Week 1 - Neural develop., Meninges, and Cerebellum

Question 1

What is a deep cerebellar nuclei, how many are there, and what are their names?

Answer 1

Grey matter nodules embedded within the white matter (Arbor vitae) of the cerebellum.

Four

1. Dentate
2. Emboliform (fused with globose in humans)
3. Globose (fused with Emboliform in humans)
4. Fastigii

Question 2

What is “
Localisation of function”?

Answer 2

areas of cortex and subcortical areas are specialised for a particular cognitive modules

Question 3

Describe the three layers of the three layered structure that is the first stage of embryo development (and what each layer becomes)

Answer 3

Three layers

1. Endoderm (digestive tract, respiratory system)
2. Mesoderm (skeleton and muscles)
3. Ectoderm (Skin and CNS)

Question 4

Describe the process of neuralation.

Answer 4

The ectroderm develops into neural crest and neural tube - The neural plate creases inward (forming the neural groove), it continues to fold until the edges come in contact and fuse and close on the dorsal suface of a structure called the neural crest - thus forming the neural tube.

The neural crest cells become glia and PNS, the hollow fluid filled tube becomes CerebroSpinalFluid system (e.g., the ventricles).

Neurulation refers to the folding process invertebrate embryos, which includes the transformation of the neural plate into the neural tube.

Question 5

Partial closure at rostral end of the neural tube during development results in?

Answer 5

Anencephaly

Question 6

Anencepahly results from?

Answer 6

Only partial (or no) closure at the rostral end of the neural tube during embryotic development.

Question 7

Partial closure at caudal end of the neural tube during development results in?

Answer 7

spina bifida and myelomeningocele

Question 8

spina bifida and myelomeningocele result from ? (embryotic development)

Answer 8

Only partial (or no) closure at the causal end of the neural tube during embryotic development.

Question 9

What is spina bifida?

(its cause, its physical symptoms, things it is comorbid with including possible neuroanatomy consequences and pattern of neuropsych strengths and weaknesses for patients)

Answer 9

• Results from a failure of the posterior portions of neural tube (3-4 weeks of gestation)
• Impaired movement below level of lesion
• Co-morbid with arnold chiari-ii malformation (herniation of cerebellum through foramen magnum) -> obstruction of CSF flow to the 4th ventricle -> hydrocephalus; clausal agencies or hypolasia, abnormalities in the tact (midbrain, see slide 37) polymicrogyria, thinning of posterior cortex, cerebellum abnormalities.
• Pattern of strengths and weaknesses: as a whole, score below pop average but within normal on most tests, with PUQ more impaired than FIQ even when motor component is minimised; fluent speech, but “cocktail party-like; problems with attention, problems with exec function documented using BRIEF, verb generation….higher order language impairments (poorly on inference but not literal parts of the bishop and adams 1992 test (See slides)

Question 10

What are the physical facial symptoms of fetal alcohol syndrome?

Answer 10

• Thin upper lip
• Smooth philtrum (cupids bow)
• flat mid face
• short, upward nose
• prominent epicanthal folds (eye fold)
• Low nasal bridge

Question 11

What is fetal alcohol syndrome?

Answer 11

Used to describe the effects of prenatal exposure to alcohol

Fetal alcohol syndrome results in growth retardation (at or below 10%) facial features and behavioural/cognitive abnormalities

Question 12

What are some consequences of Fetal alcohol syndrome?

Answer 12

Taken as a whole the literature suggests structural and hence functional abnormalities vary as a function of amount and timing of exposure

• Decreased neuron production
• Abnormal migration [small brain or structural abnormalities] - cells are destroyed and thus do not make there way to become parts of the brain. less cells to build with.
• Abnormal neurotransmitter levels & changes in electrical signalling
• Abnormal apoptosis (the death of cells, a usually normal and controlled thing)
• Pons dysfunction
• Microcephaly (small head circumference) - with effects more prominent in white than gray matter but found in both
• Polymicrogyria (excessive number of small convolutions) in frontal lobes AND reduced frontal lobe volume in a dose-related manner
• Corpus Callosum including complete or partial agenesis, volume reductions, particularly in the anterior and posterior sections, and altered positioning.
• Reductions in other white matter pathways esp in frontal lobes and tracts connecting the occipital loves with parietal and frontal lobes
• Cerebellum: decreased surface are and volume, particularly in anterior vermis
• Decreased volume of thalamus, caudate nucleus, and probably putamen and globes palladus -> comprised fronto-striatal circuits
• decreased volume of hippocampus.

Question 13

In fetal alchohol syndrome where does Polymicrogyria tend to occur?

Answer 13

Polymicrogyria (excessive number of small convolutions) in frontal lobes AND reduced frontal lobe volume in a dose-related manner

Question 14

What consequences does fetal alchohol syndrome have on the corpus callosum?

Answer 14

Corpus Callosum including complete or partial agenesis, volume reductions, particularly in the anterior and posterior sections, and altered positioning.

Question 15

What consequences does fetal alcohol syndrome have on the cerebellum?

Answer 15

Cerebellum: decreased surface are and volume, particularly in anterior lobe and vermis

Question 16

What areas of the brain tend to have reduced volume in fetal alcohol syndrome?

Answer 16

• Microcephaly (small head circumference) - with effects more prominent in white than gray matter but found in both
• Corpus Callosum
• White matter pathways (esp in frontal lobes and tracts connecting the occipital loves with parietal and frontal lobes)
• Cerebellum: particularly in anterior lobe and vermis
• Thalamus
• Caudate nucleus
• Putamen
• Globus palladus (i.e., few above = the fronto-striatal circuits
• Hippocampus.

Question 17

What are the differences between Broca’s and Wenicke’s Aphasia?

Answer 17

Broca’s aphasia (non-fluent/expressive aphasia) characterised by the loss of the ability to produce language (spoken or written). Speech is difficult to initiate, non-fluent, labored, and halting. Intonation and stress patterns also deficient. Presents as disjointed words and poor sentence construction which omits function words and inflections.

In contrast, Wernickes aphasia (fluent/receptive aphasia) is a type of aphasia characterised by fluent (grammar, syntax, rate, and intonation are normal), but nonsensical, speech/written word. Denotes an inability to understand spoken (lacks meaning) and written language (and patient may be unaware that this is the case).

Question 18

How might someone with broca’s aphasia respond to the cookie test? (“What is the boy doing”)

Answer 18

Disjointed words, non-fluent, but what IS said is sensical (has meaning)

e.g.,
wife is dry dishes. Water down! oh boy! okay alright. Okay. coolie is down….fall, and girl, okay, girl…boy…um

Question 19

What is double dissociation?

Answer 19

when one brain lesion causes a deficit in cognitive function A but not cognitive function B. and a different brain lesion cause the converse deficit (a deficit in function B but not A).

Question 20

What is the concept of ‘modularity’?

Answer 20

the concept that the mind has some internal architecture the mind consists of informationally encapsulated systems that topics distinct and limited sources of sensory, cognitive or affective information

Question 21

What were the three disorders of prenatal development (Discussed in class)?

Answer 21

1. Abnormalities in gyria (i.e., brain folds, e.g., Polymicrogyria) - can be seen in epilepsy
2. Failure in the neural tube (anencephaly, spina bifida/myelomenigocele
3. Fetal Alcohol Syndrome

Question 22

What are the parts of the corpus callosum from anterior to posterior?

Answer 22

1. Genu (inferior, superior, posterior) + Rostrum (the end of the front ‘hook’-shape)
2. body (anterior, middle, posterior)
3. Isthmus
4. Splenium

Question 23

What are the neuropsychological consequences of fetal alcohol syndrome?

Answer 23

• lowered IQ (approx 25% have IQ below 70, average IQ estimate of individuals with heavy prenatal alcohol exposure is 70 for those with FAS and 80 nondysmorphic individuals)
• **Poor Executive Function ** (including: inhibitory control, working memory, problem solving, perseveration, rule violations, decreased initial planning, non-verbal memory [rey figure])
• **Speech and Language problems ** (dysarthria (speech production difficulty), expressive (naming) and receptive (word comprehension) difficulties, language skills + narratives may be poorly organised, ego-centric and lack integration with context)
• Visuo-spatial deficits (constructional apraxia [clock drawing, block design]; difficulties with local processing)
• Motor (hand eye coordination, impaired gross and fine motor skills)
• Attention and activity (hyperactivity and attention deficits)
• Increase in adverse life outcomes (poor academic achievement, major depression and mood disturbance, alcohol-related problems at 21 year)

Question 24

What four general mechanism protect the brain?

Answer 24

1. Bones of the skull
2. Meninges
3. Cerebrospinal fluid
4. Blood brain barrier

Question 25

What are the superior bones of the skull?

Answer 25

• frontal
• parietal
• occipital
• temporal

Question 26

through what part of the skull do the olfactory nerves ascend?

Answer 26

Cribriform plate

Question 27

________ is the gap in the inferior skull where the brain stem descends

Answer 27

Foramen Magnum

Question 28

What is the foramen magnum?

Answer 28

The large hole in the inferior skull where the brain stem descends.

Question 29

What is the cribriform plate?

Answer 29

where the olfactory nerves go up into the brain

Question 30

Because the brain tends to rub on the skull in some areas of the sharp/rough inferior surface this is a common site of _______

Answer 30

brain injuries.

Question 31

What is the Meninges?

Answer 31

the three membranes (the dura mater, arachnoid, and pia mater) that line the skull and vertebral canal and enclose the brain and spinal cord.

Question 32

What are the three layers of the meninges?

Answer 32

1. DURA
2. Arachnoid
3. Pia

Question 33

What is the dura?

Answer 33

Part of the meninges, a parchment like covering called the Dura which contains blood vessels (actually two layers fused together)

Question 34

What are the different parts of the dura?

Answer 34

• Falx Cerebri - fits between the two hemispheres of the cerebrum intervening between to two hemispheres
• Tentorium cerebelli - extra bit of dura that sits above the occipital lobe (also seen between the hemispheres) (there is a hole in the tentorium where the brain stem can go through and out of the foramen magnum - pressure can cause the brain to herniate through the tantrum)

Question 35

What tends to happen to the dura in older people?

Answer 35

It tends to stick to the skull itself

Question 36

Are the arachnoid and pia layers of the mininges very visible?

Answer 36

NO!

Question 37

What is the Falx Cerebri?

Answer 37

The piece of dura that fits between the two hemispheres of the cerebrum intervening between to two hemispheres

Question 38

What is the name of the piece of dura which intervenes between the two cerebral hemispheres?

Answer 38

Falx Cerebri

Question 39

What is the Tentorium cerebelli

Answer 39

extra bit of dura that sits above the occipital lobe (also seen between the hemispheres) (there is a hole in the tentorium where the brain stem can go through and out of the foramen magnum - pressure can cause the brain to herniate through the tantrum)

Question 40

What is the name of the extra bit of dura that sits above the occipital lobe and between the occipital lobe and the cerebellum?

Answer 40

Tenorium cerebelli

Question 41

What is the arachnoid and subarachnoid layers?

Answer 41

Arachnoid is a layer of blood vessels in tissue that sits below the dura and above the pia. The subaracnoid space is where cerebrospinal fluid pools, between the arachnoid and pia (which adheres to the surface of the brain).

Question 42

What and where is the pia?

Answer 42

A non-visible part of the mininges that is below the arachnoid and sub-arachnoid space and that adheres to the brain.

Question 43

How does cerebrospinal fluid protect the brain?

Answer 43

Acts by cushioning the brain.

Question 44

as a general rule the (1) _________ thickens with age and the (2) ______thins with age.

But this effect is mediated by intelligence with more thickening for (3) _______ IQ and less thining for (4) ____ IQ.

Answer 44

1. Parahippocampal area
2. Superior frontal area
3. High/above average
4. High/above average

Question 45

What is the technical name for the forebrain and what two sub-systems does it contain?

Answer 45

Prosencephalon

1. Telencephalon
2. Diencephalon

Question 46

What parts of the brain are in the telencephalon (within the prosencephalon)?

Answer 46

• Cerebreal hemispheres
  
  • Cerebral cortex
  • subcorticol white matter
  • basal ganglia
  • basal forebrain nuclei

Question 47

What is the technical name for the midbrain, and was parts of the brain are in there ?

Answer 47

Mesencephalon

• Cerebral penduncles
• Midbrain tectum
• Midbrain tegmentum

Question 48

What is the technical name for the hindbrain? and what are its two subgroups?

Answer 48

Rhombencephalon

1. Metencephalon
2. Myelencephalon

Question 49

What parts of the brain are in the Metencephalon ?

Answer 49

• Pons
• Cerebellum
• Cerebellar peduncles

Question 50

What part of the brain is in the Myelencephalon?

Answer 50

Medulla

Question 51

What connects the left and right lateral ventricles?

Answer 51

Nothing!

Question 52

What connects the two lateral ventricles with the 3rd ventricle?

Answer 52

Interventricular foramen

Question 53

What connects the 3rd ventricle with the 4th ventricle?

Answer 53

Cerebral aqueduct

Question 54

Via what three paths does the CSF in the 4th ventrical flow to the subarachnoid space?

Answer 54

left and right Lateral apetures, medial apeture

Question 55

via what path does the CSF flow from the subarachnoid space to the Dural sinuses?

Answer 55

Arachnoid villi

Question 56

Describe the flow of Cerebrospinal fluid from ventrical through to reabsorption.

Answer 56

1. Produced by Choroid plexus and circulated by epithelium cilia (‘eyelashes’).
2. left and right lateral ventricles
3. To 3rd ventricle via interventricular foramen
4. To 4th ventricle via cerebral aqueduct
5. To central canal AND
6. To subarachnoid space via left/right lateral apertures and medial aperture
7. To Dural Sinuses via arachnoid villi

Question 57

What is the septum pellucidum?

Answer 57

is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosumdown to the fornix.

Question 58

the ______ is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosumdown to the fornix.

Answer 58

Septum Pellucidum.

Question 59

What are brain commissures? Name all five of them!

Answer 59

refers to a bundle of nerve fibers that cross the midline at their level of origin or entry

There are five in the brain:

1. Anterior commissure
2. Posterior commissure
3. Corpus callosum
4. Hippocampal commissure (commissure of fornix)
5. Habenular commissure

These consist of fibre tracts that connect the two cerebral hemispheres (corpus callosum, anterior commisure [at midline]) and span the longitudinal fissure. In the spinal cord is found the anterior white commissure.

Question 60

Where is the Anterior commisure?

What functions does it affect?

Answer 60

The anterior commissure (also known as the precommissure) is a bundle of nerve fibers (white matter), connecting the two cerebral hemispheres across the midline, and placed in front of the columns of the fornix. The anterior commissure works with the posterior commissure to link the two cerebral hemispheres of the brain and also interconnects the amygdalas and temporal lobes

The anterior commissure plays a key role in:

• Pain and pain sensation (specifically sharp, acute pain)
• Sense of smell ( It also contains decussating fibers from the olfactory tracts, vital for the sense of smell and chemoreception)
• contributing to the role of memory, emotion, speech and hearing. (due to role with amygdalas and temporal lobes)
• It also is involved in olfaction, instinct, and sexual behavior.

Question 61

What is the posterior commisure?

What role does it play?

Answer 61

The posterior commissure (also known as the epithalamic commissure) is a rounded band of white fibers crossing the middle line on the dorsal aspect of the upper end of the cerebral aqueduct (which leads to the fouth ventricle). It is important in the bilateral pupillary light reflex.

Question 62

What is the hippocampal/Fornix Commisure?

Answer 62

The lateral portions of the body of the fornix are joined by a thin triangular lamina, named the psalterium (lyra). This lamina contains some transverse fibers that connect the two hippocampi across the middle line and constitute the commissure of fornix (hippocampal commissure).

Question 63

What is the Habenular commissure?

Answer 63

The habenular commissure, is a brain commissure (a band of nerve fibers) situated in front of the pineal gland that connects the habenular nuclei on both sides of the diencephalon (across brain of the prosencephalon [forebrain]).

Question 64

What is the blood-brain barrier and how does it protect the brain?

Answer 64

It is a property of the walls of the cerebral vessels such that cells in the capillary walls are tightly packed.

Question 65

What are some failures of brain protective mechanisms which were discussed in class?

Answer 65

• Subdural hematoma
• Obstructive and comminicating hydrocephalus
• Chronic traumatic encephalopathy
• Creutzfeldt-Jakobs disease
• Herpes simplex encephalitis

Question 66

Describe the types of brain herniation (due to increased intracranial pressure) that can occur due to subdural hematoma.

Answer 66

• Subfalcine herniation - the displacement of the cingulate gyrus from one hemisphere to the other, under teh falx cerebri. This can compress the pericallosal arteries causing an infarct in their distribution.
• Central herniation -
• Uncal (transtentorial) herniation -herniation of the medial temporal lobe from the middle into the posterior fossa, across the tentorial opening. The uncus of the temporal lobe is forced into the gap between the midbrain and the edge of the tentorium.
• **Tonsillar herniation - **Pressure on the posterior fossa contents from above or from within compresses the pons against the clivus and displaces the cerebellar tonsils into the foramen magnum

Question 67

What is a subfalcine herniation and what are its consequences?

Answer 67

Subfalcine herniation - the displacement of the cingulate gyrus from one hemisphere to the other, under the falx cerebri. This can compress the pericallosal arteries causing an infarct in their distribution.

Question 68

what type of herniation causes the displacement of the cingulate gyrus from one hemisphere to the other, under the falx cerebri; that can compress the pericallosal arteries causing an infarct in their distribution.

Answer 68

Subfalcine herniation.

Question 69

What is an uncal (transtentorial) herniation? what are its consequences?

Answer 69

herniation of the medial temporal lobe from the middle into the posterior fossa, across the tentorial opening. The uncus of the temporal lobe is forced into the gap between the midbrain and the edge of the tentorium.

This compresses the ipsilateral oculomotor nerve, causing a fixed and dilated pupil, and collapses the ipsilateral posterior cerebral artery, causing an infarct in its distribution – Cortical blindness resulting from this infarct is a false localizing sign because it gives the erroneous impression that the primary lesion is in the occipital lobe

Question 70

_____________ is a herniation of the medial temporal lobe from the middle into the posterior fossa, across the tentorial opening. The uncus of the temporal lobe is forced into the gap between the midbrain and the edge of the tentorium. This compresses the ipsilateral oculomotor nerve, causing a fixed and dilated pupil, and collapses the ipsilateral posterior cerebral artery, causing an infarct in its distribution. Cortical blindness resulting from this infarct is a false localizing sign because it gives the erroneous impression that the primary lesion is in the occipital lobe.

Answer 70

Uncal (transtentorial) herniation.

Question 71

what is tonsillar herniation, what are its consequences?

Answer 71

Pressure on the posterior fossa contents from above or from within compresses the pons against the clivus and displaces the cerebellar tonsils into the foramen magnum (cerebellar tonsillar herniation). This may cause stiffness of the neck and head tilt. Compression of the pons and medulla damages vital centers for respiration and cardiac function, resulting in cardiorespiratory arrest.

Question 72

What type of brain herniation does the following text describe:?

Pressure on the posterior fossa contents from above or from within compresses the pons against the clivus and displaces the cerebellar tonsils into the foramen magnum. This may cause stiffness of the neck and head tilt. Compression of the pons and medulla damages vital centers for respiration and cardiac function, resulting in cardiorespiratory arrest.

Answer 72

(cerebellar) tonsillar herniation.

Question 73

What is a subdural hematoma?

Answer 73

A subdural hematoma (American spelling) or subdural haematoma(British spelling), also known as a subdural haemorrhage (SDH), is a type of hematoma, usually associated with traumatic brain injury. Bloodgathers between the dura mater, and the brain. Usually resulting from tears in bridging veins which cross the subdural space, subdural hemorrhages may cause an increase in intracranial pressure (ICP), which can cause compression of and damage to delicate brain tissue. Subdural hematomas are often life-threatening when acute. Chronic subdural hematomas, however, have better prognosis if properly managed.

Question 74

What is the difference between communicating and non-communicating hydrocephalus?

Answer 74

Communicating hyrdocephalus = impaired CSF reabsorption in the arachnoid granulations OR obstruction of flow in the subarachnoid space e.g., by meningitis, excess CSF production (tumours of choroid plexus)

Non-communicating or obstructive hydrocephalus = obstruction of flow within the ventricular system

Question 75

What is hydrocephalus and what two general categories can cause it?

Answer 75

marked dilation of the cerebral ventricles

Hydrocephalus can be due to (1) lack of absorption of CSF (communicating) or (2) due to an obstruction (non-communicating) to flow of CSF.

Question 76

What is hydrocephalus ex vacuo? how does it differ from hydrocephalus?

Answer 76

an enlargement of cerebral ventricles and subarachnoid spaces, and is usually due to brain atrophy (as it occurs in dementias), post-traumatic brain injuries and even in some psychiatric disorders, such as schizophrenia.[citation needed]

As opposed to hydrocephalus, this is a compensatory enlargement of the CSF-spaces in response to brain parenchyma (functional tissue) loss - it is not the result of increased CSF pressure.

Question 77

_______ is an enlargement of cerebral ventricles and subarachnoid spaces, and is usually due to brain atrophy (as it occurs in dementias), post-traumatic brain injuries and even in some psychiatric disorders, such as schizophrenia.[citation needed]

As opposed to hydrocephalus, this is a compensatory enlargement of the CSF-spaces in response to brain parenchyma (functional tissue) loss - it is not the result of increased CSF pressure.

Answer 77

Hydrocephalus ex vacuo.

Question 78

What is chronic traumatic encephalopathy? Describe its macro and micro scopic neuropathology.

Answer 78

A dementia resulting from repetative/chronic (mild) traumatic brain injury (concussion), may be confused with alzheimers disease due to some similar diagnostic cues.

Gross neurpathology:

• Reduction in brain weight
• Atrophy in the frontal, parietal, and temporal lobes (occipital lobe usually preserved)
• Pallor of substantial nigra
• Enlargement of lateral and third ventricles
• Cavum septum pellucidum (CSP), typically in anterior region (when a septum pellucidum has a seperation between its two leaflets (septal laminae) this cavity contains cerebropspinal fluid (CSF) that filters from the ventricles through the septal laminae.

Microscopic Neuropathology:

• A tau positive disorder with NFTs(neurofibrillary tangles) in cortical laminae ii and iii (Alheimer Disease in layers iii and V) with an irregular distribution in the frontal, temporal, and insula
• Beta amyloid deposits found in about half of cases (vs in almost all AD (alzeihmers disease)
• TDP - 3 inclusions in about 80%

Question 79

(1)__________________is a dementia resulting from repetative/chronic (mild) traumatic brain injury (concussion), may be confused with alzheimers disease due to some similar diagnostic cues.

Gross neurpathology:

Reduction in brain weight
Atrophy in the frontal, parietal, and temporal lobes (occipital lobe usually preserved)
Pallor of substantial nigra
Enlargement of lateral and third ventricles
Cavum septum pellucidum (CSP), typically in anterior region (when a septum pellucidum has a seperation between its two leaflets (septal laminae) this cavity contains cerebropspinal fluid (CSF) that filters from the ventricles through the septal laminae.

Microscopic Neuropathology:

A tau positive disorder with NFTs(neurofibrillary tangles) in cortical laminae ii and iii (Alheimer Disease in layers iii and V) with an irregular distribution in the frontal, temporal, and insula
Beta amyloid deposits found in about half of cases (vs in almost all AD (alzeihmers disease)
TDP - 3 inclusions in about 80%

Answer 79

Chronic traumatic encephalopathy

Question 80

What disorder are the following neuropathologies suggestive of?…

• Widing of temporal horns, 3rd ventricle and space between the septum pellicidum
• reduction in brain weight and atrophy in the frontal, parietal, temporal lobes (but occiptal usually preserved)
• Atrophy of corpus callosum, cerebellar tonsils, thalamus, mammillary bodies, hypothalamus, thalamus, hippocampus
• Pallor of substantial nigra
• Enlargement of lateral and third ventricles
• cavum septum pellucidum (typicall in anterior region)
• A tau positive disorder for NFTs in cortical laminae ii and iii, with an irregular distribution in frontal temporal and insula
• Beta amyloud deposits found in about have the cases

Answer 80

Chronic traumatic encephalopathy

Question 81

In Chronic traumatic encephalopathy, neurofibrillary tangles (aggregates of hyperphosphorylater tau protein) are often found in the (1)______ # and #.

Whislt in Alzeheimers disease they are usually found in (2)_______ # and #.

Answer 81

1. Cortical laminae ii and iii
2. Cortical laminae iii and V

Question 82

What are neurofibrillary tangles?

Answer 82

Neurofibrillary Tangles (NFTs) are aggregates of hyperphosphorylated tau protein that are most commonly known as a primary marker of Alzheimer’s Disease. Their presence is also found in numerous other diseases known as tauopathies. Little is known about their exact relationship to the different pathologies.

Question 83

(1)_____________________are aggregates of hyperphosphorylated tau protein that are most commonly known as a primary marker of Alzheimer’s Disease. Their presence is also found in numerous other diseases known as tauopathies. Little is known about their exact relationship to the different pathologies.

Answer 83

Neurofibrillary tangles

Question 84

What is another name for a split (filled with CFS) in the septi pellucidi?

Answer 84

Cavum septum pellucidum

Question 85

What is the most striking syptom of of creutzfeldt-jakob disease?

Answer 85

CJD usually appears in later life and runs a rapid course of progressive dementia. Rapid neurodegeneration - huge holes in brain tissue, brain takes on sponge-like texture. Dilation of ventricles (hydrocephalus ex-vacuo) and massive and rapid cerbral atrophy.

subacute spongiform virus encephalopathy

Question 86

What is the most common viral encephalitis in humans?

Answer 86

Herpes Simplex Virus Encephalistis

Question 87

What is the entorhinal cortex (EC) and where is it in the brain?

Answer 87

The entorhinal cortex (EC) (ento = interior, rhino = nose, entorhinal = interior to the rhinal sulcus) is an area of the brain located in the medial temporal lobe and functioning as a hub in a widespread network formemory and navigation. The EC is the main interface between the hippocampus and neocortex. The EC-hippocampus system plays an important role in declarative (autobiographical/episodic/semantic) memories and in particular spatial memories including memory formation, memory consolidation, and memory optimization in sleep. The EC is also responsible for the pre-processing (familiarity) of the input signals in the reflex nictitating membrane response of classical trace conditioning, the association of impulses from the eye and the ear occurs in the entorhinal cortex.

Question 88

What type of damage can occur in herpes simplex viral encephalistis?

Answer 88

widespread damage in the temporal lobes including the amygdala, hippocampus, peri-/entorhinal and parahippocampal gyri, the orbito frontal cortex, insula and cingulate gyri.

Question 89

What are the major lobes, joinings and fissures of the cerebellum? What connects the cerebellum to the brain stem (three)?

Answer 89

• Vermis
• anterior, posterior and flocculo-nodular lobes
• primary and horizontal fissures;
• Cerebellum tonsils
• superior, middle and inferior cerebellar peduncles

Question 90

What are the distinct cell types found the the cerebellum?

Answer 90

• Molecular cells
• purkinje cells
• granule cells

Question 91

What function does the cerebellum have?

Answer 91

• Inputs from the cerebral cortex including sensory and motor cortices, areas controlling eye movement, vestibular system) and proprioceptors in the limbs arrive at cerebellar cortex via pontine nuclei (pons nuclei involved in motor activity) and cerebellar peduncles (cerebellum to brain stem connections).
• Also extensive input from non-motor areas of the cortex (e.g., frontal-like cognition/affect)

Question 92

What is the name fore the white matter pathways in the cerebellum?

Answer 92

Arboe Vitae (tree of life!)

Question 93

What is the Arboe Vitae (tree of life!)?

Answer 93

White matter pathways in the cerebellum.

Question 94

What are the four pairs of (internal) nuclei of the cerebellum? (bonus: which is the only one that can be seen macroscopically and which two are joined)

Answer 94

1. Dentate (able to be seen macroscopically)
2. Fastigial
3. Globose
4. Emboliform (joined with GLOBOSE to form the interposed n.)

Question 95

Vestibular signs (emesis, dizziness and vertigo) result from lesions in which part of the cerebellum?

Answer 95

• Vermis in the middle region of the posterior lobe
• Flocculonodular lobe

Question 96

Damage to the vermis in the the middle region of the posterior lobe of the cerebellum and damage in the flocculonodular lobe results in what types of symptoms?

Answer 96

Vestibular Signs (emesis, dizziness, vertigo)

Question 97

Motor signs of oculomotor abnormalities, gait/truncal ataxia result from lesions in which part of the cerebellum?

Answer 97

• Damage to the vermis in the anterior lobe
• Damage to the superior portions of the posterior lobe

Question 98

Damage to the vermis in the anterior lobe of the cerebellum and in the superior options of the posterior lobe result in what symptoms?

Answer 98

Motor signs: oculomotor abnormalities, gait (or truncal) ataxia.

Question 99

Motor signs of appendicular ataxia and dysmetria; and dysarthic speech result from lesions in which part of the cerebellum?

Answer 99

Lesions of the intermediate and lateral portions of the cerebellum posterior love

Question 100

What symptoms result from lesioning to the intermediate and lateral portions of the posterior lobe of the cerebellum?

Answer 100

Motor signs: appendicular ataxia and dysmetria and dysarthric speech.

Question 101

Cognitive signs result from lesions in which part of the cerebellum? (how?)

Answer 101

Lateral region of posterior lobe

(there seems to be a crossed cerebro-cerebellar organisation (projections between left hemisphere of cerebral cortex and right cerebellum and vice a versa, shown by fMRI in normals, reorganisation after stroke and reorganisation after congenital left hemisphere damage)

Question 102

Roughly describe the cerebro-cerebellar circuit (inputs and outputs and major structures it goes via)

Answer 102

The cerebellum possess complex connectivity with multiple subcortical structures including vestibular nuclei (in the pons) and the basal ganglia.

Input projections (Cortex –> cerebellum)

1. input projections from the cerebral cortex first synapse on the ipsilateral pons
2. then cross to the contralateral cerebellar cortex

Output projections (Cerebellum —-> cortex)

1. First synapse on the dentate
2. then cross to synapse in the contralateral thalamus
3. Finally project to the cerebral cortex.

Unfortunately little is known about the relationship between the cortex and its projection zones in the cerebellum (due to limitations in conventional tract tracing techniques which rely on the presence of monsynaptic connections - of which there are none!)

Question 103

What are some of the cognitive (non-motor) effects of damage to the lateral portions of the posterior hemisphere of the cerebellum? (as in PFS and CerebellarCognitiveAffectSyndrome)

(why might this occur?)

Answer 103

Non-motor roles of the cerebellum: inferred from signs and symptoms after damage to the lateral portions of the posterior hemisphere and from fMRI studies

• Poor executive function: planning, set shifting, abstract reasoning, working memory, verbal fluency, perseveration, naming and word stem completion, verb generation
• Impaired spatial cognition: including visuospatial disorganisation and impaired visuo-spatial memory
• Cerebellar mutism
• Language output difficulties: dysprosodia and agrammatism
• Personality change: blunting of affect, disinhibited or inappropriate behaviour

(Schmahmann’s (1998) proposed a cerebellar cognitive affective syndrome or dysmetria of thought “it may also be so transpire that in the same way the cerebellum regulates the rate, force, rhythm and accuracy of movements, so may it regulate the speed, capacity, consistency, and appropriateness of mental or cognitive processes.)

Question 104

Which lobe of the cerebellum tends to be selectively affected by alcholic cerebella degeneration?

Answer 104

Anterior love