L18: Higher brain functions Flashcards
1
Q
Vegetative state
A
- may show signs of being conscious - e.g. eyes open, sleep wake cycles, autonomic function → pupil reflexes
- no cognitive function, no sense of self awareness
2
Q
Coma
A
prolonged absence of wakefulness or awareness, no response to external stimuli, unable to be roused, lacks normal sleep-wake cycle.
3
Q
normal brain activity vs during a seizure
A
- normal brain activity = not synchronised, small amplitude
- seizure = large amplitude, synchronised events, brain areas appear to be firing at the same time
4
Q
anti-seizure drugs
A
- ion channels → don’t completely block but subtilely modulate
- or increase GABAa receptors - neurotransmitter modulated ion channels
= lower levels of excitability in the brain
5
Q
drivers of sleep (2)
A
homeostatic: build up of homeostatic pressure to sleep (comes back to the definition)
- adenosine → inhibitory effect on CNS activity
circadian
- Controlled by suprachiasmatic nucleus (SCN)
- informs rest of body via endocrine circuits
- regulated by exposure to light
- SCN outputs: pineal gland - secretes melatonin, promotes sleep
6
Q
3 sleep states
A
drowsy, slow wave sllep, REM sleep
7
Q
5 stages of SLS
A
- stage 1 = theta waves
- stage 2 = theta interupted by sleep spindes (burst of activity at higher frequency) and K complexes (large slow spikes)
- stage 3 = delta waves with spindles
- stage 4 = just delta waves (long, slow waves)
8
Q
Sleep → wakefulness transitions
A
- regulated neurons in the brainstem called the reticular activating system (RAS)
9
Q
reticular activating system (RAS)
A
- projects to the hypothalamus, thalamus and cortex
- RAS & thalamus modulates throughput of sensory information to cortical regions
- hypothalamus: makes neuropeptide orexin = wakefulness
10
Q
orexin
A
- wakefulness hormone
- orexin inhibited by melatonin
- defective orexin system = narcolepsy
