Chapter 3: Habituation, Sensitization, & Familiarization

Question 1

Define habituation.

Answer 1

A decrease in the strength of occurrence of a behaviour due to repeated exposure to the stimulus that produces the behaviour

Question 2

What is the acoustic startle response?

Answer 2

When a loud sound is played, over time we get habituated to it and we don’t show the shock with as much intensity.

Question 3

How is habituation tested for in babies?

Answer 3

We record how long it takes them to look away from a novel object (meaning they are bored from it), this is called the orienting response.

Question 4

List the similarities in how animals experience habituation (6)

Answer 4

1. Dishabituation
2. Stimulus specificity
3. Spontaneous recovery
4. Short and long-term effect
5. Spaced works better than massed
6. Innocuous (weak stimuli work better than strong)

Question 5

Define dis-habituation.

Answer 5

a novel/arousing stimulus can temporarily recover (Recovery) responses to the habituation stimulus, this fades quickly though

Question 6

Define stimulus specificity.

Answer 6

Generally responses only decrease to the habituating stimulus, for very similar stimuli there can be some generalization

Question 7

Define spontaneous recovery.

Answer 7

When repeated stimulus stops, behavior gets back to normal, with time, the response goes up again, time for recovery depends on several factors.

Question 8

Define short and long term forms of habituation.

Answer 8

More repetitions of the stimulus, longer-lasting habituation; with many repetitions, effects can become relatively permanent. By day four, we start from a lower baseline of startlement and habituate.

Question 9

Explain why spaced works better than massed use of stimulus.

Answer 9

Taking breaks between sessions of repeated stimuli makes habituation develop more slowly but last much longer (works better for studying, too)

Question 10

Explain why habituation works better with weak stimuli than strong stimuli.

Answer 10

The stronger the stimulus the less habituation develops.

Question 11

Define sensitization.

Answer 11

Painful stimuli actually have the opposite effect of habituation (we become more sensitive)

Question 12

What is reductionism?

Answer 12

Reduce a complex phenomenon to its most basic parts

Question 13

Explain the steps in the gill-withdrawal reflex done by Aplysia.

Answer 13

When you touch the siphon the gill contracts within the mantle. The time to relaxation is measured.

Question 14

Talk about habituation in Aplysia.

Answer 14

On trial 1 of the stimulus the response has the largest time response (12+ seconds to go back), progressively the response gets weaker with shorter withdrawal durations.

Question 15

Talk about sensitization in Aplysia.

Answer 15

A gentle touch to siphon produces a gill withdrawal. After this the animal is given an aversive stimulus (shock). When the snail is touched next, it has a much longer withdrawal duration. It recovers quickly but becomes long-lasting with multiple sessions.

Question 16

Describe the neural mechanism for habituation.

Answer 16

The key is the connection between sensory neuron on the siphon and the motor neuron. Over time, repeated touch depletes sensory neuron of glutamate (excitatory NT), this is called synaptic depression). Glutamate facilitates the action potential of the motor neuron, so if there is less of it, it is less likely to activate.

Question 17

What can happen to neurons in very long-term habituation.

Answer 17

Some sensory-motor synapses are actually pruned away (reduced in number)

Question 18

How does sensitization in Aplysia work on a neurological basis?

Answer 18

Once the tail is shocked, the interneuron (a modulating neuron) releases serotonin and sends it to the sensory neurons of the siphon and mantle which prompts the sensory neurons to release more NTs (glutamate) on the next activation of this neuron (the touch).

Question 19

What happens in long-term sensitization? What mental illness is associated with this?

Answer 19

New sensory motor synapses are added, which may be one of the factors influencing PTSD?

Question 20

What happens on the chemical level when serotonin is sent to the motorsensory synapse?

Answer 20

Seratonin prevents K+ ion channels to open on the presynaptic neuron and so the result is a broadened action potential since the ions cannot restore the action potential. This results in more Ca2+ channels staying open which facilitates Ca2+ uptake and in turn releasing more NT (glutamate)

Question 21

What are the characteristics of short-term habituation? (3)

Answer 21

1. Lasting 10 minutes,
2. presynaptic NT depletion
3. homosynaptic.

Question 22

What are the characteristics of long term habituation?

Answer 22

Lasting several days or more. Pre and post synaptic changes (structural and synaptic), most likely multi-synaptic.

Question 23

What is Long Term Depression (LTD)?

Answer 23

When cells become out of sync because the first fires but the second does not over time.

Question 24

What is activity dependent LTD?

Answer 24

requires 1 Hz electrical stimulation, quite different from the rate of stimulation that we’re used to (for short habituation) that results in long-term habituation/depression

Question 25

What is sensitization?

Answer 25

Increase in strength or occurrence of a behaviour due to exposure to an arousing or noxious stimulus

Question 26

What’s a real life example of sensitization?

Answer 26

We’re much more alert to the dark after we’ve watched a scary movie.

Question 27

What common characteristic does sensitization have? (4)

Answer 27

1. Painful stimuli work better than weak
2. More generalizable than habituation (less stimulus specificity)
3. Can develop with a single noxious stimuli (again more generalizable)
4. A mechanism is in place to increase the stimuli that are important

Question 28

What is the process of familiarity?

Answer 28

The perception of similarity that occurs when an event is repeated

Question 29

What is the novel object recognition task?

Answer 29

a task in which an organism’s detection of and response to unfamiliar object during exploratory behaviour measure it’s recollection of previous events, SIMILAR to habituation (finding the environment non-threatening)

Question 30

How is the rate of exposure-based learning calculated?

Answer 30

Ratio of amount of time spent examining old vs new object

Question 31

What is priming?

Answer 31

A phenomenon in which a prior exposure to a stimulus can improve the ability to recognize that stimulus later. Priming effects may persist much longer than recognition of past encounters

Question 32

What is the word-stem completion task measuring?

Answer 32

Priming, it is a task in which participants are asked to fill in the blanks in a list of word stems,

Question 33

What is perceptual learning?

Answer 33

Learning in which repeated experiences with a set of stimuli make those stimuli easier to tell apart, can happen without explicit training, sometimes called statistical learning. Similar to priming in that it leads to more effective processing on the next encounters with stimuli.

Question 34

What are the mechanisms of perceptual learning?

Answer 34

Repeated exposures to a stimulus lead to improved ability to recognize/process that stimulus (can be passive)

Question 35

Define cortical plasticity.

Answer 35

Refinement in the receptive field of neurons due to experience

Question 36

Describe the experiment with the pin pricks.

Answer 36

There is a maximum distance (threshold) where people can discriminate between two pin pricks on their finger.
fMRI tests confirm which areas are lighting up in the brain. After 2 hours of training to right hand only (repeated trials at varying time intervals to prevent habituation). Post-test for sensitivity + fMRI scan shows that we can discriminate a smaller distance (this effect virtually disappears the next day).

Question 37

What does the hippocampus have to do with spatial learning?

Answer 37

The hippocampus is important for spatial navigation and memory.

Question 38

What do hippocampal place cells do when they encounter a familiar environment?

Answer 38

Hippocampal place cells are firing when the arm is the correct orientation of the card (not the smell of the tunnel)

Question 39

What is a place cell?

Answer 39

Cells whose receptive field seems to be a particular location or place that is familiar

Question 40

What is a grid cell?

Answer 40

Grid cells are spatially oriented to represent the space we are in, similar to the environment itself

Question 41

What is the role of the dentate gyrus?

Answer 41

the first region where all sensory modalities merge together to form unique representations and memories that bind stimuli together, and thus, it plays a critical role in learning and memory.

Question 42

What is the role of the medial entorhinal cortex and subiculum?

Answer 42

Medial entorhinal cortex is a widespread network hub for memory, navigation, and the perception of time.

Question 43

How did researchers differentiate between habituation and fatigue?

Answer 43

A baby’s orienting response was to be startled when it was a completely new object. If the baby was tired, they would not react strongly to a new stimulus.

Question 44

How does long term habituation potentially lead to sex addition.

Answer 44

Think about this.

Question 45

What is habituation dependent on?

Answer 45

The severity of the event, the frequence of times that it is presented and the time between presenting the stimulus.

Question 46

What is long term habituation?

Answer 46

LTH happens when an infant for example habituates to a toy over 20 trials. A week later than infant is brought in, and even though the infant can initially look at the toy for as long as it did the first trial, it will take LESS trials in total (n <20) to get habituated again.

Question 47

What is electrodermal activity (EDA)?

Answer 47

Fluctuations in the electrical properties of a person’s skin that are a
consequence of activity in the peripheral nervous system. Active in sensitization experiments.

Question 48

What is prepulse inhibition?

Answer 48

Playing a weak tune before a sensitizing one can reduce our response. But it is similar to sensitization in that (1) the initial weak stimulus can affect responding to
a wide range of subsequent stimuli, including stimuli in
other modalities; and (2) a single presentation of the weak
stimulus can produce the effect

Question 49

What is dual process theory?

Answer 49

The theory that habituation and sensitization are independent of each other but
operate in parallel.
The response is the sum of the two processes working in tandem.

Question 50

What is opponent process theory?

Answer 50

The opponent process (excitement) becomes stronger and eventually suppresses the initial reaction to the stimulus (aversion), creating habituation. The rebound (or opposing process is triggered by the initial emotional response. Both processes are associated with the emotional response of the individual.