Biophysics
Latest
Prof. Erik De Schutter
The Computational Neuroscience unit at the Okinawa Institute of Science and Technology, Japan has an opening for a postdoctoral researcher or technician to contribute to the software development of the nanoscale simulator of neuronal electrophysiology and molecular properties STEPS. The software developer will join the STEPS team and contribute to maintenance and further expansion of the software capacities. Recent versions of STEPS improved its parallel performance and added modeling of vesicles. The ideal candidate will have a scientific background but also possess good programming skills, but experienced software engineers can also apply.
Dr. Fleur Zeldenrust
For the Vidi project ‘Top-down neuromodulation and bottom-up network computation,’ we seek a postdoc to study neuromodulators in efficient spike-coding networks. Using our lab’s data on dopamine, acetylcholine, and serotonin from the mouse barrel cortex, you’ll derive models connecting single cells, networks, and behavior. The aim of this project is to explain the effects of neuromodulation on task performance in biologically realistic spiking recurrent neural networks (SRNNs). You will use the efficient spike coding framework, in which a network is not trained by a learning paradigm but deduced using mathematically rigorous rules that enforce efficient coding (i.e. maximally informative spikes). You will study how the network’s structural properties such as neural heterogeneity influence decoding performance and efficiency. You will incorporate realistic network properties of the (barrel) cortex based on our lab’s measurements and incorporate the cellular effects of dopamine, acetylcholine and serotonin we have measured over the past years into the network, to investigate their effects on representations, network activity measures such as dimensionality, and decoding performance. You will build on the single cell data, network models and analysis methods available in our group, and your results will be incorporated into our group’s further research to develop and validate efficient coding models of (somatosensory) perception. Therefore, we are looking for a team player who is willing to learn from the other group members and to share their knowledge with them.
Dr. Fleur Zeldenrust
For the NWO project ‘DBI2’ we are looking for a PhD candidate to study predictive error responses in the auditory cortex. The main goal is to design an experimental approach to distinguish between two alternative theories of predictive coding and processing. Predictive coding and predictive processing are compelling theories to explain brain function. The idea that the brain continually maintains and updates an internal model of the outside world, and compares the incoming input with the expectations generated by this model, can explain many phenomena including adaptive behaviour and sensory effects such as oddball responses. However, until now there is no consensus on how such predictive coding could be implemented in real neural tissue. Importantly, there are two alternative theories on how error signals in predictive processing could be coded in neural signals: either as (1) top down signals from ‘higher order’ brain areas (hierarchical predictive coding, [2]) or (2) local signals, resulting in membrane potentials reflecting error signals ([3], for a review, see [1]). The goal of the research presented here, under the primary supervision of Dr Zeldenrust, is to design an experimental approach to distinguish between these two theoretical approaches. Measuring error signals in neural tissue is experimentally challenging. Therefore, a direct exchange between theory and experiment is needed, so that hypotheses and specific predictions about which neurons to record from and stimulate and the results expected can be quickly updated for the design of optimal experiments. The student will work in close collaboration with the Englitz lab, so that there is a direct link between modelling, data analysis and experiment. As a PhD candidate you will use data on oddball paradigms [4,5], which provide the ability to directly observe predictions and distinguish them from prediction errors. The data are a combined approach of widefield imaging of the entire auditory cortex with local and layer-specific imaging using 2-photon recordings in the same animals. To directly test the top-down hypothesis, neurons in subareas of the prefrontal cortex will be transfected with an inhibitory opsin (eNpHR3.0) to modulate their top-down influence. You will develop a model of the hierarchical interaction between the auditory cortex and the prefrontal cortex, in which error signals are either coded as top-down (theory 1) or local (theory 2). You will use this model to formulate testable predictions, distinguishing theory 1 from theory 2. These predictions will be tested by both analysing existing data from the Englitz lab and formulating new experimental paradigms that are suitable to distinguish between the local and top-down hypothesis. [1] N’dri, A. W., Gebhardt, W., Teulière, C., Zeldenrust, F., Rao, R. P. N., Triesch, J., & Ororbia, A. (2024). Predictive Coding with Spiking Neural Networks: A Survey (arXiv:2409.05386). arXiv. https://doi.org/10.48550/arXiv.2409.05386 [2] Rao, R. P. N., & Ballard, D. H. (1999). Predictive coding in the visual cortex: A functional interpretation of some extra-classical receptive-field effects. Nature Neuroscience, 2(1), 79–87. [3] Zeldenrust, F., Gutkin, B., & Denéve, S. (2021). Efficient and robust coding in heterogeneous recurrent networks. PLOS Computational Biology, 17(4), e1008673. https://doi.org/10.1371/journal.pcbi.1008673 [4] Nieto-Diego, J. & Malmierca, M. S. Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat. (2016) PLOS Biol. 14, e1002397 [5] Lao-Rodríguez, A. B. ... Englitz B, (2023) Neuronal responses to omitted tones in the auditory brain: A neuronal correlate for predictive coding. Sci. Adv. 9, eabq8657 * We will give you a temporary employment contract (1.0 FTE) of 1.5 years, after which your performance will be evaluated. If the evaluation is positive, your contract will be extended by 2.5 years (4-year contract). * You will receive a starting salary of €2,901 gross per month based on a 38-hour working week, which will increase to €3,707 in the fourth year (salary scale P). * You will receive an 8% holiday allowance and an 8,3% end-of-year bonus. * We offer Dual Career Coaching. The Dual Career Coaching assists your partner via support, tools, and resources to improve their chances of independently finding employment in the Netherlands. * You will receive extra days off. With full-time employment, you can choose between 30 or 41 days of annual leave instead of the statutory 20.
dr. Fleur Zeldenrust
My lab is looking for a PhD candidate in Modelling Predictive Error Responses: https://www.ru.nl/en/working-at/job-opportunities/phd-position-in-computational-neuroscience-modelling-predictive-error-responses For the NWO project ‘DBI2’ we are looking for a PhD candidate to study predictive error responses in the auditory cortex. The main goal is to design an experimental approach to distinguish between two alternative theories of predictive coding and processing. Predictive coding and predictive processing are compelling theories to explain brain function. The idea that the brain continually maintains and updates an internal model of the outside world, and compares the incoming input with the expectations generated by this model, can explain many phenomena including adaptive behaviour and sensory effects such as oddball responses. However, until now there is no consensus on how such predictive coding could be implemented in real neural tissue. Importantly, there are two alternative theories on how error signals in predictive processing could be coded in neural signals: either as (1) top down signals from ‘higher order’ brain areas (hierarchical predictive coding, [2]) or (2) local signals, resulting in membrane potentials reflecting error signals ([3], for a review, see [1]). The goal of the research presented here, under the primary supervision of Dr Zeldenrust, is to design an experimental approach to distinguish between these two theoretical approaches. Measuring error signals in neural tissue is experimentally challenging. Therefore, a direct exchange between theory and experiment is needed, so that hypotheses and specific predictions about which neurons to record from and stimulate and the results expected can be quickly updated for the design of optimal experiments. The student will work in close collaboration with the Englitz lab, so that there is a direct link between modelling, data analysis and experiment. As a PhD candidate you will use data on oddball paradigms [4,5], which provide the ability to directly observe predictions and distinguish them from prediction errors. The data are a combined approach of widefield imaging of the entire auditory cortex with local and layer-specific imaging using 2-photon recordings in the same animals. To directly test the top-down hypothesis, neurons in subareas of the prefrontal cortex will be transfected with an inhibitory opsin (eNpHR3.0) to modulate their top-down influence. You will develop a model of the hierarchical interaction between the auditory cortex and the prefrontal cortex, in which error signals are either coded as top-down (theory 1) or local (theory 2). You will use this model to formulate testable predictions, distinguishing theory 1 from theory 2. These predictions will be tested by both analysing existing data from the Englitz lab and formulating new experimental paradigms that are suitable to distinguish between the local and top-down hypothesis. [1] N’dri, A. W., Gebhardt, W., Teulière, C., Zeldenrust, F., Rao, R. P. N., Triesch, J., & Ororbia, A. (2024). Predictive Coding with Spiking Neural Networks: A Survey (arXiv:2409.05386). arXiv. https://doi.org/10.48550/arXiv.2409.05386 [2] Rao, R. P. N., & Ballard, D. H. (1999). Predictive coding in the visual cortex: A functional interpretation of some extra-classical receptive-field effects. Nature Neuroscience, 2(1), 79–87. [3] Zeldenrust, F., Gutkin, B., & Denéve, S. (2021). Efficient and robust coding in heterogeneous recurrent networks. PLOS Computational Biology, 17(4), e1008673. https://doi.org/10.1371/journal.pcbi.1008673 [4] Nieto-Diego, J. & Malmierca, M. S. Topographic Distribution of Stimulus-Specific Adaptation across Auditory Cortical Fields in the Anesthetized Rat. (2016) PLOS Biol. 14, e1002397 [5] Lao-Rodríguez, A. B. ... Englitz B, (2023) Neuronal responses to omitted tones in the auditory brain: A neuronal correlate for predictive coding. Sci. Adv. 9, eabq8657 We offer * We will give you a temporary employment contract (1.0 FTE) of 1.5 years, after which your performance will be evaluated. If the evaluation is positive, your contract will be extended by 2.5 years (4-year contract). * You will receive a starting salary of €2,901 gross per month based on a 38-hour working week, which will increase to €3,707 in the fourth year (salary scale P). * You will receive an 8% holiday allowance and an 8,3% end-of-year bonus. * We offer Dual Career Coaching. The Dual Career Coaching assists your partner via support, tools, and resources to improve their chances of independently finding employment in the Netherlands. * You will receive extra days off. With full-time employment, you can choose between 30 or 41 days of annual leave instead of the statutory 20.
Biophysics coverage
4 items