is the function of the Anterior Cingulate Cortex?

Answer 46

- Generates/ controls emotions | - Unsettling/ unpleasant pain activate

Question 47

What 2 structures make up the parabrachial nucleus?

Answer 47

- Amygdala | - Hypothalamus

Question 48

Where is the allocortex found?

Answer 48

Deep temporal lobe

Question 49

How many layers is the allocortex?

Answer 49

3

Question 50

What are the 3 layers of the allocortex?

Answer 50

- Molecular - Pyramidal/ granule - Polymorphic

Question 51

What 4 structures make up the allocortex?

Answer 51

- Subthalamus - Hippocampus - Dentate gyrus - Parahypocampal gyrus