Transcript Hormones

Chap.03 Proximate
factors
鄭先祐 (Ayo) 教授
國立台南大學 環境與生態學院
生態科學與技術學系
環境生態研究所 + 生態旅遊研究所
Proximate factors
1. Ultimate and proximate perspectives
2. Hormones and proximate causation
3. Neurobiological underpinnings of
behavior
4. Molecular genetics and animal
behavior
5. Development and animal behavior
6. Foraging in Honeybees: an
integrated proximate analysis
7. Interview with Dr. Geoggrey Hill
Significant natural variation exists in house finch coloration.
Artificially brightened (top left to top right photo) or lightened (bottom left to
bottom right photo) the plumage coloration of male house finches.
Hill examined how brightening and lightening plumage coloration
affected a suite of variables in male house finches. There were 40
males in the brightened condition, 20 males in the same control, and 40
males in the lightened condition.
Hormones and Proximate causation
 introduction
 Endocrine system (Fig. 3.7)
 Neuro-hormones
 兩個案例：
1. The long-term effects of in-utero
exposure to hormones
2. Stress hormones and spatial memory in
rats
Hormones can affect input systems (sensory systems like
those for smell, sight, or hearing), central nervous system
function (processing), and output systems.
1. The long-term effects of in-utero exposure to hormones
When male
Mongolian gerbils
were castrated,
they spent more
time with pups
than did “sham”
castrated males
that had
undergone a
similar operation
but were not
actually castrated.
2. Stress hormones and spatial memory in rats
The swimming path of the
control rat was consistently
near the target (T), indicating
that its memory for the
location of the platform was
not impaired, while the
swimming path of the rat that
was shocked thirty minutes
before being put in the water
maze was random, indicating
that its memory for the
location of the platform was
impaired by the shock.
(A) Rats that
receive a shock
thirty minutes
before their trial in
the water maze
spend less time
near the platform
(target) than did
rats in the other
three groups.
Corticosterone levels
 Only rats in Group 1 (the group with
decreased ability to find the area of the
platform) had higher levels of corticosterone,
suggesting an important memory inhibiting
role for this hormone.
 Injected rats with a drug called methrapone,
rats did not show impaired memory compared
to control one.
 Methrapone, inhibits the production of
corticosterone by blocking certain cheical
reactions in the adrenal glands, where
corticosterone is produced.
Neurobiological
underpinnings of behavior
Neurobiology and learning in voles
Meadow voles
 Males showed superior spatial learning
abilities.
 From a neuroethological perspective,
we can
1. Examine the neural substrate underlying
the differences in male and female spatial
learning abilities
2. Examine how components of the nervous
system change as a function of a spatial
learning experience.
Male meadow
voles spent
more time near
the platform in
water maze
trials than did
female
meadow voles.
In meadow
voles, males
have more
dentritic spines
in both the
frontal and the
parietal cortex
of the brain
than do
females.
Neural plasticity
The rats went through the spatial
learning trails would have more
dendritic spines than the control
animals.
This is a good example of neural
pasticity.
 The ability of neurons to undergo change
as a function of experience.
Vocalizations in plainfin midshipman fish
(A) The two smaller fish on the ends are type II sneaker
males (who do not sing), while the fish that is second from
the left is a “singing” type I parental male.
Sleep and predation in Mallard ducks
 Sleeping individuals are more susceptible to
being attacked by predators.
 Sleeping with one eye open and one eye
shut.
 This type of sleep was first recorded in chickens
and is best examined in mallard ducks.
 Birds are capable of putting one hemisphere of the
brain– the hemisphere active during – into what is
called slow-wave sleep.
Slow-wave sleep
 “slow-wave” refers to the frequency of the
brain waves that investigators record using a
device called an electroencephalogram
(EEG).
 This slow-wave state allows quick responses
to predators, but it does not interfere with the
sleeping half of the bird’s brain until danger is
present.
 EEG recordings indicate that the part of the
brain controlling the open eye during
unihemispheric sleep showed the low
frequency range characteristic of slow-wave
sleep, while the other half showed EEG
patterns that were similar to those of true
sleep.
In some aquatic mammals, like the fur seal,
unihemispheric sleep is thought to allow individuals to
swim to the surface and breathe during sleep.
問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/