Learning and Memory - Chapter 5

central executive

The control system of working memory that coordinates and manages cognitive processes.

delayed nonmatch-to-sample task

A memory test where subjects must identify which stimulus doesn't match a previously shown sample.

depth of processing

How deeply information is analyzed and encoded in memory.

dopamine

A neuromodulator that alters neuron-to-neuron communication, important in prefrontal cortex function.

dorsolateral prefrontal cortex

Region of the brain critical for working memory and executive control.

dysexecutive syndrome

Condition involving impaired executive function.

executive control

Ability to plan, organize, and manage cognitive processes.

iconic memory

Brief visual sensory memory.

perseveration

Repetition of a response despite changed circumstances.

phonological loop

Component of working memory that handles verbal and acoustic information.

prefrontal cortex (PFC)

Brain region responsible for complex cognitive behavior and executive function.

sensory memories

Brief initial storage of sensory information.

short-term memory

Temporary storage of limited information.

transient memories

Briefly held memories.

visual sensory memory

Initial processing and brief storage of visual information.

visuo-spatial sketchpad

Component of working memory that handles visual and spatial information.

word-length effect

Phenomenon where longer words are harder to remember than shorter ones.

working memory

System for temporarily holding and manipulating information.

working memory

Active, temporary representation of information maintained in mind to help thinking and decision-making. Helps with multitasking, planning, and dealing with changing situations.

Sensory Memory

Brief sensations from immediate perceptions that last less than a second and can hold more information than we can recall.

Short-Term Memory

Capacity: About 5-9 items; Duration: Requires active rehearsal and can be disrupted by distractions.

Baddeley's Working Memory Model

Three Main Components: 1. Visuo-spatial sketchpad: Stores visual and spatial information. 2. Phonological loop: Stores verbal information through rehearsal. 3. Central executive: Controls and manipulates information.

Central Executive Functions

Key Functions include controlled updating of memory buffers, setting goals and planning, task switching, and stimulus selection and response inhibition.

Memory Transfer

Short-term to Long-term Memory: Passive rehearsal alone is not sufficient; deep processing enhances long-term storage, and active engagement with material improves retention

What is the role of the prefrontal cortex (PFC) in humans?

The PFC is critical for working memory and executive control. In humans, it makes up about 1/3 of the cerebral cortex, compared to just 4% in cats and other mammals.

What happened to Elliot after frontal lobe damage?

Despite normal intelligence and memory, his personality changed dramatically - he became impulsive, lost organizational ability, made poor decisions in relationships and business, leading to divorce and bankruptcy.

What deficits do patients with frontal lobe damage typically show?

They show difficulties with: 1. Working memory tasks 2. Short-term memory span 3. Planning and organizing 4. Task switching 5. Learning new rules (perseveration)

What are the key regions of the prefrontal cortex?

Three main regions: 1. Orbital prefrontal cortex 2. Medial prefrontal cortex 3. Lateral prefrontal cortex (divided into dorsolateral and ventrolateral)

What did Fuster's research reveal about prefrontal cortex neurons?

He found that certain PFC neurons fired only during delay periods when animals had to maintain spatial information, suggesting the PFC 'holds in mind' information needed for later responses.

What did Goldman-Rakic discover about 'delay neurons'?

She found that individual neurons in the dorsolateral PFC were tuned to specific directional movements, with about 80% encoding target location and 20% encoding intended movement.

What is Earl Miller's theory about the PFC's role in working memory?

___ proposed that the PFC's key contribution is its ability to sustain activity despite distractions, unlike other brain regions that are easily disrupted.

How do the dorsal and ventral regions of the PFC differ in function?

The ventrolateral PFC handles encoding and maintenance (like Baddeley's sketchpad and phonological loop), while the dorsolateral PFC handles executive control functions like monitoring and manipulation.

How is verbal vs. spatial working memory lateralized in humans?

The left PFC is essential for verbal working memory, while the right PFC handles visuo-spatial processing. This lateralization is more pronounced in humans than in other primates.

How does the PFC interact with long-term memory?

The dorsolateral PFC activates during memory retrieval and source monitoring, while the ventrolateral PFC (especially left side) activates during intentional encoding of new memories.

What are the two main disorders discussed that affect prefrontal circuits?

Schizophrenia and Attention-deficit/hyperactivity disorder (ADHD).

What are the primary symptoms of schizophrenia?

Hallucinations and delusions (seeing/hearing things that aren't real, holding bizarre/paranoid beliefs).

How does schizophrenia affect working memory?

It impairs working memory when patients need to keep many items in mind during a delay, particularly affecting the dorsolateral prefrontal cortex.

What brain region shows dysfunction in schizophrenia patients?

The dorsolateral prefrontal cortex shows reduced blood flow and activity during working memory tasks.

What role does dopamine play in schizophrenia?

Deficiencies in cortical dopamine processing affect working memory; patients show increased D1 dopamine receptors as possible compensation.

What genetic factor is linked to schizophrenia?

Mutations in the COMT gene, which affects dopamine metabolism in the frontal lobes.

How common is ADHD in children?

It affects 2-5% of children.

What are the main difficulties people with ADHD experience?

Problems with executive control processes like planning, organizing time, focusing attention, and inhibiting responses to distractions.

What brain differences are seen in ADHD?

Smaller right prefrontal cortex region and dysfunction in prefrontal cortex connections.

How do ADHD medications work?

They alter dopamine function by either increasing dopamine release or blocking its reuptake at synapses.

What is the duration of ADHD medication effects?

Effects are temporary, lasting only 3

How does Roberta use her dorsolateral prefrontal cortex (DLPFC)?

For sorting through class schedules, planning, maintaining reminders, and retrieving information from long-term memory.

How does Roberta use her ventrolateral prefrontal cortex?

For brief representation of objects, phonological loop rehearsal, and processing semantic and phonological information.