Quiz 2 Flashcards
Conversion of light to neural signals
light passes through cornea then through pupil (which changes size with iris to control light amount), lens focus light onto retina, retina converts light energy to nerve signal, optic nerve carries signal to brain
What is presbyopia?
Age-related loss of visual acuity (sharpness)
What are the causes of age related vision loss?
cornea less transparent/sensitive, lens hardens, pupils become smaller/react slower, muscles become less able to rotate eye
Why are atypical age-related vision concerns not a cause of age related vision loss?
Atypical vision concerns occur more frequently with age but are not an effect of age
Selective Attention
the ability to both focus on information of relevance to the organism AND inhibit or ignore info which is task-irrelevant
Divided Attention
The ability to concurrently attend and process info from different locations in the auditory, visual, or somatosensory environment or concurrently perform or switch among different skills or tasks (driving)
Overt Attention
selectively processing one location over others by moving the eyes to point at that location
Covert Attention
paying attention without moving the eyes…looking at a fixation and putting things in the periphery
Top-down Attention
EF process
Goal directed; a person’s ability to intentionally and selectively process info in the environment
Someone decides what to focus on
Bottom-up Attention
EF process
Stimulus driven; the control of attention by characteristics of the environment, independent of an observer’s intentions, expectancies, or experience
ex: loud sound in the other room
Alerting (inc. age effects)
state of enhanced vigilance and preparedness to respond to incoming information
Orienting (inc. age effects)
selection of information from sensory inputs (shifting resources)
taking one’s attention and moving it a physical location or concept based on a cue
Executive Inhibitory Control (inc. age effects)
top-down processes involved in inhibitory function (deleting conflict and inhibiting, distracting or conflicting info)
INHIBITION, ignoring or deleting info that is not necessary
Task-switching (inc. age effects)
rapid switching between different tasks or skills, often with overlapping stimuli and responses
Reduce performance and less accurate
YAs: increased recruitment of prefrontal regions during dual vs single tasks
OAs: compensation during single tasks, over recruit PFC, no difference between dual and single tasks (ceiling effect)
Dual-tasking (inc. age effects)
What is the role of experience/expertise?
dual tasking/multitasking is the attempt at concurrent performance of different tasks…
expertise can reduce age-related deficits in attention
Global switch costs (inc. age effects- behavioral and neural)
the efficiency of maintaining multiple task sets in working memory of next tasks
OAs > YAs which is attributed to impairments in working memory and attentional capacity…greater switch costs in frontal lobe
dif. between homogeneous and heterogeneous and working memory
Local switch costs (inc. age effects- behavioral and neural)
within heterogeneous, sometimes you switch and sometimes you don’t
attention control processes responses
Age effects are nearly eliminated when slowing is controlled for
memory capacity is same but making that switch is the differences
OA > YA when they exist
Executive function
Control station of brain and control processes (other cog. processes, behavior, emotion, impulses), limited by a person’s ability, and opposed to automatic processes
EF IS A MODERATOR IN A MODEL BECAUSE THE RELATION BETWEEN AGE AND MEMORY IS GREATER FOR PEOPLE WITH LOW EF
Dimensions of EF - Unity vs. Diversity
Unity: common EF factor
Diversity: multiple dimensions of EF
Shifting
moving from one thing to another
Updating/monitoring
Keeping an eye on process going on and keeping an eye one updating if needed
Inhibition
Something that holds you back or restrains you from doing or thinking something
EF as a mediator of age effects
MEDIATOR: age related impairments in cognitive performance can be fully or partially explained by OAs EF deficits
EF as a moderator of age effects
MODERATOR: The negative relation between age and performance is greater for OAs with greater EF deficits, the strength of arrow depends on strength of relationship, variability is huge, which influences how age effects accuracy
Frontal-executive hypothesis of cognitive aging
Says age is associated with disproportionate atrophy and function changes in the PFC leading to EF deficits
Where do we see inhibitory deficits?
Individual differences like age (development and aging) and neurological status
Intra-individual variability like developmental (PFC does not develop fully until early 20s) and Time of day circadian rhythm (inhibition impaired during “off times”)
Controlling access to attention’s focus
Activation in response to familiar cues and thoughts is largely automatic as it is spread of activation through brain, equivalent across people and circumstances (does not change with age)…In order to focus, we move attention in a controlled way and focus on things that matter
Deleting irrelevant information from attention and working memory
Removing the spot around the spotlight, which can be difficult of OAs, once one narrows in you should delete things from the space that is not important…OAs CANNOT do this bc they have a hard time shutting out other info…also have a hard time deleting info once it is in their working memory
Suppressing or restraining strong but inappropriate responses
Some responses and concepts are strongly activated by a retrieval cue, but are incorrect or inappropriate given the context, must be inhibited…difficult for OAs
Spread of activation
Has to do with their spotlight
Decreased activation
spotlight not as strong, with same mental space
Decreased inhibition
everything else around is not getting dimmed down in the same way, bright spot light but everything else is still lit up
Only when there is competition between spotlight and surrounding space age differences are shown
Pros of decreased inhibition
If the information that is still obtained is relevant
Cons of decreased inhibition
If the distractor is harmful and not relevant…aka taking up working memory to the task
Factors contributing to inhibitory deficits
Individual differences and Intra-individual differences (developmental…20 years old and circadian rhythm)
Absolute sensory threshold
The amount of info required for a stimulus to be detected
Differential sensory threshold
The amount needed to detect a difference between two stimuli (JND)
Conversion of sound waves to neural signals
Sound waves enter ear at pinna and travel down ear canal, waves vibrate eardrum which vibrates ossicles causing fluid in cochlea to ripple, hair cells along cochlea allow vibrations to be changed into nerve signals, then signals carried to brain by auditory nerve ….hair cells have dif frequencies
Presbycusis
Age-Related hearing loss
Causes of age-related hearing loss
Impacted ear wax, thickened ear drunk, damage to ossicles, damage to sensory hair cells
HAROLD
Hemispheric Asymmetry Reduction in Older Adults.
OAs over recruit the other side of the brain, compensation by reorganization
PASA
Posterior to Anterior Shift in Aging.
OAs recruit interior regions and under recruit posterior sensory regions, compensation by selection…
Univariate analysis: age is associated with inc. recruitment of PFC during long-term memory and short term memory … PFC contained less info about cognitive outcome as function of age …MVB adding PFC does not improve model
CRUNCH
Compensation Related Utilization or Neural Circuits Hypothesis.
Inefficiencies cause the aging brain to over recruit neural resources, as demand increases a resource ceiling is reached…leading to age-related decrements for harder tasks, compensation by up regulation.
overcompensation and recruit regions more but keep level of YAs but hit ceiling and at high level of difficulty and not be able to do the task aka decrease in performance.
STAC/STAC-r
Scaffolding Theory of Aging and Cognition.
operates to counteract and adverse effects of neural degradation, saying influencing a person’s ability to utilize compensatory scaffolding (things that contribute to reserve…exercise, edu, healthy eating…increase ability which helps to mitigate age related deterioration.
Dedifferentiation
Compensation is increased recruitment in response to a gap. Greater similarity or reduced distinctiveness of neural responses, such that brain activation patterns are less specific to a particular type of input or mental state…Impairment of age.
Measured with receptive field mapping.
Explains HAROLD but check to see how it is tied to performance.
It is not ubiquitous because we do not see it across the entire cortex
Attenuation
Brain regions can be specialized for particular features, stimuli, or processes.
The specialization decreases with age…THE WEAKENING IN STRENGTH, VALUE, OR QUALITY OF A STIMULUS
Broadening
exploratory thoughts or actions
Cellular vs. population level measures of dedifferentiation
Cellular: Receptive Field Mapping, item FEATURES (orientation, frequencies, etc.)
Population: (of neurons) fMRI bold amplitude…differentiation index, MVPA,
Hyperdifferentiation (where?)
Anterior temporal lobe
There is a shift when other brain regions show support in tasks than other regions
BOLD amplitude
Differentiation Index (Difference in BOLD), Repetition Suppression
Dopamine binding
Critical for higher order cog. function, reduced dopamine binding as people age (PET)
Common cause/factor hypothesis (role as a mediator)
All the deficits we see in aging are due to a common factor, all are potential explanations that contribute to memory changes
Speed of Processing hypothesis
Mechanisms that may influence cognition: limited time and simultaneity.
Salthouse reported evidence that the relation between age and decision accuracy was 0 (non existent) when speed of processing was added to the model
ROLE: mediator because it fully explains the role of accuracy and age, aka high for some people and low for others
Limited time mechanism
Cognitive operations are executed too slowly for time window, additional time taken for early operations restrict time abatable for later operations.
Complexity effect: greater age differences for more complex tasks…bc they are slower they may not have time to reach the later processes and not be able to finish other task
Simultaneity mechanism
Slow processing makes it so operations are not occurring at the same time, output of one operation is no longer available by the time the next operation is completed.
If you are taking a long time with one process, by the time you move on to the next your working memory cannot remember the later
White matter in speed of processing
Myelin sheath speeds neural transmission and deterioration may lead to slowing.
myelin sheath around axons which allow productive movement and aging deteriorates it and therefore slower
MVPA (Multi-Voxel Pattern Analysis)
Look at pattern of activation within a reason and ask how does that pattern distinguish between groups of OAs/YAs
Item-Level Representational Stability
Ask are all of the objects more similar to some another for both groups then compare the groups
Functions of Inhibition
Controlling access to attention’s focus
Deleting irrelevant info from attention and working memory
Suppressing or restraining strong but inappropriate responses
