Meta-modeling the effects of non-invasive brain stimulation

Non-invasive brain stimulation is a great tool to temporarily modulate cognition and behavior. However, the effects are subtle and differ from study to study. One major reason for this is that different montages are applied in different research studies. To understand the cumulative effect, I developed a meta-modeling approach. In this method, classic meta-analyses are combined with computational electric field modeling of tDCS, tACS, or TMS. As a result, brain maps are generated, which identify regions that most strongly relate to behavioral changes when being stimulated.

tDCS and working memory

We retrieved effects sizes in 87 studies. Next, we calculate the relation with the tDCS-related electric fields per brain region. The results is a new map showing the performance-electric field correlation (PEC). We found that targeting the lower DLPFC/upper IFG with tDCS most optimally increase working memory performance. (Wischnewski et al., Neurosci & Biobehav Rev, 2021).

Working memory types

We delved further into the data, by investigating the effects on different memory domains (verbal and visuospatial), outcome types (accuracy and reaction time), and time of stimulation (online and offline). We found that verbal working memory can be targeted in the lower DLPFC. These results were driven by online tDCS and mostly accuracy outcome measures. On the other hand visuospatial working memory is not positively affected by tDCS. 

Source

Wischnewski, Mantell & Opitz (2021). Identifying regions in prefrontal cortex related to working memory improvement: a novel meta-analytic method using electric field modeling. Neurosci Biobehav Rev, 130, 147-161. https://doi.org/10.1016/j.neubiorev.2021.08.017 

 

Wischnewski, Berger & Opitz (2024). Meta-modeling the effects of anodal left prefrontal transcranial direct current stimulation on working memory performance. Imag Neurosci, 2, 1-14. https://doi.org/10.1162/imag_a_00078