Olfactoryfunction

The psychobiological approach to understanding basic biological systems

Behavior

Direct monitoring

Comparative models

Experience

Manipulation pharmacology ablation

genes

Learning mediated changes in behavior

Learning is: A persistent change in behavior based upon experience

Learning can be broken into two classes:

1. Non associative: Habituation Latent inhibition or CS pre exposure effect

2. Associative: Pavlovian or classical conditioning Instrumental or operant conditioning

Thompson and Spencer (1966) •A negative relationship between response strength and number of trials.•Spontaneous recovery of response strength following an extended intertrial interval.

•Recovery should be less than full.•Interstimulus interval (ITI) affects rate of habituation.

•Short ITI produces rapid habituation, long ITI produces slow habituation.•More intense stimuli produce greater response and slower habituation.•Very intense stimuli produce an initial increase in response (sensitization) then habituate.•Excessive habituation training produces subzero response.

Habituation

Helothis virescens Facts

Heliolithine moth larvae are serious agricultural pests causing hundreds of millions of dollars in agricultural damage annually.

A method of behavioral control of this species is mating disruption. – The control of male reproductive behavior with

synthetic female sex pheromones.

While mating disruption strategies have been successfully deployed for many years, exactly how they work is not well understood.

MEAN ETHOGRAM SCORES FOR ALL THREE GROUPS

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CONTROLS

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Habituation of pheromone response in male H virescens

hexanal

geraniol

blank (air)

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HABITUATION TO ODORS IN Drosophila

Criteria Operant Conditioning Classical Conditioning

Type of BehaviorNon-reflexive, voluntary behaviors 

Reflexive, involuntary behaviors

Source of Behavior Emitted by organism  Elicited by stimulus

Basis of LearningAssociating a response and the consequence that follows it 

Associating two stimuli

Responses ConditionedActive behaviors that lead to reinforcement

Physiological and emotional responses

Extinction ProcessResponding decreases with elimination of reinforcing consequences 

Conditioned response decreases when conditioned stimulus is repeatedly presented alone 

Associative conditioning: Operant vs classical

Pavlovian conditioning: distinguishing associative and non associative effects

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C.

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odor (CS)

food (US)

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forward-paired and air-paired CS-US relationship

backward-paired CS-US relationship

random-paired CS-US relationship

on -25sec +25sec

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Associative learning in the moth Manduca sexta

Photo: W. Armstrong

Development of an olfactory-learning behavioral paradigm

EMG electrode in feeding muscle

exposed proboscis tip for sucrose application

reference electrode

odor blown across antennae

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2-hexanone1-hexanol1-decanol

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A.pre post

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odor on

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odor on

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odor on

1-trial learning

Moths learn most odors with interesting exceptions

Once trained moths will respond to odor until they expire

Acquisition of conditioned response

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Only forward pairing produces a conditioned response

*N=30 per group