Identify innate rules, assumptions and shortcuts of perception which explain visual illusions.
- Your brain creates the contours of objects
- The context of the visual scene influences perception
Ex. Phantom Limbs
Provide an example of how perception affects neuroplasticity.
Phantom limb
-Sensation of missing limb
-Caused by neuroplasticity (cortical reorganization) in somatosensory cortex
Ex. Mirror therapy for Phantom Limb pain
Provide and example of how memory affects perception.
- Inferior Temporal Cortex: Visual perception meets memory
- Visual Agnosia: Loss of visual perception when the inferior temporal cortex is lost
Provide an example of how perception and memory share neural correlates.
- Brain "fills in" a lot of perceptions using your memories
Ex. The number 13 (Do you see 13 or a B?)
Phantom Limb
- Homunculus: how our body is represented in the brain
- Following amputation neurons in the somatosensory area reorganize and invade the area of the missing limb
- Painful sensation perceived by a missing body part
- 80% of amputees experience some phant
Apperceptive Agnosia
- Cannot see object parts as a unified whole
- Unable to construct sensory representations of visual stimuli
Associative Agnosia
- Cannot interpret, understand, or assign meaning to objects
- Sensory representation is created normally, but cannot be associated with meaning, function, or utility
Frog Experiment
- Normal frog optic tectum is entirely crossed
- Implant a 3rd eye on the frog and we see functional plasticity. Optic nerve is not wired properly, but allows the third eye to work.
Neurons in high-level visual areas (IT)
- Have complex "receptive fields"
- Show associative memory
Monkey Experiment
- Stitch a monkey's middle fingers together
- Wait
- Map out the receptive fields spanning the two fingers
Sensory Cortex
- Neurons in primary sensory cortex have receptive fields
- In the hand, these never span across fingers
Visual learning
- Learning visual categories changes early visual processing regions
Test:
- Study distortions of a prototype
- Test on related (in category) and unrelated (not in category) items
- Difference in activity found in early visual regions
Ex. Juggling, learni
Compare attention needed for analyzing the meaning of message versus analyzing whether the speaker is male or female.
- Analyzing the meaning of message requires more attention than analyzing whether the speaker is male or female
- We have considerable control over how we allocate attention
- We can choose to analyze a stimulus fully or partially
- TOTAL CAPACITY IS LIMI
Determine how diverting our attention to multiple tasks affects our ability to carry out tasks.
- Ability to carry out multiple tasks is slightly impaired
-Attention can act as a mental spotlight to help us detect objects and analyze their features faster
- Knowing where an event is going to occur, can allow us to better prepare and process the even
Define change blindness and selective attention, and describe how they relate to one another.
- Change Blindness: when a change in a visual stimulus occurs and the observer doesn't notice
- Selective Attention: the capacity for or the process of reacting to certain stimuli selectively when several occur simultaneously
Apply knowledge of limited capacity of attention to predict outcomes in everyday life.
Ex. Texting while driving
- We do not have the capacity to equally do one or the other
- We are either diverting more attention to texting or driving
Describe how prefrontal cortical size differs in different animals.
- Phenomenal expansion of prefrontal cortes (PFC) volume in primates, especially humans
Describe an experiment which showed the dorsolateral PFC is important for working memory.
A monkey (uncovered) sees food in a well (uncovered)
The monkey and the food are both covered
The monkey is uncovered and remembers which covered well the food is under
Dorsolateral PFC: a subsystem within PFC
PFC cortex damage:
- Show personality changes (flat affect, indifference)
- Show high susceptibility to incidental distractions
- Show impaired ability to initiate, terminate, or change behavior
- Show impaired "executive functions"
- Paying attention to
Describe how amygdala-PFC connections alter fear learning.
- Connections are designed to amplify the fear signal
Training: Pair cue to shock
Test: Is there a correlation between duration of PFC activation and duration of the fear response?
Identify at what stage is the PFC involved in motor learning.
Early Learning
- Prefrontal cortex, parietal cortex, and cerebellum are engaged in early motor learning
After practice with the skill:
PFC, parietal cortex and cerebellum all show less activity.
Motor cortex and nearby supplementary motor cortex become mo
Prefrontal Cortex (PFC)
- PFC is a region composed of several distinct subdivisions, each with different connection profiles (within and outside the PFC)
- Strongly connected with many other areas of the brain
Lobotomies
- Sever the connection between the PFC and the rest of the brain
- Quick
- Severed the PFC from the rest of the brain
- Widely given to stop psychosis and children's temper tantrums
- Sometimes calmed psychosis but also made patient mentally dull
- Shamef
Lobotomy Examples
- Jacobsen and colleagues (1935): shown that PFC damage had a "calming effect" in aggressive monkeys
-Brickner (1936): removal of the PFC in a patient did not appear to produce intellectual impairments
- Moniz and Freeman popularized a quick surgical meth
Orbitofrontal cortex: A Subsystem within PFC
Patients with orbitofrontal cortex damage:
- Show behavioral and emotional disinhibition
- Rarely emotional neutral ( exhibit euphoria and rage)
- Common selfish, boastful, childish, profane, sexually explicit
Cannot inhibit urge for instant gratification
Development of PFC
- PFC is the brain region that takes the longest to fully develop (~age 25)
- The PFC gradually becomes able to oversee and regulate behavioral responses initiated by the more "primitive" limbic structures
Memory
- Allows us to use experiences to adapt and have better behaviors or make better choices
- Limited capacity, attend to few details, memory held by prior knowledge and expectations
-Becomes more generalized and less detailed over time
- Reconstruction base
Eyewitness testimony
Altered by how the question is asked.
How fast was the black car going when it hit the blue car? - 34 MPH
How fast was the black car going
when it smashed into the blue car? - 41 MPH
Misinformation
Misinformation after the fact can distort memories
How fast was the white car going while on the country road? - 3% report a barn
How fast was the white car going when it passed the barn while on the country road? - 17% report a barn
THERE WAS NO BARN
High False Memory
High false memory rates even after high-stress, realistic events
- High stress led to fewer true positives and more false positives
Leading and Non leading
Non Leading: Asking to describe something, if subject cannot remember indicate it
Leading: Asking a specific and precise question
Reconsolidation
Retrieving a memory makes it labile and open to updating (alteration) or elimination
Prior knowledge
(What you think should happen) intrudes with our memory
Witness characteristics
Own race is identified more accurately
- Looking "deathworthy"
- how stereotypically "black" you look affects sentencing
Implicit bias
Clear despite no (or reverse_ explicit bias
False Memory
- Memory system is designed to produce these "errors"
- Hippocampus rapidly stores a bit from any given episode
- Gradual learning in neocortex over events leads to "semanticized" (gist) memories based on multiple similar svents and replays of those event
Aging
- Brain changes as we age
- Brain structures tied to memory shrink as we leave our 30's
- Associated with a loss in synapses in prefrontal cortex area 46
- Likely source of age- related problems in executing function and challenging working-memory tasks.
Memory Loss
Occurs with increasing age, but not all kinds
Problems with:
- Episodic memories
- Source memory
- Recollection
- Contextual memory
- Increase in false memories
- Executive functions in working memory
Fine on:
- Skill an habit memory
- Vocabulary
- Gist/
Area 46
- Prefrontal cortex shows age related changes
- Area 46: dorsolateral prefrontal cortex is the most widely studied in rhesus monkeys
- Critical role in executive function and working memory
Synaptic and Spine loss in area 46
- 30% decrease in synaptic density
- Similar loss in dendritic spines averaging 33%
- Declines are strongly correlated with scores on working memory tasks
Old Rats Tale
- Aged rats over-generalize & don't discriminate like young rats
- Also show cognitive aging
- Aged impaired rats have smaller, less effective synapses in the perforant path (quality not quantity)
- Aging (in rats) leads to alterations in connectivity in
Mnemonic Similarity Task (MST)
- Provides multiple measures
- Damage to hippocampus selectively impairs the mnemonic discrimination
White matter integrity
White matter integrity declines with age
Perforant Path
- Human perforanth path degrades with age
- Area correlates with mnemonic discrimination
Dementia
- Impaired memory
- Impairment in at least one
other cognitive domain
- Impairs social or
occupational functioning
- Gradual onset and continual
decline
Vascular Dementia (VaD)
Widespread damage from "Mini Strokes"
- Caused by blockages in the brain's blood supply leading to widespread, diffuse damage and cognitive loss.
- The second most common form of dementia (behind Alzheimer's)
- May cause or exacerbate Alzheimer's (complic
Frontotemporal Dementia (FTD)
Frontal and Temporal damage
- No amnesia in the early stages
- Clinical syndrome associated with shrinkage of the frontal and temporal lobes
- Impulsive or bored and listless
- Inappropriate social behaviors
- Neglect of personal hygiene
- Repetitive or c
Dementia with Lewy Bodies (DLB)
- Abnormal protein aggregations
- Presence of Lewy Bodies (alphasynuclein neuronal inclusion bodies).
- Similar to AD in terms of cognitive features and can sometimes be confused with it, however it also includes other symptoms e.g.
- Bradykinesia (slow m
AD Cognitive Profile
Early Changes
- Episodic Memory
- Executive function, working memory and attention
- Language and semantic knowledge
Later Changes
- Visuospatial deficits
- Decline across all cognitive domains
Risk factors for Alzheimers Disease
- Every 5 years after 65, the
risk doubles.
- One in every 8 people over
65 will get AD
- One in every 2 people over
85 will get AD
- Genetics
- ApoE4
- High blood pressure, smoking, diabetes, high cholesterol, lack of exercise, heart disease, stroke, hea
Mild Cognitive Impairment (MCI) - Prodromal Alzheimer's?
- An individual's report of his or her own memory problems, preferably confirmed by another person
- Measurable, greater-than-normal memory impairment detected with standard memory assessment tests
- Normal general thinking and
reasoning skills
- Ability
Prevention of AD
- Cognitive and social activities along with physical exercise
- Prevention trial: Anti-Amyloid Treatment in Asymptomatic AD (A4 Trial)
- Acetylcholinesterase inhibitors:
Increase amounts of acetylcholine in synapses by inhibiting its breakdown
- Tacrine
Prevent AD: Exercise
- Established effects in the
hippocampus (neurogenesis)
- Physical activity linked to
reduced risk for AD in
epidemiological studies
- Small benefits in clinical
trials, most notably in
executive function
- Need more studies
Prevent AD: Social and Leisure Activities
- Engaging in mentally stimulating
activities such as reading, playing
board games, playing musical
instruments, knitting, gardening,
and dancing have been tied to decreased dementia risk.
- Maintaining a larger social network has protective effects. Soci
Being "Engaged
Being "engaged" and mentally active rather than specific "brain training games
Video Games
Video Gamers have better memory for the details than non-gamers
In non-gamers, playing a more complex 3D game for 2 weeks improved memory ability
Savant Syndrom
Unknown biological basis and incredible performance in a limited domain
- Some cases originate from neural developmental "disorders" and others from injury
-Exceptional performance in a limited domain
- Typically, they have no knowledge how it's being don
Mnemonics
learning techniques that aid memory retention
- Practice, practice, practice.
Techniques:
- Method of Loci
- Depth of processing / elaboration
4=dog, 9=Bob
- Dates back centuries (Cicero, 55 BCE)
- Used to be required of being "educated
Highly Superior Autobiographical Memory (HSAM)
- Can tell you what happened on exact dates
- Memory ability is honed in at their own own particular aspects of life
- Does not pertain to any other memory systems from other domains
- Specific to their personal life story!!
- Cant remember most stuff at
I showed you earlier a number of visual illusions. What do these illusions tell us about how the brain works?
Our perceptions are not always accurately representing the world we experience.
The context of a visual scene can influence our perception.
Our brain is actively involved in perception, not passively processing it.
Our sensory systems are using specific r
Which of the following correctly characterizes the relationship between perception and memory?
Both are dependent on our brain "filling in" missing details.
These data so far show that:
Cortical plasticity not is limited to higher-level sensory regions
Cortical plasticity is not limited to happening during development
Cortical plasticity does not require the hippocampus and MTL
Using those last experiments as a guide - suppose I took a group of people who had never played the piano before and gave them lessons and had them practice for several months,. What changes might I expect to see in MRI scans taken before and after this t
Increased gray matter volume in primary cortical motor regions responsible for the left and right hands and perhaps changes in connectivity with these regions
We just covered an experiment which deciphers the limits of our attention and the effects of multi-tasking. Which statement is true about the experiment?
The difference between the two group conditions is that the one group needs to distinguish the lists based solely on content (rather than using tips like what type of voice said it).
Which statement(s) is/are true about change blindness, selective attention, and how they relate to one another?
Change blindness is the failure to notice surprisingly large change from moment to the next.
A suspected serial killer is on trial for a series of heinous murders. He was also famous for fits of rage during the trial. His lawyer makes the arguments that none of this is his fault because he (allegedly) suffered damage to:
the orbitofrontal cortex
Teenagers
can understand that particular actions are risky, but may still engage in them.
How many differences did you notice? (if any) when you watched the video? 0? 1? More? Enter your number
21.0
If someone is aware of his or her explicit bias, can they make unbiased decisions?
Somewhat - being aware of your explicit bias might reduce the effects of implicit bias, but the implicit bias effects will still be there
Svetlana is a 70 year-old woman without any signs of dementia. Suppose I gave her a list of words with some printed in red ink and some in blue ink. After a 15 minute delay, I test her memory for what she saw. When comparing this to typical "young, health
Problems remembering which color each word was shown in
If the age-related neurobiological changes we saw in the rats hold in humans, what is a good hypothesis that would account for the age-related memory problems in humans just covered?
The age-related memory loss stems from disruption of connectivity or circuitry in the hippocampus
Here is an MRI scan of an elderly person suffering from some kind of cognitive impairment. Based on the MRI scan, what would your best guess be about the diagnosis?
Vascular dementia
What is the most effective, disease-modifying compound (drug or supplement) used to treat Alzheimer's Disease?
There are no disease-modifying treatments for AD
Kenya is a 14 year-old who just read Moonwalking with Einstein. If she tries to do the same things the author did and trains her memory to compete in memory championships like he did, will she get better at things like memorizing history dates and biology
Yes, but only if she adapts the techniques to the kinds of material she's trying to learn
I have three decks of cards that are all randomly shuffled. I hand one to an HSAM (like Jill, Louise, or Marilu), one to Joshua Foer (Moonwalking with Einstein / memory champ) and one to a regular schmo (you) and give you all 2 minutes to try to memorize
Memory Champ > (HSAM ~= You)