Detecting differences with magnetoencephalography of somatosensory processing after tactile and electrical stimuli

Magnetoencephalography Responses to Unpredictable and Predictable Rare Somatosensory Stimuli in Healthy Adult Humans

“…In this study, the stimulation is presented as electrical stimulations of fingers, and the three stimulus types differ in location of the stimulation. Consistent with previous studies investigating the location deviance detection and where the fingers or hands have been stimulated in an ignore condition (Shinozaki et al, 1998;Akatsuka et al, 2005Akatsuka et al, , 2007aRestuccia et al, 2007;Strömmer et al, 2014Strömmer et al, , 2017Hautasaari et al, 2019), we expect that the stimulation will elicit activity in two main time windows at approximately 30-70 and 100-200 ms after the stimulus onset. We also expect both the early and later responses to show a larger amplitude to rare stimuli in comparison to standard stimuli (Mima et al, 1998;Akatsuka et al, 2005Akatsuka et al, , 2007aStrömmer et al, 2017;Hautasaari et al, 2019).…”

“…Consistent with previous studies investigating the location deviance detection and where the fingers or hands have been stimulated in an ignore condition (Shinozaki et al, 1998;Akatsuka et al, 2005Akatsuka et al, , 2007aRestuccia et al, 2007;Strömmer et al, 2014Strömmer et al, , 2017Hautasaari et al, 2019), we expect that the stimulation will elicit activity in two main time windows at approximately 30-70 and 100-200 ms after the stimulus onset. We also expect both the early and later responses to show a larger amplitude to rare stimuli in comparison to standard stimuli (Mima et al, 1998;Akatsuka et al, 2005Akatsuka et al, , 2007aStrömmer et al, 2017;Hautasaari et al, 2019). Since previous studies have not controlled for stimulus rarity (for example, by using the many-standards control condition), we cannot predict whether increased responses in comparison to the FRE will be elicited by the UR alone or by both the UR and the PR.…”

“…The MEG data were then preprocessed and analyzed using the Brainstorm software (Tadel et al, 2011). First, a notch filter of 50 Hz (3 dB notch bandwidth: 2 Hz) and a low-bandpass filter of 60 Hz were applied, as described previously (Hautasaari et al, 2019). Cardiac and eye blink artifacts were attenuated with signal space projection (SSP) in Brainstorm by visually inspecting and removing the corresponding SSP components separately for gradiometers and magnetometers.…”

“…Here, we focus on the somatosensory mismatch response [sMMR, instead of MMN due to its positive polarity in some previous electroencephalography (EEG) measurements], which is less studied than its auditory and visual counterparts. The sMMR has been observed for changes in stimulus location (Shinozaki et al, 1998;Huang et al, 2005;Restuccia et al, 2009;Strömmer et al, 2014Strömmer et al, , 2017Yamashiro et al, 2014;Shen et al, 2018;Hautasaari et al, 2019; for animal models, see: Astikainen et al, 2001;Musall et al, 2017), duration (Akatsuka et al, 2005;Spackman et al, 2007Spackman et al, , 2010Zhao et al, 2014), intensity (Mima et al, 1998;Ostwald et al, 2012), frequency (Kekoni et al, 1997;Spackman et al, 2007), and omissions of the stimuli (Tesche and Karhu, 2000;Naeije et al, 2018). However, one critical confounder should be considered in the context of all the previously mentioned studies, namely, that the probability of the rare stimulus in the traditional oddball paradigm is always smaller than the probability of the standard stimulus and that probability, as such, affects the brain responses (Hari et al, 1990).…”

Vibration Alert to the Brain: Evoked and Induced MEG Responses to High-Frequency Vibrotactile Stimuli on the Index Finger of Dominant and Non-dominant Hand

“…Previous MEG studies have shown that the somatosensory information processing involves activation in primary and secondary somatosensory cortices (Forss et al, 1994;Hari and Forss, 1999;Karhu and Tesche, 1999;Kakigi et al, 2000;Hoechstetter et al, 2001). Most studies, however, used electrical stimulation of peripheral nerves to activate a broad range of cutaneous receptors or tactile stimulation to activate mainly slowly adapting mechanoreceptors (Forss et al, 1994;Rossini et al, 1996;Jousmäki, 2000;Inoue et al, 2005;Hautasaari et al, 2019). Much less is known about brain responses activated by rapidly adapting mechanoreceptors, i.e., Meissner and Pacinian corpuscles.…”