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3 functional zones of the frontal lobe
- prefrontal cortex (most anterior region – cognition, planning, etc…)
- premotor cortex (anterior to motor cortex - movement)
- primary motor cortex (or precentral gyrus - movement)
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_____ is important for Working Memory
Prefrontal Cortex
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What is working memory? 3
- Coordinated, temporary storage of information in various sites in the cerebral cortex.
- allows you to perform calculations in your head, to read, and solve problems.
- Intelligence may be linked to working memory capacity.
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Working Memory for Object Identification 3
- can hold an object or series of objects in mind
- thus can put a series of objects in order (face recognition)
- IT cortex (visual object recognition) and PFC (storage centers)
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Working Memory for Spatial Location 2
- holding in memory the spatial location of several objects at the same time (playing chess)
- right hemispheric regions are involved: posterior parietal, hippocampus, PFC
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Working Memory for Verbal Information 4
- holding words in mind (reading or listening to someone speaking)
- Broca’s and Wernicke’s areas (speech centers in the left hemisphere)
- anterior cingulate cortex (in medial PFC)
- left premotor cortex (rehearsing verbal material sub-vocally)
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2 functions of the Anterior Cingulate Cortex
- activated when working memory is used
- coordinates working memory
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Short-term memory (working memory) 4
- limited memory system (can hold 7 pieces of information)
- holds information effortlessly for 30 seconds before decaying
- can hold information longer with rehearsal
- Donald Hebb
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Consolidation (& Reconsolidation)
the shift of a memory from short-term to long-term form
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Long-term memory 3
- memory system capable of storing large amounts of information for long periods of time
- results from structural changes to memory circuits
- two main long-term memory systems: declarative & nondeclarative
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Declarative Memory 3
- Also called explicit memory
- conscious retention of facts and events
- Requires hippocampus for initial storage
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patients with hippocampal damage exhibit
amnesia. What are the 2 types of amnesia?
- retrograde amnesia (backward)
- anterograde amnesia (forward)
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Retrograde Amnesia
cannot remember events just prior to injury
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Anterograde Amnesia 2
- cannot create new declarative memories
- cannot remember events after brain damage
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2 Forms of Declarative Memory
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Episodic Memory 3
- memory for events or episodes in one’s own life (what one did yesterday or a meeting you had recently)
- such memories are organized in time and identified by a particular context
- also includes perceptions (can visualize the surroundings while recalling the information)
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Semantic Memory 2
- general knowledge or learned facts (knowing the multiplication tables, history, geography, etc…)
- does not include information about the context in which facts were learned
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2 Effects of Emotional Arousal on Long-Term Memory
- Memory is greater for emotionally charged events (easier to remember where you were on 9/11/2001 than other 9/11s)
- When aroused, your body releases hormones (epinephrine, which activates the amygdala which enhances consolidation of memory; drugs that block effects of epinephrine interfere with enhanced memory formation
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Nondeclarative Memory 3
- Also called implicit or procedural memory
- Involves nonconscious memory for learned behaviors
- Does NOT require the hippocampus - instead, involves cerebellum and corticostriatal system
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One example of nondeclarative memory is the _____. List brain regions involved.
- Priming Effect
- improved ability to recognize particular stimuli after experience with them
- e.g., word-stem completion task
- involves posterior parietal and occipital cortex for the visual information and Broca’s area for conceptual information
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Alzheimer’s disease 3
- neurodegenerative disease characterized by severe memory loss
- Diagnosed by presence of plaques and tangles which first form in temporal lobes and spread throughout forebrain
- initially, the disease destroys synapses and then eventually kills the neurons in the later stages of AD
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4 Disorders Associated with Prefrontal Cortex Damage
- Dysexecutive Syndrome
- Disinhibition
- Emotional Impairments
- Difficulty Planning
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Dysexecutive Syndrome 2
- inability to coordinate complex behaviors with respect to goals and task specific constraints
- might stir coffee cup first and then add cream to the coffee
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Disinhibition 3
- lack of behavioral control
- impulsive, quick to anger, prone to rude childish remarks
- can be tested using the Stroop Test or Wisconsin Card Sorting Test
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Emotional Impairments
indifferent and apathetic to their own situation and to the needs of others
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Difficulty Planning 2
- unable to organize behavior to plan several steps in advance
- assessed by Tower of Hanoi Test or Multiple Errands Task
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Classical or Pavlovian Conditioning
Model system for studying associative learning (implicit & explicit)
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Delay Conditioning 4
- Conditioned Stimulus and Unconditioned Stimulus are contiguous (overlap in time or simultaneous)
- requires fewer training trials
- depends on brainstem and cerebellar circuitry
- implicit learning
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Trace Conditioning 4
- Conditioned Stimulus and Unconditioned Stimulus are discontiguous (separated)
- requires many more training trials
- still depends on brainstem and cerebellum to elicit a CR but also depends on hippocampus to learn
- explicit learning
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How are Synapses plastic?
- they can be added or removed
- they can be strengthened or weakened
- Synaptic Plasticity has two basic forms:
- 1. long-term potentiation or LTP (strengthening)
- 2. long-term depression or LTD (weakening)
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LTP 5
- a form of cellular memory based on glutamate
- first discovered in Hippocampus
- input-specific
- Associative
- long lasting
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Induction of LTP Requires Strong Postsynaptic _____
depolarization
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3 Steps of LTP Induction
- 1. Glutamate is released & binds to AMPA, depolarizing postsynaptic membrane (because sodium enters) and activates NMDA as well
- 2. Calcium enters postsynaptic cell when NMDA are activated (Mg unblocks)
- 3. Cell fires action potential
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insertion of AMPA receptors or strengthening of synapse strength
LTP
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removal of AMPA receptors or weakening of synapse strength
LTD
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