Matthias Ziegler

Transcranial Direct Current Stimulation Modulates Neuronal Activity and Learning in Pilot Training

Skill acquisition requires distributed learning both within (online) and across (offline) days to consolidate experiences into newly learned abilities. In particular, piloting an aircraft requires skills developed from extensive training and practice. Here, we tested the hypothesis that transcranial direct current stimulation (tDCS) can modulate neuronal function to improve skill learning and performance during flight simulator training of aircraft landing procedures. Thirty-two right-handed participants consented to participate in four consecutive daily sessions of flight simulation training and received sham or anodal high-definition-tDCS to the right dorsolateral prefrontal cortex (DLPFC) or left motor cortex (M1) in a randomized, double-blind experiment. Continuous electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) were collected during flight simulation, n-back working memory, and resting-state assessments. tDCS of the right DLPFC increased midline-frontal theta-band activity in flight and n-back working memory training, confirming tDCS-related modulation of brain processes involved in executive function. This modulation corresponded to a significantly different online and offline learning rates for working memory accuracy and decreased inter-subject behavioral variability in flight and n-back tasks in the DLPFC stimulation group. Additionally, tDCS of left M1 increased parietal alpha power during flight tasks and tDCS to the right DLPFC increased midline frontal theta-band power during n-back and flight tasks. These results demonstrate a modulation of group variance in skill acquisition through an increasing in learned skill consistency in cognitive and real-world tasks with tDCS. Further, tDCS performance improvements corresponded to changes in electrophysiological and blood-oxygenation activity of the DLPFC and motor cortices, providing a stronger link between modulated neuronal function and behavior.

A Neurostimulation-based Advanced Training System for Human Performance Augmentation

Transcranial direct current stimulation (tDCS) is an emerging therapeutic tool for many neuropsychiatric disorders with applications in enhancing learning and memory. Despite human clinical trials showing promising results for memory retention and recall, the underlying cellular mechanisms that promote DC stimulationinduced plasticity have not been characterized. tDCS produces a weak electric field (0.1 V/m per mA current applied) across the brain, which results in incremental passive membrane polarization (up to 0.4 mV polarization per V/m in cortical pyramidal cells). The change in membrane potential alters current flow through voltagegated ion channels that can modify synaptic transmission and synaptic plasticity. We have previously demonstrated in vitro that somatic polarization by DC stimulation modulates neuronal output, specifically firing rate and spike timing. Changes in synaptic input can also have profound effects on neuronal output (firing rate and spike timing). In this study we show that DC stimulation of the rat hippocampal CA1 modifies the neuronal input-output function. Our results indicate DC stimulation can change the threshold and latency of population spikes as a function of the EPSP amplitude, electric field magnitude and duration. Additionally, we demonstrate in vitro that DC stimulation can amplify neuronal output by modulating synaptic efficacy. These results indicate an important role of DC stimulation in modifying the neural code, synaptic computation and ultimately facilitating plasticity.

The neural basis of decision-making during sensemaking: Implications for human-system interaction

We have created a high-fidelity model of 9 regions of the brain involved in making sense of complex and uncertain situations. Sense making is a proactive form of situation awareness requiring sifting through information of various types to form hypotheses about evolving situations. The MINDS model (Mirroring Intelligence in a Neural Description of Sensemaking) reveals the neural principles and cognitive tradeoffs that explain weaknesses in human reasoning and decision-making.

Learning to Prognostically Forage in a Neural Network Model of the Interactions between Neuromodulators and Prefrontal Cortex

Abstract Neuromodulatory systems and prefrontal cortex are involved in a number of decision-making contexts. In this work, we adapt a recent neural network model that simulates interactions between neuromodulatory and prefrontal areas to the problem of prognostic foraging—that is choosing information to update or form a hypothesis. In the context of a simulated geospatial intelligence task, the model assesses a number of decision variables and strategies to choose actions that maximize information utility to more accurately predict the actions of an adversary. The model is also capable of modeling biases in decision making such as deviations from the optimal solution of maximizing information gain. Comparisons to other approaches and problem domains in information foraging are also discussed.