chapter 5 control of behavior - columbia university · 2002. 9. 30. · early ethologists studied...
TRANSCRIPT
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Chapter 5Control of Behavior
(1st lecture)
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Early ethologists studied simplebehaviors that appeared in nearly
complete form the first time they wereperformed, and were usually elicited by a
simple cue of some sort. They called these behaviors Fixed Action Patterns.
Greylag goose retrieving an egg that had rolled out of its nest.Once the retrieval behavior has begun, the goose will complete
the action, irrespective of whether the egg has rolled away from its bill.
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Illustration of a young gull begging for food fromone of its parents
The chicks peck at the red spot on the lower bill.All young gulls instinctively peck at this spot.
In so doing, they stimulate the parent to regurgitate food for them.Without the pecking, the parent would never feed the chicks.
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What elicits the pecking response?
It turns out that a simple model, which enhances specific featureof the stimulus, is more effective at eliciting the behavior
than a model that resembles a gull parent
This simplemodel wascalled a signstimulus
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Another example of a sign stimulus,as revealed through the use of simple models
Typical male three-spinedstickleback during breeding
season. His presence normally elicits aggression in conspecific
males
However, it turned out that models with a red underside
were more effective at eliciting aggression than was the male
lacking a red underside
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Flow diagram showing early ethological conceptsof the mechanisms involved in a simple behavior
pattern such as egg retrieval or bill pecking
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Do humans express fixed action patterns?
Yawns are very similar in appearance no matter who is doing the yawning.
They last about 6 sec, are difficult to stop in mid-performance, and are infectious, releasing yawns in other humans that observe (or hear) the yawner.
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Tinbergen’s original definition of a FAP:an innate behavior pattern that is
stereotypedspontaneous
independent of immediate controlgenetically encoded
independent of individual learning
Later studies found that this strict definitiondid not apply neatly to any behavior
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Many bats literally seewith sound, using biosonar
How is this possible?
see the following website:http://www.biosonar.bris.ac.uk/
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Moth ears contain 2 auditory cells, called the A1 and A2 cell
How to flying insects like moths cope with the persistentthreat of bat attacks?
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The A1 and A2 cell each have different response properties
The A1 cell respondsto low-intensity bat
calls, and increases its firing rate in response
to louder calls
The A2 cell respondsonly to high-intensity
bat calls
Note that these auditory cells cannot discriminate between calls that range in frequency between 20 and 100 kHz
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Neural records of how the A1 and A2 cells in each earresponse to low- and high-intensity bat calls
Responseof A1 cell tolow-intensity
bat call
Left ear
Right ear
Response ofA1 + A2 cells
to high-intensitybat call
A2 cell !
!! ! !
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Activation of A1 cells produces different behavioral responsethan activation of A1 + A2 cells
Stimulation ofA1 cell causesmoth to veeraway from bat
Stimulation ofA1 + A2 cellscauses moth tomake a powerdive
Sensory input fromA1 and A2 cellshave direct but
distinct pathways to flightmuscles (via severalinterneurons in CNS)
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Some moths have evolved mechanisms for determining the locationof approaching bats, which resemble those used by owls to locate prey