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).
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
90
Two paradigms will be tested: visual perspective taking and reading the mind in the eyes.
tDCS either over the dmPFC or the rTPJ.
University Medicine Greifswald
Greifswald, Germany
Response Time in milliseconds in Visual-Perspective Taking Paradigm (VPT) in the active tDCS.
The outcome in the VPT paradigm will be response time in milliseconds (for correct answers only).
Time frame: at Day 1 or 7 (depends on randomization)
Response Time in milliseconds in Visual-Perspective Taking Paradigm (VPT) in the sham tDCS.
The outcome in the VPT paradigm will be response time in milliseconds (for correct answers only).
Time frame: at Day 1 or 7 (depends on randomization)
Response Time in milliseconds in the Reading the mind in the eyes test (RMET) in the active tDCS.
Outcome in the RMET will be reaction times in milliseconds (of correct answers only) in either rTPJ or dmPFC stimulation in comparison to sham stimulation.
Time frame: at Day 1 or 7 (depends on randomization)
Response Time in milliseconds in the Reading the mind in the eyes test (RMET) in the sham tDCS.
Outcome in the RMET will be reaction times in milliseconds (of correct answers only) in either rTPJ or dmPFC stimulation in comparison to sham stimulation.
Time frame: at Day 1 or 7 (depends on randomization)
Functional and structural connectivity (via MRI)
It will be investigated 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.Structural and functional connectivity will be assessed.
Time frame: MRI Assessment takes places before participants are stimulated with tDCS at Baseline (Day 1).
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