Session 10 Flashcards
(35 cards)
What is the role of the reticular formation?
Regulates the level of arousal.
What are the main inputs to the reticular formation?
Sensory system and the cortex.
What are the main outputs from the reticular formation?
Thalamus, hypothalamus, basal forebrain nuclei and the spinal cord.
Which neurotransmitter is used between the reticular formation and the thalamus/hypothalamus/basal forebrain nucleus?
ACh
Which neurotransmitter is used between the thalamus and the cortex?
Glutamate
Which neurotransmitter is used between the hypothalamus to the cortex?
Histamine
Which neurotransmitter is used between the basal forebrain nucleus to the cortex?
ACh
What is the role of the reticular formation?
Functions in sleep regulation, motor control, cadiorespiratory control, autonomic functions and motivation and reward.
What is the role of the ascending reticular activating system?
Has many inputs, all of which output to the motor system, autonomic centres, thalamus and cortex, to raise the levels of consciousness.
What is the role of the ARAS when an individual is awake (and REM sleep)?
Stimulates the cortex for consciousness. Also stimulates inhibitory neurones to act on inhibitory interneurones, further stimulating the cortex.
What is the role of the ARAS during slow wave sleep?
The neurones from the ARAS are silent, hence no thalamo-cortical neurones are firing and there is significantly reduced consciousness.
What inhibits the ARAS?
Hypothalamic sleep centres for sleep to occur.
Describe the EEG recording of a normal, awake subject at rest.
High frequency beta-activity, low voltage pattern.
Describe the EEG recording if a subject closed their eyes and became drowsy.
Lower frequency alpha-activity, but slightly higher voltage. Due to firing of many cortical neurones following thalamocortical activity.
Describe the EEG recording of stage 1 sleep.
Alpha-activity with some theta waves.
Describe the EEG recording of stage 2 sleep.
Mainly theta waves, with sleep spindles and k-complexes.
Describe the EEG recording of stage 3 sleep.
Large amplitude, slow delta rhythms. Few eye and body movements.
Describe the EEG recording of stage 4 sleep.
Deepest stage, large EEG rhythms of 2Hz or less.
Give two reasons why sleep is important.
Resetting the CNS, memory and homeostasis.
Describe non-REM sleep.
Stage 3 and 4. Slow wave sleep, active body and inactive brain. Eyes are still. Large role in neuroendocrine functioning. Decreased cerebral blood flow, oxygen consumption, blood pressure, and resp rate.
Describe REM sleep.
Active brain and inactive body. EEG will appear as if awake. Individual is hard to disturb and commonly dreams. Irregular HR and RR, increased BMR and penile erection. Cholinergic and serotonergic neurones switch on REM sleep.
What is narcolepsy?
Attacks of sleep where it does not normally occur. Can also cause sleep paralysis in which they remain awake at night. May be deficient in orexins.
What is insomnia?
Chronic inability to fall asleep despite appropriate opportunities to do so. Can give hypnotics, e.g. benzodiazepines.
What is sleep apnoea?
Interruption in breathing during sleep, leading to arousal from sleep or results in the lighter stages on non-REM sleep in order for breathing to be maintained. Upper airway at the back of the throat collapses during sleep.