Cognitive Neuroscience Unit 3

Broadbent's Filter Model

early-selection model, filters message before incoming information is analyzed for meaning, leaky filter

attenuator

another early-selection model that says less important info is just dampened

perceptual load

limit of brain's processing ability, has to do with info volume and task difficulty

inattention blindness

results when perceptual load is exceeded, attention thresholds and exclusion criteria compromised

change blindness

inability to notice difference between complex scenes, especially if changes are illogical and break natural laws

attentional blink

small gap in attention following shift between stimuli

distributed representation

neurons that encode different features must "bind" together to inform a complete scene

binding problem

complex, competing info from multiple neurons has to somehow be tied to 1 scene

feature integration theory

says info is first processed in a pre-attentional phase where everything's processed unbound, followed by focused attention

illumination, reflection, transmittance

knowledge usually required for adequate visual perception

inverse projection problem

task of determining the object that caused a particular image on the retina given identical stimulations can result from different things

knowledge, external energy

key aspect that inform human perception, can't be completely recreated by computers

occlusion, blurs

other things that can cause issues in visual perception for computers

complex scenes

aid human perception since there's more to draw on

unconscious inference

idea that perceived scene isn't entirely what's seen, brain uses clues to infer based on existing knowledge

likelihood principle

most likely perceptual outcome is considered true, based on Gestalt cues

proximity, similarity, common motion, symmetry, good continuation

primary Gestalt groupings

apparent motion

groups objects together if they move continuously in similar orientation across retina

apparent motion quartet

a display in which four symmetrically placed stimuli presented at alternating moments in time are perceived as two stimuli in apparent motion

visual feedback

ability to update visual info as it changes and act accordingly, limited by how fast it can update

speed-accuracy tradeoff

seen in human perception when trying to keep up with rapidly presented information, related to visual feedback

optic flow

speed at which objects move past your perception, shifts based on focus to guide body through space, puts you off balance due to vestibular system when it's messed with at unpredictable rate

prism adaptation

allows adjustment to erroneous spatial cues based on refracted light

action plan

schedule for how physical environment will be acted on to achieve a task, allows better object identification

perihand space

space near hands where interaction with environment occurs, visual perception focused on this area with low spatial frequency, perception quicker and more accurate here

somatosensory and motor cortices

proximity of these structures in the brain allows them to update mapping, input and output

LIP

region in parietal lobe that controls eye movement and intention behind it, fires most when retaining info about future movements, starts with stimulus and ends with saccade

MIP

region of parietal lobe responsible for hands reaching towards objects in specific orientations

AIP

region of parietal lobe that controls fingers grasping or manipulating specific orientations of objects

bimodal neurons

integrate visual and tactile info, respond strongest when they overlap

hand-centered receptive field

receptive field based on bimodal cells for visual and tactile use, tools activate more as they become more familiar, overlaps with perihand space and its functions

perceptual bistability

a phenomenon in which an unchanging visual stimulus leads to repeated alternation between two different perceptual experiences

binocular rivalry

when differing stimuli are presented to each eye with perception switching as different brain areas are activated, involves perception as early as V1

synchronous firing

theorized to occur in the brain more than localized functions, integrates higher order thinking

Bistable image

Image where perceptual bistability is present, believed to be a perceptual flip that occurs at higher level of consciousness

PPA (parahippocampal place area)

Responds to locations such as buildings

Late-selection model

Theory that says attention is drawn after processing of meaning

Dictionary unit

part of attenuator theory of attention that contains stored words and thresholds for activating the words

Saccade

eye movements in rapid jumps between perceived points of interest

Illusory conjunction

a perceptual mistake where features from multiple objects are incorrectly combined, results from pre-attentional phase of feature integration theory

Magnocellular

Level of V1 that affects movement in space, works with perihand space in low spatial frequency

Cross-talk

Occurs between motor and somatosensory cortices, work together to build mapping of body in space

Stroop Effect

Tendency to confuse features of conflicting stimuli, effect especially strong with language, occurs due to high perceptual load