Is It Possible to Improve Working Memory With Prefrontal tDCS? Bridging Currents to Working Memory Models

Area of Science:

• Neuroscience
• Cognitive Science
• Neuromodulation

Background:

• Working memory (WM) is a critical cognitive function targeted for enhancement.
• Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique explored for improving WM.
• Previous research yielded mixed results, suggesting oversimplified assumptions about tDCS mechanisms.

Purpose of the Study:

• To revise assumptions about tDCS effects on WM by employing multilevel models.
• To focus on circuit-level analysis and biophysical models of WM to inform tDCS research.
• To explore the role of excitation-inhibition (E/I) balance and gamma oscillations in tDCS effects on WM.

Main Methods:

• Reviewing critical aspects of tDCS and WM across multiple levels of analysis.
• Focusing on circuit-level analysis and biophysical models to understand tDCS mechanisms.
• Investigating the relationship between E/I balance, gamma activity, and tDCS outcomes.

Main Results:

• tDCS effects on WM are complex, showing non-linearities and dependency on individual traits.
• tDCS may preferentially affect WM control functions.
• Limitations exist related to the dynamical aspects of neural coding in persistent activity models.

Conclusions:

• Oversimplified assumptions regarding tDCS and WM need revision.
• Multilevel models and circuit-level biophysical WM models are crucial for understanding tDCS.
• The E/I balance and gamma activity may serve as intermediate indices for tDCS effects, but dynamical coding aspects require further investigation.