Chapter 7 Flashcards
selective attention
the ability to focus awareness on one stimulus, thought, or action, while simultaneously ignoring others. Selective attention can be directed at spatial locations, at object features, or at an entire object.
Inattentional blindness
is the failure to notice a fully-visible, but unexpected object, because our attention is focused elsewhere
Properties of Selective attention
-Prioritizing some “things” for cognitive processing while deprioritizing or ignoring other things
Voluntary (top-down) vs reflexive (bottom-up) attention
-reflexive (exogenous) – catches eye, attention drawing, incoming stimulus that draws our attention to it
-voluntary (endogenous) – higher level of processing
overt attention
major shifting of attention by moving the eyes or body (outside). For example, when a person moves his or her head in the direction of an object, they are paying overt attention to the object
covert attention (Herman von Helmholtz)
shifting attention from one place to another without moving the eyes; Spatial attention is often thought of metaphorically as a “spotlight” of attention that can move around as the person consciously desires
voluntary attention
Top-down, endogenous (internal decision): purposely directing your attention; focused and choose to focus. For example, cocktail party event - focus on specific conversation among large group of people (voluntary).
reflexive attention
Bottom-up, exogenous (what is driving the attention outside), stimulus-driven process in which a sensory event, such as a flash of light, motion or smn yelling your name captures our attention, even when you didn’t try to listen to it. (intrusion) The more salient the stimulus, the more easily our attention is captured: Think of how we respond to rapid movement that we see out of the corner of the eye (eek! a rat!) or the shattering of glass in a restaurant.
dichotic listening task? which kind of attention?
two different auditory stimuli (different speech) are presented simultaneously on different sides of headphone, person pays attention to one side and most can’t remember any details what other side said (unattended ear). In fact, all they could reliably report from the unattended ear was whether the speaker was male or female. Attention—in this case voluntary attention—affected what was processed.
cocktail party effect
when you speak with a friend in a busy room, but your attention may be drawn away if you hear something interesting in another conversation (covert attention)
global arousal vs selective attention
Global arousal is a physiological and psychological brain state, a general ability to be alert (general awareness), which includes 2 global states: wakefulness and sleep; whereas selective attention describes what we attend and ignore (pay attention to or not)
spatial cuing paradigm
When a cue correctly predicts the location of the sub- sequent target, it is a valid trial. If the relation between cue and target is strong—that is, the cue usually (say, 90 % of the time) predicts the target location—then participants learn to use the cue to predict the next target’s location. Sometimes, the target may be presented at a location not indicated by the cue, so the participant is misled in an invalid trial. Finally, the researcher may include some cues that give no information about the most likely location of the impending (coming) target—a neutral trial
It’s an example of spatial, covert and voluntary attention.
What is the benefit and cost of spatial attention?
The benefit of spatial attention is that we have a lower reaction time for the right fixation (valid) and the cost of spatial attention is that we have a higher reaction time for the left fixation (invalid)
Early vs Late selection
Early-selection - marking something as important before it has been fully processed, only the “most important,” or attended events pass through, which shows that we can focus on so much input at once. For example, cocktail party experiment.
2) the idea that a stimulus can be selected for further processing at early processing stages
* Only attended objects get high level processing and irrelevant stimuli are tossed out before perception
In contrast, late-selection - attention would act only after complete processing of the sensory inputs; ex: if your name was spoken in the other side of a dichotic listening task and you don’t know what was said but you know you heard your name
2) it argues that all information reaches higher processing stages
* Selection determines what information gains access to awareness
Attention function
Attention influences how we process sensory inputs, store that information in memory, process it semantically, and act on it.
What do descending auditory pathways show us about the early vs. late selection debate?
-outer hair cells see changes in otoacoustic emissions activity when we actively pay attention to stuff
-descending auditory pathways may modulate early auditory processing basically as early as auditory info enter the cochlear nuclei
What do ERPs in dichotic listening tasks show us about the early vs. late selection debate?
-larger N1 deflection/response when a person pays attention to sound being played
-smaller N1 deflection when person is not paying attention to sound
-proof that attentional selection in auditory sys. is treated differently early on
Where is evidence for early auditory attentional selection from MERFs found?
localized in primary auditory cortex
ERP in spatial attention tasks
-Covert change in spatial attention
-brain shows bigger attentional selection response (P1) when paying attention to correct side of screen
-evidence for early selection
What parts of the visual process are influenced by attentional selection?
visual cortex and thalamus
What does the Bestmann study show us about visual processing?
Attention modulates visual processing, even if the stimulus bypasses (miss) the thalamus and goes directly to the visual cortex
-evidence of late selection w/o early selection
V4 vs V5
V4 - processing of color and shapes (achromatopsia: total colorblindness, different from regular colorblindness)
V5 - How objects are moving (damage leads to akinetopsia)
Ocular apraxia
inability to make voluntary eye move. When the physician overlapped the spoon and comb in space as in Figure 7.1c, the Bálint’s patient should have been able, given his direction of gaze, to see both objects, but he could not.
Simultanagnosia (Balint’s Syndrome)
difficulty in seeing more than one part of a scene at once (the whole scene), such as when the patient saw only the comb or the spoon, but not both at the same time (Figure 7.1).
Optic ataxia
Type of dorsal stream/perception damage for action where a person has trouble using eyes for guiding movement
Ex: not having your hand in the correct position to grab an object/can’t put a card into a slot (action tasks)
(If the doctor had asked the Bálint’s patient to reach out and grasp the comb, the patient would have had a difficult time moving his hand through space toward the object.)
What’s Balint’s syndrome? What are the 3 main deficits of this disorder?
A condition resulting from damage to a person’s parietal lobe. Patients with Bálint’s syndrome have three main deficits for the disorder:
1) Simultanagnosia (difficulty perceiving the visual field as a whole scene);
2) Ocular apraxia (an inability to guide eye movements voluntarily);
3) Optic ataxia (difficulty reaching to grab an object).
unilateral spatial neglect
type of damage, typically as the result of a stroke to the right hemisphere, which is contralateral, resulting in an inability to recognize objects or body parts in the left visual field
ex: drawing half of something
Types of unilateral spatial neglect?
- extrapersonal space neglect
- object-centered neglect
extrapersonal spatial neglect VS object-centered spatial neglect
extrapersonal spatial neglect - type of unilateral spatial neglect where a person ignores the entire left side
ex: drawing a picture of a tree on your right but not the house on your left side
object-centered spatial neglect - type of unilateral spatial neglect where patient ignores one half of an object (usually left); ex: drawing half of a tree, half of a house etc.
extinction and neglect
A person can attend to objects on their left and right side, but when two objects are shown at the same time, the person pays more attention/prioritizes what is to the right side and only sees the object on the right
test for unilateral neglect
Line cancellation task.
Patients are given a sheet of paper containing many horizontal lines and are asked to bisect them in the middle. Patients with left-sided neglect tend to bisect the lines to the right of the midline (for a right-hemisphere lesion).
Sources of attention
-Dorsal attention network (where pathway, spatial relationships)
-Ventral attention network (what pathway)
-subcortical attention network
dorsal attention network responsible
(frontal and parietal lobe): top down, endogenous attentional control, which is voluntary, goal-directed attention; concerned primarily with orienting attention (ex: concerned with cueing tasks) - not lateralized
ventral attention network responsible
(frontal, parietal, and some temporal lobe): bottom up, exogenous attentional control (reflexive), responsible for disengaging and reorienting attention (invalid); highly lateralized to the right hemisphere (neglect left side)
subcortical attention network
-superior colliculus: important for attentional movement (ex: moving attention from one place to another, damage cause issues with shifting)
-pulvinar of the thalamus: has cells that are sensitive to visual stimuli, which helps guide and direct attention
Inhibition of return
a slowing of reaction time at detecting stimulus that caught your reflexive attention, your attention shifts back somewhere else so you will be slower to detect anything. Inhibition of return occurs if delay between stimuli is greater than 300 ms
What are the types of visual search?
pop-out and conjunction
Pop-out search
- Target defined by a single feature
- Pre-attentive
- Not affected by number of items to be searched
(e.g. find a red “o” in a group of green “x”s)
This phenomenon is called pop-out because the red O literally appears to pop out of the array of green letters on the basis of its color alone.
Conjunction search
the target is defined by the conjunction of two or more features. If the target shares features with the distractors, how- ever, so that it cannot be distinguished by a single feature (e.g., a red O among green X’s and O’s and red X’s, as in Figure 7.29b, or a red suitcase among black suitcases and differently shaped red and black backpacks), then the time it takes to determine whether the target is present or absent in the array increases with the number of distractors in the array
object-based attention
attention that is directed to a specific object. its faster when it’s perceived the same object
Neglect in Mental Imagery
Person imagines a place and only describes places on the right side of mental image
-gives us evidence that it is not a memory issue, it is an attentional issue
Hallmark of reflexive attention
A hallmark of reflexive attention is inhibition of return, the phenomenon in which the recently reflexively attended location becomes inhibited over time such that responses to stimuli occurring there are slowed
bottlenecks
A stage of information processing where not all
of the inputs can gain access or pass through (the eardrum, when you become aware of what was said)
object constancy
the brain correctly perceives objects as constant in countless situations despite viewing angles (variation in the physical stimulus)
Variation of visual stimuli emerges from 3 factors:
- viewing position
- illumination
- context
primary visual cortex location
the region of the occipital cortex, where most visual information first arrives
ventral (occipitotemporal) stream function
visual pathway in the brain specialized for object perception and recognition (what), identify what an object is. It focuses on vision for recognition (identification).
dorsal (occipitoparietal) stream function
visual pathway in the brains specialized for spatial perception of objects (where), location of an object. It focuses on vision for action.
superior longitudinal fasciculus location
location of the dorsal stream (where) proceeds to the posterior parietal cortex
inferior longitudinal fasciculus location
location of the ventral stream (what) proceeds to the inferior temporal cortex
Experiments carried out on animals with bilateral lesions of the temporal lobe showed that… stream
…the ventral stream (“what”) was totally disrupted, while
the dorsal stream (“where”) was unaffected
Experiments carried out on animals with bilateral lesions of the parietal lobe showed that… stream
… the dorsal stream (“where”) was totally disrupted, while the ventral stream (“what”) was unaffected
Do neurons in the ventral stream show object constancy? If yes, explain why and give an example.
Neurons in the ventral stream (“what”) show object constancy. In the brain of someone with a functioning ventral stream, the neurons of the pathway need to be able to recognize the stimuli regardless of its orientation etc. (e.g. hand)
Damage to parietal cortex on right hemisphere
Damage to this area can cause visuo-spatial deficits (e.g., the patient may have difficulty finding their way around new, or even familiar, places)
D.F. tasks & visual agnosia
EX: D.F. performed a task, patient with visual agnosia
- could not do the IDENTIFICATION (explicit-matching) task D.F. was given a card and asked simply to orient her hand so that the card would fit into the slot. D.F. failed miserably, for example, orienting the card vertically even when the slot was horizontal - the ventral (what) stream was affected
- could do the ACTION task (where), when asked to insert the card into the slot, however, D.F. quickly reached forward and inserted the card - dorsal stream was fine
Optic Ataxia disorder? Which part of brain affected?
problem with picking up and interacting with objects, but no problem with matching/recognizing the object (e.g. can see a pen in front of them but can’t grab it) opposite of visual agnosia. Optic ataxia is associated with lesions of the dorsal stream (where) in the parietal cortex
Gnostic units (grandmother cells)
Neurons that can recognize a complex object, referring to the idea that the cell (or cells) signals the presence of a known stimulus—an object, a place, or an animal that has been encountered in the past.
Ex: wrong hypothesis: having a chair gnostic unit, an apple gnostic unit etc.
we have feature gnostic unit, shape gnostic unit etc
Ensemble coding theory
recognition is due not to one unit, but to the collective activation of many units (collection of cells). “Granny” is recognized here by the co-occurrence of her wrinkles, face shape, hair color, and so on.
Integrative visual agnosia
can perceive parts of an object, but cannot perceive the “whole”; can’t identify the objects correctly
they can draw some parts of lego
e.g. seeing Lego windows, doors etc. but not the Lego house
Associative visual agnosia?
- can copy objects, but unable to recognize them
- no connection between stored (semantic) knowledge and visual object recognition area, we can’t name it. A patient with associative agnosia can perceive objects with her visual system but cannot understand them or assign meaning to them. At Legoland she may perceive a house and be able to draw a picture of that house, but still be unable to tell that it is a house or describe what a house is for.
Category-specific deficits (agnosia)?
Visual agnosia can be category specific. Category- specific deficits are deficits of object recognition that are restricted to certain classes of objects, which are inanimate and animate (such as cat); sensory motor hypothesis - animate objects share similar features, which is much more difficult to recognize comparing with nonliving objects
single cell recordings
ventral stream cells in the inferior temporal cortex, which demonstrate strong object selectivity. The cells respond to more complex objects, such as hands.
Hierarchical coding hypothesis
-As we move through the ventral stream, each level represents specific features of an object and gets more complex as you go on
Ex: features —> conjunction of features —> component shapes —>object
-explains how we have specific specialized cells that fire in response to specific features of objects.
anterograde amnesia? which kind of memory impairment?
forward-going, the loss of memory for events that occur after a lesion, you can’t remember what just happened to you. It leads to the inability to learn new things. You can’t form new long-term memories
retrograde amnesia
A loss of memory for events and knowledge that occurred before a lesion or trauma. Sometimes retrograde amnesia is temporally limited, extending back only a few minutes or hours. In severe cases, it is extensive, sometimes encompassing almost the entire previous life span.
modal memory (Richard Atkinson and Richard Shiffrin)
proposes that information is first stored in sensory memory (a few ms to seconds). After which, items selected by attentional processes can move into short-term storage (seconds to minutes). Once in short-term memory, if the item is rehearsed, it can be moved into long-term memory (minutes to years)
central executive mechanism? which kind of memory?
a central executive mechanism controls 2 subordinate systems: the phonological loop, which encodes information phonologically (acoustically) in working memory; and the visuospatial sketch pad, which encodes information visually in working memory.
it is modality specific
Brodmann area 40 vs Brodmann area 44
Lateral view of the left hemisphere, indicating that there is an information loop involved in phonological working memory ( flowing between BA44 and the supramarginal gyrus (BA40).
Patients with lesions of the left supramarginal gyrus (Brodmann area 40) have deficits in phonological working memory, so that they cannot hold strings of words in working memory. The rehearsal process of the phonological loop involves a region in the left premo- tor area (Brodmann area 44).
evidence for dissociations in the brain regions activated during the performance of spatial VS verbal working memory tasks
Changes in local cerebral blood flow on working memory tasks, measured with PET.
Verbal (a) and spatial (b) working memory tasks were tested in healthy volunteers. The verbal task corresponded primarily to activity in the left hemisphere, whereas the spatial task lateralized mainly to the right hemisphere.
Word priming study
is a perceptual priming of non-declarative memory. Perceptual priming acts within the perceptual representation system (PRS). In the PRS, the structure and form of objects and words can be primed by prior experience. For example, participants can be presented with lists of real words — for example, “t_ou_h_s” for thoughts. These fragments can be from either new words (not present in the original list) or old words (originally present). The participants are asked to simply complete the fragments. Participants are significantly better and faster at correctly completing fragments for words that were also presented in the initial list; they show priming.
Classical conditioning
Mismatch field
responses are elicited by the presentation of a rare devi- ant stimulus, such as a high-frequency tone and more commonly presented low-frequency tones.
Data collected by MEG, 2 stimuli match or mismatch (2 sounds are same or deviant). When we past 10 s there is no distinction between 2 sounds, no mismatch, echoic memory gone after 10 s, which you can’t see on MEG. This result can be interpreted as evidence for an automatic process in auditory sensory (echoic) memory that has a time course on the order of about 10s.
Fuster’s delay response task? Which part of brain?
Looking at center of screen light line up, during delay monkey has to remember where the light was, after which monkey can move eyes to light – gets reward. Monkey doesn’t remember the flash of light, when neurons stop firing.
Dorsal-lateral prefrontal cortex is engaged
C – q phase, D – delay period before the monkey allowed to respond, r – response period when monkey responds. Different cells different things that monkey has to remember. Once cells would stop firing – the info is lost (gone).
H.M. mirror tracing task
- H.M. could learn some things: tasks that involved motor/perceptual skills or procedures (non-declarative memory, implicit) became easier over time, though he could not remember practicing the new skills (declarative memory - episodic).
- Mirror tracing task: non declarative memory.
He was able to trace a shape by look at a mirror, overtime he got better at the task but didn’t consciously remember practicing.
Amygdala function? Which memory?
Responsible for the response and memory of emotions, especially fear; part of the limbic system
lose amygdala – no fear conditioning
Nondeclarative memory – fear learning;
no hippocampus still can learn;
Delayed nonmatch-to-sample task
A monkey is placed in a box with a retractable door in the front. While the door is closed so that the monkey cannot see out, a food reward is placed under an object. The door is opened, and the monkey is allowed to pick up the object to get the food. The door is then closed again, and the same object plus a new object are put in position. The new object now covers the food reward, and after a delay, the door is reopened and the monkey must pick up the new object to get the food reward. If the monkey picks up the old object, there is no reward. With training, the monkey picks the new, or nonmatching, object.
Fear conditioning
Fear responses to (US) pathway
In this pathway, the sensory information projects to the thalamus, which then sends the information to the sensory cortex for a finer analysis. The sensory cortex projects the results of this analysis to the amygdala (innate fear: US). Innately feared stimulus is presented (ex: shock), which triggers everything that will happen in response to fear, behaviorally, hormonally and autonomically, (ex: freezing to a shock, releasing hormones, fight or flight response)
Mechanism of Habituation of aplysia (invertebrate slug) Gill-Withdrawal Reflex
Touch syphon - animal pull their gills and tries to protect;
Habituation - pulls gills less and less until it stops.
Simple reflex arc, neuron responds to touching the syphone; motor neurons fire – gills triggered; motor neurons fire less and less as habituation occurs, it releases less neurotransmitter
AMPA and NMDA receptors (amygdala?)
AMPA: detects glutamate receptor that controls a sodium (Na) channel and depolarize post-synaptic neuron
When you activate AMPA receptors, you allow glutamate to depolarize the cell (postsynaptic neuron).
NMDA: glutamate receptor that controls a calcium channel is blocked by Mg 2+ ions, which prevents other ions from entering the postsynaptic cell; involved in long-term potentiation
NMDA are Hebb’s law detectors, they only allow Ca influx, when both cells (presynaptic and postsynaptic) are firing together, which triggers LTP
When you have NMDA receptor (antagonist) present in the amygdala, you are not scared of tone, because we can’t change the strength of the synaptic connection
Fear conditioning
Conditioned stimulus (CS) pathway
What does this response show us about the brain?
-learned fear responses: conditioned stimulus is heard and processed by the auditory cortex and info is sent to basolateral amygdala.
- Fear conditioning causes basolateral amygdala to trigger the central nucleus to make the response prior to the unconditioned stimulus, shows plasticity
