Irina Harris

Question 1

How much of the monkey brain is dedicated to the visual cortex?

Answer 1

About half of the monkey brain is dedicated to the visual cortex.

Question 2

Episodic memory and semantic memory are both part of which memory system? (From the reading)

Answer 2

Episodic memory and semantic memory are both part of declarative memory

Question 3

Which part of the brain, crucial for acquiring new memories, was removed from HM?

Which types of memories were deficit as a result, and which were spared?

What type of memory test did he respond to (part of the implicit system)?

Answer 3

The MTL (medial temporal lobe) was removed from HM, leaving him with impaired anterograde memory.

he was unable to acquire new autobiographical memories, but still had some ability to acquire new semantic memories, however this was slow and relied on recognition rather than free recall. He could still acquire procedural memories.

He responded to priming, a type of implicit memory test.

Question 4

How much of HMs retrograde memories were lost?

Answer 4

HM lost retrograde memory for the last 2 years before the bilateral lesion

Question 5

Describe the LT memory multiple trace theory, which challenged the standard memory consolidation theory.

Answer 5

The multiple trace theory purports that the hippocampal complex (the hippocampus and subiculum) functions as an index for the multiple traces of memory in respective processing cortices. For example, auditory, visual and emotional aspects of the memory. The spatial context is provided by the hippocampal complex.

Question 6

According to memory trace theory, how are memories strengthened over time?

Answer 6

Each time the memory is remembered, a new trace is created, which shares some elements with the original trace (neuronal/ contextual), but also has new elements.

Over time memories become stronger because there are multiple traces, and the memory becomes devoid of contextual information, becoming similar to a factual memory.

Question 7

What regions of the brain are irrigated by the largest branch of the internal carotid, the middle cerebral artery?

Which fissure does it sit in, and which motor and sensory areas are included?

Answer 7

The middle cerebral artery irrigates a portion of the frontal lobe and the lateral surface of the temporal and parietal lobes.

This includes motor and sensory areas for the face, throat, hand and arm. It also includes Broca’s area in the dominant hemisphere (usually the left).

Question 8

What regions of the brain are irrigated by the anterior cerebral artery?

Answer 8

The anterior cerebral artery irrigates the medial sides of the frontal and parietal lobes.

Question 9

What regions of the brain are irrigated by the posterior cerebral artery?

Answer 9

The posterior cerebral artery irrigates the occipital lobes and the medial temporal lobes.

Question 10

Where are Broca’s and which Brodmann areas does it span?

Name 2 important landmarks used to locate it and the functional areas it contains.

Answer 10

Broca’s area is in the inferior frontal gyrus (think motor strip - mouth and tongue) in the left hemisphere.

Broca’s area includes Brodmann’s areas 44 and 45, and contains the pars triangularis and the pars opercularis (the ‘lid’ of Broca’s which is the lateral part encompassing the motor strip)

Question 11

Compare and contrast the major symptoms of Broca’s and Wernicke’s aphasia.

Answer 11

Wernicke’s aphasia involves comprehension difficulties, and fluent yet often slurred or muddled speech. Broca’s aphasia

Question 12

Which artery supplies blood to the temporal lobe, anterolateral frontal lobe, parietal lobe, basal ganglia (caudate and globes pallidus), the thalamus and adjacent white matter?

Which fissure does it sit in?

Answer 12

The middle cerebral artery supplies blood to the temporal lobe, anterolateral frontal lobe, parietal lobe, basal ganglia (caudate nucleus and globus pallidus) and adjacent white matter.

Question 13

The perisylvian area, in the vascular domain of the middle cerebral artery, contains a number of which functional areas?

Answer 13

The perisylvian area, in the vascular domain of the middle cerebral artery, contains a number of language-related areas.

Question 14

Fluent speech but impaired comprehension and reading are associated with which aphasia?

Answer 14

Fluent speech but impaired comprehension and reading are associated with Wernicke’s aphasia.

Question 15

The posterior division of the middle cerebral artery supplies which area which is associated with which aphasia?

Answer 15

The posterior division of the middle temporal artery supplies blood to Wernicke’s area, which is at the parietal border of the temporal lobe.

Question 16

Which structures are connected by the arcuate fasciculus?

Answer 16

Broca’s and Wernicke’s are connected by the arcuate fasciculus

Question 17

According to the classical CMS model of aphasia, what is the C in the triangle which connects with both M (motor) and S (sensory)?

Answer 17

The C in the classical CMS model of aphasia is Concepts, which are stored in various parts of the brain.

Question 18

Using the classical CMS model for aphasia, what would happen if the S (sensory) part of the triangle was damaged, compared to the pathway between the C (concept) and the S?

Answer 18

If the A is damaged in the CMS pathway, Wernicke’s aphasia results - comprehension (receptive) aphasia. If the CS pathway is damaged, a word might be recognised but not understood.

Question 19

Which ways do the arrows go in the classical CMS aphasia pathway?

Answer 19

Arrows go from S (sensory) to both M (motor) and C (concept), and from C to M.

Question 20

What is conduction aphasia, and what is it’s symptom?

What is transcortical aphasia; which parts of the CMS triangle would be damaged?

Answer 20

Conduction aphasia results from damage to the arcuate fasciculus, so that Wernick’s and Broca’s can’t communicate. This causes lack of ability to repeat words, especially nonsense words, because there is no connection between comprehension and utterance.

People with transcortical aphasia can repeat words but don’t understand them. Therefore the arcuate fasciculus connecting Broca’s and Wernicke’s could be intact but they may have damage between C (concept) and S (sensory) –> they don’t understand the concepts.

Question 21

What is global aphasia?

Answer 21

Global aphasia would mean Broca’s (production - expressive aphasia), Wernicke’s (receptive aphasia) and varied repetition problems potentially including conduction (can’t repeat words) or transcortical (can repeat but don’t understand) some words.

Question 22

Broca’s involves apraxia of speech and dysarthria. Describe each one, and which is a high VS low level problem

Answer 22

Apraxia of speech is a high level problem; problems involving programming (motor cortex) articulations. It’s a disorder of skilled movement of the lips and tongue.

Dysarthria is a lower level problem involving loss of control over articulations such as slurred speech.

Question 23

What is anomia and what aphasia is it common to?

Answer 23

Anomia is difficulty finding words, especially when stringing words together in a sentence. It’s common to Broca’s.

Question 24

Why would right-sided hemiparesis of the hand be present in Broca’s?

Answer 24

Because the hand is close to the mouth on the motor cortex, could be affected by the stroke

Question 25

Why does the classical model of aphasia (Lichtheim 1885, revived by Geshwind in the 60s) not always hold?

Answer 25

Because some people with symptoms of Broca's don't have damage to that area, and likewise for Wernicke's. Not all patients with lesions in those areas have the same symptoms either.

Question 26

When Dronkers (1996) used the lesion overlay method to study 25 patients with apraxia of speech and 19 without, what did she find?

Answer 26

Dronkers found that all patients with apraxia of speech had damage to their precentral gyrus of the insula, and none without apraxia did. Damage to Broca's area 'proper' was not the deciding factor for apraxia of speech, Broca's is close to the surface whereas the insula is buried underneath the operculum.

Question 27

In line with the processing requirements of the functional organisation ventral stream viewpoint, name 2 arguments against the idea that the FFA, EBA and PPA are innate.

Answer 27

1. Bird experts get activation in the FFA when they look at birds 2. The FFA gets stronger across development; this insinuates that it's learnt

Question 28

The network requirements of the ventral stream presents evidence for connections of brain areas underlying the functional oganisation. Give 3 examples

Answer 28

1. The FFA us strongly connected to areas important for emotional and social processing 2. The PPA is more of a spatial layout module - it just so happens that we apply it to our environment of buildings and scenes. 3. The VWFA (visual word form area) is well connected to Brocas, planum temporale (auditory cortex) and other important areas for word comprehension and production

Question 29

What is Malach, Grill-Spector and colleague's fMR (functional magnetic resonance) adaptation? How does it get around the spatial limitations of fMRI, and discern whether neurons in a particular area respond differently or homogenously to objects?

Answer 29

fMR looks at adaptation of neuronal populations pixel by pixel. If, in a 1mm pixel, neurons show adaptation, meaning that they do not recover from adaptation following a stimulus change, then the population is homogenous. On the other hand, a diverse population of neurons would show recovery from adaptation when presented with a new stimulus. Adaptation is shown via BOLD response decrease when stimulus is repeated. Response would not be recovered following a change of stimulus if neurons were not responsive to that stimulus.

Question 30

from p266 object recognition text ch 6: When D.F. was asked to orient her hand so that she could put the card in the slot, she failed miserably. But when asked to insert the card into the slot she had no problem. What kind of agnosia does she have, and why does this demonstrate the vision for action VS vision for perception ventral streams?

Answer 30

This demonstrates that her vision for action was intact; she could complete the action of putting the card in the slot. But when asked to orient her hand so that the card would go into the slot, her perceptive difficulties made it impossible. D.F. has apperceptive agnosia.

Question 31

What kind of agnosia might be caused by lesioning the LOC?

Answer 31

Apperceptive agnosia - lesioning the LOC would cause a lack of recognition of objects

Question 32

Which discipline aims to understand the relationship between mind and brain ("what are the neural substrates of cognitive processes"?), and which aims to understand the architecture of the normal cognitive system (brain substrates are of no interest, patient studies allow us to better understand the system)?

Answer 32

Cognitive neuroscience aims to understand the relationship between the mind and brain, and cognitive neuropsychology aims to understand the architecture of the normal cognitive system

Question 33

The perirhinal cortex (the anterior part of the parahippocampal gyrus), is associated with which memory function (part of the implicit system)? What would a lesion incur?

Answer 33

The perirhinal cortex is associated with familiarity-based item recognition. A lesion would incur difficulty recognising objects, words and faces

Question 34

In a recognition task, Davachi et al (2003) used fMRI during encoding to probe differences between the perirhinal cortex and the hippocampus. What differences emerged between them, in regards to familiarity and context?

Answer 34

The perirhinal cortex cares about the item but not the context it was learnt in, whereas the hippocampus shows a larger response when both the item and context it was learnt are remembered together.

Question 35

The hippocampus, perirhinal and entorhinal cortices are part of which memory system?

Answer 35

The hippocampus, perirhinal and entorhinal cortices are part of the declarative memory system

Question 36

What aspect of memory are the hippocampus and parahippocampal cortex (PHC) both important for?

Answer 36

The hippocampus and the parahippocampal cortex (PHC) both code for context of memory at encoding, and are more active during retrieval when context is remembered successfully

Question 37

The temporal gradient of the standard memory consolidation theory assumes that older memories are more stable and hippocampally remote than new memories. Which declarative memory types does this include and exclude?

Answer 37

The temporal gradient of the standard memory consolidation theory applies to all declarative memories (no distinction between episodic and semantic), but not to 'general semantics' i.e. conceptual knowledge and words.

Question 38

Damage to any part of the extended hippocampal-diencephalic system (parahippocampal cortex, perirhinal cortex, entorhinal cortex, hippocampus, fornix, anterior thalamic nuclei, mamillary bodies & prefrontal cortex) produces similar memory impairments. What does this inform us about the system's connectivity?

Answer 38

This informs us that the extended hippocampal-diencephalic system is very tightly connected.

Question 39

In the extended hippocampal-diencephalic system, which parts are involved with episodic encoding and retrieving and which are involved in familiarity-based recognition?

Answer 39

The hippocampus is involved with episodic encoding and retrieval and other areas outside of this, especially the PRC (perirhinal cortex) are involved with familiarity

Question 40

How did the rare case of JG, who suffered an acute right thalamic lesion and had an older bilateral lesion which affected parts of the mediodorsal nucleus of the thalamus and mammillo-thalamic tract, show the involvement of the diencephalon in the memory system?

Answer 40

After the lesion occurred, JG suffered severe autobiographical and personal semantics memory loss. Both recollection and recognition were affected