Higher Cortical Funtion Flashcards by Ronit Hardasani

The cerebral cortex is 6 layers thick and most outputs are axons of pyramidal neurones

List 3 type of fibres that are outputs from the cerebral cortex

Projection fibres
Association fibres
Commissural fibres

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Where are most inputs to the cerebral cortex from?

Thalamus and other cortical areas

An important set of inputs is that from the Reticular Formation, which maintains cortical activation

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List 6 functions of the Frontal Lobe

Motor
Expression of Speech (usually left hemisphere)
Behavioural regulation/ judgment
Cognition
Eye movements
Continence

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Describe the Motor function of the Frontal Lobe

How can damage present?

Primary Motor Cortex found here

- Damage can-> Contralateral weakness

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Describe the Expression of Speech function of the Frontal Lobe

What can damage lead to?

Broca’s Area is here

- Damage can-> Expressive dysphasia

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Describe the Behavioural regulation/ judgment function of the Frontal Lobe

What can damage lead to?

Prefrontal Cortex is here

- Damage can lead to impulsive behaviour (aggression, sexual inappropriateness)

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Describe the Cognition function of the Frontal Lobe

What can damage lead to?

Prefrontal Cortex

- Difficulty with tasks such as complex problem solving, including calculation

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Describe the Eye movements function of the Frontal Lobe

What can damage lead to?

Contain frontal eye fields

- Problems with conjugate gaze and other disturbances

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Does Diplopia WITHOUT other cortical features suggest Frontal lobe or brainstem/ cranial nerve problems?

Brainstem/ cranial nerve problems

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Describe the Continence function of the Frontal Lobe

What can damage lead to?

Cortical areas responsible for maintaining continence

- Urinary incontinence

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List 5 functions of the Parietal Lobe

Not including the visual pathway running through

Sensory
Comprehension of speech (Usually left hemisphere)
Body image (Usually right)
Awareness of external environment
Calculation of writing

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Describe the Sensory function of the Parietal Lobe

What can damage lead to?

Primary sensory cortex

- Contralateral anaesthesia (all modalities)

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Describe the Comprehension of Speech function of the Parietal Lobe

What can damage lead to?

Contains part of Wernicke’s Area

- Receptive dysphasia

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Describe the Body Image + Awareness of External Environment function of the Parietal Lobe

What can damage lead to?

Acknowledgement that things exist

- Neglect

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Describe the Calculation and Writing function of the Parietal Lobe

What can damage lead to?

Works with frontal lobe

- Can affect calculation ability

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Damage to which 2 lobes can affect calculation ability?

Parietal and Frontal (work together)

List 4 functions of the Temporal lobe

Not including the visual pathway running through

Hearing
Olfaction
Memory
Emotion

Describe the Hearing function of the Temporal Lobe

What can damage lead to?

Primary Auditory Cortex on superior surface, near Wernicke’s Area
Various effects on hearing, such as auditory hallucinations

Describe the Olfaction function of the Temporal Lobe

What can damage lead to?

Primary Olfactory Cortex on inferno-medial aspect

- Various effects on smell, such as Olfactory hallucinations

Describe the Memory function of the Temporal Lobe

What can damage lead to?

Hippocampus crucial for consolidating declarative/ explicit memories
Amnesia
Can trigger memories-> Deja vu (temporal lobe epilepsy may cause)

How many Hippocampi are there?

2 (1 in each temporal lobe)

Describe the Emotion function of the Temporal Lobe

What can damage lead to?

Contain Limbic System structures such as Hippocampus and Amygdala
Possible relation to pathogenesis of some psychiatric disorders

What does Cerebral Dominance mean?

The idea that some functions are represented more prominently in 1 hemisphere

In 95% of people which hemisphere is dominant for Language and mathematical/ logical functions?

Sequential processing (processes in steps)

Left

In 95% of people which hemisphere is dominant for Body image, emotion, music, visuospatial awareness Whole picture processing (processes all at once)

Right

What syndrome can corpus callosum destruction cause?

Alien hand syndrome (acts independently of mind) | Also effects on language processing

For Broca’s Area, describe the; - Location - Function it is responsible for - Effect of damage

- Inferolateral Frontal lobe, near mouth/ pharynx region of motor cortex - Production of speech - Can cause Staccato Speech/ Broca’s/ Expressive dysphasia (Patient does understand what is being said)

For Wernicke’s Area, describe the; - Location - Function it is responsible for - Effect of damage

- Parietotemporal junction, near Auditory cortex - Responsible for comprehension of speech - Can cause fluent, nonsensical speech/ Wernicke’s/ Receptive dysphasia (Patient does not understand what is being said)

What connects Broca’s and Wernicke’s areas? What can damage to this structure cause?

- Connected by Arcuate Fasciculus | - Damage can cause the inability to repeat heard words

Describe the pathway of the process of repeating a heard word

- Auditory information sent to Primary Auditory Cortex then to Wernicke’s Area (From visual cortex if speaking a written word) - Sent to Broca’s Area via Arcuate Fasciculus - Impulse sent from B’s area to Primary Motor Cortex to innervate the muscles associated with speech

What effect on speech can be caused by large Middle Cerebral Artery infarcts?

Global aphasia, where both B+W Areas are destroyed, leading to virtually no verbal language function

Compare the 2 categories of memory, including where they are stored

Declarative/ explicit; - Factual information - Usually stored in cerebral cortex Nondeclarative/ implicit; - Motor skills or Emotions - Usually stored in cerebellum and subcortical structures

Compare the storage of Short and Long term memory

Short; - Stored for seconds to mins as an ‘echo’ in Cortical circuits Long; - Stored for long periods in Cerebral cortex, Cerebellum etc. following consolidation

What is Consolidation? Suggest 3 factors that influence it

Conversion of Short-> Long term memories - Emotional context - Rehearsal - Association (easier to remember if associated with something known)

Describe the location and role of the Hippocampus (seahorse shaped) in consolidating Declarative memories

- Sits deep in temporal lobe - Has inputs from many brain systems (visual, auditory, limbic, somatosensory etc) - Has a role as an ‘Oscillator’, able to induce Long Term Potentiation within the synapses of the cortex via its circuit with the cortex

What is the key molecular mechanism of memory consolidation?

Long Term Potentiation (LTP)

Describe LTP in consolidating memories

- Changes in glutamate receptors in synapses lead to synaptic strengthening - New physical connections can also form (more pre-synaptic terminals acting on the post-synaptic terminal)