The Forebrain: Cerebral Functional Areas and Circulation

Question 1

What is the structural components of the grey matter?

Answer 1

cerebral cortex, basal nuclei and limbic structures

Question 2

What is the structural components of the white matter?

Answer 2

projection, commissural and association fibres

Question 3

What is the frontal lobe specialised in?

Answer 3

motor output (action)

Question 4

What are the parietal, occipital and temporal lobes specialised in?

Answer 4

sensory input

Question 5

What is the function of the insular cortex?

Answer 5

primary gustatory (taste) cortex

Question 6

What is the operculum?

Answer 6

‘lid’ overlying the insular

Question 7

What are the 4 main gyri of the frontal lobe?

Answer 7

precentral gryus (vertically orientated), inferior frontal g, middle frontal g, superior frontal g

Question 8

What are the 3 sections of the interior frontal gyrus?

Answer 8

frontal operculum (posterior), triangular (anterior to operculum), orbital (most anterior)

Question 9

What are the 3 gyri of the temporal lobe?

Answer 9

superior temporal g, middle temporal g and inferior temporal g
(below each one is a sulcus of a similar name)

Question 10

What is the sulcus behind the post central sulcus in the parietal lobe?

Answer 10

intraparietal sulcus (at a right angle)

Question 11

What are the two gyrus in the inferior parietal lobule?

Answer 11

supramarginal gyrus (at the end of lateral sulcus) and angular gyrus (at the end of superior temporal sulcus)

(remaining area is superior parietal lobule)

Question 12

What are the main features of the occipital lobe?

Answer 12

lateral occipital gyru, cuneus (wedge between parietoccipital sulcus and calcarine sulcus), posterior part of the occipitotemporal gyrus

Question 13

Describe the simplified hierarchial organisation of the sensory cortices.

Answer 13

(see notes for picture)

1) 1 sensory cortex (PSC) receives sensory information from the thalamus
2) PSC conveys information to the 2 association cortex for interpretation (e.g. 20 somatosensory area combines tactile, pressure and proprioceptive information to ‘recognise’ an object)
3) Multiple 2 association cortices send their sensory information to the multimodal posterior association area for integration

Question 14

Describe the simplified hierarchial organisation of the motor cortices.

Answer 14

(see notes for pictures)

1) Motor command is initiated in the brain and exits the brain via the primary motor cortex (M1)
2) The prefrontal cortex/anterior association area generates motor commands and transfers them to secondary motor cortices (SMC and PMC) for purposes of integration of motor skills
3) Secondary association cortices (SMC and PMC) transfer the motor commands to the primary motor cortex (M1) for execution

Question 15

Describe the simplified organisation of perception and action.

Answer 15

(see notes for picture)

Question 16

In the frontal lobe, what is the primary motor cortex, secondary motor areas and . prefrontal cortex

Answer 16

• Primary motor cortex: precentral gyrus- outflow= corticospinal tract
• Secondary motor areas: planning and initiation of movements, motor maps
  o Premotor area: posterior middle frontal gyrus and opercular part inferior frontal gyrus
  o Supplementary motor area: posterior portion superior frontal gyrus
  o Frontal eye field: posterior end middle frontal gyrus just rostral to premotor
  o Broca’s area: triangular and opercular parts, inferior temporal gyrus in dominant hemisphere= motor aspects of language symbols- spoken, written and sign
• Prefrontal cortex: executive functions, motor expression of emotions and behaviour

Question 17

In the parietal lobe, what is the primary somatosensory cortex, somatosensory association area and parietal association area?

Answer 17

• Primary somatosensory cortex: postcentral gyrus- tactile and proprioceptive inputs
• Somatosensory association area: posterior edge postcentral gyrus and anterior portions of superior and inferior parietal lobules
• Parietal association area: multimodal sensory integration, perception of ‘self’ and visuospatial perception, right= orients our attention in space, left= orients our attention in time

Question 18

In the temporal lobe, what is the primary auditory cortex, auditory association area and temporal association areas?

Answer 18

• Primary auditory cortex: 2 heschel/transverse temporal gyri
• Auditory association area: part of superior temporal gyrus lateral to heschel gyri
• Temporal association areas: recognising stimuli or patterns
  o Wernicke’s area (continues into inferior parietal lobule): understanding of written and spoken language; only present in the dominant hemisphere- interconnected with Broca’s area (= motor speech area) of the frontal lobe
  o Occipitotemporal gyrus- recognition of meaning or identity of object/face

Question 19

In the occipital love, what is the primary visual cortex and remaining cortex?

Answer 19

• Primary visual cortex: located around the calcarine (fissure) sulcus, contains the stripe of gennari (white line in the grey matter)
• The rest of the occipital cortex is occupied by the visual association area and posterior association area

Question 20

What are some features regarding the lateralisation of brain function?

Answer 20

see notes

Question 21

What arteries are involved in the anterior circulation?

Answer 21

o Internal carotid arteries (ICA’s): ophthalmic artery, anterior choroidal artery
o Anterior cerebral artery (ACA)
o Middle cerebral artery (MCA)

Question 22

What are the arteries involved in the posterior circulation?

Answer 22

o Vertebral arteries (VA): anterior spinal artery, cerebellar arteries
o The VA’s unite to form basilar artery: cerebellar arteries
o Posterior cerebral arteries (PCA’s)

Question 23

What area of the brain does the anterior cerebral artery supply?

Answer 23

medial surface of frontal and parietal loves and narrow strip superiorly

Question 24

What area of the brain does the middle cerebral artery supply?

Answer 24

lateral surface of all lobes

Question 25

What area of the brain does the posterior cerebral artery supply?

Answer 25

medial and basal surfaces of occipital and temporal lobes