Workgroup 3: Functional neuroanatomy

Occipital lobes

1b. Which visual cortical area (V1, V2, V3, V4, V6, V8) is also known as the ‘primary visual cortex’ and ‘Brodmann’s area 17’?

V1 is also known as the primary visual cortex and V4 is also known as Brodmann’s area 17.

1c. Why is this area called the ‘PRIMARY visual cortex’?

This area receives all the rough data from the eyes and sends these to the other brain areas. It is the first area to receive visual information.

2. Match the visual cortical area with the most appropriate function listed below:

“Dynamic form” perception     +                     V3 (extrastriate cortex)

Any kind of visual input           +                     V1 (striate cortex)

Color perception                     +                     V4 (extrastriate cortex)

Motion perception                  +                     V5 (extrastriate cortex)

3. a) which two cortical streams of visual processing could be distinguished? b) To which lobes do these streams project information from V1? c) Which stream is also called the ‘where’ stream and which the ‘what’ stream? d) Which stream is mostly involved in conscious vision and which more in subconscious vision? e) What problems could occur in case of damage to those two pathways?

4. What is the blind spot?

Inability to see due to naturally occurring lack of photoreceptors.

5. Agnosia is the inability to recognize sensory stimuli. Indicate the inability and location of the damage related to each of these types of visual agnosias.

Parietal lobes

6. What does the drawing of the primary somatosensory cortex represent (homunculus)?

The Homunculus is a representation of a small human being. It’s a neurological map which represents all the brain areas with regards to motor functions and sensory functions for different parts of the human body.

7. At the anterior side of the central sulcus (in the frontal lobe), such a representation is present as well. What is the name of this cortex?

Primary motor cortex

8. Damage to the anterior parietal cortex could lead to somatosensory agnosias. Match the name of the somatosensory agnosia with the accompanying inabilities.

9. Damage to the anterior parietal cortex could also lead to afferent paresis. Which sensory information is lacking in patients with afferent paresis?

There is a lack of feedback about the exact positions of the fingers, which causes the finger movements to be clumsy.

10. Damage to the posterior parietal cortex could result in apraxia. Patients with apraxia are unable to make voluntary movements in the absence of paralysis. Two forms of apraxia are ideomotor apraxia and constructional apraxia. What problems occur in patients with these forms of apraxia?

Ideomotor apraxia: unable to copy movements or to make gestures

Constructial apraxia (visuomotor disorder): spatial organization is disturbed, patients are not able to create a puzzle, to make a drawing, to copy facial movements

11. Some symptoms occur more often after right posterior parietal cortex damage, while others occur more often after left posterior parietal cortex damage. Fill in for each symptom in the table below whether it is more common after left or right posterior parietal cortex damage.

Temporal lobes

13. Match the four functional zones of the temporal lobe with the processes in which they are involved

14. The parietal lobe and the temporal lobe both process spatial location. What is the difference between the two lobes with respect to the spatial location process?

Parietal lobe: processes spatial location with respect to movement.

Temporal lobe: uses spatial location both as a feature of object recognition and for developing memories for object location

15. Damage to different regions of the temporal lobes lead to different deficits. Match the region of damage with the deficits.

Frontal lobes

17. Match the functional zones of the frontal lobe with the function in which they are involved.

18. Just as you’re about to complain to a friend about the unjustly bad grade you received on a recent exam, you recognize your professor approaching. You manage to smile and withhold your angry comments until he passes out of earshot. Describe the brain regions and their respective functions likely to have been particularly involved in helping you to avoid this potentially embarrassing social situation.

This behavior could be described as emotional regulation or response inhibition. Instead of lashing out with an angry comment that could be overheard (a behavior that would be socially inappropriate), your prefrontal cortices, and more specifically ventral medial prefrontal cortex, mediates the more socially acceptable smile. The amygdala projections to frontal regions are also likely to contribute.

20. What happens in case of damage to the premotor cortex?

Have difficulty with learning to respond to visual cues with specific movements (pushing the breaks when the traffic turns red), even though they understand what they are supposed to do.

Finding it hard to move in response to spoken demands (raising a hand when asked).

Finding it hard to select the right muscles to begin new movements.