Attention

arousal

general orienting

selective attention

focus on limited information

exogenous

reflexive/stimulus driven

endogenous

voluntary/goal driven

overt

fixating on target

covert

independent of fixation

what does attention allow us to do?

attention allows us to pick out a small portion of sensory inputs for further processing

why do we process basic properties like shape and colour easily?

why is feature conjunction so hard to identify?

searching for feature conjunctions requires binding features together in a location

why is attention important?

without attention, we don't encode detail about the sensory world, this is called change blindness

BUT when our attention engages, we can ask miss information around our environment (intentional blindness)

impairments of attention: neglect

when one half of visual space is ignored

are people with neglect able to notice objects in their affected field?

however, may notice objects in affected field id they are exogenously cued/indicated. BUT demonstrate extinctoin when exogenous cues are presented to BOTH hemisphere

what is optic ataxia

can identify objects, but difficulty using visual information to guide actions

occulomotor apraxia

difficulty directing saccades (fast eye movements)

simultagnosia

difficulty identifying more than one object at a time or difficulty perceiving visual field as a whole scene

cocktail party effect

even with background noise, we are skilled at focusing on relevant auditory streams

explain the early selection model

low level physical properties processed in parallel

early attention filters out irrelevant signal

large capacity for pre-attentive info (properties such as colour, movmement, form which does not require concious attention), small capacity for attentive info

peopel able to automatically shift to unattended content when identical or follows form to attended content

explain the late selection model

all sensory input is processed in parallel up to high level and filtering occurs later

stimuli processed for meaning before selected based on relevance

explain hybrid models or early and late selection

adaptive filters let some unattended sensory input through to perceptual processing

this allows attended information to dominate behaviour, but unattended information to be processed as well.

exogenous cues and reflexive attention

exogeneous cues capture reflexive attention. but in comparison to voluntary attention, is short lived and can produce opposite effect (inhibition of return) -> causes people to respond more slowly to targets that appear in places they have already attended

sources of attention

direction attention to relevant information (frontal regions)

sites of attention

targets for modulating relevant information processing (VI, V4, MT)

endogenous control dorsal or ventral

dorsal

exogenous control dorsal or ventral

ventral

dorsal attention network

intraparietal cortex

superior frontal cortex

frontal eye field

ventral attention network

parieto temporal cortex

inferior frontal gyrus

insula

characteristics of endogenous attention

goal directed

voluntary

slow

interruptible

effortful

characteristics of exogeneous attention

stimulus driven

involuntary

fast

effortless

disruptive

effects of attention in the primary visual cortex

enhanced brain response

receptive field mapping

if stimulus is within receptive field, it is more likeley to fire

where does endogenous attention increase activity in the brain?

increases visual cortical activity both in preseance and absence of visual stimulatoin

which parts of the brain does exogenous attention activate?

control areas in parietal cortex, FEF, SEF (dorsal attention system)

exogenous shifts of attention activate temporo parietal junction (TPJ), middle frontal gyrus (MFG) and inferior frontal gyrus (IFG) ventral attention system

what areas of the brain is spatial neglect associated with?

right temporo parietal junction and impairments in disengaging spatial attention