title: Modeling motor-evoked potentials from neural field simulations of transcranial magnetic stimulation

authors: Wilson, Marcus T.

subjects: Science & Technology

abstract: Objective
To develop a population-based biophysical model of motor-evoked potentials (MEPs) following transcranial magnetic stimulation (TMS).

Methods
We combined an existing MEP model with population-based cortical modeling. Layer 2/3 excitatory and inhibitory neural populations, modeled with neural-field theory, are stimulated with TMS and feed layer 5 corticospinal neurons, which also couple directly but weakly to the TMS pulse. The layer 5 output controls mean motoneuron responses, which generate a series of single motor-unit action potentials that are summed to estimate a MEP.

Results
A MEP waveform was generated comparable to those observed experimentally. The model captured TMS phenomena including a sigmoidal input–output curve, common paired pulse effects (short interval intracortical inhibition, intracortical facilitation, long interval intracortical inhibition) including responses to pharmacological interventions, and a cortical silent period. Changes in MEP amplitude following theta burst paradigms were observed including variability in outcome direction.

Conclusions
The model reproduces effects seen in common TMS paradigms.

Significance
The model allows population-based modeling of changes in cortical dynamics due to TMS protocols to be assessed in terms of changes in MEPs, thus allowing a clear comparison between population-based modeling predictions and typical experimental outcome measures.

text: Modeling motor-evoked potentials from neural field simulations of transcranial magnetic stimulation Objective
To develop a population-based biophysical model of motor-evoked potentials (MEPs) following transcranial magnetic stimulation (TMS).

Methods
We combined an existing MEP model with population-based cortical modeling. Layer 2/3 excitatory and inhibitory neural populations, modeled with neural-field theory, are stimulated with TMS and feed layer 5 corticospinal neurons, which also couple directly but weakly to the TMS pulse. The layer 5 output controls mean motoneuron responses, which generate a series of single motor-unit action potentials that are summed to estimate a MEP.

Results
A MEP waveform was generated comparable to those observed experimentally. The model captured TMS phenomena including a sigmoidal input–output curve, common paired pulse effects (short interval intracortical inhibition, intracortical facilitation, long interval intracortical inhibition) including responses to pharmacological interventions, and a cortical silent period. Changes in MEP amplitude following theta burst paradigms were observed including variability in outcome direction.

Conclusions
The model reproduces effects seen in common TMS paradigms.

Significance
The model allows population-based modeling of changes in cortical dynamics due to TMS protocols to be assessed in terms of changes in MEPs, thus allowing a clear comparison between population-based modeling predictions and typical experimental outcome measures.

year: 2021

title: Source code for "Parallel computing efficiency of SWAN"

authors: Rautenbach, Christo

subjects: SWAN

abstract: Source code for  the paper "Rautenbach, C., Mullarney, J. C., and Bryan, K. R.: Parallel computing efficiency of SWAN, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2020-314, in review, 2020."

text: Source code for "Parallel computing efficiency of SWAN" Source code for  the paper "Rautenbach, C., Mullarney, J. C., and Bryan, K. R.: Parallel computing efficiency of SWAN, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2020-314, in review, 2020."

year: 2020

title: Māori men, relationships, and everyday practices: towards broadening domestic violence research

authors: King, Pita

subjects: Māori

abstract: Relationships are central to the health and wellbeing of Māori (indigenous people of New Zealand). Through processes of colonisation, cultural ways of relatedness embedded within Māori social structures experienced disruption and were reshaped over decades of assimilation. Māori knowledge and everyday practices that assisted in protecting Māori from societal problems, such as domestic violence, began to dwindle. In contemporary New Zealand, Māori are over-represented in domestic violence statistics. Utilising an auto-ethnographic approach and case studies, our research focuses on five Māori men’s experiences within intimate relationships and whānau (extended family) life. A significant feature of this research is that it provides insights into the ways Māori men draw on their cultural ways-of-being to enhance intimate relationships and maintain bonds within whānau and community life to forge new ways-of-being. Such insights have the potential to inform preventative measures against domestic violence within Māori communities.

text: Māori men, relationships, and everyday practices: towards broadening domestic violence research Relationships are central to the health and wellbeing of Māori (indigenous people of New Zealand). Through processes of colonisation, cultural ways of relatedness embedded within Māori social structures experienced disruption and were reshaped over decades of assimilation. Māori knowledge and everyday practices that assisted in protecting Māori from societal problems, such as domestic violence, began to dwindle. In contemporary New Zealand, Māori are over-represented in domestic violence statistics. Utilising an auto-ethnographic approach and case studies, our research focuses on five Māori men’s experiences within intimate relationships and whānau (extended family) life. A significant feature of this research is that it provides insights into the ways Māori men draw on their cultural ways-of-being to enhance intimate relationships and maintain bonds within whānau and community life to forge new ways-of-being. Such insights have the potential to inform preventative measures against domestic violence within Māori communities.

year: 2017