A Theta Oscillatory Approach to Interstimulus Interval Effect During Non-Painful Tactile Stimulation

Akın Öztürk G., Ülgen Z., Çağlayanel I., Güdücü Ç.

7th International Aegean Conference on Natural & Medical Sciences, İzmir, Türkiye, 26 - 27 Nisan 2023, ss.65-66

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: İzmir
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.65-66
  • Dokuz Eylül Üniversitesi Adresli: Evet

Özet

The sense of touch, somatosensation, is a crucial component of human existence, enabling us

to discover and engage with the world around us. Even though there are ongoing studies within

scope of somatosensation, especially on painful stimuli and innocuous (vibration, mechanical,

electrical) stimuli, to our knowledge the brain responsiveness of non-painful tactile stimuli is

not well understood. In this study, fingertip is decided upon for non-painful tactile stimulation

since it is more resemble to daily tactile environment for humans. Apart from the literature, we

aimed to investigate the constant interstimulus interval effect on the oscillatory activity during


non-painful tactile stimuli. 24 volunteers (12 female; mean age: 22.08 ± 3.38 years) with right-

handed participated. The local ethical committee of university approved the study (DEU-EK


2018/12-29). Brain responses were recorded using a 64-channel electroencephalography. Non-

painful tactile stimuli were applied to the index finger pulp of the right hand via a pneumatic


stimulator unit (air pressure 140 kPa). The stimuli were applied in separate sessions with inter-

timulus intervals of 2, 4, and 8 seconds. Somatosensory evoked potential paradigm was used


and total 40 stimuli (200ms duration) delivered. Theta frequency band powers were calculated

(via a complex morlet transform) since this oscillation is related with the involuntary attentional

processes. Three-way repeated measures ANOVA was conducted to investigate the effect of

ISI (ISI2, ISI4, ISI8) on pre (-500ms) and post (0-500ms) theta activity depending on region of

interest (ROI) (C4, Cz, C3). There was a significant main effect on time, ROI and ISIs (all p’s

<0.001). Also, there is a significant interaction between time, ISI, and ROI. A simple effect

analysis showed that there are no significant differences between ROI and time at ISI2.

However, theta power increases significantly after stimulation and this increase differ

significantly between ROI at ISI4 and ISI8.