Consciousness and Pain Flashcards
What is consciousness?
Consciousness stems from sentience- awareness of internal or external existence
What two dimensions can consciousness be considered across?
Level of arousal/wakefulness and representational capacity for consciousness
What are the missing labels on the diagram? (exclude 5 and 6)
Is there a sleep-wake cycle in the following:
(a) coma
(b) vegetative state
(c) minimally conscious state
(d) locked-in syndrome
(a) No
(b) yes
(c) yes
(d) yes
What is locked in syndrome?
Usually occurs after a brain-stem stroke, where patients are unable to move to sense anything with their bodies. Can sometimes move eyes
What are 3 factors of the sleep wake cycle?
Circadian rhythm
Homeostasis
Cognitive pressure
What is the circadian rhythm?
Spontaneous 24 hr cycles that govern many things.
In line with melatonin (peak during day), cortisol (peak in the morning) and body temperature patterns throughout the day
Also influenced by light
What nucleus gets input from the retina about light levels and affects the circadian rhythm?
Suprachiasmatic nucleus
What is the ‘c process’ and ‘s process’ of sleep wake cycle?
Circadian rhythm= c
Homeostasis= s
What does the circadian rhythm regulate?
It regulates the body’s internal biological processes and alertness levels. This is what controls the timing of sleep and it coordinates the light-dark cycle of day and night. Your circadian rhythm is what regulates your body’s sleep patterns, feeding patterns, core body temperature, brain wave activity, and hormone production
What hormones rise and fall during the circadian rhythm?
Melatonin peaks during the day
Cortisol peaks in the morning
What is homeostasis (related to sleep wake cycle)?
the accumulation of sleep-inducing substances in the brain. It’s an internal biochemical system that operates like a timer, generating homeostatic sleep drive or the need to sleep after a certain amount of time awake
What do the graphs of process c and process s look like?
What did Constantin Van Economy find with hypothalamus damage?
Patients with frontal damage= insomnia state
Patients with posterior damage= zombie like, awake but not fully conscious
How are we sent off to sleep?
The ventrolateral pre-optic area (VLPO) sends out inhibitory GABAergic neurotransmitters that project to a number of conscious controlling centres
How do we wake up?
The tubberomammilary nucleus switches on histamine -> wakes up the cortex.
Then the posterior lateral hypothalamus secretes orexin/hypocretin -> activates the reticular activating system -> releases dopamine and AhC.
What is narcoplexy?
Low levels of CSF orexin, causes patient to fall asleep at inappropriate times
What are the 4 stages of sleep?
Awake, light, deep and REM
How long does a sleep cycle last?
Around 90 mins
What happens to the proportion of REM sleep as we sleep longer?
REM sleep (dream state) increases in proportion
What does the graph of sleep stages look like throughout the night?
What are some non-REM sleep disorders?
Sleep walking, confusional arousals and night terrors. Occurs in deeper stages of sleep