title: Numerical modelling of plasticity induced by transcranial magnetic stimulation

authors: Wilson, Marcus T.

subjects: Transcranial Magnetic Stimulation

abstract: We use neural field theory and spike-timing dependent plasticity to make a simple but biophysically reasonable model of long-term plasticity changes in the cortex due to transcranial magnetic stimulation (TMS). We show how common TMS protocols can be captured and studied within existing neural field theory. Specifically, we look at repetitive TMS protocols such as theta burst stimulation and paired-pulse protocols. Continuous repetitive protocols result mostly in depression, but intermittent repetitive protocols in potentiation. A paired pulse protocol results in depression at short (<∼10 ms) and long (>∼ 100 ms) interstimulus intervals, but potentiation for mid-range intervals. The model is sensitive to the choice of neural populations that are driven by the TMS pulses, and to the parameters that describe plasticity, which may aid interpretation of the high variability in existing experimental results. Driving excitatory populations results in greater plasticity changes than driving inhibitory populations. Modelling also shows the merit in optimizing a TMS protocol based on an individual’s electroencephalogram. Moreover, the model can be used to make predictions about protocols that may lead to improvements in repetitive TMS outcomes.

text: Numerical modelling of plasticity induced by transcranial magnetic stimulation We use neural field theory and spike-timing dependent plasticity to make a simple but biophysically reasonable model of long-term plasticity changes in the cortex due to transcranial magnetic stimulation (TMS). We show how common TMS protocols can be captured and studied within existing neural field theory. Specifically, we look at repetitive TMS protocols such as theta burst stimulation and paired-pulse protocols. Continuous repetitive protocols result mostly in depression, but intermittent repetitive protocols in potentiation. A paired pulse protocol results in depression at short (<∼10 ms) and long (>∼ 100 ms) interstimulus intervals, but potentiation for mid-range intervals. The model is sensitive to the choice of neural populations that are driven by the TMS pulses, and to the parameters that describe plasticity, which may aid interpretation of the high variability in existing experimental results. Driving excitatory populations results in greater plasticity changes than driving inhibitory populations. Modelling also shows the merit in optimizing a TMS protocol based on an individual’s electroencephalogram. Moreover, the model can be used to make predictions about protocols that may lead to improvements in repetitive TMS outcomes.

year: 2013

title: Evaluation of agri-environmental policies for water quality improvement accounting for firm heterogeneity

authors: Doole, Graeme J.

subjects: diffuse pollution

abstract: Policy makers worldwide are interested in the identification of cost-effective policy instruments to reduce diffuse pollution. A large economic model representing heterogeneous farms is used to evaluate a broad set of policies for reducing nitrate regulation within a large catchment dominated by dairy production. A policy instrument that allows the level of abatement to vary among producers according to differences in abatement cost is most cost-effective. The primary goal of 26 kg N ha⁻¹ can be achieved at a cost of $15 ha⁻¹ under this cap and trade policy, while a uniform cap on emissions for all farmers would be more than three times as expensive ($49 ha⁻¹). In contrast, requiring uniform reductions in stocking rate, banning the application of nitrogen fertiliser, and land retirement perform poorly. These instruments are at least three times more costly than a cap and trade policy over all simulated reductions. Moreover, the differentiated policy does not greatly alter the distribution of farm profit, relative to what exists without regulation. The use of a large, complex economic model incorporating disaggregated farms provides unique insight into the economic benefits accruing to a differentiated policy.

text: Evaluation of agri-environmental policies for water quality improvement accounting for firm heterogeneity Policy makers worldwide are interested in the identification of cost-effective policy instruments to reduce diffuse pollution. A large economic model representing heterogeneous farms is used to evaluate a broad set of policies for reducing nitrate regulation within a large catchment dominated by dairy production. A policy instrument that allows the level of abatement to vary among producers according to differences in abatement cost is most cost-effective. The primary goal of 26 kg N ha⁻¹ can be achieved at a cost of $15 ha⁻¹ under this cap and trade policy, while a uniform cap on emissions for all farmers would be more than three times as expensive ($49 ha⁻¹). In contrast, requiring uniform reductions in stocking rate, banning the application of nitrogen fertiliser, and land retirement perform poorly. These instruments are at least three times more costly than a cap and trade policy over all simulated reductions. Moreover, the differentiated policy does not greatly alter the distribution of farm profit, relative to what exists without regulation. The use of a large, complex economic model incorporating disaggregated farms provides unique insight into the economic benefits accruing to a differentiated policy.

year: 2011-07

title: He Matapihi Mā Mua, Mō Muri: The Ethics, Processes, and Procedures Associated with the Digitization of Indigenous Knowledge—The Pei Jones Collection

authors: Whaanga, Hēmi

abstract: The digital era has transformed how people live their lives and interact with the world and knowledge systems around them. In Aotearoa/New Zealand a range of initiatives incorporating Indigenous knowledge have been implemented to collect, catalog, maintain, and organize digital objects. In this article, we report on the ethics, processes, and procedures associated with the digitization of the manuscripts, works, and collected taonga (treasures) of the late Dr. Pei Te Hurinui Jones—and describe how it was transformed into a digital library. It discusses the decision-making processes and the various roles and responsibilities of the researchers, family members, and institute in this process.

text: He Matapihi Mā Mua, Mō Muri: The Ethics, Processes, and Procedures Associated with the Digitization of Indigenous Knowledge—The Pei Jones Collection The digital era has transformed how people live their lives and interact with the world and knowledge systems around them. In Aotearoa/New Zealand a range of initiatives incorporating Indigenous knowledge have been implemented to collect, catalog, maintain, and organize digital objects. In this article, we report on the ethics, processes, and procedures associated with the digitization of the manuscripts, works, and collected taonga (treasures) of the late Dr. Pei Te Hurinui Jones—and describe how it was transformed into a digital library. It discusses the decision-making processes and the various roles and responsibilities of the researchers, family members, and institute in this process.

year: 2015