chap 6 Learning and memory

chap 6 Learning

WHAT IS LEARNING?

It is the process by which we acquire knowledge about the world.

• long term potentiation

WHAT IS MEMORY?

It is the process by which knowledge is encoded, stored, consolidated, and subsequently retrieved.

LEARNING: Process 

• Experiences modify our nervous system (memories), and therefore, our behavior.

• PERCEPTUAL LEARNING - process sensory information & association information

• STIMULUS-RESPONSE LEARNING - modify NS

• RELATIONAL LEARNING - memories

  MOTOR LEARNING - behaviour

MOTOR LEARNING

• AUTOMATED AND ROUTINE BEHAVIORS.

• The cortex would send sensory and movement planning information to subcortical areas. BASAL ganglia (striatum, globus pallidus, caudate, putamen, substantia nigra...).

• The basal ganglia receive information about movement planning from the neocortex.

Areas in the brain involved in MOTOR LEARNING

• basal ganglia

• cerebellum

• pre-frontal cortex

RELATIONAL LEARNING

• It is the most complex learning.

• It represents the use of all the resources we have at brain level.

• It is based on the evaluation & conscious comparison of all the information we have about a thing “a dog”.

• Context, previous experiences, what we know about that object.

• (A MIX OF SEVERAL LEARNING MECHANISMS)

STIMULUS-RESPONSE LEARNING

• Classical conditioning

• Instrumental/Operant Conditioning

Classical conditioning

• Types of behaviour: Involuntary (reflexive) unlearned

• Types of association: Association between two stimuli

Instrumental/Operant Conditioning

• Types of behaviour: Voluntary, learned

• Types of association: Association between the stimulus & the response.

PERCEPTUAL LEARNING

• occurs as a result of changes in the synaptic connections in the different sensory processing areas and sensory association areas.

Different circuits involved in PERCEPTUAL LEARNING

• Influence on object recognition tasks and short-term memory. VENTRAL STREAM. (WHAT IS?)

• Influence of object localisation tasks. DORSAL STREAM. PARIETAL CORTEX. (WHERE IS?)

What does PERCEPTUAL LEARNING depend on?

• The task & activity we perform, we will see the activation of certain sensory areas.

Perceptual learning

• Short-term perceptual memory

• Delayed matching

Short-term perceptual memory

• Recall of a stimulus or an event that lasts for a short period of time.

• Necessary especially if the response is not immediate.

Delayed matching

• The subject indicates which object has just been perceived.

Classical conditioning (order ranged)

• Unconditioned Stimulus (US)

• Unconditioned Response (UR)

• Neutral Stimulus (NS)

• Conditioned Stimulus (CS)

• Conditioned Response (CR)

CONDITIONING

The conditioned stimulus elicits a conditioned response.

Neural Model of Classical Conditioning

THE HEBB RULE

THE HEBB RULE

• The cellular basis of learning involves the strengthening of a synapse that is repeatedly activated when the postsynaptic neuron fires.

Hebb affirmed

• if the axon of neuron A is sufficiently close to cell B and repeatedly contributes to firing it, certain structural or metabolic changes will increase the efficacy of such a synapse.

• neural networks → storehouse of memory and the basis of learning

Example related to Hebb-rule

• When a rat is exposed with a painful stimulus, amygdala connections are activated evoking an unconditioned response. If this response is coupled with a tone, synapses in the lateral amygdala are strengthened.

Instrumental/Operant Conditioning

• Effects of a certain behavior in a particular situation increase (by reinforcement) or decrease (by punishment) the probability of repeating that behavior.

Reinforcing Stimulus

Appetitive stimulus that follows a certain behavior, making such behavior more frequent.

Punishing Stimulus

Aversive stimulus that follows a certain behavior, making such behavior less frequent.

Encoding

• The process of transforming sensory input into a form that can be stored “boxes” in memory.

  STM (Phonological Storage).

  LTM (Storage by meaning).

Manteinanc

The act of preserving or keeping information in memory over time, often through rehearsal or consolidation.

Retrieval

• The process of accessing or recalling stored information from memory when needed.

•  Retrieval of information previously stored in our brain.

What can affect memory retrieval

• Motivation and emotion

• Our preferences and interests

• The coding process (and tricks)

• The learning context

• Other individual factors (ability,...)

HOW DOES NEURAL PROCESSING OF MEMORY OCCUR?

1. Encoding: Sensory information (like sights or sounds) is turned into a form that the brain can store, mainly in the hippocampus.

2. Storage: Once encoded, memories are stored in different brain regions, especially the cortex, and strengthened over time through consolidation.

3. Retrieval: When you need to recall a memory, the brain reactivates the neural patterns that were created when the memory was formed, involving areas like the hippocampus and prefrontal cortex.

HOW IS OUR MEMORY DISTRIBUTED?

• Hippocampus: Primarily responsible for forming new memories and consolidating them from short-term to long-term memory. It plays a key role in episodic memory (memories of specific events) and spatial memory (remembering locations).

• Cortex (particularly the Temporal and Frontal Lobes): Long-term storage of memories, especially semantic memory (facts and general knowledge) and procedural memory (how to do things, like riding a bike). The cortex helps organize and store information over time.

• Prefrontal Cortex: Involved in working memory (short-term memory for current tasks) and in decision-making and retrieving memories.

• Amygdala: Plays a key role in emotional memory, helping to store memories that have emotional significance.

• Cerebellum and Basal Ganglia: Important for procedural memory, especially motor skills and habits (e.g., playing an instrument or riding a bike).

Executive memory

• This involves the brain's ability to plan, make decisions, solve problems, and control attention.

• It’s associated with the prefrontal cortex, which helps in managing and coordinating memory retrieval and application for tasks.

• Executive memory is crucial for organizing and using memory in goal-directed activities, such as problem-solving or multitasking.

• DORSAL AREAS ARE MORE ABSTRACT

• More anterior areas record more abstract and conceptual memories (Wisdom).

• The more frontal, the more complex memory.

Perceptual memory

• Refers to the memory of sensory experiences (such as sights, sounds, smells, and touch).

• It involves remembering details about the world based on what we perceive through our senses.

• Perceptual memory helps recognize patterns and objects we’ve encountered before.

• It is primarily processed in sensory areas of the brain, like the temporal lobe for visual and auditory information.

• VENTRAL AREAS ARE MORE PERCEPTUAL

• Sensory memories, mostly stored in posterior areas. Sensitive areas.

WHAT DEPENDS ON OUR MEMORY AND LEARNING?

• DEPENDS ON WHAT IS MEMORIZED, SOME AREAS WILL BE ACTIVATED OR OTHERS, ALSO RELATED TO THE FACT THAT SOME AREAS WILL ASSIST IF THERE IS AREAS OF THE BRAIN WHICH ARE NOT FUNCTIONING AS THEY SHOULD

The cerebral cortex plays a very important role in memory.

• The consolidation of learning or memory is the result of widely distributed networks of synaptic connections between neurons modulated by experience.

Hierarchies in Memory acquisition.

• Information is recorded in different regions following a gradient structure.

Memory is divided into different processes

Types of Memory

Sensory Memory

Short-term memory

Long-term memory

Implicit Memory

Explicit or declarative memory

SHORT-TERM MEMORY

• WORKING MEMORY

Implicit Memory

• Unconscious Memory.

• Learning and Habits.

• Involvement of the neocortex & basal ganglia

Explicit or declarative memory

• Conscious memory.

• Recall of a fact.

• Expressed in a variety of situations and contexts, different from those of the original learning.

• Corteza, Hipocampo y otras regiones cerebrales

Role of the Hippocampus

The hippocampus has an important role in information retrieval and storage.

Different parts of the hippocampus

• Dentate gyrus (divided in: CA1, CA2 y CA3)

• Subinculum

HIPPOCAMPUS IS Significant involvement in

Declarative memory

Spatial memory

Declarative memory

Semantic & episodic

Spatial memory

recognize, encode, store and retrieve information about the layout of objects, specific routes, configurations and spatial locations.

Place cells

• Neurons that are activated when the animal is in a particular location in the environment.

• Most often located in the hippocampal formation.

The hippocampus and entorhinal cortex 

contain “spatial” cells → functions of spatial representation & spatial memory

Spatial memory

• Information regarding the location of rooms, corridors, buildings, roads and other important elements of the environment.

• as we get used to the environment, the cells gets more abscent.

AMYGDALA

• involved in emotions, learning, and storage of memory