...Chapter 6: Attention Pt.II Flashcards
What neural area appears to be the ‘site’ of the attentional spotlight (according to Brefczynski & DeYoe, 1999)?
he extra striate cortex. moving attention stimulates contralateral occipital lobe
Does P1 follow a retinotopic map? Is overt attention necessary for this to occur?
P1 follows a retinotopic pattern, regardless of whether it is generated by a sensation or by covert attention.
What is visual N1?
Visual N1 is at 140-200 (N100) has to do with initial processing of the stimulus
Know about the relationship between late selection and the attentional blink.
In the attentional blink (AB) paradigm, participants are instructed to detect a target (X or Y). However, a distracting stimulus (e.g., a coloured letter) appears before the target. If the distracting item appears close in time (approx. 300ms) to the target, participants will not see the subsequent target.
How does attention to an object’s features affect activity in different visual association cortices? In ‘higher-order perceptual areas’ such as the fusiform face area?
selective negative when you’re actively searching for something. Area MT shows enhanced activation when participants pay attention to moving dots rather than to the colour of the dots. Area V4 (colour perception) shows the opposite pattern. If participants allocate attention to the face, activity is found in the fusiform gyrus. (N170 waveforms) House perception leads to activity in the parahippocampal place area. Activity correlates with our conscious perception of stimuli
What is reentrant processing?
The same brain structures can be involved at different stages of processing. Feedback loops or ‘re-entrant processing’. (info enters one are goes to more complex but can loop back to the first area again and influence that. Attention influences slightly dif areas first colour then focus on shape)
Describe Woodman and Luck’s (1999) experiment with the N2pc waveforms.
Woodman and Luck (1999) found that N2pc switches between hemispheres as attention is covertly shifted across visual fields. N2 posterior contralateral component Related to shifting attention to salient stimuli in a visual array. Contralateral parietal and ventral occipital cortex.
What is the difference between a processing negativity and a selection negativity (p. 196-7)?
Selection negativity (A sustained negative wave over the posterior (parieto-occipital scalp). It begins approximately 150ms after the stimulus. Does not influence occipital P1 and N1 (primarily spatial). Feature-based activity. from attention to non spatial visual feature of the stimulus ) Processing Negativity (prolonged negative wave during auditory selective attention, reflects how well stimuli match attentional template)
What is extinction and what is neglect?
extinction (The failure to respond to stimuli contralateral to the lesion when these stimuli are presented simultaneously with stimuli ipsilateral to the lesion. l. parietal damage, can only see one shape) Neglect (R.pareietal lobe damage, can’t see the left side at all [think controlaterally] not sense problem but consciousness
Which visual field is neglected—ipsilateral or contralateral? -Is the information presented in the neglected field processed at all? If so, to what degree? Be able to provide some evidence supporting your answer.
The left visual field is neglected which is contralateral to the area. The info is still processed just to a very small degree. if it was a harmful stimulus they’d be able to detect that, bu otherwise nothing.
Describe Bisiach and Luzzatti’s (1978) study of the visual imagery of a neglect patient.
They got neglect patients to describe a famous square if they were standing on the north side (they didn’t include buildings on the left) then as is they were on the south side (they didn’t include buildings on the right) so overall they were able to describe all the building present, they just couldn;t think of the left side of things.
What is Balint’s Syndrome? What are three symptoms of Balint’s syndrome? Describe Humphreys and Riddoch’s (1992) study of this patient group using the ‘connecting lines’.
Balients: Bilateral damage to the dorsal parietal lobe and lateral occipital cortex. Patients can only perceive one object at a time, even if they are close together or overlapping. Suggests bilateral systems allow us to simultaneously perceive multiple objects. Symptoms; optic ataxia [can’t use vision to ctrl movement], occulomoter apraxia [eyes don’t go where they should], simultanagosia [can only perceive one object]
Describe Wolfe’s study of top-down mechanisms and visual search. How does it differ from the feature integration theory?
examined whether voluntary attentional movements lead to faster visual searches than random (automatic) attentional shifts.
What brain areas are involved in attentional control?
The frontoparietal attentional system is involved in the control and maintenance of attention.
What did Tineke and colleagues find regarding the timing of neural activity during attentional control?
performed ERP and fMRI studies to isolate the effect of attentional orienting: Attentional shifting vs. no-shift (baseline) conditions). orientation involved medial areas. frontal=goals/strategies activated first then shifts to parietal. (if exogenous its bottom up so no goal so parietal then frontal lobe.) therefore frontal lobes are control shift
