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Task 3: what brain areas are involved in attention? (Attention (Selective…

- - - - gives specific measure of warning influence
  - - - Cognitive view: ACC has role in monitoring conflict and in relation to lateral frontal areas in resolving conflict
      - Dual network view: there are two different top-down control networks: 1) Cingulo-opercular control system: shows maintenance across trials and acts as a stable background maintenance for task performance as a whole (sustained) ==> overlaps with original executive network 2) Frontoparietal system: shows start-cue signals, is thought to relate to task switching and initation and to adjustment within trials in real time (transient) ==> distinct from first orienting network of Posner
        
        Support: 1) lateral frontal and parietal regions that showed start-cue activity correlated well 2) midline and anterior insular regions that showed additional sustained activity correlated well
  - - - Dorsal attention system: top-down visuospatial ==> Some parietal regions, Frontal Eye Fields (FEF) and intraparietal sulcus/superior parietal lobe (IPS/SPL)
      - Ventral attention system: bottom-up reorienting ==> Temporoparietal junction (TPJ) and ventral frontal cortex (VFC)
        
        When target miscued: you have to break your focus of attention on the cued location and switch to the target location. TPJ and VFC have to do with this switch
  - - - endogenous: cue is presented in the center of the screen, usually at the same location as the center of focus. It is an arrow or other directional cue pointing to the left or right box on the screen. This cue relies on input from the central visual field.
      - exogenous: cue is presented outside of the center of focus, usually highlighting the left or right box presented on the screen. An exogenous cue can also be an object or image in the periphery, a number of degrees away from the centre, but still within the visual angle. This cue relies on visual input from the peripheral visual field
    - - In invalid trials, the stimulus is presented on the side opposite to that indicated by the cue. In this case, the arrow pointed to the right (directing attention to the right), but the stimulus in fact appeared in the box on the left. Posner used a ratio of 80% valid trials and 20% invalid trials in his original studies. The observer learns that usually the cue is valid, reinforcing the tendency to direct attention to the cued side
      - In valid trials, the stimulus is presented in the area as indicated by the cue. For example, if the cue was an arrow pointing to the right, the subsequent stimulus indeed did appear in the box on the right.
  - - - Center Cue (alerting cue) / control (no orienting effect, because you're already oriented)
      - Double Cue (When)
      - No cue
      - Spatial cue (location cue)
      - Target could be: neutral (lines), congruent (same direction) and incongruent (opposite direction)
    - - warning cue
      - short fixation period after the warning cue and then the target and flankers appeared simultaneously
      - Fixation period
      - after the response, target and flankers disapeared
      - Posttarget fixation period for a variable duration (interval) and the next target began
    - - The orienting effect: was calculated by substracting the mean RT of the spatial cue conditions from the mean RT of the center cue (center cue- spatial cue) #
      - The conflict (executive control) effect: calculated by substracting the mean RT of all congruent flanking conditions, summed across cue types, from the mean RT of incongruent flanking conditions. Incongruent minus congruent/ congruent (interference effect, because the flankers interfere with the task) -neutral (facilitations) #
      - Alerting effect: calculated by substracting the mean RT of the double-cue conditions from the mean RT of the no clue-condition (double cue- no cue) #
      - Results demonstrate (1) no correlation between any combination of alerting, orienting, and conflict resolution, suggesting that these are functionally orthogonal constructs. (2) Under all cuein conditions, the presence of incongruent flankers increased RT, however, this effect was enhanced when subjects were given alerting cues (center or double cues) that contained no spatial information (interaction between alerting and orienting => executive functioning) =>it appears that there are some interactions between the network suggesting that they may not prove to be independent in all behavioural studies even though they use different anatomy and chemical modulators
- - - - Arguments for
        
        Neglect is more frequent after damage to the right than to the left hemisphere
        
        Patients with neglect have deficits primarily in stimulus detection rather than in top-down goal-directed orienting
        
        Lesions that cause neglect are located more ventrally in the brain that the core regions of the IPs-FEF network, and most frequently involve the TPJ
      - Arguments against
        
        Detection deficits in neglect show a gradient across the visual field
        
        − The TPJ is not well activated by motor preparation/execution, whereas neglect patients
        clearly show a deficit in initiating arm movements contra to the lesion.