Circuit Development
circuit development
Molecular Logic of Synapse Organization and Plasticity
Connections between nerve cells called synapses are the fundamental units of communication and information processing in the brain. The accurate wiring of neurons through synapses into neural networks or circuits is essential for brain organization. Neuronal networks are sculpted and refined throughout life by constant adjustment of the strength of synaptic communication by neuronal activity, a process known as synaptic plasticity. Deficits in the development or plasticity of synapses underlie various neuropsychiatric disorders, including autism, schizophrenia and intellectual disability. The Siddiqui lab research program comprises three major themes. One, to assess how biochemical switches control the activity of synapse organizing proteins, how these switches act through their binding partners and how these processes are regulated to correct impaired synaptic function in disease. Two, to investigate how synapse organizers regulate the specificity of neuronal circuit development and how defined circuits contribute to cognition and behaviour. Three, to address how synapses are formed in the developing brain and maintained in the mature brain and how microcircuits formed by synapses are refined to fine-tune information processing in the brain. Together, these studies have generated fundamental new knowledge about neuronal circuit development and plasticity and enabled us to identify targets for therapeutic intervention.
Mechanisms of visual circuit development: aligning topographic maps of space
Wiring & Rewiring: Experience-Dependent Circuit Development and Plasticity in Sensory Cortices
To build an appropriate representation of the sensory stimuli around the world, neural circuits are wired according to both intrinsic factors and external sensory stimuli. Moreover, the brain circuits have the capacity to rewire in response to altered environment, both during early development and throughout life. In this talk, I will give an overview about my past research in studying the dynamic processes underlying functional maturation and plasticity in rodent sensory cortices. I will also present data about the current and future research in my lab – that is, the synaptic and circuit mechanisms by which the mature brain circuits employ to regulate the balance between stability and plasticity. By applying chronic 2-photon calcium and close-loop visual exposure, we studied the circuit changes at single-neuron resolution to show that concurrent running with visual stimulus is required to drive neuroplasticity in the adult brain.
Imaging the influences of sensory experience on visual system circuit development
Using a combination of in vivo imaging of neuronal circuit functional and structural dynamics, we have investigated the mechanisms by which patterned neural activity and sensory experience alter connectivity in the developing brain. We have identified, in addition to the long-hypothesized Hebbian structural plasticity mechanisms, a kind of plasticity induced by the absence of correlated firing that we dubbed “Stentian plasticity”. In the talk I will discuss the phenomenology and some mechanistic insights regarding Stentian mechanisms in brain development. Further, I will show how glia may have a key role in circuit remodeling during development. These studies have led us to an appreciation of the importance of neuron-glia interactions in early development and the ability of patterned activity to guide circuit wiring.
Synapse and Circuit Development
The symposium will start with A/Prof Jenny Gunnersen who will present “New insights into mechanisms of excitatory synapse development”. Then, Dr Tommas Ellender will deal with the “Embryonic neural progenitor pools and the generation of fine-scale neural circuits” and Dr Thomas Marissal will talk about “Parvalbumin interneurons: the missing link between the micro and macroscopic alterations related to neurodevelopmental disorders?"”.
Inter-cellular interactions during neural circuit development
Developmental origin of individuality in brain and behaviour
The “Nature versus Nurture” debate on the origin of behaviour has long been dominated by a genome versus experience dichotomy. However, evidence that genetically identical individuals kept under identical conditions are behaviourally different is incontrovertible. Where might such individuality come from? Neither genes nor the environment directly encode behaviour. They encode or influence processes, notably the development of neuronal circuits, that in turn control behaviour. An understanding of how neuronal circuits develop and function at the individual organism level is therefore essential for understanding the origin of individuals. I will discuss our efforts to address this issue over the past decade using the Drosophila fruit fly as a model system.
Unraveling the role of NALCN in neural circuit development
FENS Forum 2024