Oscillatory Contributions to Working Memory and Attention
Condition: Young Adults
Study type: Interventional

Summary: 
      The objectives are articulated in the proposal's specific aims:

      Aim 1: To test the hypothesis that the cognitive control of unattended memory items (UMI) is
      implemented by the same frontoparietal mechanisms that control spatial and nonspatial
      attention.

      Aim 2: To test the hypothesis that the selection of visual stimuli, whether from the
      environment or from WM, is accomplished, in part, by the hijacking of low-frequency
      oscillatory dynamics that are fundamental to the waking-state physiology of the
      corticothalamic circuitry of the visual system.

      Aim 3: To test the hypothesis that the function of context binding contributes to
      delay-period activity of the posterior parietal cortex (PPC).
    

Detailed description: 
      4.2.a Narrative Study Description There are 11 distinct experiments proposed, and each is
      described in turn. Experiment 1.a.: Unconfounding cognitive state from the passage of time
      for UMI reactivation This experiment entails recording the EEG, and delivering spTMS, while
      healthy young adult subjects perform two types of WM trials: dual serial retrocuing (DSR)
      trials and single-retrocue trials. DSR trials begin with the presentation of two items (drawn
      from categories face, motion, word), followed by an initial Delay 1.1, then Cue 1 indicating
      which of the two will be probed by the first memory probe. After Probe 1, Cue 2 indicates
      which item will be tested by Probe 2. Both trial types will feature 3 types of probe: match
      (50% of trials); nonmatch/same-category (drawn from same category as retrocued sample, 30% of
      trials); and nonmatch/lure (probe is the uncued item, 20% of trials. spTMS will also be
      delivered, unpredictably on half of the delay periods, to IPS2. Prospective power analysis,
      using the results from PMC 5221753 (and taking into account that Exp. 1.a., unlike PMC
      5221753, will use a repeated measures design), indicates that 360 trials per subject, and 12
      subjects, are required to achieve 80% power for the critical behavioral comparison, which is
      the comparative influence of spTMS on the FAR to nonmatch/lure probes for dual serial- vs.
      single-retrocue trials, assessed with the contrast [(FAR nonmatch/lure, dual -
      FARnonmatch/same-category, dual) - (FAR nonmatch/lure, single - FARnonmatch/same-category,
      single)]. (To balance the number of match and nonmatch probes, there will be a total of 720
      trials per subject.) Each subject will participate in two 2.5-hr experimental sessions.
      (Allowing for 15% attrition inflates the target n from 12 to 14.)

      Exp. 2.a. spTMS/EEG of the frontoparietal salience map. Study PMC 4893488 used n of 17 to
      achieve reliable single-trial regression results, which are least-powered analyses planned
      with this dataset; 18 subjects will allow for same number of subjects per targeted
      hemisphere. From the perspective of counterbalancing order of region targeted with spTMS, 12
      subjects would be needed (2 hemispheres * 6 possible orders); once the 12 counterbalancing
      cells have been filled, the remaining 6 subjects will be selected two-at-a-time, and assigned
      the same randomly selected order-of-region, one to each hemisphere). (Allowing for 15%
      attrition inflates the target n from 18 to 21.)

      Exp. 2.b. 1 Hz rTMS of the frontoparietal salience map. Study PMC 5725229 recruited 27
      subjects, based on its own power analysis based on the literature, to use a rTMS procedure
      comparable to what Exp. 2.b. will use to disrupt the function of PFC, one of the regions that
      will be targeted in this study. Because several previous studies using TMS to study
      attentional selection have found evidence of hemispheric asymmetries in the control of
      spatial attention, 27 subjects per hemisphere to be targeted will be recruited, yielding a
      total of 54. (Allowing for 15% attrition inflates the target n from 54 to 62.)

      Exp. 2.c.1 Hz rTMS of FEF and IFJ. Considerations are identical to those for Exp. 2.b.

      Experiment 3.a. Studying alpha-band dynamics of spatial and temporal attention with EEG.

      Study PMC 4500270 found reliable effects of temporal prediction-related frequency-shifting in
      the alpha band with 15 subjects. Sixteen (16) subjects will be recruited in order to achieve
      equal counterbalancing. (Allowing for 15% attrition inflates the target n from 16 to 18.)

      Exp. 4.a. Strategic control of alpha-band dynamics for perceptually unchallenging visual
      selection.

      Considerations are identical to those for Exp. 3.a.

      Exp. 4.b. Strategic control of alpha-band dynamics for selection in visual WM. Considerations
      are identical to those for Exp. 3.a.

      Experiment 5 (addressing Aim 3). Testing WM storage vs. context binding accounts of the CDA
      Power analyses, carried out with resampling of simulated data derived from the preliminary
      results of this study, indicate that 36 subjects are needed for 90% power to detect a load
      effect (i.e., CDA for 3C trials > CDA for 1C trials). (Allowing for 15% attrition inflates
      the target n from 36 to 41.)

      Experiment 6 (addressing Aim 3). Varying the domain of context. Considerations are identical
      to those for Exp. 5.
    

Intervention name(s): working memory and attention
Intervention type(s): Behavioral
Intervention description(s): Behavioral tests of working memory and attention
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science