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P239 A novel approach to neuromodulation using transcranial magnetic stimulation-based neurofeedback
Abstracts / Clinical Neurophysiology 128 (2017) e1–e163
conditions, as well as lower interference scores (Fig. 2), likely caused by practice effects. Both, iTBS and cTBS, yielded improvements in the Digits Backward task and the Word score of the Stroop test. Moreover, similarly to the sham group, following iTBS participants showed lower Interference scores. In contrast, expected improvements in color score were not induced. Finally, cTBS decreased the number of movements necessary to complete the Tower of Hanoi. Nonetheless, at difference with the sham group, no improvements were observed in the Interference score of Stroop test. Conclusions: TBS over DLPFC modulates working memory performance and executive processes. Both protocols resulted in similar working memory and information processing speed outcomes, whereas their effect on executive functions differed: cTBS impaired inhibitory control but improved planning abilities in a spatial task, meanwhile, no specific effects were observed following iTBS. doi:10.1016/j.clinph.2016.10.353
P238 Working memory enhancement in young and older adults using rTMS—B. Luber a,*, S. Davis b, S.H. Lisanby a (a NIMH, Experimental Therapeutics and Pathophysiology Branch, Bethesda, United States, b Duke University, Psychology and Neuroscience, Durham, United States) ⇑
Corresponding author.
Question: A great deal of the cognitive decline due to aging can be explained by decline in working memory (WM). Our previous work has demonstrated a TMS paradigm which has enhanced WM performance in young adults and has remediated WM deficits in the context of sleep deprivation. Methods: Here, following an initial fMRI session to obtain individual cortical targets, two groups, older adults (N = 17) and younger adults (N = 17), performed a delayed-match-to-sample WM task while 5 Hz rTMS was applied during the 7 s delay period in the task. As part of a repeated measures design, across four TMS sessions each subject received active or sham rTMS, targeted to either left lateral occipital complex (LOC) or left premotor cortex (PMC) using individualized fMRI targeting. Results: There were Site TMS interactions for both %Correct and reaction time (RT) (p < 0.025 for both measures) across both groups. Both groups showed speeded RT relative to sham (p < 0.05) with LOC stimulation, while showing slowed RT and lower accuracy with stimulation to PMC. In a second follow up experiment, rTMS was applied to PMC prior to task onset instead of during the delay period, using the same subjects, who were brought back for two sessions of active and sham TMS. This time, instead of disrupted performance, young but not older adults showed enhanced accuracy and RT (both p < 0.025) with PMC stimulation. Conclusions: The opposing results of PMC stimulation prior to task onset or during the delay period demonstrate the sensitivity of task phase as to when to apply TMS to produce cognitive enhancement. Our interpretation of the results is that TMS to PMC during the delay period most likely disrupted ongoing verbal rehearsal, a phonological loop process known to rely on this region, while stimulation prior to such processing augmented that processing in young adults. For LOC, TMS during the delay period likely enhanced processing occurring during the test phase of the WM task in both age groups. Processing in the LOC may act as part of the visuo-spatial scratchpad, which, along with the phonological loop, are two components of WM suggested by Baddeley in his model of WM. These results encourage our continuing work to use TMS to remediate WM deficits found with aging.
e131
doi:10.1016/j.clinph.2016.10.354
P239 A novel approach to neuromodulation using transcranial magnetic stimulation-based neurofeedback—K. Ruddy *, N. Wenderoth (ETH Zurich, Health Science and Technology, Zurich, Switzerland) ⇑
Corresponding author.
Introduction: Various transcranial brain stimulation techniques have been used in an attempt to modulate excitability of the human corticomotor system, often with weak or mixed results. To date, there exists no reliable method to robustly upregulate or downregulate the output of the motor system. Objectives: Using a novel neurofeedback approach, our goal was to train participants to achieve endogenous neuromodulation by making them consciously aware of the size of their motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS). The goal was to harness experimental control over the excitability of the motor system, in order to investigate the oscillatory brain activity that mediates these states, using electroencephalography (EEG). Materials and methods: Separate sessions were carried out for ‘upregulation (UP)’ and ‘downregulation (DOWN)’ of MEP amplitude. In the UP condition subjects were rewarded for larger than average first dorsal interosseous (FDI) MEPs, with visual feedback showing amplitude as a green bar, a positive sound-byte, and a small financial incentive. Smaller than average MEPs were not rewarded, a red bar displayed the amplitude, and a negative sound-byte was heard. The reverse occurred in the DOWN sessions. Background muscle activity was monitored throughout and each trial would not begin until muscles were sufficiently relaxed. The final blocks of training occurred during simultaneous EEG recording. Results: MEP amplitudes in the muscle from which neurofeedback was provided were significantly altered from baseline by the end of 120 training trials (p = 0.002). Additionally, MEP amplitudes remained altered (UP or DOWN) following training when neurofeedback was removed (p < 0.001). No changes in MEP amplitude occurred in a nearby control muscle which was not providing neurofeedback. Preliminary EEG data collected during upregulation and downregulation suggests that these two states are mediated by distinct oscillatory signatures. Conclusion: Our approach uses brain stimulation in a nontraditional way to achieve robust endogenous neuromodulation. Using this method to harness experimental control over the excitability of the motor system opens many possibilities for future investigations of how altered brain state influences motor behaviour. doi:10.1016/j.clinph.2016.10.355
P240 Neural and functional bases of error monitoring: A TMS study—F. Masina a,b,*, A. Vallesi c,d, E. Di Rosa a, F. Saini a, D. Mapelli a,b (a University of Padua, Department of General Psychology, Padua, Italy, b University of Padua, Human Inspired Technologies Research Center, Padua, Italy, c University of Padua, Department of Neuroscience, Padua, Italy, d University of Padua, Cognitive Neuroscience Center, Padua, Italy) ⇑
Corresponding author.
Error monitoring is essential both to detect when an action deviates from a goal and to implement post-error adjustments. In
conditions, as well as lower interference scores (Fig. 2), likely caused by practice effects. Both, iTBS and cTBS, yielded improvements in the Digits Backward task and the Word score of the Stroop test. Moreover, similarly to the sham group, following iTBS participants showed lower Interference scores. In contrast, expected improvements in color score were not induced. Finally, cTBS decreased the number of movements necessary to complete the Tower of Hanoi. Nonetheless, at difference with the sham group, no improvements were observed in the Interference score of Stroop test. Conclusions: TBS over DLPFC modulates working memory performance and executive processes. Both protocols resulted in similar working memory and information processing speed outcomes, whereas their effect on executive functions differed: cTBS impaired inhibitory control but improved planning abilities in a spatial task, meanwhile, no specific effects were observed following iTBS. doi:10.1016/j.clinph.2016.10.353
P238 Working memory enhancement in young and older adults using rTMS—B. Luber a,*, S. Davis b, S.H. Lisanby a (a NIMH, Experimental Therapeutics and Pathophysiology Branch, Bethesda, United States, b Duke University, Psychology and Neuroscience, Durham, United States) ⇑
Corresponding author.
Question: A great deal of the cognitive decline due to aging can be explained by decline in working memory (WM). Our previous work has demonstrated a TMS paradigm which has enhanced WM performance in young adults and has remediated WM deficits in the context of sleep deprivation. Methods: Here, following an initial fMRI session to obtain individual cortical targets, two groups, older adults (N = 17) and younger adults (N = 17), performed a delayed-match-to-sample WM task while 5 Hz rTMS was applied during the 7 s delay period in the task. As part of a repeated measures design, across four TMS sessions each subject received active or sham rTMS, targeted to either left lateral occipital complex (LOC) or left premotor cortex (PMC) using individualized fMRI targeting. Results: There were Site TMS interactions for both %Correct and reaction time (RT) (p < 0.025 for both measures) across both groups. Both groups showed speeded RT relative to sham (p < 0.05) with LOC stimulation, while showing slowed RT and lower accuracy with stimulation to PMC. In a second follow up experiment, rTMS was applied to PMC prior to task onset instead of during the delay period, using the same subjects, who were brought back for two sessions of active and sham TMS. This time, instead of disrupted performance, young but not older adults showed enhanced accuracy and RT (both p < 0.025) with PMC stimulation. Conclusions: The opposing results of PMC stimulation prior to task onset or during the delay period demonstrate the sensitivity of task phase as to when to apply TMS to produce cognitive enhancement. Our interpretation of the results is that TMS to PMC during the delay period most likely disrupted ongoing verbal rehearsal, a phonological loop process known to rely on this region, while stimulation prior to such processing augmented that processing in young adults. For LOC, TMS during the delay period likely enhanced processing occurring during the test phase of the WM task in both age groups. Processing in the LOC may act as part of the visuo-spatial scratchpad, which, along with the phonological loop, are two components of WM suggested by Baddeley in his model of WM. These results encourage our continuing work to use TMS to remediate WM deficits found with aging.
e131
doi:10.1016/j.clinph.2016.10.354
P239 A novel approach to neuromodulation using transcranial magnetic stimulation-based neurofeedback—K. Ruddy *, N. Wenderoth (ETH Zurich, Health Science and Technology, Zurich, Switzerland) ⇑
Corresponding author.
Introduction: Various transcranial brain stimulation techniques have been used in an attempt to modulate excitability of the human corticomotor system, often with weak or mixed results. To date, there exists no reliable method to robustly upregulate or downregulate the output of the motor system. Objectives: Using a novel neurofeedback approach, our goal was to train participants to achieve endogenous neuromodulation by making them consciously aware of the size of their motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS). The goal was to harness experimental control over the excitability of the motor system, in order to investigate the oscillatory brain activity that mediates these states, using electroencephalography (EEG). Materials and methods: Separate sessions were carried out for ‘upregulation (UP)’ and ‘downregulation (DOWN)’ of MEP amplitude. In the UP condition subjects were rewarded for larger than average first dorsal interosseous (FDI) MEPs, with visual feedback showing amplitude as a green bar, a positive sound-byte, and a small financial incentive. Smaller than average MEPs were not rewarded, a red bar displayed the amplitude, and a negative sound-byte was heard. The reverse occurred in the DOWN sessions. Background muscle activity was monitored throughout and each trial would not begin until muscles were sufficiently relaxed. The final blocks of training occurred during simultaneous EEG recording. Results: MEP amplitudes in the muscle from which neurofeedback was provided were significantly altered from baseline by the end of 120 training trials (p = 0.002). Additionally, MEP amplitudes remained altered (UP or DOWN) following training when neurofeedback was removed (p < 0.001). No changes in MEP amplitude occurred in a nearby control muscle which was not providing neurofeedback. Preliminary EEG data collected during upregulation and downregulation suggests that these two states are mediated by distinct oscillatory signatures. Conclusion: Our approach uses brain stimulation in a nontraditional way to achieve robust endogenous neuromodulation. Using this method to harness experimental control over the excitability of the motor system opens many possibilities for future investigations of how altered brain state influences motor behaviour. doi:10.1016/j.clinph.2016.10.355
P240 Neural and functional bases of error monitoring: A TMS study—F. Masina a,b,*, A. Vallesi c,d, E. Di Rosa a, F. Saini a, D. Mapelli a,b (a University of Padua, Department of General Psychology, Padua, Italy, b University of Padua, Human Inspired Technologies Research Center, Padua, Italy, c University of Padua, Department of Neuroscience, Padua, Italy, d University of Padua, Cognitive Neuroscience Center, Padua, Italy) ⇑
Corresponding author.
Error monitoring is essential both to detect when an action deviates from a goal and to implement post-error adjustments. In