The brain Flashcards
1
Q
Utilisation behaviour
A
Phenomenon where patients exhibit an automatic, yet exaggerated and contextually inappropriate, response to environmental stimuli and objects. It is characterized by the involuntary use of objects that are within reach, often in a manner that is appropriate to the object but not the situation. For instance, a patient may automatically start brushing their teeth when presented with a toothbrush, even in an inappropriate setting, such as during a doctor’s consultation.
This behaviour typically arises from frontal lobe lesions, leading to a disruption of the normal inhibitory control over actions.
2
Q
Imitation behaviour
A
Observed when a patient involuntarily replicates the actions of an examiner, while ‘alien hand sign’ refers to involuntary hand movements that feel out of the patient’s control.
3
Q
Manual groping behaviour
A
Describes a scenario where the patient’s hand, often along with the eyes, seems magnetically drawn to follow and manipulate objects after tactile stimulation, like incessantly fiddling with buttons or the fabric of clothing.
4
Q
The Grasp Reflex
A
An involuntary grip on objects or stimuli, such as the examiner’s hand, and is a normal reflex in infants but is considered abnormal in older children and adults.
5
Q
Environmental Dependency Syndrome
A
A loss of autonomous action control, with the patient overly reliant on environmental cues for behavioural direction. An example includes a patient treating a doctor’s office as an art gallery, engaging with items as if they were exhibits, based solely on the examiner’s description.
6
Q
CN VI (Abducens nerve)
A
A purely motor nerve. It innervates the lateral rectus muscle of the eye, which allows for outward gaze (abduction). There are no sensory functions associated with this nerve.
7
Q
CN X (Vagus nerve)
A
Provides parasympathetic innervation to many organs in the body, including the heart and digestive tract. It also carries sensory information from these organs back to the brain.
8
Q
CN IX (Glossopharyngeal nerve )
A
Provides taste sensation from the posterior third of the tongue and innervates muscles involved in swallowing, elevated larynx and pharynx.
9
Q
CN VII (Facial nerve)
A
Controls muscles used for facial expressions and transmits taste sensations from the anterior two-thirds of the tongue.
10
Q
CN V (Trigeminal nerve)
A
Provides sensation to the face and controls muscles involved in chewing.
11
Q
CN I (Olfactory nerve)
A
Purely sensory nerve, detecting smell
12
Q
CN II (Optic nerve)
A
Purely sensory nerve originating in the diencephalon and exiting the skull via the optic foramen.
13
Q
CN III (Occulomotor nerve)
A
Motor nerve responsible for eye movement, pupillary constriction and lens accommodation
14
Q
CN IV (Trochlear nerve)
A
Motor nerve involved in eye movement
15
Q
CN VIII (Vestibulocochlear nerve)
A
Sensory nerve responsible for transmitting sound and equilibrium information from the inner ear to the brain. It consists of two parts: the cochlear part, which carries information about hearing, and the vestibular part, which carries information about balance.
16
Q
CN XI (Accessory nerve)
A
Motor nerve for head shrugging and head turning
17
Q
CN XII (Hypoglossal nerve)
A
Motor nerve involved in tongue movement
18
Q
Perseveration
A
Frequently found characteristic behaviour of patients with organic brain involvement.
It refers to the conscious continuation of an act or an idea.
It is seen in the following conditions:-
Delirium
Epilepsy
Dementia
Schizophrenia
Normal subjects under extreme fatigue
In drug induced states
19
Q
How and where is norepinephrine synthesised
A
Norepinephrine is synthesised by dopamine from the enzyme dopamine beta-hydroxylase.
It is released mainly from the locus coeruleus
Broken down by MAO and COMT
20
Q
Signs of upper motor neuron lesions
A
- Weakness
- Increased reflexes
- Increased tone (spasticity)
- Mild atrophy
- An up-going plantar response (Babinski reflex)
- Clonus
- Pronator drift
21
Q
Signs of lower motor neuron lesions
A
- Atrophy
- Weakness
- Fasciculation’s
- Decreased reflexes
- Decreased tone
22
Q
What is Hemiballismus?
A
A rare movement disorder that causes involuntary, violent limb movements on one side of the body. It’s caused by damage to the basal ganglia
23
Q
What are features of cerebellar dysfunction?
A
- Ataxia
- Intention tremor
- Nystagmus
- Broad based gait
- Slurred speech
- Dysdiadochokinesis
- Dysmetria
24
Q
Medium spiny neurons
A
A special type of GABAergic inhibitory cell representing 95% of neurons within the human striatum, which is a major component of the basal ganglia in the brain. MSNs play a crucial role in the regulation of motor function and are also involved in various cognitive processes related to action selection and reward-based learning.
25
D1-type MSNs (Medium spiny neurons)
These neurons express D1 dopamine receptors and are part of the direct pathway of the basal ganglia. Activation of D1-type MSNs generally facilitates movement and is associated with the initiation of actions based on expected rewards.
26
D2-type MSNs (Medium spiny neurons)
These neurons express D2 dopamine receptors and are part of the indirect pathway. Activation of D2-type MSNs typically inhibits movement and is involved in stopping or preventing actions that are deemed unnecessary or potentially harmful.
27
Parkinson's disease pathology
Loss of dopaminergic neurons in the substantia nigra of the midbrain
And
Presence of Lewy bodies (abnormal protein aggregates in nerve cells)
28
Huntington's disease pathology
Degeneration of medium spiny neurons in the striatum
29
Hemiballism pathology
Typically due to a lesion in the subthalamic nucleus leading to contralateral involuntary flinging movements of the limbs
30
What are the components of the basal ganglia?
Striatum (caudate, putamen and nucleus accumbens)
Subthalamic nucleus
Globus palidus
Substantia nigra (divided into pars compacta and pars reticulate)
31
What are the components of the lenticular nucleus?
Putamen and globus pallidus
32
Describe Broca's aphasia
Non-fluent aphasia with preserved comprehension.
Damage to the Broca's area of the brain which is located in the Left frontal lobe
33
Describe Wernicke's aphasia
Fluent but non-sensical speech and impaired comprehension. Due to damage to Wernicke's area in the superior temporal gyrus in the dominant cerebral hemisphere.
34
Describe anomic aphasia
Persistent inability to supply the words for the very things they want to talk about, particularly major nouns and verbs.
Speech is fluent and grammatically correct but it is filled with vague circumlocutions and expressions of frustration because they know what they want to say but cannot find the words.
35
Describe transcortical sensory aphasia
Disturbance in retrieving words (anomia) and in repetition of phrases, sentences or word sequences, despite preserved comprehension. This type of aphasia is usually caused by lesions that isolate Wernicke’s area from other brain regions.
36
Describe conduction aphasia
Involves difficulty repeating spoken language. The hallmark feature of conduction aphasia is a strong ability to understand spoken language, coupled with an inability to repeat it - however these patients do not lose fluency when speaking spontaneously. Conduction aphasia arises from damage to the arcuate fasciculus, a bundle of nerves that connects Wernicke's and Broca's areas.
37
Describe and give examples of catecholamines
Catecholamines have a unique structure of a benzene ring with two hydroxyl groups, an intermediate ethyl chain, and a terminal amine group.
The following catecholamines are present in the body:
- Dopamine
- Adrenaline
- Noradrenaline
All the catecholamines are derived from the amino acid tyrosine.
38
What are the macroscopic pathological features of schizophrenia?
1. Ventricular enlargement
2. Subtle reductions in total grey matter volume
3. Reduced brain volume (up to 5%)
4. Reductions in grey matter volume
5. Reduced asymmetry (planum temporale)
39
What are the functional brain changes associated with schizophrenia?
1. Decreased activation of prefrontal cortex (hypofrontality)
2. Increased activation of temporal regions during hallucinations
40
Describe contructional apraxia
An inability to copy a picture or combine parts of something to form a whole.
Damage in the parietal lobe of the brain, specifically the non-dominant hemisphere.
It is a common finding in patients with Alzheimer's disease
41
What is ideomotor apraxia
An inability to carry out learned tasks when given the necessary objects.
Patients with this type of apraxia can understand the concept of a task but cannot execute it on demand.
42
What is ideational apraxia
An inability to follow a sequence of actions in the correct order.
Patients with ideational apraxia can perform individual steps correctly but have difficulty linking them together in a coherent sequence.
43
What is limb kinetic apraxia
An inability to make fine/delicate movements.
Typically results from damage to the contralateral primary motor cortex.
44
What is occulomotor apraxia?
Difficulty moving eyes voluntarily from side-to-side while vertical eye movements are preserved. This condition usually presents as an inability to initiate rapid eye movements (saccades) towards an object of interest without using head thrusts.
45
What is Kluver-Bucy syndrome?
Bilateral dysfunction of the medial temporal lobes, including structures such as the amygdala and hippocampus, results in Kluver-Bucy syndrome. This syndrome is characterised by symptoms such as hyperorality, hypersexuality, visual agnosia, docility, and changes in emotional behaviour.
46
What is Kleine-Levin syndrome
A neurological disorder characterised by recurrent episodes of excessive sleep (hypersomnia), cognitive disturbances, and altered behaviour.
Its exact aetiology is unknown and it involves different brain regions.
47
What is Lesch-Nyhan syndrome
A genetic disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). It is not related to medial temporal lobe dysfunction. This syndrome is characterised by self-mutilating behaviours, hyperuricaemia, and neurological dysfunction.
48
Gourmand syndrome
A rare condition associated with lesions in the right frontal lobe. Characterised by a preoccupation with fine food.
49
Balint's syndrome
Caused by bilateral parietal lobe lesions.
It is characterised by optic ataxia, oculomotor apraxia, and simultanagnosia, affecting the patient's ability to perceive the visual environment as a whole.
50
Characteristics of Kuru (prion disease)
Tremors, ataxia, and emotional changes, including bouts of laughter, leading to the nickname 'laughing sickness'.
51
What is Amok
A culture-bound syndrome often seen in Southeast Asia, where individuals suddenly exhibit aggressive or violent behaviour following a period of social withdrawal or brooding.
'Running amok' is sometimes triggered by a perceived insult or stressor.
52
What is Dhat?
Dhat syndrome is a culture-bound syndrome primarily reported in South Asia. It involves anxiety and somatic symptoms associated with semen loss, which individuals may perceive as a depletion of vitality or masculinity.
53
What is Susto?
Commonly reported in Latin American cultures, Susto is believed to occur after a frightening or traumatic experience. It is characterised by a range of symptoms, including sleep disturbances, anxiety, and somatic complaints, which sufferers attribute to 'soul loss'.
54
What is Latah?
Latah is a culture-bound syndrome found primarily in Malaysia and Indonesia. It involves an exaggerated startle response, often accompanied by echolalia, echopraxia, and trance-like behaviours. It is often triggered by a sudden shock or fright.
55
Describe the differences between classic and variant Creutzfeldt-Jakob disease
In classic CJD: duration is shorter lasting a few months, it presents neurologically, MRI shows bilateral anterior basal ganglia high signal, EEG shows biphasic and triphasic waves 1-2 per second, it is genetic in origin, and affects older people aged 55-65.
In variant CJD: duration is longer lasting a year or more, it presents with psychiatric and behavioural symptoms, only later neurological symptoms, MRI shows Pulvinar sign, EEG shows generalised slowing, its origin is infected meat products and it affects younger people age 25-30.
56
What is Gerstmann-Sträussler-Scheinker (GSS) Syndrome?
An inherited prion disease caused by specific mutations in the PRNP gene, leading to slowly progressive ataxia and dementia.
57
What is Fatal Familial Insomnia (FFI)?
A genetically inherited prion disease caused by a mutation at codon 178 of the PRNP gene. It is characterised by progressively worsening insomnia, followed by autonomic and endocrine dysfunction, hallucinations, and motor disturbances.
FFI affects the thalamus, a region crucial for regulating sleep and consciousness, resulting in its hallmark insomnia. The disease course usually lasts about 12 to 18 months, ending fatally as severe neurodegeneration ensues.
58
How abundant is glutamate in the brain?
It is the most abundant neurotransmitter in the brain
59
Is glutamate an excitatory or inhibitory neurotransmitter?
It is always excitatory
60
Does glutamate act through ionotropic or metabotropic receptors?
It acts through both
61
What is prosopagnosia?
Face blindnesss
Usually resulting from damage to the fusiform gyrus
62
What is Astereognosia?
The inability to identify objects by touch. Typically arises from damage to the somatosensory cortex, particularly in the parietal lobe.
63
What is Anosognosia?
Inability to recognise own condition/ illness. Occurs due to brain injuries, particularly those affecting the right hemisphere of the brain.
64
What is Autotopagnosia?
Inability to orient parts of the body.
Associated with lesions in the left parietal lobe.
65
What is Phonagnosia?
Inability to recognize familiar voices
Linked to damage in the right temporal lobe or the right superior temporal sulcus.
66
What is Simultanagnosia?
Inability to appreciate two objects in the visual field at the same time or Inability to recognise a whole image although individual details are recognised.
(subtype of visual agnosia).
Usually results from bilateral damage to the occipital-parietal areas of the brain.
67
Name the 5 Projection white matter tracts
1. Corticospinal
2. Corticobulbar
3. Corona Radiata
4. Internal capsule
5. Geniculocalcarine Tract
68
Name the 2 Commissural white matter tracts
1. Corpus callosum
2. Anterior commissure
69
Name the 6 Association white matter tracts
1. Cingulum
2. Superior Occipitofrontal Fasciculus
3. Inferior Occipitofrontal Fasciculus
4. Uncinate Fasciculus
5. Superior Longitudinal (arcuate) Fasciculus
6. Inferior Longitudinal (occipitotemporal) Fasciculus
70
What is visual agnosia?
The inability to recognise familiar objects despite normal sensory apparatus
71
What is auditory agnosia?
A rare form of agnosia that manifests as an inability to recognise or differentiate between sounds, even though the person's hearing is normal.
72
What is the function of the lateral nucleus of the amygdala?
Often considered the primary input region of the amygdala, it receives sensory information and is involved in the initial stages of emotional learning, particularly fear conditioning.
73
What is the function of the basolateral nucleus of the amygdala?
It plays a crucial role in the processing and interpretation of emotional valence from the sensory input. It’s involved in cognition and attention, particularly regarding the emotional significance of events.
74
What is the function of the central nucleus of the amygdala?
It's the main output region for the amygdala and plays a significant role in the expression of emotional responses and initiation of the fight-or-flight response via connections with various brainstem areas.
75
What is the function of the medial nucleus of the amygdala?
This nucleus has connections with the olfactory system and is implicated in social and emotional behaviours, particularly those associated with olfactory cues.
76
What is the function of the Corticomedial Nuclei of the amygdala?
They are involved in the emotional response to olfactory stimuli and certain social behaviours. This nucleus projects to the ventromedial nucleus of the hypothalamus and it plays a role in behaviours associated with hunger and eating.
77
What is the role of the Basomedial Nucleus of the amygdala?
Involved in the modulation of autonomic responses and memory processing.
78
What is are the three classic features of Normal Pressure Hydrocephalus? (Hakim's triad)
Gait instability (wobbly)
Urinary incontinence (wet)
Dementia (wacky)
79
What is does imaging show in Normal Pressure hydrocephalus?
Hydrocephalus with an enlarged fourth ventricle
In addition to the ventriculomegaly there is typically an absence of substantial sulcal atrophy
80
What is the management of Normal Pressure Hydrocephalus?
Ventriculoperitoneal shunting
- around 10% of patients who have shunts experience significant complications such as seizures, infection and intracerebral haemorrhages
81
What is Nissl substance or Nissl bodies
Nissl bodies are specific to neurons.
These granules are made of rough endoplasmic reticulum and ribosomes, essential for the synthesis of neurotransmitters and other proteins that neurons require for their specialised functions.
82
What is the function of the smooth endoplasmic reticulum of the neuron?
1. Involved in lipid synthesis
2. Metabolism of carbohydrates
3. Regulation of calcium concentration
4. Drug detoxification
5. Attachment of receptors on cell membrane proteins
83
What is the node of Ranvier?
A gap in the myelin sheath of a nerve, between adjacent Schwann cells, which facilitates the rapid conduction of nerve impulses
84
What are the Perisylvian aphasias?
1. Global aphasia (MCA and ICA infarcts)
2. Broca's aphasia (superior division of the MCA)
3. Wernicke's aphasia (inferior division of the MCA)
4. Conduction aphasia (
85
What are the Extrasylvian aphasias?
1. Anomic aphasia (The lesion is often temporal parietal area. The angular gyrus may also be affected.)
2. Transcortical motor aphasia
3. Transcortical sensory aphasia
86
What is Alexia (without agraphia)?
Acquired loss of reading ability in a literate person, with preserved ability to write spontaneously.
Recognition of words spelled aloud and traced on the palm is normal. Only words presented visually pose difficulty.
Most commonly due to lesions of the left occipital lobe and the splenium of the corpus callosum, depriving the angular gyrus region critical for word recognition of visual input from either the left or right hemisphere. Causes include left PCA infarction, tumour, and demyelinating disorders such as multiple sclerosis (MS).
86
What is Alexia with agraphia
Loss of literacy (inability to read or write) but relatively well-preserved oral language function.
Lesion classically involves the dominant inferior parietal lobule (angular gyrus).
86
Which amino acid is essential for the synthesis of catecholamines?
(Dopamine, adrenalin and noradrenalin)
Tyrosine
86
Which amino acid is essential for the synthesis of serotonin and melatonin?
Tryptophan
86
What are the four most common types of brain tumours in adults?
1. Metastatic tumours
2. Glioblastoma multiformae
3. Anaplastic astrocytoma
4. Meningioma
87
What are the three most common types of brain tumours in children?
1. Astrocytoma
2. Medulloblastoma
3. Ependymoma
88
Describe the process of dopamine synthesis
Tyrosine - tyrosine hydroxylase - L-DOPA - dopa decarboxylase - dopamine
Firstly, tyrosine is converted into DOPA (dihydroxyphenylalanine) by the enzyme tyrosine hydroxylase. This step is rate-limiting, meaning it determines the speed of dopamine production. In the second step, DOPA decarboxylase converts DOPA into dopamine.
89
Aside from sleep regulation what other physiological roles does melatonin play?
1. Antioxidant properties
2. Immune modulation
3. Mood regulation
89
Describe melatonin synthesis and regulation.
Melatonin is a hormone synthesised in the pineal gland by serotonin. Its production is regulated by the circadian rhythm and environmental light exposure.
Release of melatonin is influenced by the suprachiasmatic nucleus (SCN) of the hypothalamus
89
What is the main site of norepinephrine release?
The locus coeruleus ("the blue spot" in the pons
90
Where is the foramen spinosum and what runs through it?
The middle cranial fossa
Middle meningeal artery
91
Where is the foramen ovale and what runs through it?
The middle cranial fossa
Mandibular division of the trigeminal nerve
92
Where is the foramen lacerum and what runs through it?
The middle cranial fossa
Small meningeal branches of the ascending pharyngeal artery and emissary veins from the cavernous sinus
93
Where is the foramen magnum and what runs through it?
The posterior cranial fossa
Spinal cord
94
Where is the jugular foramen and what runs through it?
The posterior cranial fossa
Cranial nerves IX, X, XI
95
Location, function and pathology of the Mammillary bodies.
Diencephalic structures located on the inferior and posterior aspect of the hypothalamus.
Functions in memory processing
Damage to the mammillary bodies can lead to diencephalic amnesia, as seen in Korsakoff's syndrome.
96
What is Korsakoff's syndrome?
This condition is characterised by severe memory impairment, including both anterograde and retrograde amnesia, often associated with chronic alcoholism and thiamine deficiency.
97
What are the hormones secreted by the anterior pituitary?
1. Growth Hormone
2. Thyroid stimulating hormone
3. Follicle stimulating hormone
4. Lutenising hormone
5. Adrenocroticotrophic hormone
6. Prolactin
98
What are the hormones secreted by the posterior pituitary?
1. Oxytocin
2. Antidiuretic hormone (vasopressin)
99
What is the Arbor vitae?
The tree-like arrangement of white matter in the cerebellum.
It facilitates the communication between different parts of the cerebellum, as well as between the cerebellum and other regions of the brain.
Clinically, damage to the arbor vitae can result in coordination and balance issues, as the cerebellum is essential for these functions.
100
What is the insula?
A region of the cerebrum deep within the lateral sulcus
Processes information associated with hearing and equilibrium
101
What is the fornix?
A region of white matter inferior to the corpus callosum
Links regions of the limbic system
102
What is the vermis?
An area of the cerebellum associated with bodily posture and locomotion
103
What is the folia?
An area of the cerebellum with fine, transversely-oriented pleat-like gyri on the surface of the cerebellum; increase surface area
104
What are the cerebellar peduncles?
Three pairs (superior, middle, and inferior). The cerebellum communicates with the rest of the nervous system via these peduncles
105
What dysfunction would arise from a lesion to the dominant parietal lobe?
1. Gerstmann's Syndrome: symptoms such as agraphia, acalculia, finger agnosia (inability to distinguish fingers), and left-right disorientation.
2. Language disorders: Such as aphasia
3. Alexia: The inability to read.
4. Anomia: Difficulty in finding the correct word
5. Impaired Writing and Mathematics
106
What dysfunction would arise from a lesion to the non-dominant parietal lobe?
1. Spatial Disorientation: Difficulty in perceiving the relationship of the body to space
2. Hemispatial Neglect: Ignoring or being unaware of objects or people on the opposite side of the lesion, commonly on the left if the right parietal lobe is damaged.
3. Constructional Apraxia: Difficulty in drawing or constructing objects.
4. Dressing Apraxia
107
What dysfunction would arise from a lesion to the dominant temporal lobe?
1. Language Disturbances: Since the dominant temporal lobe typically houses Wernicke's area, its dysfunction can lead to problems with language comprehension.
2. Memory Difficulties: specifically verbal memory and the ability to remember and understand language-based information.
3. Auditory Verbal Agnosia: Difficulty recognising spoken words.
108
What dysfunction would arise from a lesion to the non-dominant temporal lobe?
1. Impaired Recognition of Non-Verbal Sounds: Such as music or environmental sounds (auditory agnosia).
2. Emotional Recognition Issues: Trouble interpreting emotional cues in spoken language, like tone of voice.
3. Visual Memory Deficits: Problems may arise with non-verbal memory, such as remembering faces or places
109
What dysfunction would arise from a lesion to the dominant frontal lobe?
1. Hemiparesis/hemiplegia
2. Broca’s Aphasia
3. Executive Dysfunction: Challenges with planning, reasoning, problem-solving, and engaging in goal-directed behaviour.
4. Impaired Working Memory
5. Mood Changes
6. Motor Apraxia
110
What dysfunction would arise from a lesion to the non-dominant frontal lobe?
1. Hemiparesis/hemiplegia
2. Spatial Attention Deficits
3. Disinhibition
4. Poor Judgment of Time and Sequence
5. Expressive Deficits in Non-verbal Communication
6. Prosody Changes: Problems with the rhythm and inflection of speech
111
What dysfunction would arise from a lesion to the occipital lobe?
1. Visual Field Loss
2. Visual Agnosia: Difficulty recognising objects even though visual acuity is intact. This includes an inability to recognize faces (prosopagnosia) if the fusiform gyrus is involved.
3. Cortical Blindness: Complete or partial loss of vision in a normal-appearing eye. Sometimes associated with Anton's syndrome, the patient is unaware of their blindness.
4. Difficulty with Colour Perception (achromatopsia).
5. Hallucinations and Illusions
112
What dysfunction would arise from a lesion to the cerebellum?
1. Ataxia e.g. gait abnormality, clumsy body movements, and uncoordinated hand and eye movements.
2. Dysarthria
3. Nystagmus
4. Tremor: Particularly an intention tremor
5. Hypotonia
6. Cognitive Impairment
7. Dysmetria: The inability to judge distances or range of movement, leading to over or undershooting the target (as seen in finger-to-nose testing).
8. Adiadochokinesia
113
What dysfunction would arise from a lesion to the bilateral posterior parietal / occipital (Balint's) lobes?
1. Oculomotor apraxia (inability to voluntarily shift gaze despite the intact function of extraocular muscles).
2. Optic ataxia (disorder that affects the ability to interact with objects presented in the visual modality e.g. misreaching beyond a pencil when asked to touch it).
3. Simultanagnosia (the lack of ability to perceive more than a single object at a time.
114
What conditions are associated with damage to the medial thalamus and mammillary bodies
Wernicke's and Korsakoff's syndrome
115
What condition is associated with damage to the subthalamic nucleus of the basal ganglia?
Hemiballism
116
What condition is associated with damage to the striatum (caudate nucleus) of the basal ganglia?
Huntington's disease
117
What condition is associated with damage to the substantia nigra of the basal ganglia?
Parkinson's disease
118
What syndrome is associated with dysfunction of the amygdala?
Kluver-Bucy syndrome
- hypersexuality
- hyperorality
- hyperphagia
- visual agnosia
119
What syndrome is the result of occipital lobe damage?
Anton's syndrome
- Patients are cortically blind but unaware and deny they have a problem (anosognosia).
Often presents as the patient starts falling over furniture as they can't see. Affected individuals believe they can still see and describe their environments in detail but are wrong in their description (confabulation).
120
What condition would arise from damage to the cingulate cortex?
Akinetic mutism: severe reduction in voluntary movement and speech despite appearing alert
121
What is the function of the primary motor cortex (precentral gyrus)
Controls voluntary movements of specific body parts
122
What is the function of the premotor cortex?
Involved in the planning and execution of movements
123
What is the function of the prefrontal cortex?
Responsible for complex cognitive behaviour, decision making, and moderating social behaviour
124
Give two examples of ionotropic receptors
GABA-A
Glutamate
Nicotinic
Glycine
Serotonin (only 5HT-3)
125
Give two examples of metabotropic receptors
GABA-B
Glutamate
Muscarinic
Dopamine
Norepinephrine
Epinephrine
Serotonin (except 5HT-3)
Histamine
126
Which type of receptor results in an instant, short-lived, specific effects
Ionotropic
127
Which type of receptor results in longer, slightly delayed, diffuse effects
Metabotropic (G-protein)
128
What does the dexamethasone suppression test measure?
The response of the adrenal glands to ACTH.
Dexamethasone is given and levels of cortisol are measured. Cortisol levels should decrease in response to the administration of dexamethasone.
In 50% of depressed patients cortisol levels often do not decrease as expected. Abnormalities in the dexamethasone suppression test have also been reported in mania, chronic schizophrenia, and dementia.
129
What is the glucocorticoid-receptor hypothesis of depression?
Dysfunction of the HPA axis is linked to genetic or acquired defects of glucocorticoid receptors.
Some antidepressants (tricyclic) increase expression of glucocorticoid receptors but this is not the case for SSRIs
130
What symptoms are associated with Anti-NMDA receptor encephalitis?
Psychosis
Involuntary movements
Seizures
Reduced consciousness
Depression
Catatonia
Mutism
Paranoia
Cognitive impairment
131
What tumours are associated with Anti-NMDA receptor encephalitis?
Ovarian teratomas (less than 50%)
Occasionally other tumours in patients >45yo
132
Neurons in which area of the brain are usually localised in Anti-NMDA receptor encephalitis?
Hippocampus
133
What clinical manifestations usually arise from anti-AMPAR antibodies?
Associated with limbic encephalitis
Can present with:
Memory impairment
Confusion
Seizures
Mood and behaviour changes
Motor function changes
134
What are the clinical differences between GABA-A encephalitis and GABA-B encephalitis?
GABA-A tends to result in more serious seizures (which are also more treatment resistant) and GABA-B tends to show more limbic involvement with more prominent mood and memory symptoms.
135
Which hormones control appetite?
- Neuropeptide Y is produced by the hypothalamus and increases appetite
- Leptin is produced by adipose tissue and reduces appetite
- Ghrelin is produced mainly by the gut and increases appetite
- Cholecystokinine (CCK) is produced mainly by the gut and reduces appetite
136
How is dopamine metabolised?
Breakdown involves monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT).
137
What are the main effects of dopamine?
Affects reward pathways (mesolimbic), motivation (mesocortical), and movement (nigrostriatal pathway).
138
What is Hebbian theory?
When neurons fire simultaneously and repeatedly, the synaptic connection between them is strengthened.
This principle is foundational in understanding neuroplasticity and is crucial for both learning and memory formation.
139
Which area of the brain will show atrophy on a CT scan in Huntington's Disease?
The caudate nucleus
140
Asteroid bodies are characteristic of which inflammatory condition?
Sarcoidosis
141
What is the main metabolite of serotonin?
5-Hydroxyindoleacetic acid (5-HIAA) is the primary metabolite of serotonin.
Low levels of 5-HIAA in the CSF have been associated with increased risk of suicide and aggressive behaviour.
142
What is Atkinson-Shiffrin Memory Model?
Describes memory as a sequence of processes involving sensory memory, short-term memory, and long-term memory. This model focuses on how information is stored.
143
What is Broadbent’s Filter Theory?
Focuses on how information is filtered and processed through attention mechanisms in the brain. It deals with the sensory overload that humans experience by explaining how stimuli are selectively transmitted to conscious awareness.
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What is Lashley’s Mass Action Theory?
That memory is distributed across the cerebral cortex rather than confined to any specific area. It emphasises the role of cortical areas as a whole in the consolidation and retention of memories.
145
Serotonin receptors are mostly which type of receptor and what is the exception?
Serotonin receptors are G protein receptors except for 5-HT3 which is ligand gated
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5-HT1A activation receptors
- Decreased aggression
- Increased sociability
- Decreased impulsivity
- Inhibition of drug-seeking behaviour
- Facilitation of sex drive and arousal
- Inhibition of penile erection
- Diminished food intake
- Prolongation of REM sleep latency
- Reversal of opioid-induced respiratory depression
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How does the stimulation of 5-HT2A receptors affect sexual arousal?
Can lead to anorgasmia due to their role in inhibiting dopamine release, which is crucial for sexual arousal and orgasm.
148
What is 5-HT3 mostly associated with and name antagonists of this receptor
Agonism of this receptor leads to nausea
Antagonists include:
- ondansetron (primary mechanism)
- mirtazapine (secondary effect)
- vortioxetine (secondary effect)
- olanzapine (secondary effect)
- clozapine (secondary effect)
- aripiprazole (secondary effect)
149
Which serotonin receptor is mostly linked to circadian rhythm?
5-HT7
149
What are the genetic and environmental risk factors for MS?
HLA-DRB1 gene variations
Vitamin D deficiency
EBV infection
Smoking
150
Where is the planum temporale located?
The planum temporale is a region of the brain just posterior to the auditory cortex (Heschls' gyrus) and forms part of Wernicke's area.
Plays a role in language processing.
151
In which two areas of the brain is cerebral asymmetry noted?
Heschl's (transverse temporal) gyrus and Planum temporale
152
What is the role of Heschl's gyrus?
Initial auditory processing and basic auditory processing
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What is the role of the planum temporale?
Involved in more complex processing of auditory information e.g. determining the location of sounds in space and aspects of language comprehension.
Particularly known for its role in language processing.
Also involved in the cognitive processing of music.
154
Reduced planum temporale asymmetry is seen in which two conditions?
Dyslexia
Schizophrenia
155
Regarding asymmetry of the planum temporale, how much larger is it and on which side?
When can asymmetry be observed from and is there a sex difference?
Up to ten times larger in the left cerebral hemisphere than the right. This is true for up to 70% of right handed people. The asymmetry can be observed in gestation. There are no consistent sex differences in asymmetry
156
What are the common causes of Kluver-Bucy syndrome
Herpes
Late stage Alzheimer's
Frontotemporal dementia
Trauma
Bilateral temporal lobe infarction
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When (and where in the brain) would you see delta waves on an EEG?
Frontally in adults and posteriorly in children.
Seen in slow wave sleep (stage III) and in babies.
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When would you see theta waves on EEG?
Young children, drowsy and sleeping adults (stage I), certain medications, meditation.
Small amount seen in awake adults, excessive amount when awake may indicate pathology.
159
When and where in the brain would you see alpha waves on EEG?
Posteriorly
Seen when relaxed and when the eyes are closed (whilst awake). Also seen in meditation.
160
When and where in the brain would you see sigma waves on EEG?
Frontal and central regions
Also called sleep spindles
Bursts of oscillatory activity that occur in stage 2 sleep. Along with k-complexes they are the defining characteristic of stage 2 sleep
161
When and where in the brain would you see beta waves on EEG?
Frontally
When busy or concentrating
162
When would you see gamma waves on EEG?
Seen in advanced / very experienced meditators
163
What EEG findings would you see in sporadic CJD?
Early on there is non specific slowing, later periodic biphasic and triphasic synchronous sharp wave complexes superimposed on a slow background rhythm
164
What EEG findings would be seen in Huntington's?
Low voltage EEG, in particular no alpha (flattening)
165
What EEG changes would be seen in delirium?
Diffuse slowing, decreased alpha, increased theta and delta
166
What EEG findings would be seen in delirium tremens?
Hyperactive trace, fast
167
What EEG findings would be seen Alzheimers?
Reduced alpha and beta, increased delta and theta
168
What EEG findings would be seen in normal aging?
Diffuse slowing, which can be focal or diffuse, if focal most commonly seen in the left temporal region
169
What EEG findings would be seen in encephalopathy?
Diffuse slowing
170
Is lithium likely to increase or decrease alpha, beta, delta and theta waves?
Increase all
171
Which medications are likely to decrease alpha waves?
Clozapine
Lamotrigine
Valproate
172
Which medications are likely to increase theta and delta waves?
Clozapine and lithium
173
What is the effect of beta waves from lamotrigine and valproate?
Lamotrigine - decrease
Valproate - increase
174
What is palinopsia?
A visual disturbance characterised by the persistence or recurrence of visual images after the stimulus has been removed.
175
What macroscopic findings are evident in Huntington's disease?
Frontal atrophy
Marked atrophy of the caudate and putamen
Enlarged ventricles
176
What microscopic findings are evident in Huntington's disease?
Neuronal loss and gliosis in the cortex
Neuronal loss in the striatum
Inclusion bodies in the neurons of the cortex and striatum
177
What are the common auras preceding a temporal lobe seizures?
Abdominal aura (a rising epigastric sensation)
Psychic aura (fear, deja vu, jamais vu)
178
Describe Pseudobulbar affect and name a condition it is associated with.
A condition characterised by episodes of involuntary and uncontrollable laughter or crying that are disproportionate or inappropriate to the patient's emotional state.
It results from dysfunction in the pathways between the cerebral cortex, brainstem, and cerebellum, which are involved in emotional expression.
It is seen in motor neuron disease, especially ASL (Amyotrophic lateral sclerosis) and PBP (Progressive bulbar palsy)
179
What enzyme is responsible for alcohol related brain damage?
Transketolase (as it requires B1/thiamine as a co-factor)
180
What would possessing very active forms of alcohol dehydrogenase cause to occur when alcohol is drunk.
One would metabolise ethanol to acetaldehyde very quickly. This rapid conversion results in a build-up of acetaldehyde, which is toxic and can cause unpleasant effects such as flushing, nausea, headache, and palpitations when drinking alcohol. T
Similar to those experienced by people taking disulfiram (Antabuse).
