How Lightbulbs Made Alarm Clocks

How light bulbs made alarm clocks

Lorcan Walsh, Ph.D. @lc_walsh

Why do we Sleep?

Why do we sleep

3 psychological theories of sleep: Restorative/repair

• Increased cell division & protein synthesis

• Flushing out of waste toxins from the brain

Evolutionary / Adaptive / Homeostatic

• Avoiding predators

Memory consolidation

• Neurons activating in response to stimuli in correct order during REM sleep

• Sleep deprivation reduces short-term memory consolidation

Berger - Brain waves & EEG in Man

1953 Kleitman & Aserinsky - REM Sleep

1937 Loomis - EEG during Sleep and characterisation of Non REM sleep

1929

1957 Dement & Kleitman - Human Sleep CycleSlee

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A Brief History of Sleep Research

1999

1963 Light & suppressing melatonin

1999 Melanopsin ganglion cells

Intrinsic circadian period 24.2 hrs

1971 Retino-hypothalamic tract

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1929


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A Brief History of Sleep ResearchTimeline


1999

1963 Light suppresses melatonin

1999 Melanopsin ganglion cells



1929

Intrinsic circadian period of 24.2 hrs

1971 Retino-hypothalamic tract


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Narcolepsy - Excessive daytime sleepiness and cataplexy. Early REM onset.

1880

Restless Leg Syndrome (up to 10%) - Severe discomfort in the legs, and jerking legs while asleep

1950s

REM Sleep Behaviour Disorder - skeletal muscle remains active during sleep. - associated to neurologic disorders (LBD, Parkinsons)

1990s

Obstructive Sleep Apnea - Upper airway constriction and resulting sleep fragmentation. 2-4% of women, men respectively.

1966

TimelineSl

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Bio

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Med

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Narcolepsy - Excessive daytime sleepiness and cataplexy. Early REM onset.

1880

Restless Leg Syndrome (up to 10%) - Severe discomfort in the legs, and jerking legs while asleep

1950s

REM Sleep Behaviour Disorder - skeletal muscle remains active during sleep. - associated to neurologic disorders (LBD, Parkinsons)

1990s

Obstructive Sleep Apnea - Upper airway constriction and resulting sleep fragmentation. 2-4% of women, men respectively.

1966


How light bulbs made alarm clocks

Our Sleep Routines have changed

7am 11pm12pm 6pm

Industrial & post-industrial era

7am 11pm12pm 6pm


7am 11pm12pm 6pm

Pre-industrial era


7am 11pm12pm 6pm


7am 11pm12pm 6pm

Pre-industrial era


Why? The ‘second sleep’

Thanks

How Lightbulbs Made Alarm Clocks

Health & Medicine

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