- Memory
- Frontal lobe
- Prefrontal cortex
- 3 regions
- 1. dorsolateral (previously)
- 2.orbitofrontal (previously)
- 3. ventralmedial
- Prefrontal cortex
- Frontal lobe
- 3. Ventralmedial
- Anterior cingulate cortex
- Collar around corpus collosum
- Corpus collosum
- Two Computers
- Left and Right Hemispheres
- Each controls contralateral side
- Except taste and smell
- Uncrossed
- Its own side of the tongue
- Work together
- Control trunk & facial muscles
- Staying Connected
- Corpus Callosum is a set of axons
- Interconnect hemispheres
- Exchange information
- Wide, flat bundle of neural fibers
- Under cortex
- Largest white matter structure
- 200–250 million axons
- Fast transmission (myelinated)
- Parts
- 1. Genu = anterior (knee)
- Thin axons
- Connect prefrontal cortexes
- Larger in musicians
- 2. Truncus = middle (body)
- Thick axons
- Connect motor cortexes
- M1, premotor & supp. motor
- 3. Splenium = posterior portion
- Soatosensory info
- Parietal lobes
- Visual cortexes
- 1. Genu = anterior (knee)
- Size
- Sexual Dimorphism
- Different size in men & women? No.
- R. B. Bean,1906
- Larger is intelligence
- Men
- Race
- Ultimately refuted
- Larger in left-handed?
- 11% bigger
- Dyslexic children have smaller CC
- Two Computers
- Childhood
- Gradually thickens as grow
- Slow growth until about age 10
- Eventually develop adult patterns
- Young children behavior similar to split-brain people
- Fabric identification task
- Five-year olds
- Equally well w/ one or two hand
- Three-year olds
- 90% more errors w/ two hands
- Anterior cingulate cortex
- Lateralization of Function
- Epilepsy
- Seizures = excessively synched neural activity
- Most treated with drugs (90%)
- More severe, tissue ablation
- Extreme, severe CC
- Neural activity rebounds between prolongs seizures
- Called split-brain people
- Split-brain people
- Present input of object to L field
- Info to R hem (noses cross)
- L hand controlled by R hem
- Can point to it with L hand
- Can’t do it with right hand
- Present input of object to R field
- Info to L hem (noses cross)
- Can name or describe what see
- Language in L hem
- 95% of R-handed
- 80% of L-handed
- Independence
- Each hem. can process info
- Multitask
- Draw circles
- One with each hand
- One hand going faster
- For a few weeks, feels like two people in one body
- Competition vs Cooperation
- Take item off grocery self with L
- Return them with R
- Eventually
- Brain uses smaller connection routes to avoid conflicts
- CC not the only path
- Just the biggest
- Cooperation
- Flash different word to each visual field at same time
- Report combined concept
- Present input of object to L field
- HM
- Henry Molaison (1926-2008)
- 1 generalized seizure a week
- began bilaterally
- in medial aspects of both temporal lobes
- Removed both of H.M.’s medial temporal lobes (in 1953)
- included most of
- hippocampus
- amygdala
- adjacent temporal cortex
- Post-surgery symptoms
- Major seizures almost completely eliminated
- Minor seizures down to 1-2 day
- IQ increased (104 to 118)
- Normal short-term memory
- Moderate retrograde amnesia
- loss for events shortly before
- Severe anterograde amnesia
- memory loss for events after
- *******************
- Amnesia
- Types
- retrograde amnesia = before
- anterograde amnesia = after
- Progression
- Normal cognition
- Retrograde amnesia
- Coma
- Confusion
- Anterograde amnesia
- Normal cognitive function
- Amnesia
- *******************
- HM (more)
- Post-surgery symptoms
- Can’t transfer anything to LTM
- Everything is forgotten when attention shifts
- Impaired ability to form LTM
- newer words like Jacuzzi and granola regarded as nonsense
- When distracted
- underestimate his own age by 10+ years
- Can’t form episodic memories
- memories of a single event
- could describe previously learned facts
- not recount personal events
- Retained ability to
- Weakly retain semantic (factual) memories
- Difficult to describe the future
- Post-surgery symptoms
- HM’s Implicit Memory
- Mirror Drawing
- First to show improvement in HM
- Spatial –motor learning
- Implicit learning
- Rotating Disc
- Keep pen on target (rotating disk)
- Improved over 7-day period
- Each time saw task, claimed he had never seen it before
- Mirror Drawing
- Hippocampus
- Temporal lobe & Dorsalmedial area of frontal lobe
- Semi-circle
- If damaged, amnesia
- Remember before & after accident
- Not accident or around it
- If small damage
- Retrograde amnesia
- Can’t remember past
- Just before accident
- If bilateral damage
- Anterograde amnesia
- Can’t form new memories
- Consolidation memory
- move from short to long term
- not necessary to retrieve info
- must work to put into long term
- Reproduces patterns during sleep
- Encodes patterns
- Sparse representations (non-overlapping)
- Sparse encoding allows quick learning
- Componential encoding
- 9×9 pixel bit map
- 81 pixels
- like cortex
- efficient
- good for generalization
- Sparse encoding uses 13 lines
- Trains cortex
- Repeats pattern over time
- Find L in field of Ts
- Patterns repeated
- Ss unaware of pattern
- Improves over time
- No “thinking” required
- Priming
- Repeats pattern over time
- Memory Systems
- Procedural Memory
- What you can do
- Sensory Memory
- Buffers for vision & audition
- Prospective Memory
- Remember what going to do
- Sensitive to elderly
- Declarative (things you know)
- Episodic (life story of events)
- right hemisphere
- Semantic (names and facts)
- left hemisphere
- Episodic (life story of events)
- Procedural Memory
- Neurotransmitters
- Epinephrine
- enhances consolidation
- if blocked, interferes with memory formation
- Cortisol
- enhances consolidation
- increase glucose availability?
- Ginkgo Biloba may increase blood flow
- Acetylcholine is necessary to form new declarative memories
- Epinephrine
- Non-Declarative Memory
- Doesn’t use hippocampus
- Non-word learning
- Acquired slowly
- Includes
- conditioned responses
- skills
- habits
- priming
- Types of Memory
- Short-term memory
- Memory of events just occurred
- About seven items (+-2)
- Rehearsal to get it in
- Once gone, lost forever
- Long-term memory
- Memory of previous events
- Long-term memory is vast
- Difficult to estimate how big
- Rehearsal not needed
- May recall with hints
- STM can be moved to LTM
- Held in working memory
- If score changes, throw out old score
- Consolidation
- Varies widely between people & material
- Interesting facts more than boring
- Emotional items learned quickly
- Cortisol activates
- Amygdala
- storage of emotional events
- Hippocampus
- Consolidates emotional event
- Amygdala
- Cortisol activates
- LTM not permanent
- Change, fade & vary in detail
- Reconsolidate a memory if:
- A reminder followed by similar experience
- New experiences during reconsolidation can modify memory
- Short-term memory
- Working Memory
- Temporary storage of tasks
- Attending to right now
- Delayed-response task
- Ss given signal
- Give response after a delay
- Damage to prefrontal cortex
- Impairs working memory tasks
- Older people often have impaired working memory
- Prefrontal cortex may change as age?
- Amnesia
- Memory loss
- Better Implicit Memory
- Nearly all patients with amnesia show better implicit memory
- Impact of recent experience on behavior
- even if not realize using memory at all
- Not good at deliberate recall
- Good at doing without knowing
- Memory loss
- Usually
- better implicit than explicit
- normal working memory
- nearly intact procedural memory
- some retrograde amnesia
- severe anterograde amnesia
- Hippocampal damage
- Impairs performance on
- Delayed matching-to-sample tasks
- Task used in animals
- Animals see an object (sample)
- After a delay choose between two objects
- Goal: choose one matches the sample
- Delayed nonmatching-to-sample tasks
- Same procedure
- Except animal must choose the different object
- Delayed matching-to-sample tasks
- Impairs performance on
- Spatial Memory
- Hippocampal neurons
- spatially tuned
- to particular spatial locations
- Cab drivers
- Larger than normal posterior hippocampus
- When answering spatial Qs
- hippocampus activated
- Need to recall detail & context
- Recent memories have sig detail
- Recalling recent memories
- activates hippocampus
- Recalling older memories
- may not require hippocampus
- Hippocampal neurons
- The Basal Ganglia
- Needed for implicit learning
- habit learning
- Other Brain Areas in Memory
- Almost all brain involved in some aspect of memory
- Amygdala used in fear learning
- Parietal lobe damage
- Affects ability to associate one type of info with another
- Temporal lobe damage
- Anterior & inferior lobes results in
- Semantic dementia
- Impaired semantic memories
- Prefrontal lobe damage
- Impairs ability to learn about rewards and punishments
- Summary
- Don’t lose all aspects of memory equally
- Several somewhat independent kinds of memory
- Each depends on different brain areas
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