Special Senses Anatomy

Question 1

What is the Stria of Gennari?

Answer 1

Well developed layer IV of V1

Inputs from thalamus

Question 2

Where are the dorsal and ventral cochlear nuclei?

Answer 2

Dorsolateral surface of the medulla

Question 3

Where is the lateral lemniscus?

Answer 3

Pons
As ascend, moves dorsally to lie superficially
SO and cochlear fibres to rectum IC of midbrain

Question 4

Where is the MLF?

Answer 4

Runs through the whole brainstem
Continues caudally into the upper cervical segments
For vestibuloocular eye movements, connects vestibular nuclei to oculogyric nuclei
For head movement, connects superior colliculus to cervical motor neurons in upper spinal cord
Dorsal medulla
Deep to aqueduct in midbrain

Question 5

What are the four vestibular nuclei?

Answer 5

Superior inferior lateral medial

Question 6

Which vestibular nucleus gives rise to the vestibulospinal tract? What does it do?

Answer 6

Balance
the lateral/Deiter’s nucleus
Large neurons

Question 7

Which vestibular nucleus projects to the thalamus?

Answer 7

Superior

Question 8

Where do the striate arteries enter and what is their significance?

Answer 8

Anterior perforated substance
Supply internal capsule and striatum
Susceptible to stroke

Question 9

What is the function of the pretectal projection of the visual pathway?

Answer 9

Pupil response

Question 10

What is the function of the superior chiasmatic nucleus projection of the visual pathway?

Answer 10

Circaidan rhythms

Question 11

Where does the optic radiation run? What are lesions in it called?

Answer 11

LGN
Curls around temporal horns, atria and occipital horns of LVs
In parietal cortex: contralateral inferior quadrantanopia
In temporal cortex: contralateral superior quadrantanopia

Question 12

Where is V1? What are lesions in part of it called?

Answer 12

Occipital lobe around the banks for the calcarine fissure

Scotoma

Question 13

What do optic chiasm lesions give?

Answer 13

Bitemporal hemianopia

Question 14

What do optic tract lesions give?

Answer 14

Homonymous hemianopia

Question 15

Where is the oculomotor nucleus?

Answer 15

Upper midbrain

Midline

Question 16

What can MLF damage be caused by and lead to?

Answer 16

MS

Nystagmus, diplopia, defects in gaze control

Question 17

How do eye movements happen?

Answer 17

Eye fields in cerebral cortex (frontal and parietal)
Project to retinotopic map in SC
Gaze centres in reticular formation of pons translate position into appropriate motor commands to the three oculogyric nuclei, carried in MLF

Question 18

What are the major thalamic nuclear groups? What do they each do?

Answer 18

Medial, ventral, anterior
Ventral:
- Ventroposterior ascending somatosensory relays
- Ventrolateral relays from cerebellum and basal ganglia to primary motor cortex
- Ventroanterior relays from cerebellum and basal ganglia to supplementary motor areas

Posterior to all of these LGN and MGN

Anterior:

• Projects to cingulate gyrus
• Important for perception of internal emotional state

Medial + Pulvinar:

• Cortico-thalamo-cortical relays
• Project to areas of association cortex
• Medial to prefrontal association area
• Temporal-parietal-occipital association area: input from pulvinar

Question 19

What is a major input to the anterior thalamus?

Answer 19

Mammillary bodies of the hypothalamus, which are important for the formation of declarative memory

Question 20

Which are the largest thalamic nuclei?

Answer 20

The medial and pulvinar

Question 21

What is Brodmann’s map?

Answer 21

A map of the cerebral cortex

52 areas based on cytological structure

Question 22

What is the Brodmann number for the primary motor cortex?

Answer 22

4

Question 23

What is the Brodmann number for the premotor and supplementary motor areas?

Answer 23

6

Question 24

What is the Brodmann number for the primary somatosensory cortex?

Answer 24

3, 2, 1

Question 25

What is the Brodmann number for V1?

Answer 25

17

Question 26

What is the Brodmann number for the primary auditory cortex?

Answer 26

41

Question 27

How big is a brain? How much of it is primary cortex and how much association cortex?

Answer 27

1200cm2 Primary 65-70cm2 Association 1130cm2

Question 28

Where is the uncus?

Answer 28

The most anterior part of the para-hippocampal gyrus in the MTL

Question 29

Where is the primary cortex for taste?

Answer 29

Anterosuperior temporal just post to lateral fissure

Question 30

Which way do the layers of cortex run?

Answer 30

I = superficial, VI = deep

Question 31

What do the layers of the cortex do?

Answer 31

``` I molecular layer. II, III project to other cortical layers IV thalmic input V output to subcortical structures VI feedback to thalamus ```

Question 32

What do the layers of the cortex look like?

Answer 32

I molecular layer. fibres parallel to cortical surface, but very few neurons, so not visible with Golgi or Nissl stain II Outer granular layer - small rounded neurons III Outer pyramidal layer - triangle shaped pyramidal neurons IV inner granular layer V inner pyramidal VI Multiform layer - thin innermost with some scattered cells in it

Question 33

What does Golgi stain stain?

Answer 33

Entire cells

Question 34

What does Nissl stain stain?

Answer 34

Nucleic aicds

Question 35

What does Weigart stain stain?

Answer 35

Myelinated axons

Question 36

What does the primary motor cortex look like histologically?

Answer 36

Fat layer V output | Few granule cells in layer IV

Question 37

What does association cortex look like?

Answer 37

Lacks anatomical specialisation in any particular layer - homotypic

Question 38

What is 3 layered cortex and what is 4-5 layered cortex called? Where do you find it?

Answer 38

Allocortex - hippocampus Juxtallocortex - parahippocampal gyrus/cingulate gyrus

Question 39

What are auditory processing disorders?

Answer 39

Apparatus of ear is functional but CNS deficits make auditory processing difficult Can affect different aspects of hearing e.g. sound recognition and sound localisation

Question 40

What is anosmia/hyposmia/dysosmia?

Answer 40

Anosmia - inability to detect odours Hyposmia - decreased ability to detect odours Dysosmia - poor identification of odour

Question 41

Give two examples of dysosmia

Answer 41

Phantosmia: perception of smell in the absence of an odorant Agnosia: odours can be detected but not distinguished

Question 42

What is retrosigmoid craniotomy?

Answer 42

Removing and replacing the bone posterior to the sigmoid sinus and inferior to the transverse sinus Allows access to lateral cerebellum and cerebellopontine angle Used to remove ependymoma

Question 43

What is an ependymoma?

Answer 43

Tumour that arises from the ependymal cells that line the ventricles, esp 4th ventricle and in childhood