In Vitro Analog of Operant Conditioning in Aplysia. I.Contingent Reinforcement Modifies the Functional Dyna

mics of an identified Neuron

Interdisciplinary Program in Brain ScienceEye Movement & Vision LAB.

Hwang, Jae Won

Outline

Classical Conditioning vs Operant Conditioning

Feeding Behavior of Aplysia In Vitro Analog of Operant Conditioning Experimental Procedures Yoked Control Procedure

Classical vs Operant Classical

Conditioning Operant Conditioning

US CS

Organism UROrganism

Response(Action)

Reward

ReinforcementSystem

Classical vs Operant(Cont’d)

Classical Conditioning : Learning about relations between stimuli Operant Conditioning : Learning about the consequences of one’s own behavior

Most learning situations inseparably comprise operant and classical components. So the analysis of operant conditioning is complicated.

Feeding Behavior of Aplysia

1. Biting occurs spontaneously as well as reflexively.2. If food is present, biting leads to the ingestion of f

ood through the buccal cavity.

AplysiaBiting

FoodReinforcement

System

In Vitro Analog of OC

Isolated buccal ganglia preparation Biting → Tonic stimulation of the ventral branch of buccal nerve 2 (n.2,3) Food → Stimulation of the anterior branch of the esophageal nerve (E n.2)

C-B conn. : Cerebrobuccal connectivesE n. : Esophageal nerveI2 n. : Nerve to intrinsic buccal muscle 2 n. : Buccal nerveR n. : Radular nerve

In Vitro Analog of OC(Cont’d) Tonic stimulation of n.2,3 elicits two different motor

program.- Pattern I (ingestion-like pattern) : Neural activity associated with closure and retraction

of the radula- Pattern II (egestion-like pattern) : Neural activity associated with closure and protractio

n of the radula

In Vitro Analog of OC(Cont’d) Neuron B51 participates in the buccal pattern gener

ator, and a postsynaptic follower motor neuron has been described as being active only during ingestion(Cropper et al., 1990).

☞ Thus, activity in B51 could participate in the genesis of pattern I and may contribute to the probabilistic occurrence of pattern I and the switching between this and other patterns.

Experimental Procedures

Determination of whether contingent stimulation of E n.2 on pattern I modified the dynamical activity of B51

Comparison of B51 activity in three groups of preparations

1. a contingent reinforcement group 2. a yoke-control group 3. a control group Measurement of contingent-dependent change

in burst threshold and input resistance

Experimental Proc.(Cont’d)

In all group of preparations, the neuronal activity was induced by monotonic(4Hz) stimulation of n.2,3.

The training lasted 10 min and began with the first occurrence of pattern I in the contingent-reinforcement preparation.

Yoked Control Procedure

A yoked-control procedure deprives one rat of sleep but forces both members of the pair to exercise an equal amount of time.