Learning and Memory - Chapter 6

acoustic startle reflex

A reflexive response to sudden loud sounds

Aplysia

A sea slug used in studying simple forms of learning

associative learning

Learning that involves making connections between different events or stimuli

cochlear implant

A sensory prosthesis that electrically stimulates auditory nerves to produce hearing sensations in deaf individuals

comparator model

A model explaining how the brain compares expected and actual stimuli

cortical plasticity

The ability of the brain's cortex to reorganize and change in response to experience

differentiation theory

Theory explaining how repeated exposure leads to better stimulus discrimination

dishabituation

Recovery of a habituated response after presentation of a different stimulus

dual process theory

Theory proposing two separate processes in learning

habituation

Decreased response to a repeated stimulus

Hebbian learning

Learning through strengthening of connections between simultaneously active neurons

heterosynaptic

Involving changes in synapses other than those directly stimulated

homosynaptic

Involving changes in directly stimulated synapses

landmark agnosia

Inability to use landmarks for navigation due to brain damage

latent learning

Learning that occurs without obvious reinforcement

learned non-use

When patients stop using a limb after losing sensation, despite having motor control

learning specificity

When learning is limited to specific conditions or stimuli

mere exposure learning

Learning through simple repeated exposure

multimodal

Involving multiple sensory modes

non-associative learning

Simple forms of learning that involve repeated exposure to single stimuli

orienting response

Initial response to a novel stimulus

parahippocampal region

Brain area important for processing landmarks and spatial information

perceptual learning

Improved ability to detect or discriminate stimuli through practice

place cell

Neurons that respond to specific locations in an environment

place field

The specific area in space where a place cell becomes active

priming

Improved processing of a stimulus due to prior exposure

receptive field

The area of sensory space that can activate a neuron

sensitization

Increased response to stimuli after exposure to an intense or noxious stimulus

sensory prosthesis

Mechanical devices that interface with the brain to provide sensory processing capabilities

skin conductance response (SCR)

A measure of emotional arousal through skin conductivity

spontaneous recovery

Return of a habituated response after a period without exposure to the stimulus

synaptic depression

Decreased synaptic strength from repeated use

word-stem completion task

A test measuring implicit memory through word completion

What is habituation and what are its key characteristics?

Habituation is a decrease in behavior strength/frequency after repeated stimulus exposure. The three key features are: it can show spontaneous recovery after a delay period, it can be renewed by introducing a novel stimulus (called dishabituation), and it is specific to the stimulus that was repeatedly presented.

How does sensitization differ from habituation?

While habituation decreases response, sensitization increases response to stimuli after exposure to threatening/attractive stimulus. Key difference: sensitization is not stimulus-specific.

What is priming?

A phenomenon where prior exposure to a stimulus improves later recognition of that stimulus.

What is perceptual learning and what are its forms?

Experience-based improvement in stimulus discrimination ability. This includes mere exposure learning through passive exposure, discrimination training with active feedback, and latent learning where learning occurs without observable performance changes.

How does spatial learning relate to perceptual learning?

Spatial learning is often a form of perceptual learning that occurs through latent learning during environmental exploration.

What are the main theories explaining habituation and perceptual learning?

Three main theories explain these phenomena: The comparator model views habituation as a type of perceptual learning, the dual process theory explains how habituation and sensitization work together to decrease and increase responses, and the differentiation theory suggests learning occurs by adding more detailed stimulus representations.

How does habituation work in Aplysia (marine invertebrates)?

Through homosynaptic synaptic depression in stimulus-response circuits. Differs from sensitization which is heterosynaptic.

What is cortical plasticity and how does it relate to perceptual learning?

The brain's ability to adapt to changes, shown through its capacity to refine neuron receptive fields, alter cortical mapping, and reorganize when sensory input is missing.

What is Hebbian learning?

Learning mechanism based on "neurons that fire together, wire together" - strengthening associations between co-activated neurons.

What are place cells and how do they function?

Hippocampal neurons that activate at specific locations. They become more selective with environmental familiarity, though exact mapping mechanism is unclear.

What is landmark agnosia?

Inability to identify familiar buildings/landscapes, usually from parahippocampal cortex damage.

What is learned non-use and how is it treated?

Post-stroke condition where functional limb takes over for desensitized limb. Treated through restraint therapy forcing use of affected limb.

What are sensory prostheses and how do they work?

Electronic devices interfacing with neurons/receptors to provide sensory capabilities. Example: cochlear implants for deafness, requiring perceptual learning for speech discrimination.

What is non-associative learning?

Learning that involves one relatively isolated stimulus at a time, without necessarily associating it with other stimuli or responses

Define habituation

A decrease in the strength or occurrence of a behavior after repeated exposure to the stimulus that produces the behavior

What factors influence habituation?

Major factors include the intensity of the initial stimulus, the frequency of exposure, and the intervals between exposures.

What is sensitization?

When a startling stimulus leads to a strong response to a later stimulus that might otherwise have evoked a weaker response

How does sensitization differ from habituation?

Sensitization differs from habituation in several ways: it requires fewer exposures, can persist for days or weeks, is not specific to a particular stimulus, and increases response intensity to any subsequent stimulus.

What is perceptual learning?

Learning in which experience with a set of stimuli makes those stimuli easier to distinguish

What are the two main types of perceptual learning?

1. Mere exposure learning: Learning through simple exposure without explicit training, 2. Discrimination training: Learning through active practice with feedback

What are the three main theories?

1. Dual Process Theory: Habituation and sensitization operate independently but in parallel, 2. Comparator Models: Learning occurs through comparing new stimuli with stored representations, 3. Differentiation Theory: Stimulus representations become more detailed over time

What is spatial learning?

The acquisition of information about one's surroundings, often occurring through perceptual learning and mere exposure

What did Pavlov discover about dogs and habituation?

When a dog's cortex was removed, it could no longer habituate to auditory stimuli and continued showing orienting responses to sounds after many exposures

Why is Aplysia useful for studying learning?

It has a simple nervous system with only 20,000 neurons, some visible to naked eye, and neurons are consistently located in same places across individuals

How does habituation work in Aplysia?

With repeated stimulation, sensory neuron S releases less glutamate, reducing likelihood of motor neuron M firing. This reduction lasts up to 10 minutes

What is a key feature of habituation in Aplysia?

It is homosynaptic - only affects synapses activated during habituation, not other sensory neurons

What is cortical plasticity?

Changes in cortical organization resulting from experience. The receptive fields of neurons can change with repeated exposure to stimuli

What happens in perceptual learning through mere exposure?

People can improve tactile discrimination through repeated exposure, showing temporary improvements in distinguishing between touch points

What is Hebbian learning?

Learning principle that neurons that "fire together, wire together" - when neurons repeatedly activate together, their connections strengthen

What are place cells?

Hippocampal neurons that fire when an animal is in specific locations, with each cell having a preferred location called its place field

What affects place cell formation?

Experience - with repeated exposure to an environment, place fields become more selective and precise in their firing patterns

How does perceptual learning affect daily life?

It influences every experience we have, from understanding speech to navigation, through memories acquired from repeated experiences

What role do cortical networks play in perceptual learning?

They are the primary neural basis for perceptual learning and can be damaged through brain injury, leading to changes in perception

What is landmark agnosia?

A condition where people lose the ability to identify location or navigate using familiar buildings and landscapes

What causes landmark agnosia?

Generally caused by loss of brain tissue in the parahippocampal region, often from stroke

Why isn't hippocampal damage the cause of landmark agnosia?

Because hippocampal damage causes anterograde amnesia, while landmark agnosia patients can form new memories and draw familiar areas

What is the role of the parahippocampal region?

The parahippocampal region receives and integrates sensory information from processing areas, sends inputs to the hippocampus, and maintains connections with the visual cortex.

What is learned non-use?

When stroke patients stop using affected body parts despite having motor control, due to lack of sensation

How does restraint therapy work?

By immobilizing the functioning limb, forcing use of the affected limb, which promotes cortical plasticity

What limits stroke rehabilitation?

Understanding of how older adult cortex adapts to tissue loss is limited, making it difficult to promote cortical changes

What are sensory prostheses?

Mechanical devices with sensory detectors that interface with brain areas to provide new sensory processing capabilities

How do cochlear implants work?

Cochlear implants electrically stimulate auditory nerves to create virtual sounds from environmental sounds. They require training for users to learn how to interpret these new sounds, and patients typically show gradual improvement in understanding speech and other sounds over time.

What has research on cochlear implants in cats revealed?

They lead to massive reorganization of auditory cortex, showing different organization from both deaf and hearing cats

What are the key characteristics of non-associative learning?

Non-associative learning ranges from simple processes like habituation to complex interactions between brain regions. It can take place without producing visible responses, and its effects on learning speed can vary depending on the situation.

How can understanding non-associative learning help medicine?

It helps clinicians interpret cortical damage effects and develop treatments for sensory deficits through brain adaptation