Spatial working memory in humans depends on theta and high gamma synchronization in the prefrontal cortex

Alekseichuk, Ivan, Zsolt Turi, Gabriel Amador de Lara, Andrea Antal, and Walter Paulus. 2016. 'Spatial working memory in humans depends on theta and high gamma synchronization in the prefrontal cortex', Current Biology, 26: 1513-21.
 
Summary:        Slow frequency neural oscillations couple to higher frequency neural oscillations during tasks that require cognitive control. Alekseichuk et al. use a novel approach to customize the waveform of tACS to mimic the cross-frequency coupling pattern. Using a high-definition electrode montage to target left prefrontal cortex, cross-frequency tACS was delivered as participants performed a spatial working memory task. Cross-frequency tACS increased behavior performance.
 
Pros:

• Behavioral improvement specific to theta coupled to high gamma frequency with many control stimulation conditions
• High-definition tACS increases the interpretability of the findings
• Many participants and follow-up experiments
• Functional connectivity in EEG increased from tACS

 
Open questions:

• Does cross-frequency tACS increase cross frequency coupling?
• Can these methods be adopted to interregional cross-frequency coupling?

 
Contributed by: Justin Riddle, PhD