CNS Motor Flashcards
What is consciousness?
The level of arousal (awake, sleep)
What are the 2 ways of measuring consciousness?
With behaviour and brain activity
What is conscious experience?
Thoughts, feelings, desires, ideas, etc
Brain activity to determine consciousness is measured using […]
EEG
What does the EEG measure specifically?
The neuronal activities of neurons located near the scalp in the grey matter of the cortex
In an EEG, frequency is related to […] and amplitude is related to […]
Levels of responsiveness (state of concsiousness)
Synchronous neural activity
How can you tell when a seizure is occurring from an EEG?
The activity is VERY synchronized (Big amplitude)
How will an EEG differ between when an individual is relaxed and when an individual is alert?
When relaxed, an EEG will have slow frequencies and higher amplitudes Whereas an alert individual will have fast frequencies and lower amplitudes
When an individual is awake, their EEGs have a […] amplitude and a […] frequency.
low
fast
When an individual is relaxed with their eyes closed, the EEG pattern produced is called […]
Alpha rythm
When an individual is alert, the EEG pattern produced is called […]
Beta rythm
Describe how EEGs change as you go through different stages of sleep.
You start with an awake state (low amplitudes, high frequencies) and slowly, the amplitudes get higher and the frequencies slower. Until you reach the REM which is equivelant to being awake
Describe the sequence of a sleep cycle.
Stages: 1 -> 2 -> 3 -> 4 -> 3 -> 2 -> 1 -> REM -> 1…
In REM sleep, name 4 physiological differences from the rest of the sleep cycles.
- Increased eye movement
- Increased inhibition of skeletal muscles
- Increased heart rate
- increased respiration
What is sleep apnea? Describe its cause.
when there is a sudden reduction of respiration during sleep. often cause by relaxed skeletal muscles of the tongue that block the airways
What are the 3 major regions of the brain responsible for circadian rhythm?
Hypothalamus (preoptic area and Suprachiasmic nucleus)
Reticular activationg system
When you are awake, […] neurons are active.
Aminergic
When you are asleep, […] neurons are active.
Cholinergic
When you’re awake, describe the activity of the reticular activating system and the hypothalamus.
- There is a release of Neurotransmitters (norepinephrine and serotonin) by the reticular activation system which decreases acetylcholine
- There is less GABA so more histamine is released which activates the thalamus and cortex by the Hypothalamus
When you’re asleep, describe the activity of the reticular activating system and the hypothalamus.
- There is an increase in GABA release by the hypothalamus which reduces histamine release and decreases thalamus and cortex activity
- There is less norepinephrine and serotonin released by the reticular activating system which increases acetylcholine
What is motivation?
it produces goal directed behaviours
The motivational pathway is called the […]
Mesolimbic dopamine pathway
What is the major neurotransmitter involved in motivation?
Dopamine
How do drugs take advantage of the mesolimbic dopamine pathway?
They activate the pathway and make the behaviour enjoyable
Describe the major components of the mesolimbic dopamine pathway.
Dopamine goes in the locus ceruleus in the reticular activating system. It activates the midbrain and then the prefrontal cortex
What is the amygdala responsible for?
It modulates emotional response
What is the hippocampus responsible for?
Memory
Give two examples of altered states of consciousness.
Schizophrenia and mood disorders (depression, bipolar disoder)
What are the two types of memories? Explain the difference between them.
Declarative: conscious experience that can be put into words
Procedural: Skilled behaviour
What is consolidation?
The movement of information from short-term memory to long-term memory
When does consolidation occur?
During sleep
What parts of the brain are involved in short-term vs long-term declarative memory?
Short: Hippocampus and temporal lobe
Long: Associated cortex
What parts of the brain are involved in short term vs long term procedural memory?
Short: Widely distributed
long: Basal nuclei, cerebellum, premotor cortex
Where are the brain structures involved in language mainly located?
Usually in the left hemisphere, in the frontal cortex (Broca’s area) and the temporal lobe (Wernicke’s area)
What are the two regions of the brain involved in language? State their function.
Broca: articulation
Wernicke: comprehension
Someone with a language deficit has […]
Aphasia
What is the cause of sensory neglect? How does it manifest?
Usually a stroke in the parietal lobe. People don’t comprehend that the contralateral side (damaged side) exists
What are the two types of motor behaviour?
Volontary and reflexive
What is the difference between extension and flexion?
Increase the angle of the joint for flexion and decrease the angle of the joint for extension
During extension, how do the flexor and extensor muscles behave?
Extensor: contracts –> agonist
Flexor: relaxes –> antagonist
During flexion, how do the extensor and flexor muscles behave?
Extensor: relaxes –> Antagonist
Flexor: contracts –> agonist
Are motor neurons excitatory or inhibitory?
Excitatory
The neurotransmitter released by motor neurons is […]
Acetylcholine
What are the two types of motor neurons? What part of the muscle do they innervate?
Alpha: Skeletal (extrafusal) muscle
Gamma: Muscle spindles (infrafusal
Where are the cell bodies of motor neurons found?
In the ventral horn of the spinal cord or the brain stem (cranial nerves)
Describe the relationship between the spinal afferent pathways and the motor efferent pathways.
When a sensory afferent neuron makes its way the spinal cord, it splits in two:
1. It goes to the dorsal column to reach the brain
2. It activates an interneuron that will then activate a motor efferent
NOTE: the interneuron will also receive input from descending motor commands
Name the 4 types of input that interneurons respond to/are involved in.
- Proprioceptive feedback
- Pain
- Voluntary movements from descending pathways
- Coordinates complex movements with info from other spinal levels
Name 2 types of monitoring done by the spinal interneurons.
- Tension monitoring
- Length monitoring
What are the 3 types of spinal reflexes?
withdrawal reflex
stretch reflex
Inverse stretch reflex
What is the function of the withdrawal reflex?
Protects limbs from injury