Learning and Memory

• Learning involves relatively permanent changes in an organism's behavior, resulting from experience and leading to new acquisitions in understanding, behaviors, knowledge, attitudes, and skills.
• Memory is the ability to recall or recognize previous experiences, implying a mental representation or engram, a physical trace in the brain.
• Neuroscientists have found that the engram results from physical changes at synapses and within neuron nuclei.

Studying Learning and Memory in the Laboratory

• Researchers study learning and memory by observing behavioral changes at a macro level rather than directly examining the brain.
• Behavioral measures help evaluate changes, and results reveal the organization of brain learning and memory systems.
• Behavioral scientists face the challenge of having laboratory animals and people reveal what they remember.
• Researchers use paper-and-pencil or computer-based tests for humans.
• Investigators must discover alternative methods for nonhuman laboratory animals to demonstrate their knowledge.
• Tests must align with each species' capabilities due to variations in how different nonhuman species communicate.
• Mazes or swimming pools are mainly used in studies of rats, as rats naturally live in tunnels and near water.
• Monkey studies use their sharp vision and curiosity, by having them look under objects for food or watch television monitors.
• Natural behaviors such as singing are used in bird studies.
• Two training traditions for animals to "talk" to investigators originated approximately a century ago.
• These traditions are based on the work from Edward Thorndike (1898) in the United States and Ivan Pavlov in Russia, beginning in the 1890s.

Pavlovian Conditioning

• Ivan Pavlov discovered that dogs associated a stimulus, such as a tone, with food.
• When hearing the tone later, the dogs salivated, even without food present.
• Pavlovian conditioning, also known as respondent conditioning or classical conditioning, has numerous documented characteristics.
• A key feature involves animals associating two stimuli and communicating their learning by giving the same response to both, for example salivation.

Eyeblink conditioning

• Eyeblink conditioning is used in studies for learning in rabbits and people.
• A tone (or stimulus) is paired with a painless puff of air to the participant's eye.
• The tone becomes a conditioned stimulus (CS) producing a blink initially caused by the air puff.
• The air puff is an unconditioned stimulus (UCS) due to blinking being the normal reaction, called the unconditioned response (UCR).
• A participant communicates they have learned the signal that predicts a puff by blinking in response to the signal (CS) alone, known as a conditioned response (CR).
• Cerebellum circuits mediate Pavlovian learning designed to pair motor responses with environmental events, leveraging people's biological predisposition.

Fear conditioning

• Involves using an unpleasant but harmless stimulus to evoke an emotional fear response.
• An animal in a box receives a mild electric current (approximating static electricity) through the grid floor.
• A tone (the CS) is presented before a brief electric shock and when the tone is later presented alone, the animal responds fearfully.
• The animal shows it has learned by becoming motionless or urinating in anticipation.
• The animal does not response to light or other new stimili.
• The amygdala plays role in this CR because circuits of the amygdala, and not the cerebellum, which mediate fear conditioning.

Operant Conditioning

• Began with Edward Thorndike (1898), who studied problem-solving in animals.
• In one experiment, a cat was placed in a box with food outside and had to figure out how to escape to obtain the food.
• To escape the box, the cat had to press a lever to activate a pulley system to open the door.
• The cat learned that its actions had consequences, repeating the behavior before the door opened.
• The animal demonstrates that it has learned the association between its actions and the consequences.

Instrumental conditioning

• B.F. Skinner used reinforcement, training rats to press bars or pigeons to peck keys for food.
• Named instrumental conditioning by Thorndike, more commonly known as operant conditioning.
• Demonstrates the association between actions and results through increased task performance by the animal.
• Operant learning is not localized to a specific brain circuit.
• Olfactory tasks involve olfactory-related structures, spatial tasks recruit the hippocampus, and motor tasks require the basal ganglia.

Two Categories of Memory

• Human memory challenges researchers due to its verbal nature.
• Psychologists have studied memory since the 1800s, but cognitive psychologists have developed complex measures for neuropsychological investigations recently.
• Measures include tasks where participants read word lists (e.g., seasons, action words) and asked to define words.
• People who read the season list are most likely to give the meaning for the word fall as autumn, people who read the action list will give the meaning as tumble.
• Explicit: Information that you have to consciously work to remember.
• Implicit: Information that you remember unconsciously and effortlessly.

Measuring Implicit Memory

• Measures knowledge through skills, conditioned responses, or recall of events, neither intentional nor premeditated.
• Amnesia can occur even with normal performance on implicit memory tasks.
• People with amnesia show no recollection of reading the word list but are influenced by it.
• Amnesia, occurs with dissociation between the memory of unconscious learning and explicit memory.
• Amnesia: conscious recollections of training, such as the name of the person in charge of the training or the layout of the training room.
• This distinction holds for visual and motor learning as well.
• People are shown the Gollin figure test, likely to identify an image.
• When shown the same sketch later, both groups identify the figure sooner.
• Amnesia patients may not recall seeing the sketch before but behave as though they have.
• It also measures learning a skill, such as the pursuit rotor task, where one holds a stylus on a small disc moving in a circular pattern.
• There is typically significant improvement after training.

Implicit Memory vs. Explicit Memory

• Researchers prefer to distinguish between declarative memory, the specific contents of experiences recalled, and procedural memory, the ability to perform a task.
• The general distinction is that one category requires recalling specific information, and the other refers to knowledge of which we aren't consciously aware.
• Implicit learning includes conditioning and Skinner's operant learning and Thorndike's

Explicit Memory in non-speaking Animals

• Explicit memory include episodic (personal experiences) memories and semantic (general knowledge and facts) memories.
• One author had a cat that watched while a ball was put on a shelf, and for weeks afterward, the cat stared at the shelf and displayed explicit memory.
• Rats can learn to find palatable food in a new location.
• They may forget the location in a week.
• This illustrates implicit memory of the learning set and the rules of the game.

Encoding and Processing Memories

• Memories are encoded by changing into a form that can be stored in the brain.
• Various encoding types include visual, which is storing position, and semantic, which is storing input that becomes part of one's knowledge.
• Encoding includes synapse modification, new synapse creation, gene expression changes, and protein modification or creation.
• Implicit information is encoded as it is perceived: information enters the brain through sensory receptors and is processed in subcortical and cortical regions.

How the Brain Processes Memories

-Visual moves from bottom photoreceptors to the thalamus, then the occipital cortex, then through the ventral stream to the temporal lobe where the object is recognized.

• It is easy to form false memories, as demonstrated by most participants being certain that "sugar" was in the first list when it wasn't, while other sweet things were.
• The brain does not process all implicit or all explicit memories in the same way.
• Divide into categories that differ such as visual and auditory is.
• Auditory are encoded in different brain regions than the visual.
• Short-term, also is referred to as working or temporal memory, holds information such as scores or lock combinations only briefly.
• Long-term holds life time information such as you own bike lock, and complex explicit memory as well as implicit and emotional memory.
• The frontal lobes are central in short-term memory, and the temporal lobe is central in long-term storage of verbal information.
• The key point is that there is no one storage location.

Semantic memory

• Encompasses knowledge about the world.
• A meta-analysis of fMRI semantic memory studies revealed a network of seven left-hemisphere regions, including the parietal lobe, temporal lobe, prefrontal cortex, and posterior cingulate cortex.
• Subregions may specialize in object characteristics (color, shape) or knowledge types (names, places).
• Similar to the default network, the network active during rest suggesting semantic processing is a cognitive activity during passive states.

Episodic Memory, Personal Memories

• Includes records of events and our presence and role.
• Personal experiences form the basis of who we are and the rules we live by.
• Having memories not only for events but also for their context, providing meaning, a concept of time, and a sense of our role in a changing world.
• The current consensus is that the regions involved in this process are the ventromedial prefrontal cortex (vmPFC) and hippocampus, and pathways.
• An engram in the prefrontal cortex occurs over 2 years.

Personal Memories

• The hippocampus and vmPFC are critical for retrieval of personal memories.
• The vmPFC works with the hippocampus to integrate new personal memories.
• The hippocampus reconstructs memories stored in the vmPFC to make them distinctive.
• People with frontal lobe injuries would still recall events but would be unable to see your role in them.
• Injuries in the hippocampus is associated with poor episodic memory.
• People with temporal lobe epilepsy and in controls showed reduced hippocampal activity during episodic memory retrieval, which was associated with impaired episodic memory.
• They also showed increased vmPFC activity during memory retrieval.

Superior Autobiographical Memory (HSAM)

• Some people show extraordinary autobiographical, have nearly complete recall for events beginning around age 10, often including the day of the week, the date, and the weather.
• Brain imaging shows increased gray matter in the temporal and parietal lobes and increased fiber connection between temporal and frontal lobes.
• People with HSAM are as likely to develop false memories as other people.
• The source is unknown but does not appear to reflect superior cognitive function.
• They have superior personal memories but do not show signs of elevated performance with personal memories.
• HSAM is an experience that is part of the individual’s personal narrative.