This result showsthat patterns of nonmaximal responses do notrepresent low-level features that are specificto the type of stimuli, such as photographs,but, rather, appear to reflect information thatis more definitive of object category
Revealing that these patterns are not representations of low-level features but rather higher-level information - But also what do they mean by "more definitive of object category"?
Fig. 4.
Confusion Matrix - Orange is something compared to itself, everything off of that is between categories
Subtracting the maximally active areas (in contrast to activation-based models) allowed them to look at the other regions of activation that are not maximally responsive, and analyze the distinct patterns there
Fig. 3.
All about measuring pattern similarity - Linear mapping (different modes of regression) - This one just uses correlations - This paper is a good benchmark for understanding multi-variate pattern analysis and machine-learning behavior
accu-racies were significantly better than chancefor all categories except shoes.
Huh I wonder why
specificity of thepattern of response to each category wasbarely diminished by thus restricting the anal-ysis
??
evoked a distinct pattern of re-sponse in cortex that responded maximally toother categories.
Not sure I really understand this....
pattern of response in object-selective ventraltemporal cortex correctly identified the cate-gory being viewed in 96% of pairwise com-parisons
WOW
the correlation between the pattern ofresponse to chairs on even runs and the re-sponse to chairs on odd runs (within-categorycorrelation) was compared with the correla-tion between the response to chairs on evenruns and the response to shoes on odd runs(between-category correlation)
What was the point of doing this?
determine whether each stimuluscategory evoked a pattern of response in theventral object vision pathway that could bedistinguished from the patterns of responseevoked by all other individual categories
Looking for distinct responses so that they can examine the differences between stimulus category representation in the brain
Three models of the functional architecture of the ventral temporal cortex: 1) It contains two specialized areas (FFA and PPA) that represent specific categories of stimuli 2) Different areas of the VTC are specialized for different types of perceptual processes (FFA for expert visual recognition of any object category) 3) Object form topography: VTC is topographically organized to represent attributes of form that underlie face/object recognition
Shewouldthereby avoidacommonbehavioraltrapcalledthesunkcosterror—theirrationaltendencytohonoranirrevocablelosstothedetrimentofone’s present andfuturewelfar
Damn I just realized I do this all the time
Therationaleforsuch harshpreconditionsongroupmembershipisunclearuntilonerealizestheirpotentialforarousingcognitivedissonance.
Well the rationale has kinda always been "you have to work hard to get where you want to be"
varioussubtlemeansbywhichcommitmentcanbestrengthened,canyounowbegintoappreciatehowpeoplecangetsuckedintounsavoryorganizationswhosepracticesand beliefsstrikeoutsidersasabsurdandextremist?
This is how cults do it
theyhadcustomersunnecessarilywaitforhourswhiletheirfinancedealwassupposedlybeingnegotiatedupstairs.Canyouseehowthismightelicittheiracceptanceofthedealership’sfinaloffer?
Damn that's SNEAKY
rospective groupmembercalleduponatfirsttomakeasmallsacrificefor theprivilegeofgroupmembership,but thengradually seducedintomaking muchlarger sacrifices
Foot in the door method
self-reinforcingloop
I wonder what are some examples of this
groupmembershipneednot bemaintainedthroughtheprovisionofincentives;theprocessofself-justificationensuresthatpeoplecometovaluegroupmembershipforitsownsake
Okay but there has to be a line here: you can't just have people do something really hard to get in and then give them no benefits to being in the group - But where do we think the threshold is?
et,althoughsuchpower-fulincentivesareeffectiveinshapingourbehavior,theydo notnecessarilyleadustointernalizefeelingsofloyaltytoagroup.
Yeah I'm sure it's easy to switch country clubs when one gives u a better deal
subsequentresearchhasruledouteventhesealternativeexplanations.
Oh
tediousdiscussionofanimalcourtshipmorefavorably
Nope definitely not why tf
mighthaveformedamorepositiveimpressionofthegroup discussionbecauseitseemeddecidedlypleasantincomparisontothemortifyingtesttheyhadjustbeenputthrough.
Nope I don't think so. If I had just been forced to read a bunch of vulgar stuff about sex I would expect the discussion to be on the same wavelength and would disappointed if not (cuz if not why did I just put myself through that, it would make me rate the discussion even lower)
Thismayhave beenbecausederogatingthequalityofthediscussion wasmorecrucialtoreduc-ingdissonance.Alternatively, participantsmaysimply have beenreluctanttodirectlycriticizefellowstudents.
This is interesting: which one is it more likely to be? - My first assumption was the latter, but the first one could also make sense if you. think about how the experience of being in the club was more important to these participants than the people who were in it themselves. - But also it's clear that neither the Mild- nor No- Initiation groups experienced cognitive dissonance, so is this even relevant? They probably just rated the discussion low cuz it was boring af
(a)theyhadfreelysubmittedtoanunpleasantinitiationprocedure;and(b)thatgroupmembershipwasadisappointment.
Two important factors that induce cognitive dissonance: - 1) Voluntary participation in unpleasant experience with the objective of a coveted outcome - 2) Coveted outcome is not as valuable/fun/cool/rewarding as expected
we preserve our dignity or integrityby adopting an attitude that justifies the deed, and by believing that we held that attitude all along.
Sixty-three female college students volunteered to become members.
Interesting that it was all females lol
researchers pre-dicted that the more severe a person’s initiation into a group, the more they-would come to likethat group and value being a member.
Oop there's a SUCH a strong relation to hazing here
He or she needs to conduct an experiment in which thecost of attaining an outcome is varied while everything else—including the quality of the outcomeattained, and the intensity of the original desire to attain it—is held constant.
Control for these confounding variables
observation alone can provide onlycircumstantial evidence for an effort-justification effect.
Because of confounding factors that can affect how much someone has a favorable opinion towards an outcome they worked hard towards - Namely two factors: - 1) You might just like the result because it's good quality (which could be due to the amount of effort you put in, but doesn't mean you like it just because you put more effort in) - 2) You might like the result because you placed a higher value on it before even putting in the effort (which might make you work harder to achieve it, which could lead to liking it more, but doesn't mean you like it more just because you put more effort in)
tudent works hard on a term paper,his or her favorable opinion of the finished product may reflect its consequent quality, rather thanany attempt on his or her part to justify the effort exerted.
yeah and conversely, when I work really hard on something but I know it was rushed, even when it turns out to a really good paper (which I know cuz I always get good grades) I still don't think it's a good paper
fort exerted, trouble taken,pain suffered. In all cases, the greater the hardship endured, the greater the subsequent changein attitude.
Explains why playing hard to get works
ess prided herself on being a sensible spender. Hence, admitting that she had willingly wasted asizeable sum on a lousy movie would have been too much for her to bear. The most convenientway to avoid making this admission was to regard the movie in retrospect as better than it hadbeen. Tess, too, prided herself on being a sensible spender. However, having spent a smaller sumto see the movie, she did not feel any great need to revise her opinion of it upward.
Showing that cognitive dissonance can also arise from inconsistencies between our personal values and our actions (if our actions are not perceived by us to be consistent)
Findings indicate that we use the pFs specifically to do the task of discrimination - but it's different across everyone
ure 3. Inter-Participant Reliability
Interesting that the correlations between representations of participants was much higher (more reliable) in the LO than in the pFs
Perception is this study is operationalized purely by discrimination - just a behavioral correlate as it relates to discrimination, which may or may not be an indicative process of perception
stimuli were chosen such that perceptualsimilarities correlated somewhat with physical similarity, butnot perfectly, leaving room for the neural similarities tocorrelate, e.g., with perceptual similarity without necessarilyalso correlating with physical similarity, and vice-versa
Not clear on this
we therefore created our stimuli based onparametric changes in aspect ratio and skew.
Aspect ratio: distance between center of object and end point of protrusion coming off of it Skew: kind of the direction of the protrusion?
we first identified the human object-selectiveregion LOC in an independent localizer scan, using thestandard comparison of intact versus scrambled everydayobject
Objective of localizer scan is to functionally define the regions - took regions of cortex that had a larger response to intact objects vs. scrambled objects - allowed them to functionally define these areas as the ones that have preferred responses to objects (stimulus class) - but does defining a region based on intact vs. scrambled truly mean its function is to recognize objects?
LOC: a set of nuclei located kind of between occipital and temporal/parietal cortices
In a separate behavioral session that followedthe fMRI experiment with a delay of at least 1 wk,
Why a 1 week delay?
t pFs does not adapt across changes thatalter an object’s subjective appearance
Wait this is confusing because i thought the pFs had to do with the subjective perceptual experience?
pFs wasmore vulnerable to object scrambling than LO;
Interesting
posterior portion (LO), wefound significant correlations between neural and physicalsimilarity measures.
pFs: correlation between neural and perceptual LO: correlation between neural and physical
LOC adaptsacross changes in low-level physical stimulus properties thatleave perceived shape unaltered, but not across changes thataffect perceived shape
Meaning the LOC has more to do with unconscious perception, which leads to coding in high-level cortex?
timulus-basedrepresentations in posterior regions and subjective and observer-specific representations in anterior regions
This probably has implications for understanding how we both perceive and understand shapes, and how we transform perceptions to higher-level meaning
hape representations were similar acrossparticipants in LO but highly variable across participants in pFs.
Makes sense considering perceptual shape is probably quite subjective?
discriminate all categoriesfrom each other to instead learning features that can discriminateevery view from every other view
What does this even mean
visual representation formation is guided by distinct long-range network connectivity to help learn features in support ofbroad conceptual distinctions (e.g. for animate or inanimateentities 14,15 ), or to guide the learning of a specific set of categorieswith particular functional relevance (e.g., faces, bodies, andscenes3,11
So the question is: is it more conceptual or categorical?
Motion energy model - Contrast energy: when we have a response to a particular structure in the environment, you get a contrast energy response, which takes into account the response to a center excitatory region AND an off-center excitatory region - Take those responses, square them, add them together and you get a contrast energy model
step 1 is to measure motion energy and every instance of the video)
Problem: time scale
our framework could potentially be used todecode involuntary subjective mental states (e.g., dreamingor hallucination)
That's so cool - but what would be the use of that?
The correlation between luminanceand color information in natural scenes has an interesting sideeffect: our reconstructions tended to recover color borders(e.g., borders between hair versus face or face versus body),even though the encoding model makes no use of color infor-mation
Interesting...
we found that color information did not improvethe accuracy of predictions or identification beyond whatcould be achieved with models that include only luminanceinformation
Interesting, I wonder why
his is a critical step toward the creation of brainreading devices that can reconstruct dynamic perceptualexperiences
Why do we need this thooooo
revealed a significant positive correlation between eccentricityand optimal speed: relatively more peripheral voxels weretuned for relatively higher speeds.
This feels important - Also kind of makes sense?
0.24,0.39, and 0.40 for the static, nondirectional, and directionalencoding models, respectively
Makes sense prediction accuracy was highest for encoding model of both motion and direction
The modelseparately describes the neural mechanisms mediating visualmotion information and their coupling to much slower hemo-dynamic mechanisms
Not sure I really understand how this works
provides remarkable reconstructions of the viewedmovies.
Woahhh
fit the model separatelyto individual voxels.
What how
Ultimately the perception/reaction to something that is not there - could also be applied to anxiety, depression, PTSD... - Interesting clinical applications
There's an associative network generated with each person's face - So when you're dreaming and you see a face you know and associate it with a different person, that's probably a reflection of a disconnection with associative networks
Hallucinating/dreaming states complete top-down process - sensory inputs are totally shut down - the brain is generating these representations - kinda crazy how you don't know what's gonna happen next, when it's your own brain generating
regions connected to the temporal and occipital cor-tices, acting to increase cortical signaling responsiblefor perceptual release
What does perceptual "release" even mean? Or the "release" of sensory activity?
“micro-sleep” during wake periodsactually produce REM imagery experienced as if awake(and with eyes open), rather than a temporary dissocia-tion associated with a brief return to a sleep state (andeyes closed)
I don't find this to be very compelling...
disengagement of frontal functions has also been usedto explain the dreamer’s reduced self-awareness andthe bizarreness of some dream contents
This makes sense tho I guess
The apparent disengagement of prefrontalexecutive areas is an important finding, as it impliesa lack of inhibitory influences on perceptual release,along with restriction of information processingwithin a limited set of neuroanatomical loops.
Okay i don't really get this
Suspended interactions between primaryand association areas are also a hallmark of REMsleep
"primary" and "association" areas is so vague
primary and secondary sensorycortices is responsible for the spontaneous release ofperceptual images during sleep
Intersting
release of ACh by neuronsin the midbrain is particularly important for creating achain of events which includes the release of intrinsic sen-sory activity and lowered recruitment of prefrontal cor-tex
This almost sounds like the basis of dreaming
REM dreams are described as more vivid and intense,and involving a narrative
I wonder what's involved in producing the narrative that only allows it to happen in REM
internal representa-tions gradually evolve, starting with visual images only, towhich somatic and auditory images are added, followedby emotional contents with a narrative structure
What does this say about the association between EEG frequencies and brain regions
mentalfunctions during sleep involve a reorganization of thesame systems which function during the day.
Interesting
ncubusexperiences occur in a semi-waking state and may besuperimposed upon the perceptual world
Which makes them more akin to hallucinations
typically accepted as vividly real, sometimes takenas assaults by human intruders but often interpreted asoccult or metaphysical events.
Even after the fact? No right? probably just in the moment
feels awake but unable to move,perceives ominous sounds (such as approaching foot-steps), feels movement in the bed, and then feels (and/orsmells) a person, creature or unspecified entity climbingupon the chest, a smothering sensation, and sometimeseven a physical or sexual assault
Oh lol that's fucking terrifying
the phe-nomenon is necessarily experienced in retrospect
Interesting to think about what role memory might play in dream perception and our understanding of them as a whole
Hypnopompic hallucina-tions are usually continuations of dream sequences duringthe first seconds or minutes of wakefulness.
Okay yeah I've had that
Visual phenomena (86% of all hypnagogia22,26)typically consist of kaleidoscopically changing—possiblyentoptic—phenomena such as geometric patterns, shapesand light flashes.
Woah I've never had that lol - Entoptic: originating within the eye
nvoluntary,spontaneous, of varying emotionality, and are found in upto 70% of the general population.
70% is a LOT!!
consciousness represents multiple and graded mentalstates, 13,14 including several overlapping constructs suchas sensory discrimination, perceptual awareness, focusedattention, introspection, and volitional actions
Back to the issue of defining consciousness
They are usually recog-nized as non-veridical and do not lead to intense distress
Could this be because patients are more able to recognize them as being due to their eyes, rather than their brain? But also how could hallucinations soley come from the eyes... I would think it would have to do with other cortical areas, esp. those associated with imagery
aden with affect, and believedto originate from external (nonself) sources
Do "voices inside your head" count in this regard?
Hallucinations are often mistaken for veridical perceptionsand interpreted as symbolic and personally meaningful
Noetic quality ~ relates to psychedelic hallucinations - veridical means coinciding with truth/reality
allucinations may be the results of “rapid eyemovement (REM) intrusions” of visual imagery intowakefulness
OOOh interesting
hypnopompic
relating to the state immediately before waking up
hypnagogic
relating to the state immediately before falling asleep - oooh i've had some funky experiences here
ventral stream of thevisual cortex is associated with the conscious processing
The top-down stream? Does this mean that conscious processing only occurs when the face stimulus triggers our higher-level representations of the world (i.e. schemas)?
genderand race of faces could not be processed without awarenes
Interesting because while things that trigger emotional responses like facial expressions can by unconsciously processes, identity markers that require within-category discrimination (e.g. this person is female because of these specific features that differentiate it from males) require consciousness to perceive
upright facesreach awareness faster than inverted faces
As expected
amiliarity processingis an integral part of the face recognition system
Okayyyy what does this have to do with consciousness?
Does conscious vs. unconscious processing rely on emotional stimulation? I think not because studies have found that faces communicating more emotional information seem to take longer to reach conscious awareness. But direct gaze and familiarity reach awareness faster, so what does this rely on?
only famous, and not unfamiliar, face identi-ties could be processed unconsciously
Interesting, because famous faces don't necessarily elicit as high emotional arousal? or does it have to do with something else
nvisible faces with directed gaze reach awareness fasterthan faces with averted gaze
kind of makes sense, if someone's looking right at you it tend to be more stimulating
images of dominant and untrustworthy faces,compared to neutral faces, took a longer time to emerge toawareness
Meaning faces that carry more social/emotional awareness take longer to consciously process
parti-cipants were exposed to the white parts of the eyes thatwere rendered invisible; the researchers showed that theinvisible eyes with fearful, as opposed to happy, expres-sions elicited higher responses in the amygdala
Further evidence that fear penetrates more deeply into neural processes than other emotions
There are two key reasons forfocusing specifically on faces. First, the amount and rich-ness of information conveyed by a face stimulus extendsbeyond the visual image per se. Therefore, because differ-ent cognitive systems are engaged in various aspects offace processing, the use of faces provides an outstandingopportunity to explore the general mechanisms of uncon-scious processing. Second, consciously visible faces elicita reliable and large brain response. Therefore, theseface-selective neural correlates can serve as a powerfultool (i.e., biomarker) to explore mechanisms of unconsciousprocessing
Two reasons for using faces to examine conscious/unconscious processes: 1. Faces elicit a variety of responses throughout different brain areas, so there are a lot of ways to measure unconscious processing 2. They elicit reliable and large brain response--> powerful biomarker
generalize unconscious findings to ecologically valid conditions is the use of virtual reality
Ooh interesting application of VR
By comparing situations in which consciousness happens with closely matched situations in which it does not (i.e., uncon-scious processing), one can study both its functional and neural specificity.
Contrastive analysis involves the study of conscious vs unconscious processes to try to understand the functional and neurophysiological underpinnings of consciousness
coupling and synchronization is referred to as functional connectiv-ity
Functional connectivity: the increased synchronization of high-level cortices with other brain regions during conscious processing
these results suggest that the transition of information processing from sensory cortices into these higher‐level regions is a strong neural marker of conscious processing
I feel like this is important
able to retroactively retrieve this information provides strong evidence that it is processed quite deeply even if it fails to reach consciousness
processed quite deeply where??
Various levelsof priming
Like the perceptual set rigidity of spatial frequency
timuli that are rendered invisible by continuous flash suppression can still automatically attract attention
Like that study I read for VP &C
When attention is directed towards an unconscious stimulus, larger priming effects are associated with that stimulus even though it fails to reach consciousness
Interesting, I wonder why
Inattentional blindness – When attention is directly focused on a particular task, event, or object, other aspects of the scene will often go unnoticed.
like that basketball video where the ape runs through
increased objectivity about one’s own internal experience, so that one is able to observe these experiences, rather than being completely embedded in or fused with them
Relates to idea of the non-existent ego
abeyance
suspension
real and deeper than ordinary consciousness,
Noetic quality similar to psychedelic-induced mystical experiences
Illustration of the Paradigm
Take the value of the stimulus pattern and the corresponding EEG wave pattern - gives you the average response of the EEG to a temporal point on the stimulus - if there's an EEG response that corresponds with the temporal - idea is that every visual event you experience lingers in the system (assumed with motion, not static images)
e visual-evoked potential(VEP
VEP: Visual-evoked potential, short series of positive/negative deflections (300-500 ms) in response to a transient stimulus
Invisible faceVisible face
earliest signaling through the faces that aren't registering consiously - invisible precedes the visible
Spatial frequency (cpf)
This one is a matrix of data - put a data point in there if there was a significant regression between the spatial frequency and the response in the insula
Binocular rivalry paradigm - when the eyes are each presented with a diff. stimulus, they will oscillate between the two - we want one stimulus to always be outside of awareness - CSF forces one of the stimuli to stay outside of awareness, so you'll lock onto it
Ambidextrous
Handedness has to do with lateralization processes
The participants were instructed to look at all images carefullyand to press the space bar on a regular computer keyboard if theyperceived Mondrian patterns and a face together on a given trial
Forced choice paradigm: only yes or no
One of thepatients had a depth electrode implanted in the amygdala.
Why only one?
they had electrodes implanted under a clinical proto-col
Woah so it is in vivo
typically only the noise isconsciously perceived; the static stimulus is suppressed from theobserver’s awareness but nevertheless processed in the brain
oh interesting
facial expressions can influence neural activityand behavior independently of awareness, and that they constitutea stimulus class well suited for investigating differences betweenconscious and non-conscious perception in the human brain
Reasoning behind the use of facial expressions as stimuli
Non-conscious processing relied on low SFs more and was faster than consciousprocessing.
Consistent with what other studies have shown - possibly even informs the other study on facial expressions
omplex visual stimuli, such as emotional facial expres-sions, can influence brain activity independently of the observers’ awarenes
Such as the other study
Awareness oftextured stimuli thus depends critically on the presence of ap-propriate first-order information.
!!!
Wepropose that reported awareness is primarily driven by mecha-nisms responsive to low spatial frequency first-order componentsof the imag
I wonder why that is
awareness of first-order stimuli decreased as theirspatial frequency increased or their contrast decreased.
Makes sense
awareness increases with increasing cell size is consistent with theassociation of awareness, with information carried by low spatialfrequency first-order components in the stimuli
Ahhh very interesting....
Coarse-textured patterns. (F) 80% contrast second-order stimuli ofvarying texture cell sizes
Makes sense that coarse texture patterns would elicit more awareness - so luminance and spatial frequency seem to be the biggest determinants of blindsight
2008 results for 20%contrast first-order stimuli and 80% contrast second-order stimuli.
Why did the awareness of the textured stimulus go up when the contrast of the 1st order stimulus went down?
Fig. 2. Probability of reporting a 50% contrast-modulated textured gratingas more salient than a first-order grating as a function of the Michelsoncontrast of the latter
Not sure I really understand what this figure is showing...
Probability of detection and awareness for first- and second-orderstimuli as a function of spatial frequency
Clearly shows the discrimination between detection and awareness of stimuli responses - as well the large effect of first-order vs. second-order - second-order stimulus allows for strictly type 1 blindsight, while first-order allows for both types
his awareness of them iscritically dependent on the presence of low-frequency sine-waveluminance information, i.e., on first-order information
Trying to get at the characteristics of stimuli that arouse awareness
blind-sight type II to distinguish it from the type I, defined as discrimi-nation capability in the total absence of any acknowledgedawareness.
Blindsight Type 1: ability to discriminate stimuli without any awareness of its presence
Blindisight Type 2: some level of awareness, usually described as a "feeling"
“blindsight,
Blindsight: ability to detect visual stimuli in one's blind field without awareness of their presence - demonstration of dissociation between detection and perception
Se encierra en su casa para volar a mundoslejanos
idea del torre de marfil
How many decisions are we actively making during perception and how many are already pre-determined for us? - is the process even a decision?
When you're familiar with what you're looking at, why are you more likely to use LSF to categorize it?
-maybe we need to discriminate first before categorizing, so when it's an unknown face you're more likely to use HSF - but that's clearly not the case because that would mean EXNEX would be the most affected by familiarity
cognitive determination of per-ception
I like that term, cognitive determination
Parts of the image are selected ahead of time - process of perception involves what it is you're trying to perceive - the task at hand is driving the selection of aspects of the image - participants go into the task with the specific goal in mind already, so the mind is already attentionally cued/biased
Interesting to think about whether the nature of a specific half of the hybrid stimulus itself (expressive vs. non-expressive or the diff emotions) had an effect on the scale bias? - like is it possible that ppl have a bias towards seeing more expressive faces regardless of the spatial frequency
Important temporal aspect: - image flashed at 50 ms - when you flash an image at 30 ms, participants usually only see LSF - at 120 ms, it tends to be HSF biased - so the 50 ms middle ground allows for a bit more equality
Notes from class: - wonder what was going on with the participants who were able to see both faces in the hybrid - researchers threw out a lot of data
one exception arises when attention must be allocatedto certain locations or certain object properties prior to the operation of early vision
The priming of the initial task ( supporting the findings of experiment 2)
scale selection is just too flexible to observe consistent, categorization-specificbiases
Yeah obviously because in real life we don't select for just one or the other
how would we know whether X represents the object, or the task itself?
I see the importance of this, but also how is this relevant in the real world when faces and objects are not just LSF or HSF, they're broadband
naturalistic conditions such as a smoky environment, low contrast, through a dirtywindow, and so forth
True I didn't even think about that
recognition is not limited to fovealvision (where receptor density allows the representation of HSF luminance changes)and we know from eye movement research that a good deal of naturalistic recogni-tion takes place in the periphery, using LSF information
meaning LSF info does actually contribute to naturalistic recognition in real life
diagnosticity of scale cues in a task,together with perceptual set effects, best predict scale use in the categorizationstested here
Results found that the spatial scale used in categorization of faces is dependent upon the specific diagnostic cue being used both during the task and after
two processes were in a relation of asym-metric influence, revealing that they were interactive, not computationally encapsu-lated
So identity has a stronger influence tho
Thisenabled a measure of any supplementary effect of knowing the faces whilekeeping the stimulus base constant across groups.
Understandable, but doesn't this kind of make the control group invalid? - more of a placebo group
Five (of 72) subjects could never reach this level ofperformance and stopped the experiment at the second learning phase
dumb af
the constraint of locating relevant information in a first task set perceptualsystems to differently encode and perceive identical stimuli in the following task.
Suggesting that once the visual system is somewhat trained to be oriented towards a specific spatial scale, it tends to stick to that orientation at least for a little while
the perceptual set effect induced the perception of different contents inidentical stimuli.
Kind of like priming?
One group was assigned to the EXNEX task (whichfrom Experiment 1 is known to induce a HSF bias) whereas the other group solvedthe CATEX task (which induces a LSF bias). Following this, subjects were asked todetermine the gender of hybrids (an unbiased task). We then observed whether theorthogonal biases acquired in the initial categorization would transfer to the gendertask (unbiased in Experiment 1) to induce orthogonal perceptions of the samestimuli
Makes sense to determine whether or not those perceptual biases carry over into an inherently unbiased categorization task.
if a decision ofexpression required an analysis of the entire face, LSF would be the better informa-tion with the fast presentations used her
Well we know that LSF tends to get perceived first
We can therefore proposethat the task changed the perceptual content of an identical stimulus
The categorization task assigned to the participant actually had a significant impact on which spatial scale they used to identify
limited bandwidth of spatial frequen-cies is sufficient to resolve a face categorization indicates that this bandwidth med-iates some of the visual cues that could support this task
So they're trying to isolate the visual cues we get from LSF alone - by presenting both at once and taking the difference? makes sense
LSF represent coarse blobswhich, individually, do not have sufficient resolution to be identified as a nose or aneye, but which, together, represent the informative configural structures of faces
Such as the general shape, the broadness of the jaw or the length of the forehead, the hairline, the dark areas where the eyes would be
evidence that different face categorizations modify theperception of spatial scales would suggest that the diagnostic use of visual informa-tion interacts with the early stages of visual processing.
Basically evidence showing that the different ways of categorizing faces can alter our perception of spatial frequency scales would have the implication that: - taking in visual information through a categorical lens could actually alter the perception of the visual information itself
A hybrid face therefore dissociates the face informationrepresented in two distinct spatial frequency bandwidths
Very cool
selection of informationfor categorization can modify the perception of the input.
Essentially top-down processing
Together, the results suggest that categorizationcan be closely bound to perception.
This definitely has implications for real life
Resultssuggested that the categorization task changes the spatial scales preferentially used andperceived for rapid recognition.
Interesting.
Integration Abstracts.
Mindless reading is one of the mostsalient examples of the consequences of mindwandering in daily life
Yeah it keeps happening to me as I'm reading this boring ass shit
familiarize the practitioner with the phe-nomenological qualities of mind wandering andprovide strategies for reorienting attention awayfrom task-unrelated thought when necessary
interesting
thoughtitself is not something to be eliminated throughmeditation training, but rather is an aspect ofcognition that requires agenc
essentially increasing the control you have over your own mind - but interesting that it's achieved through loosening control
Task-unrelated thought can dominate awarenessat the expense of attending to one’s current taskor goal, resulting in significant performance impair-ments
yeah no shit
Example stimuli along with their SF filter reconstructions based on the 2D encoder histograms at two time points
Showing the Low SF to High SF transformation?
Specifically, this method provides 1) a general spatio-temporal view of scene encoding over an entire set of images, thereby allowing visualization ofthe general coding strategy over time, and 2) a scene-specific spatiotemporal view to visualizethe various transformations that each scene undergoes over time. Further, this technique offersa rich source of spatiotemporal data to explore a wide variety of questions concerning the vari-ous transformational states of visual coding once thought impossible to address with EEGmeasures.Fig 1. Example DETI maps from the image-general analysis at different time points. The movie version of this figure can be downloaded here https://pbsc.colgate.edu/~bchansen/HansenGreeneField2021/HansenGreeneField_Figure1_Movie.mp4. The left-hand column shows a topographical map of the posterior electrodes,illustrating the variation of DETI maps across that scalp region. On the right-hand side, each column shows the spatiotemporal evolution of the visual code for differentelectrodes (each row corresponds to the time given on the left-hand side). The color bar shows the spatial frequency tuning peak (in cycles per degree; cpd) of the encoderthat was mapped to each pixel in the DETI maps. Note that the maps are circular because the stimuli were windowed with a circular window (see Materials & Methods).https://doi.org/10.1371/journal.pcbi.1009456.g001PLOS COMPUTATIONAL BIOLOGYDynamic electrode-to-Image (DETI) mappingPLOS Computational Biology | https://doi.org/10.1371/journal.pcbi.1009456 September 27, 2021 3 / 34
WHY THIS METHOD - what it provides
our method reduces the dimensionality of VEP signals mea-sured at each electrode at different points in time and then maps those signals via an encodingmodel to each pixel within and across a relatively large set of images.
Not sure if I understand what's going on here...
, multiple networksacross lateral occipitotemporal, dorsal, ventral temporal, and medial temporal cortices have allbeen shown to possess a retinotopic organization and relative selectivity to different spatial fre-quencie
Woah that's really interesting... - so other parts of the brain that have to do with diff aspects of higher level processing that make up our personal cognition are also selective for visual information - makes you think about just how much of our understanding of the world is truly based in what we see - what we see literally IS what we know
thus hindering our understanding ofhow they enable the construction of a meaningful representation of our visual world.
We can't truly figure out what's going on when we perceive things unless we study it in a continuous way, rather than a static way, because that's how we actually perceive the world
used visual filter-based encodermodels to predict fMRI-defined patterns of blood oxygen-level dependent (BOLD) activitybased on real-world scene inputs
using these models to predict locations of neural activity using broadband stimuli (which are what we see in real life) to gain a deeper understanding of how we understand what we see and how visual information is translated to meaningfulness in our heads.
visual code varies in a location-specific manner, likely reflecting that neuralprocessing prioritizes different features at different image locations over time
depending on the image, the order of neurons responding to its features varies?
eveals maps of features that are associated with the neu-ral signal at each pixel and at each time poin
spatiotemporal af
how dynamic feedforwardand recurrent processes inform and refine high-level representations of our visual world
How the cortex interacts with the image as it's being perceived?
coordination ofbrain oscillations may play a potentially crucial role in thebrain’s building of temporary networks that can integrate cog-nitive and affective functions during learning and consciousperception, a process that can bring about lasting changes inbrain circuitry
INTERESTING!
They then observed that this additionalexercise counterbalanced the detrimental effects of training inempathy alone: negative emotions diminished, and positiveemotions increased
Big takeaway here is that empathy alone can still be helpful to others, but its drawback is that it can be hurtful to ourselves if we take on others' emotional burdens - compassion coupled with empathy counteracts the negative effects... but how?
The secondarysomatosensory and insular cortices, known to participate in em-pathetic and other emotional responses, were more activated forexperts than controls in response to the distressed voice, suggest-ing an enhanced ability to share the feelings of others withoutreporting any sign of becoming emotionally overwhelmed.
What is it about this practice that increases empathetic capabilities while keeping us from becoming emotionally overwhelmed?
intensity of thepain was not reduced in meditators, but itbothered them less than it did members of acontrol group.
What does this even mean? How is the difference between intensity of pain and how much it bothers the person distinguished and operationalized?
meditation can rewire brain circuits toproduce salutary effects not just on the mind and the brain buton the entire body
IMPORTANT
hree control spatial frequencies (scales) besides 5 cpd:square, 1.3 cpd; diamond, 14 cpd; triangle, 18 cpd
a, Suppression as a function ofthe orientation of the mask relative to the target. b, Suppression as a function of the spatialfrequency of the mask relative to the spatial frequency of the target.
Important to note that both of these were measured at 6 degrees eccentricity
We asked whether there are two distinct suppressivemechanisms in human vision and whether they are consistentwith the neurophysiological suppression mechanisms
No actual prediction being made - so no true hypothesis
A possible explanation for peripheral surround suppressioncould be that the excitatory summation zone in the periphery isdisproportionately large compared with the fovea.
Why does surround suppression only happen in the periphery? - possibly because excitatory summation zones in the periphery are much larger than in the fovea - but this explanation is unlikely b/c of the tight orientation and spatial frequency tuning of surround suppression
collinear surround was suppressedbefore it had a chance to suppress the target
Evidence that overlay suppression happens first before surround?
striking difference between the two types of suppressionsuggests that they are implemented by different mechanisms
Double-masking: either suppressing surround or overlay suppression by adding another mask
For all subjects, we found strong overlay suppression and sur-round suppression in the periphery but only overlay suppressionin the fovea.
Once again, surround suppression only strong in the periphery, overlay suppression strong in both
Suppression as a function of the spatialfrequency of the mask relative to the spatial frequency of the target.
Showing that surround suppression is selective for spatial frequency, overlay is a little but not as much - notably there was even a dip in overlay suppression when spatial frequencies were most aligned
studies in the peripheryhave noted that adjacent targets suppress sensitivity
So studies have found a key distinction between the functioning of the fovea vs the periphery: - fovea: adjacent targets enhance contrast sensitivity - periphery: adjacent target suppress contrast sensitivity
overlay suppression, originated from a region that was compara-ble with or smaller than the excitatory receptive field.
overlay suppression comes from the same or smaller region as the excitatory receptive field - What does this mean?
These phenomena are seenwhen a stimulus that does not affect the responses of a neuron byitself markedly suppresses the responses to an optimal test stim-ulus (i.e., masks the test).
suppressive phenomena in the visual cortex are when a stimulus (that elicits no response from the neurons by itself) instead suppresses neural responses to an "optimal test stimulus" - effectively masks the test stim
human surround suppression is tightly tuned tothe orientation and spatial frequency of the test, unlike overlay suppression.
Human surround suppression vs overlay suppression - Human surround suppression: acutely selective for orientation and spatial frequency, only strong in the periphery - Human overlay suppression: not - overlay suppression precedes surround suppression
Fig. 8.
Seems that LSD is the most similar to the NDE states that are most critical and unpleasant.... interesting
The hypothesis of DMT and endogenous NMDA antagonists as the sole causes of NDEs has received extensive criticism, both interms of the associated phenomenology and neurobiological plausibilit
I don't think it could be the sole cause
suggest that an endogenous ketamine-like compound is released at times of stress and is responsible for the re-markable similarities between ketamine-induced experiences and NDEs.
Suggestion only? There's been no research on this?
t ketamine shows neuroprotective andneuroregenerative effects in humans, even when administered after onset of cerebral insult, improving the clinical outcomes relatedto stroke, brain injury and status epilepticus
Woahhhh, so in addition to its therapeutic effects it can help us on a neurophysiological level too
Ketamine acts by antagonism at the PCP site of glutamateNMDA receptors. Such antagonism has been shown to prevent cell death due to the excitotoxicity caused by hypoxia
Ketamine is also a neuroprotective mechanism!
It has beenargued that memory’s primary adaptive function is toallow prediction of the future more so than to enablerecollection of the past (
makes sense, since memory is what creates our mental frameworks/schemas of the world, which help to more easily and efficiently understand the world around us
Metacognitive bias brought on by the state itself may explain the peculiar association between déjà vu andthe feeling of premonition.
Metacognitive bias in the sense that you're more inclined to believe you're right based on the familiarity of the situation and probably also the funky feeling of getting deja vu itself
feelings of premonition during déjà vu occur and canbe illusory
Deja vu makes you feel like you're better able to predict what happens next, but does not actually allow you to be better able to do so