Topic 5: Attention Flashcards
(45 cards)
what is attention?
a limited capacity to process competing options in which attentional mechanisms select, modulate, and sustain focus on information most relevant for behaviour
what is the problem, importance, and challenge of attention?
P: allocate limited resources
I: prioritizing information
C: balance the need for selective focus to handle new situations
Source: Exogenous vs. Endogenous
Exo: environmental, reflexive, automatic, “bottom-up”
Endo: in the mind, voluntary, intentional, “top-down”
Target: External vs. Internal
Ext: sensory information in the environment
Int: mental representations in the mind
Type: Overt vs. Covert
Overt: movement of the sensory surface
Covert: no actual movement
Type: Transient vs. Sustained
Transient: momentary focus
Sustained: prolonged focus
Type: Selective vs. Divided
Selective: one thing to the exclusion of others
Divided: multiple things simultaneously
Dichotic Listening
when a person has headphones on, and different messages are sent to different ears. Person is told to pay attention to one ear or the other
Cherry’s Early all-or-none filtering (Broadbent’s filter model)
low level gating mechanism can filter out irrelevant information before the completion of sensory and perceptual analysis (couldn’t report the content)
Grey and Weddenburn’s Early Attenuation (Treisman’s attenuation theory)
meaning of unattended words are taken into account
McKay’s Late Selection Model
all stimuli are processes through the completion of sensory and perceptual processing before selection occurs (meaning of the same word differed depending on what was played to the unattended ear)
Strategic Control Model
top-down selection at early, middle, or late stages depending on the circumstances
EEG
measures surface electric fields generated by post-synaptic potentials in dendrites of neurons
Event-related potentials (ERPs)
the average of EEG signals at a specific time locked event (temporal precision plotted with negative up)
Brainstem evoked responses (BERs) or Auditory brainstem response (ABR)
- series of small electrical brain waves that are elicited during the first 10 ms after onset of brief auditory stimulus
- activity in the auditory brainstem nuclei and thalamus
- no attentional stream
Midlatency responses
- 10-50 ms after auditory sound
- early activity in the auditory cortex (A1) that effects attention
P20-50 Attention Effect
in midlatency responses, an enhancement of activity in attention that supports the early-selection theories
Late Waves
- continue for several hundreds of ms
- extending activity in A2 and A3
Attentional Stream Paradigm
two or more segregated series of stimulus are presented in parallel, and subjects attend to one to perform a task (dichotic listening tasks)
- EPR of both are compared
- effect in mid latency and late waves, but not in BEPs
Endogenous vs. Exogenous in Posner’s Spatial Curing Paradigm
endo: arrows; faster to respond to validly cued targets, slow to invalidly cued; accordance with early-selection models
exo: list flashes; respond faster to target presented in the cued location than the uncued
Inhibition of return
in exogenously cued spatial attention paradigm, there is a slower behavioural response to a target stimulus present at the validly cued location later than 300ms after the cue
what is the neural effect of a stimulus on a plot
positive signal at 100ms, then a negative one
what is the difference in the spikes on neural plot between an attended EEG and an unattended EEG
attended has was more activity with bigger spikes
Attention affect reentrant activity
following a stimulus of event, a process where activity is fed back to the same brain region that was activated earlier in the process (loops to get processes by higher areas again)
