Elicited or Unconditioned Behavior Occurs without past experience Modifiable with experience (examples:

habituation and sensitization

Some Types of Elicited Behaviour An eliciting or unconditioned stimulus elicits a

response without any prior learning Types of Elicited Behaviour

Simple Reflex Orienting Reflex Taxis (taxes) Kinesis (kineses) Fixed/Modal Action Patterns

FAPs/MAPs

Sequence of behaviors directed at the eliciting (sign or releasing) stimulus

Sometimes requires underlying drive (hydraulic model)

Vigor of response depends on how closely the sign stimulus corresponds to the ideal stimulus (e.g., cute baby) Small (non-ideal) Normal (ideal) Supernormal (exaggerated ideal)

Supernormal stimulusAn accurate 3-dimensional model of a herring gull's

head (a), and a 'supernormal' bill (b).

Supernormal stimulus

Supernormal stimulus?

versus

1950s 1990s

Habituation

a simple type of learning which is shown by a change in elicited behaviour over trials

defined as a reduction in responsiveness (frequency, magnitude) over successive trials

sometimes short-lasting and sometimes long lasting

Habituation-One Type of Modifiability

Eric Kandel and Aplysia

Kandel`s Experiments

Touch Siphon

GillWithdrawal

Habituation

touch

gill withdrawal

Forms of Habituation

Short-Term lasts only a few minutes best if stimulus applied at short intervals (2-s)

Long-Term lasts weeks best if stimulus applied at longer intervals (30-s)

Simplified Circuit

What’s the Mechanism of Short-term?

loss of skinsensitivity

fatigue

decrease in motorsynapse

decreases in synaptic transmission

Pinsker et al., (1970) Science 167:1740

Evoked

Spontaneous

Not Muscle Fatigue

What’s the Mechanism of Short-term?

loss of skinsensitivity

fatigue

decrease in motorsynapse

decreases in synaptic transmission

Not Motor Synapse

skin

MN

SN

gillrecord

Kupfermann et al., (1970) Science 167:1743

electrical

After

Before

What’s the Mechanism of Short-term?

loss of skinsensitivity

fatigue

decrease in motorsynapse

decreases in synaptic transmission

Not Skin Sensitivity

skin

touch

MN

SN

gill

record MNactivity to assay

habituation

Kupfermann et al., (1970) Science 167:1743

Stage 1

Not Skin Sensitivity

Kupfermann et al., (1970) Science 167:1743

skin

touch

MN

SN

gill

record MNactivity to assay

habituation

block

What’s the Mechanism of Short-term?

loss of skinsensitivity

fatigue

decrease in motorsynapse

decreases in synaptic transmission

Mechanism of Short-term Habituation

Decrease in neurotransmitterreleased at the synapse with both the motor neuron and theinterneuron!

Mechanism of Long-Term Habituation

Change in the number of synapses!

Some Properties of Habituated Responses

1. Spontaneous Recovery 2. Dishabituation3. Generalization

Hi

Lo

Response

Number of Presentations

Spontaneous Recovery

Time Passes

Stimulus

Hi

Lo

Response

Number of Presentations

Dishabituation

Novel Event

(no timepasses)

Stimulus

HabituationDishabituation

Generalization

Sensitization- Another Type of Modifiability enhanced response to a “benign” stimulus after

exposure to a “noxious” one (most common) for example, startle

enhanced response after repeated presentations of a “not so benign” stimulus (less common) for example, kindling

RatStartle

Human Startle

Kindling

repeated stimulation of hippocampal cells increases responsiveness

after being sensitized, very little stimulation is required to produce the seizures

related to epilepsy

Dual Process Theory

1. S-R System: Habituation

2. State System: Sensitization

Competition between two separate processes

Examples

+

-

S

H

NET

+

-

S

H

NET

Trials Trials

Conditions Favouring Habituation

1. Calm organism2. Shorter interstimulus intervals3. Less variable interstimulus intervals4. Low intensity5. Less complexity6. More trials

Interstimulus Interval

Complexity

Trials

LookingTime

Imagine……… Kendra is an overly anxious person. She worries

about the smallest things. Some examples of the unpleasant symptoms she experiences include excessive sweating, heart palpitations, and a fitful sleep. Her anxiety places her at risk for depression, heart disease, and diabetes. A genetic test reveals Kendra has a vulnerability in the promoter region of her serotonin transporter gene. Her doctor tells her that if her mother had been more loving and attentive when Kendra was younger, she might have been calmer. The doctor maintains experience can program calmness, and calmness acquired by experience is inheritable.

Gene Expression-A third Type of Modifiability Genes affect bodily processes, including emotional

regulation Two copies of the “short” version of a promoter for the

serotonin transporter gene is a risk factor

Maternal Behavior

licking and grooming (LG) and arched-back nursing (ABN)

Low LG-ABN mothers

High LG-ABN mothers

Attentive Mothering Licking and arched-back nursing by mother

an immediate “calming” effect on baby rats in the first week after birth

a long-term reduction in stress responsiveness the promoter for the short version of serotonin

transporter gene is “switched on” by attentive mothering so, a vulnerable pup with two short copies of the

promoter for the serotonin transporter gene is cured by its mother’s licking (short gene works better)

this environmental effect is passed along to the pup’s own offspring

Brain of Vulnerable Baby Rat

high LG-ABN mother

short gene expressed

less anxiety

Cross-fostering Studies

Imagine………

Kendra’s doctor gives her a prescription for a pill that will promote the activity of the malfunctioning gene. No other therapy is necessary. Kendra’s children inherit the faulty gene, but its function is enhanced.