Effects of tDCS on Social Cognition in Aging
Condition: Aging; Social Cognition
Study type: Interventional

Summary: 
      The aim of the study is to explore the effect of transcranial direct current stimulation
      (tDCS) on either the right tempo-parietal junction (rTPJ) or the dorsomedial prefrontal
      cortex (dmPFC) in healthy older adults (replication in a different sample of a study by
      Martin et al., 2020).
    

Detailed description: 
      Humans are fundamentally social animals. The ability to operate within large social networks
      requires considerable cognitive capacity, often referred to as social cognition. One social
      cognitive process thought to involve embodied and nonembodied processes is
      perspective-taking. Recently, the right temporoparietal junction (rTPJ) has been suggested as
      a key hub for embodied processing relevant to social cognition. A study of Martin et al.
      (2020) could further provide causal evidence that the right temporoparietal junction is
      involved specifically in the embodied component of perspective-taking. Specifically, HD-tDCS
      (high-definition transcranial direct current stimulation) to the right temporoparietal
      junction, but not another hub of the social brain (dorsomedial PFC), increased the effect of
      body position during perspective-taking, but not tracking. As social cognition is affected by
      the aging process and decline of socio-cognitive abilities is a key feature of neurological
      diseases such as Alzheimer's or Parkinson's disease, the aim of the present study is to
      replicate the findings of Martin et al., (2020) in a sample of healthy older adults to better
      understand the modulation of socio-cognitive processes in older age.

      The aim of the study is to explore the effect of transcranial direct current stimulation
      (tDCS) on either the right tempo-parietal junction (rTPJ) or the dorsomedial prefrontal
      cortex (dmPFC) in healthy older adults (replication in a different sample of a study by
      Martin et al., 2020). 60 healthy older adults and 30 younger participants (serving as a
      control group) will be tested in a Reading the Eyes in the Mind Task (RMET) and a Task of
      Visual Perspective Taking (VPT) , while stimulation either the rTPJ or the dmPFC with either
      active or sham tDCS (stimulation only in the group of older participants). In the RMET the
      expectation is that older participants have higher reaction times after correct answers under
      rTPJ tDCS. No stimulation effects of the dmPFC are expected. In the VPT older participants
      are expected to have a selective effect on body position (similar to the results of Martin et
      al., 2020) under rTPJ stimulation, but not dmPFC stimulation.

      A further focus of the study is how functional and structural connectivity of the brain and
      individual differences measured with an MRI assessment influence with the success of the RMET
      and VPT paradigms in an explorative research question.
    

Intervention name(s): Social Cognition Task; tDCS
Intervention type(s): Behavioral; Device
Intervention description(s): Two paradigms will be tested: visual perspective taking and reading the mind in the eyes.; tDCS either over the dmPFC or the rTPJ.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: It is a randomized, balanced cross-over design with within- as well as between group comparisons. Two groups will be investigate: young participants (n = 30) and older participants (n = 60). The group of young participants will serve as a control group and will only get a neuropsychological assessment of their cognitive abilities at the beginning of the study, an MRI assessment and one session of the investigated paradigms (without tDCS). The group of older participants will conduct a session of MRI assessment and neuropsychological assessment, as well as two tDCS sessions (anodal/sham). The stimulation will either be over the rTPJ or the dmPFC. This set-up is identical to the study of Martin et al., (2020).
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: tDCS; Social Cognition