CNS/Sensory VIII Flashcards
What is consciousness?
It is the level of arousal of an individual.
What are the 2 ways of measuring consciousness?
Behaviour and brain activity.
What is conscious experience?
This refers to a capacity to experience one’s existence rather than just recording it or responding to stimuli.
Brain activity to determine consciousness is measured using […]
The EEG
What does the EEG measure specifically?
It measures the activity 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 […]
Responsiveness, synchronous neural activity
How can you tell when a seizure is occurring from an EEG?
The amplitude will be very large (very high levels of synchronicity) and the frequency will decrease.
How will an EEG differ between when an individual is relaxed and when an individual is alert?
When they are relaxed the frequencies will be slow and the amplitudes will be higher. When they are alert the frequencies will be faster and the amplitudes will be low.
When an individual is awake, their EEGs have a […] amplitude and a […] frequency.
Low, high
When an individual is relaxed with their eyes closed, the EEG pattern produced is called […]
An alpha rhythm
When an individual is alert, the EEG pattern produced is called […]
A beta rhythm
Describe how EEGs change as you go through different stages of sleep.
As you go from stage 1 to stage 4, the EEG goes from low amplitude and high frequency to high amplitude and low frequencies. When you enter REM sleep, the EEG is low amplitude and high frequency.
Describe the sequence of a sleep cycle.
Awake -> stage 1 -> stage 2 -> stage 3 -> stage 4 -> stage 3 -> stage 2 -> stage 1 -> REM -> stage 1 (restarts)
In REM sleep, name 4 physiological differences from the rest of the sleep cycles.
- Increased eye movement
- Increased inhibition of skeletal muscle
- Increased heart rate
- Increased respiration
What is sleep apnea? Describe its cause.
It is a sudden reduction in respiration during sleep because of the skeletal muscle inhibition during REM sleep, which causes the tongue to relax and block breathing. This interrupts the sleep cycle.
What are the 2 major regions of the brain responsible for circadian rhythm?
Reticular activating system and hypothalamus.
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.
Reticular activating system: releases norepinephrine and serotonin (aminergic), downregulates acetylcholine.
Hypothalamus: releases histamine and downregulates GABA.
When you’re asleep, describe the activity of the reticular activating system and the hypothalamus.
Reticular activating system: downregulates norepinephrine and serotonin (aminergic), releases acetylcholine (cholinergic).
Hypothalamus: releases GABA, which downregulates histamine.
What is motivation?
It is the ability to assess reward which produces goal-directed behaviour.
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 cause the release of amphetamines, which cause the additional release of dopamine.
Describe the major components of the mesolimbic dopamine pathway.
Starts in the reticular activating system, then travels to the midbrain, then to the prefrontal cortex.
What are the two major components of the limbic system?
Amygdala and hippocampus.
What is the amygdala responsible for?
It encodes emotional responses to a given sensory input.
What is the hippocampus responsible for?
Memory.
Give two examples of altered states of consciousness.
Schizophrenia or mood disorders such as depression and bipolar.
What is the cause of depression?
Decreased activity in the anterior limbic system.
How do you treat depression?
Increasing the levels of serotonin and norepinepherine around synapses.
How do you treat bipolar disorder?
Treatments include lithium, which reduces certain synaptic signaling pathways.
What are the two types of memories? Explain the difference between them.
Declarative: conscious experiences that can be put into words
Procedural memory: skilled behaviours
What is consolidation?
It is the transfer of information from the short-term to the 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 term: the hippocampus and other temporal lobe structures
Long term: many areas of association cortex
What parts of the brain are involved in short term vs long term procedural memory?
Short term: widely distributed
Long term: basal nuclei, cerebellum, premotor cortex
Where are the brain structures involved in language mainly located?
In the left hemisphere.
What are the two regions of the brain involved in language? State their function.
Broca’s area: articulation
Wernicke’s area: comprehension
Someone with a language deficit has […]
Aphasia.
What is the cause of sensory neglect? How does it manifest?
It is caused by damage to one parietal lobe. Individuals will stop being able to process sensory inputs from the contralateral side of the body.
