The Cerebral Cortex: Gross and Functional Anatomy Flashcards
Broca’s area consists of what brain regions?
The triangular and opercular parts of the inferior frontal gyrus
The frontal lobe accounts for what proportion of the cortical surface area?
40%
Divided into lateral, medial and orbital parts
Label the gyri and sulci of the lateral frontal lobe.
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Label the orbital, triangular and opercular parts of the inferior frontal gyrus.
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What separates the superior frontal gyrus from the underlying cingulate gyrus?
Cingulate gyrus
The postcentral gyrus is defined by which anterior and posterior boundaries?
Anterior - central sulcus
Posterior - pars marginalis
Looking at the brain from an inferior view, identify the gyrus rectus, olfactory sulcus and lateral orbitofrontal cortex.
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Describe the main features of the prefrontal cortex.
- Large region of anterior frontal lobe - 30% of human cortex
- Orbital and medial regions implicated in behaviour, personality and social conduct
- Dorsolateral region more concerned with cognitive functions
- No precise anatomical boundaries
- All areas of frontal lobe that are not motor/premotor
Which part of the primary motor cortex resembles an omega sign?
The motor hand area
How can the central sulcus be indentified easily on a midsagittal section?
- Follow the cingulate sulcus posteriorly until you reach the pars marginalis
- The central sulcus lies directly in front of this, sloping down and backwards so that it makes a right angle with the pars marginalis
Identify the superior parietal lobule, intraparietal sulcus and inferior parietal lobule from a lateral view of the brain.
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On a midsagittal brain section, identify the parieto-occpitial sulcus, calcarine sulcus, lingual gyrus and collateral sulcus.
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On a midsagittal brain section, identify the primary visual cortex and visual association cortex.
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Looking at the brain from a lateral view, identify the primary auditory cortex.
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What structures lie directly anterior to the lateral and medial motor strip?
Lateral - lateral premotor area
Medial - supplementary motor area (SMA)
Describe the function of the somatosensory association cortex.
- Visuospatial representation of objects in extrapersonal space
- Recieves a projection from the visual cortex - the “where” pathway - concerned with trajectory and speed of objects and object interaction - reaching, grasping, rotating
What is anosognosia?
Where patients (usually with severe neurological deficits) are unaware that their neurological problems exist - e.g. a patient claiming that a paralysed limb is function normally.
What are praxes and how are they controlled?
- Praxes are semi-automatic motor sequences - e.g. to use scissors, tie shoelaces
- Praxes are stored in the premotor cortex but selected by the posterior parietal lobe
- Patients who have difficulty with praxes are said to have apraxia
- This may be caused by a lesion in either region or the white matter connections between them
The inferior parietal region has been implicated in which abilities?
- Symbolic representation
- Concepts of number
- Mathematical and physics ability
- Reading and writing
What is Gerstmann syndrome?
- Problems with simple arithmetic, left-right confusion and difficulty naming individual fingers
- Caused by lesions in the inferior parietal lobe
Looking at a lateral view of the brain, identify the auditory cortex and the auditory association cortex.
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The precuneus, in the medial part of the parietal lobe, shows increased blood flow during what?
- Daydreaming
- Quiet contemplation
- Meditation
- Recall of personal memories
In visual physiology, the “what pathway”, which provides information relating to colour and form, travels to which structures, and how do these integrate the visual information?
- The temporal lobe visual stream - “what”
- Passes inferiorly into the temporal lobe
- Information integrated by the lateral and inferior temporal cortex to identify and categorise objects
- Agnosia - failure to recognise objects
Where is Wernicke’s area found?
Posterior third of the superior temporal gyrus
Conduction aphasia, where a patient has problems repeating phrases, is thought to be caused by a lesion where?
The arcuate fasciculus
What is Broca’s aphasia?
- Partial loss of the ability to speak
- Speech is effortful, disjointed, slow and hesitant, with marked word-finding difficulty
- Speech and language comprehension is usually preserved
What is Wernicke’s aphasia?
- Difficulty understanding language and following instructions - speech comprehension
- Fluent speech with intact syntactic ability and effortless speech output
- Abnormal speech content, e.g. neologisms
- Patients often unaware that they are not making sense
