learning memory

• majority of the temporal lobes; 
• amygdala 
• hippocampus

• anterograde amnesia -> moving forward 
• retrograde amnesia

• formed new memories for the next 55 years
• within minutes a new memory would disappear 
• could remember well rehearsed information (house layout)

• few memories from a decade before surgery (highschool graduation, WW2)
• memories before that time were intact

an impairment in forming new memories vs. the inability to remember events prior to impairment

process in which the brain forms a more or less permanent physical representation of a memory

process of accessing stored memories

• works in both consolidation and retrieval 
• blocking the receptors for 7 days following learning prevents the memory from being consolidated 
• blocking them during testing interferes with retrieval

directs the search strategy for retrieval only 

• temporally in the hippocampal formation
• overtime memory is moved to cortical areas; stored where information was processed (verbal stored in left frontal lobe)

• learning that results in memories of facts, people, and events that a person can verbalize or declare
• WHAT

• memories for behaviors
• results from procedural/skills learning, emotional learning, and stimulus response conditioning
• HOW 

• different origins in the brain
• radial arm rate maze
• nondeclarative with hipocampal damage (learned)
• declarative with striatum damage (memories)
• amygdala has significant role in non-declarative emotional learning (strengthens declarative memories about emotional events)

• provides a temporary "register" for the info while it is being used (phone numbers, chess move, conversations)
• chunking (ROYGBV, NESW, ACC football)

• works in tandem with sensory association areas (repeating sounds)
• acts as working memory central executive
• ->manages behavioral strategies and decision making
• ->directs neural traffic in working memory
• ->coordinates activity involved in perception and response

• if an axon of a pre-synaptic neuron is active while post-synaptic neuron is firing, synapse will be strengthened 
• ->how neurons are selected for survival during development 
• basis for learning

• increase in synaptic strength when both neurons activated 
• hippocampus and other "learning" areas

• decrease in strength of synapses when pre-synaptic neurons insufficient to activate post-synaptic cells 
• how brain modifies or clears memories
• "unlearning"

• pre-synaptic neurons influence sensitivity of nearby synapses 
• may underlie classical conditioning 
• -> auditory stimulus paired with shock=amygdala and fear behavior

• triggered by theta activity (4-7 Hz)
• ex: rats don't learn mazes during theta suppression
• ->theta in hippocampus during novelty
• ->LTP enhanced during theta peak, reversed at toughs

• LTP requires a sequence of events 
• ->glutamate activates AMPA
• ->NMDA blocked by Mg ions
• first pulse partially depolarizes membrane and dislodge Mg ions 
• further stimulation activates NMDA, depolarizing the membrane 
• CA2+ influx activates enzyme, CaMKII, strengthening the synapse 
• ->CaMKII dysregulation linked with alzheimers
• ->when missing, LTP decreases 50%

• dedrite, much depolarized
• ->if activation is strong enough to depolarize partially the post-synaptic membrane, the Mg ions are ejected 
• -NMDA receptor can be activated, allowing sodium and calcium ions to enter

• released by the post-synaptic neuron when its activated 
• diffuses across the cleft to the pre-synaptic neuron, where it induces the neuron to release more neurotransmitter
• causes for:
• ->an increased number of dendric spins
• ->enlargement/splitting of existing spines
• ->transport of additional AMPA receptors into spines
• makes the synapse more sensitive

• additional changes during learning
• increases in the hippocampus (10-20% increase in life)
• ->new neurons more likely to participate in learning (London cabbies)

• CaMKII
• protein kinase Mzeta

• critical for establishment of LTP
• ->doesn't reverse LTP once is it established when inhibited

• maintains long term memory 
• ->inhibition causes amnesia for already established conditioned responses

• changing memories
• new learning 
• requires NMDA (like LTP)
• ->blocking receptors eliminates extinction

• active, adaptive biological process
• protein phophhate 1 (PP1) and protein RAC produce memory loss after learning 
• forgetting prevents saturation of synapses

• when a memory is retrieved
• opportunity to refine memories and correct errors
• ->modify your emotional experience (therapy for phobias)
• can result in memory reconstruction and "recall" of false memories 

• most common cause of dementia
• progressive brain deterioration and declarative (memory loss)
• most behaviors suffer 
• ->language
• ->visual-spatial functions
• ->reasoning 
• effects increase with age 
• ->10% over 65
• ->50% over 85

• number of people with this disease will increase by 350% by 2050 (14.3 million people)
•