Brain and Behaviour Flashcards
1
Q
- what is consciousness?
- How does awareness differ from vigilance?
- Describe the following
a) locked in syndrome
b) minimally conscious state
c) unresponsive wakefulness syndrome
d) chronic coma
e) brain death - which part of the brain has been shown by PET scan to be involved in awareness and attention?
A
- a state of being aware and responsive to one’s surroundings
- awareness refers to the level of consciousness, whilst vigilance refers to the display of awake behaviours. People may be vigilant without being aware and visa versa
3a) normal awareness, sleep wake cycles and meaning ful behaviour but is isolated due to facial and body paralysis
3b) intermittent periods of awareness and wakefulness, displays some meaningful behaviour
3c) also known as vegetative state. normal sleep wake cycles but lack of awareness. displays only reflexive and non-purposeful behaviour
3d) lack of awareness and sleep wake cycles. Only displays reflexive behaviours
3e) lacks awareness, sleep wake cycles and brain-derived reflexive behaviour
2
Q
- what is the biggest cause of loss of consciousness worldwide?
- name 7 causes of loss of consciousness (common in UK)
A
- malaria
- stroke
- diabetes
- drug induced
- epilepsy
- head injury
- raised intracranial pressure
- dementia
- metabolic disorders
- stroke
3
Q
- What are the eye responses in the Glasgow coma scale
- what are the verbal responses in the Glasgow coma scale?
- what are the motor responses in the glasgow coma scale?
- What score or less mostly equals coma
- why is this score a critical score?
A
- 1) no response 2) opening in response to pain 3) opening in response to speech 4) spontaneous opening
- 1) no verbal response 2) incomprehensible speech 3) inappropriate speech 4) confused conversation 5) orientated conversation
- 1) no response to pain 2) extension posturing to pain 3) abnormal flexion response to pain 4) withdraws to pain 5) localising response to pain 5) obeying command
- 8
- 50% of patients with a score of 8 or less at 6 hours will die.
4
Q
- Name the 4 criteria for brainstem death
2. describe the 6 tests for brainstem death
A
- must be unconscious and fail to respond to outside stimulation
heartbeat and breathing must only be maintained using a ventilaor
clear evidence that brain damage has occurred and is irreversible
condition must not be reversible - pupil response - shine torch in eyes to examine pupil constriction
corneal reflex - stroke cornea
vestibular occular reflex - cold water in eyes
apply supraorbital pressure to elicit motor response
cough/gag reflex to pharyngeal stroking
respiratory effort when ventilator is disconnected
5
Q
- name the brainstem area that is particularly important for consciousness
- what is this area?
- name the neurotransmitters used by this part of the brainstem
A
- reticular activating system
- group of nuclei found thoughout the midbrain. It is a diffise area with no clear anatomical boundaries. They send outputs to every part of the CNS
- dopamine (ventral tegemental area)
noradrenaline (locus coerulus)
AcH (cholinergic nuclei)
Serotonin (raphe nuclei)
6
Q
What neurotransmitter, and what roles do the following RAS nuclei have? What conditions are these regions associated with?
- Locus Coerulus
- Raphe Nuclei
- Ventral Tegemental Are
- Cholinergic Nuclei
A
- Noradrenaline. Active during arousal and in response to novel stimuli. Participates in general arousal - noradrenaline acts to make the cerebrum more responsive to salient sensory stimuli. Associated with anxiety disorders and depression
- Serotonin. Active during awake state. Helps regulate circadian rhythm and enkephalin release (pain response). Associated with depression and OCD
- Dopamine. Projects to frontal cortex and limbic system. Involved in reward circuitry and promotes wakefulness and attention. Associated with addiction, schizophrenia and ADHD
- AcH. Active during states of arousal. Induce wakefulness and REM sleep. Also contributes to synaptic plasticity in learning and memory. Implicated in Dementia.
7
Q
- What is sleep?
- Describe the following EEG rhythms:
a) beta rhythms
b) alpha rhythms
c) theta rhythms
d) delta rhythms - What are the characteristics of:
a) REM Sleep?
b) non-REM Sleep?
A
- a readily reversible state of reduced responsiveness to and interaction with the environment.
2a) fastest; indicate active cortex
2b) associated with quiet waking states
2c) occur during some sleep states, primarily transitional sleep
2d) large in amplitude. Hallmark of deep sleep
3a) desynchronised EEG rhythms - beta waves. Abolition of muscle tone and increased sympathetic activity.
3b) synchronised and sloe EEG waves - delta waves. reduced muscle tension and movement. increased parasympathetic activity.
8
Q
- What are the general effects of RAS neurotransmitters?
- What happens to RAS neurons when a person is falling asleep?
- Describe the role of the thalamus during sleep-wake cycles
- Which RAS system/nuclei is implicated in REM sleep?
- How does Adenosine promote sleep?
- When and where is melatonin produced?
- Which hypothalamic nucleus is implicated in circaidian rhythms?
- How does it do so?
A
- depolarisation/increase in excitability; suppression of rhythmic firing that is seen in sleep states
- decrease in firing rate
- produce rhythmic firing projecting to all cortical areas, to produce the oscillatory EEG patterns seen in sleep states
- Ach?cholinergic neurons
- has an inhibitory effect on AcH, 5-HT and NA
- produced by pineal gland when environment darkens
- Suprachiamsatic nucleus
- indirectly modulates the pineal gland.
9
Q
- What is declarative memory?
- what is non-declarative memory?
- what is procedural memory?
- what is episodic memory?
- what is semantic memory?
- what is working memory?
- what is retrograde amnesia?
- what is anterograde amnesia?
A
- memory for facts and events
- memory that is acquired and used unconsciously
- a type of non-declaritive memory for skills behaviours and habits
- declarative memory for events
- declarative memory for facts
- temporary form of information storage that is limited in capacity and requires rehersal
- memory loss of previous events/loss of old memory
- inability to form new memories
10
Q
- Why do we forget things from short term memory?
- why do we forget things from our long term memory? (2)
- How can we make long term memory retrieval more effective? (2)
A
- attention is diverted and we do not rehearse them (decay and displacement)
- inaffective cues
many similar memories that cues can’t separate (interference) - association with spacial location (childhood home; studying at a desk)
association with emotional cue
11
Q
- What is amnesia?
- name 5 common causes of amnesia
- what are these causes all associated with?
A
- memory loss - either loss of old emotions or disruption to the process of forming new emotions
- viral infection; long term alcoholism; anoxia; head injury; alzheimer’s disease
- All are associated with damage to the medial temporal lobes
12
Q
- which structure is the most critical structure for long term memory?
- which other structures are involved in long term memory? (4)
- what is required for the formation of an episodic memory? (3)
- where are episodic memories stored?
- what happens to episodic memories over time?
A
- hippocampus
- temporal lobe. prefrontal cortex. fornix. amygdala
- combo of place, people and object. Involves synaptic plasticity within the hippocampus
- hippocampus
- direct connections are made in the neocortex; old memories become stored in neocortex
13
Q
- describe the temporal gradient of amnesia
- what types of memory are preserved in amnesia?
- what is semantic dementia?
- what is it caused by? Which structure is preferentially spared?
- what are the effects on memory of semantic dementia?
A
- childhood memories left in tact. Events shortly before brain damage are forgotten. Events since brain damage are not remembered
- semantic memories and non-declarative memories
- subtype of frontotemporal dementia, causing damage to the frontal or temporal lobes
- damage to the neocortical memory store. Hippocampus is spared
- loss of semantic memory. Episodic memory is spared (reverse temporal gradient)
14
Q
- what does behaviour concern?
- what is a behavioural phenotype?
- what is polygenic inheritance?
- what is heritability?
A
- personality, cognitive abilities and choices we make, within the normal range and those that are considered disordered/abnormal/problematic
- observed or measured behavioural traits
- contribution of a large number of genes with small cumulative effect to significant heritability of a behavioural phenotype, with a normal distribution
- the proportion of a phenotypic variance that can be accounted for by genetic differences
15
Q
- what is a “shared envionment”?
- what is a “non-shared environment?”
- what does non shared environment include (2)
- name 4 things that are considered to be “environment”:
- what is the gene-environment correlation?
- what is the gene-environment interraction?
A
- non-genetic factors experienced by all siblings/both twins
- the non-genetic factors that do not correlate between siblings or twins
- error of measurement in the behavioural trait concerned (which leads to the over estimates of non-shared environment contribution)
differences in the way siblings/twins are treated by their parents; different friends they choose etc - prenatal environment
nutrition
illness
social factors - life experiences that correlate with genetic propensity/predisposition
- impact of environment modulated by genetics or the modulation of genetics (epigenetics) by environment
