Transcript Lecture 2

Introduction to Psychology
Lectures are videotaped
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The circadian rhythm
or
Life around the clock
(Lecture 2)
We change with time !
What is changing ?
Linear changes ?
Cyclic changes ?
Source of changes?
Environmental clocks as a source of cyclic
changes
Environment is cyclic… we are sensitive to
environment, therefore…. we live in cycles.
“The Calendar” describes life timed by nature.
 365 + 1/4 days around the sun: cycles of depression,
suicide, susceptibility to schizophrenia…
 28-31 days: Gregorian timing in honor of Caesar?
No environmental cycle.
 1 day spin: light/dark cycle of biological & mental
functions.
Biological-Endogenous clocks as
a source of cyclic changes
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Annual clock: not known.
Monthly clock: female menstrual cycle.
Circadian clock: > 24 hrs, why not 24 hrs?
8 hrs clock: when the pilots are most fit?
90 min clock: when do you dream?
seconds range: localized biological processes
like sand clocks, HR, biochemistry.
A model of
short timeconstant clock
Chronobiology research is being conducted by:
• Allergists
• Animal and plant
physiologists
• Cardiologists
• Cell and molecular
biologists
• Chronobiologists
• Endocrinologists
• Environmental scientists
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Gastroenterologists
Immunologists
Nephrologists
Neuroscientists
Obstetricians/gynecologists
Pharmaceutical scientists
Psychiatrists
Toxicologists
Epidemiologists
Do you see the psychologists ???
Environment-Biology interaction as a
source of complex cycles
 Monthly: Synchronization of monthly cycle
in ladies’ dormitories.
 Circadian: ~26 hrs in isolation, but 24 hrs in
normal conditions.
 90 min: easy to detect in boring but not in
exciting conditions.
Complex cycles: 24 & 8 hrs cycles in phase
24 hrs
8 hrs
result
Complex cycles: 24 & 8 hrs cycles
out of phase
24 hrs
8 hrs
result
Cyclic changes: conclusions
Continuous change rather than stability
Change in response to environment
Change in response to endogenous clocks
Asynchronous cycles
Models of adaptation (e.g., arousal)
Models of pathology??? (e.g., arousal)
Changes in Arousal (1)
Spectrum of arousal:
Coma
Sleep - Wakefulness
Excitation - Anxiety
Drugs
Epilepsy
Circadian cycles of arousal
Momentary changes of arousal
Arousal (2)
Arousal is a major aspect of behavior and is closely
related to other concepts such as anxiety,
attention, agitation, stress, and motivation.
The arousal level can be thought of as how much
capacity you have available to work with.
Yerkes-Dodson law predicts an inverted U-shaped
function between arousal and performance.
Arousal (3)
Homeostasis:
Maintaining a
single level of
adaptive
arousal
Arousal (4)
Allostasis
rather than
homeostasis:
Stable level of
arousal is not
adaptive
Arousal (5)
Allostasis: maintaining stability of
performance through internal change, as a
fundamental process through which
organisms actively adjust to both
predictable and unpredictable events.
i.e., stay maximally adaptive by changing the
arousal
Allostatic overload being a state in which
serious pathophysiology can occur.
Arousal (4)
Allostasis:
Catastrophic
conditions are
possible
Sleep (1)
Sleep:
like
wakefulness,
is not
homogenous.
14/11/05
Sleep (2)
External clock:
Light
Biological clock:
Melatonin & the
Pineal Gland
Sleep (3)
Sleep & selective
attention
Sleep & response to
environment:
Overt – awakening
Covert - dream
Is she aware of the difference?
Sleep (4)
Sleep & Learning:
 Dawkins – “The
selfish gene”
 The song of Don
Juan
"The zebra finch appears to
store the neuronal firing
pattern of song production
during the day and reads it
out at night, rehearsing the
song, and, perhaps,
improvising variations. The
match is remarkably good."
SWS & REM builds memories
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Researchers recorded the electric signature of individual
forebrain neurons firing during the two types of sleep.
The firing pattern of recently captured memories are
especially strong during slow-wave sleep and then
decrease in force dramatically during REM.
The neural plasticity genes turn on during REM sleep.
It looks like a two-stage process: The memory echoes
strongly during SWS, which stabilizes it. Then the gene
expression machinery turns on during REM sleep to
further consolidate it.
You remember more when you have a combination of
REM and SWS.
Ribeiro et al., "Long-lasting novelty-induced neuronal reverberation during slow-wave
sleep in multiple forebrain areas," PLoS Biol, 2:0126-37, 2004.
Sleep (5)
Sleep deprivation:
 sleep pressure
 no full compensation on recovery night
 intrusion of sleep to wakefulness
* compensation
* mixture of mental processes
* model of psychopathology ???
Consciousness (1)
Consciousnes (2)
Visual field
and pathway
Consciousness (3)
Localization of consciousness:
Consciousness not in the subcortical areas
Consciousness not in the primary sensory
cortex
Consciousness in high cognitive cortex ???
Consciousness (4)
Reconstruction
of natural
scenes in
thalamus
END