Nabavi Group

Nabavi group - Memory formation and consolidation at the synaptic and circuit levels

The Nabavi group is focusing on how plasticity at the synaptic and circuit levels in the brain relates to behavioral plasticity (learning and memory formation) and how the newly formed memories are integrated into the existing network (cellular and systems consolidation) using rodents as model organism.

Research focus

The idea that changes in synaptic strength (synaptic plasticity) is the foundation of memory and learning has a long history. For this reason long term potentiation (LTP) and long term depression (LTD), the electrophysiological manifestations of synaptic plasticity, have been intensely studied. However, the proof of causality, that by changing synaptic strength one can remove and reinstate a memory, had been missing.

In our recent paper we provided the most direct evidence showing a cause-effect relation between synaptic plasticity and memory formation (Nabavi et al., 2014, Nature). With the use of optogenetics fortified by in vitro/in vivo recording and behavioral assays we generated an associative memory and showed that we could repeatedly turn off and on this associative memory simply by inducing LTD and LTP (see the figure).

An immediate question following this study is how these newly formed memories are integrated into the existing network. This is a vital concern for any system that aims to store and retrieve information. Our brain is continuously exposed to external sensory inputs. This amount of information can overwhelm any storage device no matter how large its capacity. Therefore, a challenge for our brain is to decide which information is worthy of permanent storage. The storage process itself, however, poses another challenge: how to integrate new information into a network of pre-existing memories without “catastrophic interference” (forgetting).

The first challenge is commonly known as synaptic consolidation, which takes place within the first minutes to hours after memory formation. The second challenge, known as systems consolidation, is a slower process that takes weeks, months or even years. The major focus of my research is to understand how our brain tackles these challenges. To this end we will use a combination of tools such as molecular biology, in vitro and in vivo electrophysiology, two-photon laser scanning microscopy, optogenetics, behavioral analysis (i.e. whatever it takes) to move forward.

These studies may lead us to better understand and treat better neuropsychological diseases thought to be related to aberrations in synaptic plasticity, such as posttraumatic stress disorder, schizophrenia, substance abuse disorders and dementia.

a) Fear conditioning with optogenetics. Diagram of rat’s fear memory circuit receiving optogenetically driven input stimulation (laser) paired with a shock (left). Animal is tested one day later (right) by optical activation of the input (blue). Time plot shows normalized number of lever presses (1 min bins) to a previously learned cued lever-press task. b) LTD inactivates memory. In vivo field response in lateral amygdala to single optical stimulus (left) before and after LTD induction (1Hz). Animal is tested one day later (right). c) LTP reactivates memory. Same as b) except animal receives an LTP protocol (100Hz).


2018.03.15 | People

Nehal Hassan is new Research Assistant in Nabavi Group

Nehal is new Research Assistant in Sadegh Nabavi's group from March 10th. She will join the investigation of neural circuits in aversive memories and will be supporting various lab members in their projects.

2018.03.02 | Awards

Nabavi lab received 2,000,000 DKK from Lundbeckfonden & NIH BRAIN Initiative for the project “Independent optical excitation of overlapping neural populations in behaving animals”.

In the last decade, optogenetic techniques, particularly light-gated ion channels, have been a transformational tool. They are powerful enough to manipulate a single neuron in behaving animals, and yet simple enough to be adapted by laboratories of diverse expertise. Light-gated ion channels come in different varieties, with blue and red-shifted…

2018.02.05 | SadeghNabavi

Valentina Khalil is new Research Assistant in Nabavi Group

Valentina is new Research Assistant in Sadegh Nabavi's group from February 5th. She will investigate the neural circuits implicated in innate fear.

2018.01.22 | People

Majid Erfani Moghaddam has been prolonged for 1 year as postdoc in Nabavi Group

The new project is the investigation of phosphorylation barcoding mechanism of directing dopamine receptor signaling through arrestin related pathways in memory consolidation.

2017.11.15 | Awards

Pardis Zarifkar, Research student in Sadegh Nabavi lab has been rewarded 140,000 DKK grant from DSfN-Lundbeckfond

The money is granted to study anxiety in a PD model mouse. The title of theproject is “Oxytocin attenuates anxiety caused by pathological changes in the neurocircuitry of the Amygdala in Parkinsons Disease”. This project is performed in a close collaboration with Poul Henning Jensen's lab.

2017.07.18 | People

Kathrine Meinecke Christensen is new Laboratory Technician in Nabavi Group

Kathrine is new Laboratory Technician in Sadegh Nabavi's group per July 10th. She will take over Anne-Katrines tasks while she is on meternity leave. Kathrine has worked at Copenhagen University at Department of Veterinary and Animal Science. She has just moved to Jylland after 8 years in Copenhagen.  

2017.07.04 | Research news

Sadegh Nabavi, Niels Andersen and Nathalie Krauth publish a review article in Current Opinion in Neurobiology

The title of the review is: Hebbian plasticity in vivo: relevance and induction.

2017.06.01 | People

Andrea Moreno is new Postdoc in Nabavi Group

Andrea will work in the establishment of an in vivo electrophysiological recording and stimulation setup, which will be used in the lab to bridge molecular, in vitro electrophysiology, and behavioural data together. She is interested in the mechanisms governing learning and memory, especially from a integrative systems…

2017.05.17 | Research news

Marco Capogna and Sadegh Nabavi publish a paper in the prestigious journal Neuron edited by Cell Press, 17 May 2017

The title of the paper is: “Synaptic plasticity and network oscillations in amygdala circuits for storage and retrieval of emotional memories”.

2017.05.05 | Awards

DANDRITE researchers receive DFF-Research Project Grants from the Danish Council for Independent Research

Core group leaders Anders Nykjær and Poul Nissen, group leader Sadegh Nabavi and team leader Magnus Kjærgaard are all recipients of research grants from the FNU, FSS and FTP sections of DFF.

Showing results 1 to 10 of 16

1 2 Next