Cog Neuro Exam 2

change blindness

time taken to detect change

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

attention is like a

spot light. may move from one location to another, may zoom in or out (fine vs coarse). doesn't/can't highlight everything

focus of attention doesn't necessarily mean

eye fixation

ex: highway hypnosis (eyes on road, but attention/focus not)

covert

moving attention by not the eyes/head

overt

moving attention as well as the eyes/head

Importance of cues

initially quicker response to cued location, but relationship flips after long delay

inhibition of return

a slowing of reaction time associated with going back to a previously attended location

endogenous

internally-guided attention, driven by goals/motivation, more top-down

ex: arrow points up in middle of screen, telling to shift attention up

exogenous

externally-guided attention, driven by sudden change in sensory input, bottom-up

ex: top cube flashes and captures attention

attentional blink

during a brief time after perceiving one stimulus, it is difficult to attend to something else

first target soaks up attentional resources, leading to subsequent inattentive period

hemineglect

inability to perceive one side of the visual world, typically right-hemisphere damage, left side neglect. sensory cortex responds to the info! therefore must be something wrong with attention

neglect vs blindsight

neglect: not restricted to vision, can see in neglected area, egocentric

blindsight: visual only, can move eyes to blind region, retinocentric

what happens to neglected info?

ventral stream (what) process neglected objects

burning house experiment

neglect is also about spatial reference frames

cannot detect differences on left side of an object even when falling into right side of space

spatial attention

lateral superior parietal areas (lateral = external)

nonspatial attention

lateral inferior temporal regions (lateral = external)

internally-guided spatial tasks

medial prefrontal and parietal areas (medial = internal)

attending to emotional states

medial prefrontal cortex and precuneus

bottom up

exogenous

top down

endogenous

biased competition model in attention

bias towards house vs. face

frontal-parietal attention mechanism

dorsal route: goals + importance

ventral route: circuit breaker, interrupts ongoing activity to redirect attention to some important feature

Conscious awareness is a

hierarchical process from sensory to association cortex

Attention can be seen as

focusing or strengthening sensory activation and pushing it further up the hierarchy

activity in _____ is modulated by attention

V4

Attended has

increased spike rate

ignored stimuli has

decrease spike rate

signal-to-noise ratio

it becomes harder to detect a signal as background noise increases, filter out stuff you want and ignore what you don't want

Selecting and de-selecting stimuli

blue peaks at first because it takes time to process and then allocate attention

attending to a stimuli increases

change detection accuracy, decrease in noise correlation (population of neurons becomes more synched)

synchronization of neurons

varies widely across cognitive states (lots of spikes = awake, fewer spikes = REM sleep, spikes every now and then = anesthesia, slow long waves = coma)

subliminal messaging example

measure startle response during randomly selected images (negative, neutral, positive)

conditions of consciousness

sentience, awareness of external reality, internal experience, "self"

consciousness is...

constructive! interpret inputs, and experience of reality depends on interpretive framework of the brain

brain areas involved in consciousness

midbrain, reticular formation, and thalamus

reticular formation in consciousness

traffic lights, tells what signals to go and when and projects to thalamus

if you damage your reticular formation

you lose consciousness

sleep

a state of unconsciousness, body's innate circadian rhythm

cave study

light cues influence circadian rhythm, but natural rhythm is around 25 hrs

In deep sleep

The MF (logic /reasoning/planning) is isolated

in light sleep

there are higher synchrony between brain regions

dreams

spontaneous neural activity, brain loves patterns so it tries to create a story

nightmares are remembered because

they are salient

Sleep paralysis

affects REM sleep, body immobile, person partially conscious

lucid dreaming

becoming aware in dream and taking control

anesthesia

reversibly alters consciousness without long-term damage, reduce excitatory and enhave inhibitory signals

coma

deep, prolonged state of unconsciousness , no response, no sleep cycle, abnormal breathing

coma happens with

any damage to brainstem or major damage to the cortex

vegetative states

brainstem intact (breathing, sleep-wake), but no signs of perception, awareness, brain metabolism is permanently decreased

Vegatitive patient conscious?

sometimes. answer yes/no questions by imaging playing tennis (motor cortex) or walking through their house (where - pariental)

dualism

mind and body are totally separate

Functionalism

the brain's specialized processing units underlie different aspects of conscious experience; FFA perceives face; it is a big fragmented

Integrated information theory

informative and

combined info across the brain

• Informative: experience of "red" is not "green" or "blue"

• Integrated: you perceive a face not a combination of shapes/colors/textures

default mode network

a circuit of brain regions that is active during daydreaming/thinking, medial parietal area

animals conscious?

Humans seem particularly intelligent, but non-human

animals possess much of the same neural machinery

Examples of non-human consciousness

self-recognition in mirror, human words with semantic meanings (parrot), complex learning & self-awareness in

octopuses, neural responses in crow that correlate with subjective perception of stimuli

localizationism

every brain area is an island, ex: phrenology and FFA/PPA

types of localizationism

modularity: regional preferences, not hard-separated

domain-specificity: a region does only x, never y or z

globalism

brain works as a whole, modern ex: connectionism (info stored in weighted connections)

functional segregation

Different areas of the brain are specialised for different functions

Functional integration

Networks of interactions among specialized areas

fMRI activations in task

changes in BOLD signal, lots of noise in data, lots of spontaneous activity...

spontaneous BOLD activity

occurs during task and at rest (intrinsic brain activity), resting-state networks (correlation between spontaneous BOLD signals of brain regions known to be related)

functional connectivity

what parts of the brain talk to each other

clustering brain-wide correlations into networks

can be chunked into networks and stay intact across many different tasks

default mode network association

medial prefrontal and lateral parietal lobes, hippocampus and temporal lobe, and they are physically connected with white matter bundle

DMN deactivates when

doing certain high-effort tasks that prevent you from daydreaming

DMN grows

with age

dorsal network

top-down, endogenous, goal driven, IPS, SPL, FEF

Ventral network

temporo-parietal junction, IFG/MFG, bottom up, stimulus driven

frontoparietal control network

executive functioning, control actions/behaviors, in many mental illnesses (depression, OCD, bipolar, schizo)

memory includes

long-term and short-term

long-term memory includes

explicit and implicit

implicit memory

procedural memory, ride bike, tie shoes, etc.

Types of implicit memory

classical and operant conditioning

classical conditioning

conditioned stim (bell) and unconditioned stim (food) become paired to make unconditioned response

operant conditioning

behavior-outcome association. ex: reinforcement (food when go left), punishment ( shock when go left), changes for wanted outcomes

explicit memory

semantic and episodic

semantic memory

facts

episodic memory

event from your life

HM

removed hippocampus, no new memories

anterograde amnesia

can't form new memories

retrograde amnesia

can't retrieve old memories

temporally-graded (remember more the longer before incident, and less before incident)

amnesiacs have intact

STM (normal digit span), procedural memory, semantic memory... generally intact

weather prediction task

learn rules of a weather prediction game, can't remember what cards they've seen but get more correct with time

amnesiacs have difficulty

imagining future events, loss of episodic

amnesiacs almost always have

episodic memory deficits

What happens in amnesia (recap)?

stm - good

implicit/procedural - good

semantic - might be impaired

episodic - definitely impaired

Special role of hippocampus

overcoming interference, birds with overlapping features and penguin

hippocampus does

pattern separation and completion

pattern separation

taking similar inputs and splitting into distinct representations

pattern completion

taking similar inputs and generalizing to a shared representation

working memory

keeping info actively in mind and manipulating it

timescale: tens of seconds

manipulating information

central executive, prefrontal

ST stores

visuospatial sketchpad, episodic buffer, phonological loop, parietal and lateral temporal

LT stores

visual semantics, episodic LTM, language, hippocampus/MTL/anterior temporal

ways to measure WM

digit-span task (finding limit of number of digits you can remember)

WM has

limited capacity, differs person to person, 7 plus or minus 2

chunking

organizing items into familiar, manageable units that lets you get more in WM