Open AccessIncreasing the amplitude of intrinsic theta in the human brain
Author(s) -
Pascale Voelker,
Ashley Parker,
Phan Luu,
Colin Davey,
Mary K. Rothbart,
Michael I. Posner
Publication year - 2020
Publication title -
aims neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 12
eISSN - 2373-7972
pISSN - 2373-8006
DOI - 10.3934/neuroscience.2020026
Subject(s) - stimulation , neuroscience , anterior cingulate cortex , psychology , brain stimulation , optogenetics , cingulate cortex , motor cortex , transcranial alternating current stimulation , cortex (anatomy) , transcranial magnetic stimulation , central nervous system , cognition
In a mouse study we found increased myelination of pathways surrounding the anterior cingulate cortex (ACC) following stimulation near the theta rhythm (4-8 Hz), and evidence that this change in connectivity reduced behavioral anxiety. We cannot use the optogenetic methods with humans that were used in our mouse studies. This paper examines whether it is possible to enhance intrinsic theta amplitudes in humans using less invasive methods. The first experiment compares electrical, auditory and biofeedback as methods for increasing intrinsic theta rhythm amplitudes in the Anterior Cingulate Cortex (ACC). These methods are used alone or in conjunction with a task designed to activate the same area. The results favor using electrical stimulation in conjunction with a task targeting this region. Stimulating the ACC increases intrinsic theta more in this area than in a control area distant from the site of stimulation, suggesting some degree of localization of the stimulation. In Experiment 2, we employed electrical stimulation with the electrodes common to each person, or with electrodes selected from an individual head model. We targeted the ACC or Motor Cortex (PMC). At baseline, intrinsic theta is higher in the ACC than the PMC. In both areas, theta can be increased in amplitude by electrical stimulation plus task. In the PMC, theta levels during stimulation plus task are not significantly higher than during task alone. There is no significant difference between generic and individual electrodes. We discuss steps needed to determine whether we can use the electrical stimulation + task to improve the connectivity of white matter in different brain areas.