ד"ר הגר לביאן

Hagar Lavian is a researcher in the Faculty of Life Sciences at Tel-Aviv University. She obtained her PhD in the lab of Prof. Alon Korngreen at Bar-Ilan University where she studied mechanisms of short-term synaptic plasticity and dopaminergic neuromodulation in the Basal Ganglia.

She then did her postdoc in the lab of Prof. Ruben Portugues where she studied neural networks underlying navigation, decision making and sensory processing in zebrafish larvae.

Education

2020-2025       Postdoctoral fellow, Technical University of Munich

2018-2020       Postdoctoral fellow, Max Planck institute of Neurobiology

2013-2018       PhD, Gonda Brain Research Center, Bar-Ilan University

2010-2012       M.Sc, Faculty of Life Sciences, Bar-Ilan University (magna cum laude)

2008-2011       B.Sc, Faculty of Life Sciences, Bar-Ilan University (summa cum laude)

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Academic appointments

2025-present   Assistant Professor, Tel-Aviv University

Research topic

Navigation represents one of the most sophisticated computational challenges solved by neural systems. From the remarkable path integration and celestial navigation strategies observed in insects to the extraordinary spatial memory of caching birds, animals efficiently navigate complex environments by integrating multiple spatial signals. To navigate from one location to another, an animal must track its own position, monitor its heading direction, and maintain a representation of its desired destination. These signals must then be integrated to generate the appropriate motor commands guiding the animal towards its goal. We investigate neural circuits underlying navigation, with a focus on the flexibility of neural networks and how it supports this complex process. Our current research focuses on three main directions: 

1. Representation of spatial signals and their integration to guide behavior: how are different spatial signals (e.g., goal direction) represented in the brain? how are these signals generated, and how do they interact to guide behavior?
2. The role of short-term modulation in network computation: how does short-term modulation enable neural networks to generate complex sensory representations of the environment, and how does this process support more sophisticated navigation strategies?
3. Long-term plasticity and flexible behaviors: how can long-term modulation of sensory representations allow neural networks to learn new rules and adapt to changing environments?

Animal model

To answer these questions, we study neural networks in zebrafish larvae and juvenile: tiny transparent vertebrates that are ideally suited to investigate distributed networks. As zebrafish are transparent, they enable us to perform whole brain imaging with single cell resolution in a non-invasive manner. In addition, zebrafish are highly amenable to genetic manipulations, which makes it relatively easy and fast to generate new lines suitable for various methods. By studying neural networks in the zebrafish brain, with its evolutionarily conserved neural architecture and experimental accessibility, we aim to uncover fundamental principles of neural computation.

Research methods

1. Behavioral experiments: we study different behaviors by carefully designing experiments in which animals are presented with sensory stimuli while their behavior is tracked. In our setups, we track the movement of freely swimming and head-fixed zebrafish larvae and juveniles.
2. Advanced microscopy techniques: our goal is to characterize and investigate neural networks in live behaving animals. In order to investigate whole networks, we record neural activity throughout the brain. This is done using two-photon and light-sheet microscopy, techniques that allow us to perform whole brain imaging with cellular resolution.
3. Manipulations of neural activity: chemogenetic manipulations and laser ablations allow us to determine causal relationships between different brain regions and neuronal types.
4. Anatomical and morphological techniques: we use single-cell labeling and photoactivation to reveal neuronal morphology and connectivity.

Lavian H., Prat O., Petrucco L., Štih V. and Portugues R. The representation of visual motion and landmark position aligns with heading direction in the zebrafish interpeduncular nucleus. BioRxiv (Preprint, 2024).

Petrucco L.*, Lavian H.*, Wu Y., Svara F., Štih V. and Portugues R. (2023) Neural dynamics and architecture of the heading direction circuit in zebrafish. Nat Neuro 26:765-773. * co-first author.

Lavian H. and Korngreen A. (2019) Short term depression shapes information transmission in a constitutively active GABAergic synapse. Sci Rep 9:18092.

Faynveitz A., Lavian H., Jacob A. and Korngreen A. (2019) Proliferation of inhibitory input to the substantia nigra in experimental parkinsonism. Front Cell Neurosci 13:417.

Gorodetski L., Zeira R., Lavian H., and Korngreen A. (2018) Long term plasticity of glutamatergic input from the subthalamic nucleus to the entopeduncular nucleus. Eur J Neurosci, 48(5):2139-2151.

Grobman M., Dalal T., Lavian H., Shmuel R., Belelovsky K., Xu F., Korngreen A. and Haddad R. (2018) ­A mirror-symmetric excitatory link coordinates odor maps across olfactory bulbs and enables odor perceptual unity. Neuron, 99(4):800-813.

Lavian H., Loewenstern Y., Madar R., Almog M., Bar-Gad I., Okun E. and Korngreen A. (2018) Dopamine receptors in the rat entopeduncular nucleus. Brain Struct Funct, 223:2673-2684.

Lavian H., Almog M., Madar R., Loewenstern Y., Bar-Gad I., Okun E. and Korngreen A. (2017) Dopaminergic modulation of synaptic integration and firing patterns in the rat entopeduncular nucleus. J Neurosci, 37(30):7177-7187.

Lavian H. and Korngreen A. (2016) Inhibitory short-term plasticity modulates neuronal activity in the rat entopeduncular nucleus in vitro. Eur J Neurosci, 43: 870-884.

Lavian H., Ben-Porat H., and Korngreen A. (2013) High and low frequency stimulation of the subthalamic nucleus induce prolonged changes in subthalamic and globus pallidus neurons. Front Syst Neurosci 7: 73.