CNS - Lecture 5 Flashcards
Functional divisions of the cerebellum and functions
- Vermis: posture , control of movements of neck and axial (truck) musculature
- Intermediate zone: locomotion control
- flocculonodular lobe: controlling balance
of large nuclei deep within the cerebral hemispheres
basal ganglia
the basal ganglia forms the
extrapyramidal system
The extrapyramidal system is involved in
initiating movement and suppressing the activity of muscles that would resist the intended movement
what does electroencephalogram (EEG) do?
monitors electrical activity in the brain
What are the two phases of sleep
NREM (N1, N2, N3) and REM
NREM stands for
non-rapid eye movement
REM stands for
rapid eye-movement
Each stage of NREM is characterized by an ____ pattern with lower __________ and larger _________ than the previous one; harder to wake someone as they progress through
- EEG
- frequency
- amplitutde
EEG waves in N1 (light)
- alpha waves become reduced in frequency and amplitude and the percentage of time that they are present
- some theta waves
EEG waves in N2 (further lack of sensitivity)
- alpha waves are replaced by random waves of greater amplitude
EEG waves of N3 (deep sleep)
- more theta and delta activity
The stage of sleep associated with dreaming and rapid eye movements, muscles of the body are the most relaxed and yet brain very active
Rapid Eye Movement or REM sleep
Brain waves during REM are characterized by a _____ rhythm that mimic activity during the _____ state
- beta
- awake
During ~8 hours of sleep the EEG reveals _____ cycles of deep and light sleep
5
Duration of a sleep cycle is
90 minutes
what is the sequence of stages a person moves through in each sleep cycle
N1 > N2 > N3 > N2 > REM
What are sleep spindles and what sleep state can they occur in
- large amplitude, high frequency bursts
- N2 stage
a set of characteristics used to classify the level of consciousness of a person
Glasgow Coma Scale
The Glasgow Coma Scale is based on:
- eye movements
- responses to questions
- ability to make voluntary movements
3 main determinants taken of brain death
- the nature and duration of the coma must be known
- cerebral and brainstem function are absent
- flat EEG for 30 minutes
During wakefulness, visual and other sensory inputs activate neurons in the
reticular activating system
Neurons in the reticular activating system release ______ to the _________ and other brain areas
monoamines
hypothalamus
3 types of monoamines
norepinephrine
serotonin
histamine
Hypothalamus supplies _______ to the ________ and _________ to maintain wakefulness
orexins
thalamus
cortex
What two mechanisms of the suprachiasmatic nucleus set the circadian rhythm?
- activates orexin-producing neurons in the morning
- secretes melatonin at dusk
sleep centre: location and function
- found in the preoptic nucleus of the hypothalamus
- causes GABAergic inhibition to the reticular activating system to reduce orexin levels
small lesions in the reticular-activating system can produce a
coma
the limbic system is concerned with
memory and motion
the limbic system triggers the drive to
explore and move
** see document for transtions to the awake and sleep states
what effect does the release of monoamines by orexin neurons have
- inhibits the sleep centre
- activation of large parts of the cortex via the thalamus
2 main aspects that are part of the conscious experience
- selective attention
- conscious perception
CNS areas implicated in triggering shifts:
thalamus and locus ceruleus in brainstem RAS
selective attention is when
attention shifts from one focus or attractor to another
visual and auditory inputs coming from the same direction or _________ __________ are more likely to trigger a shift than separate attractors.
coincident attractors
A central brain area selects and illuminates a temporary set of neurons in different separated brain areas
conscious perception
See document for consciousness experiences
primary motivated behaviour is directly related to
homeostasis
secondary motivated behaviour results in
pleasure
what releases dopamine
a pathway in the brainstem nuclei within the frontal lobe of the brain
emotional behaviour is
external responses to internal attitudes
electrically stimulating the lateral hypothalamus results in
rage
lesions of the amygdala can result in
the absence of fear
in what way do anti-depressants act
by maintaining levels of serotonin and norepinephrine in the CNS
T/F a single cluster of neurons is responsible for the generation of all the emotions
F - different parts of the brain can be stimulated to create different types of emotion
substance dependence is diagnosed when ___ or more of the __ specified criteria occur within a ___ month period
3
7
12
working memory is
easily acquired but quickly lost
episodic working memory refers to
recent events and places
visuospatial working memory refers to
recent sights and locations
phonological working memory refers to
recent words and sounds
Long-term memory - acquisition and length
- has a slower period of acquisition
- lasts for much longer, even a lifetime
declarative long-term memory includes
- semantic (facts: ice is cold)
- episodic (personal experiences)
procedural long term memory includes
- stimulus-response behaviours
- motor skills
laying down or consolidation of the memory trace is the transfer from
short term memory to long term memory
The caudate nucleus is part of the
basal ganglia
the caudate nucleus is involved in
consolidating stimulus to response behaviours and solving sequence tasks
amnesia is the
the absence of memory
retrograde loss of s.t.m
loss of memory of events prior to the injury
anterograde loss of s.t.m
loss of memory of event after the injury
complete anterograde amnesia resulting from damage to the hippocampus
Korsakoff’s syndrome
involves the degeneration of memory-holding neurons, perhaps due to proteins called amyloid precursor proteins that cause excitotoxicity; the neurons are damaged by over-excitation
Alzhemer’s disease
a concussion is measured by type and duration of
amnesia
