Influence of Static Magnetic Field Stimulation on the Accuracy of Tachystoscopically Presented Line Bisection

Abstract

Transcranial static magnetic stimulation (tSMS) has been known to reduce human cortical excitability. Here, we investigated whether tSMS would modulate visuo-spatial cognition in healthy humans. Subjects performed a visuo-spatial task requiring judgements about the symmetry of pre-bisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 150 ms on a computer monitor. Task performance was examined before, immediately after, and 10 min after tSMS/sham stimulation of 20 min over the posterior parietal cortex (PPC: P4 from the international 10–20 system) or superior temporal gyrus (STG: C6). Nine out of 16 subjects misjudged pre-bisected lines by consistently underestimating the length of the right-side segment (judging lines to be exactly pre-bisected when the transector was located to the left of the midpoint, or judging the left-side segment to be longer when the transector was located at the midpoint). In these subjects showing a leftward bias, tSMS over the right STG reduced the magnitude of the leftward bias. This did not occur with tSMS over the right PPC or sham stimulation. In the remaining right-biased subjects, no intervention effect was observed with any stimulation. Our findings indicate that application of tSMS over the right STG modulates visuo-spatial cognition in healthy adults.

Null Effect of Transcranial Static Magnetic Field Stimulation over the Dorsolateral Prefrontal Cortex on Behavioral Performance in a Go/NoGo Task

“…With regard to behavioral parameters, tSMS has been demonstrated to impair performance of difficult reaction time task [5], postural adjustment task [11], and force-matching task [12] when it was applied over the occipital cortex, supplementary motor area, and motor cortex, respectively. Moreover, tSMS has an ability to modulate symmetry judgements with the temporal cortex stimulation [13] and to enhance offline learning with the motor cortex stimulation [14], although the enhancement of offline learning by tSMS was not evident in another study [15]. Collectively, even though non-significant changes in sensorimotor cortical excitability by tSMS found in some previous studies should be acknowledged [16,17], tSMS has the potential to induce modulations of various human functions.…”

“…With the aid of an arm-type lightning stand (C-stand, Avenger, Cassola, Italy), the magnet or sham device was placed over F3 or F4 of international 10-20 system of electrode placement (Figure 1a). The stimulation site for sham stimulation (F3 or F4) was randomized among the participants [13].…”

“…With the aid of an arm-type lightning stand (C-stand, Avenger, Cassola, Italy), the magnet or sham device was placed over F3 or F4 of international 10-20 system of electrode placement (Figure 1a). The stimulation site for sham stimulation (F3 or F4) was randomized among the participants [13]. Each of these stimulations was given to all the participants in a random order on different days (at least one day apart), and the stimulation was blinded to the participants (single-blind study).…”

Safety for Human MR Scanners at 7T

“…13 A higher human cognition has also been reported to be affected by tSMS, where misjudgment of pre-bisected lines was observed immediately after tSMS stimulation of 20 mins over the right superior temporal gyrus. 14 At the cellular level, tSMS seems to alter the function of membrane ion channels, utilizing the diamagnetic anisotropic properties of phospholipids. 15 The effect of tSMS for 10 mins at the primary motor area was found to be temporary and recovered within 20 mins.…”

Transient Modulation of Working Memory Performance and Event-Related Potentials by Transcranial Static Magnetic Field Stimulation over the Dorsolateral Prefrontal Cortex

“…In addition, from a behavioral perspective, tSMS over the M1 has been reported to facilitate offline motor learning [21], and to impair pinch force control [22]. Moreover, visual search performance can be modulated with tSMS over the occipital [15] or temporal areas [23], and anticipatory postural control can be impaired with tSMS over the supplementary motor area [24]. Taken together, available evidence indicates that tSMS is capable of modulating human brain function and behavior.…”