Lecture 22 Flashcards
What is echolocation?
The emission of sound in order to localize objects based on echoes (outgoing signal=chirp) (incoming signal=echoe)
How do we find out how humans use echolocation?
Compare brain activity (using fMRI) between controls and blind “echolocationg experts”
What are some of the findings from human echolocation experiments?
Blind echolocators have more activity in the temporal and visual lobes
How do we measure sleep?
EEGs
What kinds of rhythms is the waking state associated with?
Beta rhythms-fast activity waves, 15-30hz
What rhythms is the drowsy state associated with?
Alpha rhythms-large regular waves, 7-11hz
What types of rhythms is deep sleep associated with?
Delta rhythms-large, slow wave activity, 1-3 hz
What are the 5 points of sleep?
- W-Waking, Beta rhythms
- N1-NREM stage 1, mixed activity (theta waves)
- N2-NREM Stage 2, sleep spindles (11-16hz)
- N3-NREM stage 3, delta rhythm
- R-Rem
Whata is rem sleep characterized by?
Twitches and eye movements, atonia (complete muscle inactivty produced by inactivation of motor neurons), sometimes referred to as paradoxical sleep.
What are the 2 general categories that sleep can be divided into?
- NREM dominant-early sleep periods
2. REM dominant-later sleep periods (occurs in 90 minute cycles)
How is sleep a biologically adaptive behaviour?
Energy conservation strategy-food gathering occurs at optimal times, energy is conserved for later.
What types of animals tend to sleep more/less?
Predators sleep more, prey sleeps less, due to time required to obtain food and predation risk
What does energy conservation using sleep help with?
Brain activity, body temperature, posture.
What is the basic-rest activity cycle?
Recurring cycle of temporal packets (roughly 90 mins), during which an animals level of arousal waxes and wanes.
What is memory consolidation?
The process of stabilizing memory trace after learning
What kinds of things can happen if you don’t get enough sleep?
Potential for build up of Alzheimer’s protein, (beta amyloid protein), less metabolic clearance.
What is the lymphatic system?
Part of the immune system that aids in the removal of toxins- removal of intersitial fluid from tissues, transport of fatty acids from digestive system, transport of white blood cells.
What is the glymphatic system?
Similar system to the lymphatic system in the brain-CSF interacts with interstitial fluid to remove protein by-products (including beta amyloid)
What happens with CSF fluid during sleep?
It floods the brain, basically cleaning it up.
What is the reticular activating system?
Regulates sleep-stimulation causes a waking state EEG< whereas damage may induce coma (slow wave EEG)
What are the 2 systems involved in producing a waking EEG?
1) Basal forebrain- secretes ACh during awake, but mobile periods
2) Median Raphe- secretes 5HT during movement
What is the flip-flop switch hypothesis?
Orexin neurons stimulate the reticular activating system, raphe, and basal forebrain causing us to feel more awake. This then goes onto the ventral lateral preoptic nucleus (hypothalamus), which induces drowsy feelings. This signal gets sent to the orexin neurons, and we basically flip flop between sleepiness and awakeness.
What are somnogens?
Endogenous substances that increase sleepiness or promote sleep
What are the 2 types of somnogens?
Prostaglandin D2- reduces body temp
Adenosine- inhibition in CNS
What somnogen does caffeine act on?
Adenosine
What is narcolepsy and why is it caused?
Uncontrollably falling asleep at inconvenient times. Caused due to a lack of orexin neurons that stimulate awakeness.
What is sleep hygiene?
The controlling of all behavioural and environmental factors that precede sleep and may interfere with sleep
What are some ways to improve sleep hygiene?
Fix a bedtime and awakening time, avoid naps, avoid caffeine 4-6 hours before bed, avoid heavy meals immediately prior to sleep, reserve bed for sleep and sex, exercise regularly (But not within 3 hours of bed time)
