Targeting the neurophysiology of cognitive systems with transcranial alternating current stimulation

Abstract

Cognitive impairment represents one of the most debilitating and most difficult symptom to treat of many psychiatric illnesses. Human neurophysiology studies have suggested that specific pathologies of cortical network activity correlate with cognitive impairment. However, we lack demonstration of causal relationships between specific network activity patterns and cognitive capabilities and treatment modalities that directly target impaired network dynamics of cognition. Transcranial alternating current stimulation (tACS), a novel non-invasive brain stimulation approach, may provide a crucial tool to tackle these challenges. Here, we propose that tACS can be used to elucidate the causal role of cortical synchronization in cognition and, eventually, to enhance pathologically weakened synchrony that may underlie cognitive deficits. To accelerate such development of tACS as a treatment for cognitive deficits, we discuss studies on tACS and cognition performed in healthy participants, according to the Research Domain Criteria of the National Institute of Mental Health.

Keywords:

• cognitive symptoms
• cortex
• non-invasive brain stimulation
• non-pharmacological treatments
• oscillations
• psychiatric illness
• RDoC
• Research Domain Criteria project
• tACS
• transcranial alternating current stimulation

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Rhythmic oscillatory activity in cortex is perturbed in neuropsychiatric disorders, particularly in those with cognitive dysfunction.

• Transcranial alternating current stimulation (tACS) is a promising neurotherapeutic for modulating endogenous oscillatory activity in the neocortex.

• Studies conducted in healthy participants have demonstrated that tACS modulates endogenous oscillations and behavior in a frequency-dependent manner.

• The Research Domain Criteria project of the National Institute of Mental Health is beneficial for conceptualizing and characterizing psychopathology and can help to organize tACS studies for targeted modulation of brain network dynamics.

• Future steps in the development of tACS as a clinical tool will likely include targeting previously characterized deficits in cortical network dynamics in patients with psychiatric disorders.

• tACS as a neurotherapeutic will depend on rational design for tailoring stimulation protocols to dynamic neurophysiological states of individual patients.

Notes

RDoC: Research Domain Criteria; tACS: Transcranial alternating current stimulation; TMS: Transcranial magnetic stimulation.

DLPFC: Dorsolateral prefrontal cortex; tACS: Transcranial alternating current stimulation; TMS: Transcranial magnetic stimulation; WM: Working memory.