NEURAL CIRCUITS FOR SENSORY PROCESSING AND SENSORY-GUIDED BEHAVIOURS

Hofer Lab

Sonja Hofer Banner
Research Area

Our perception of the environment relies on information flow from the sensory organs to the brain. However, perception is also highly dependent on the context in which a given stimulus occurs, such as the sensory surround and the animal’s behavioural state, its intentions, expectations and actions. Such contextual signals can strongly modulate sensory responses and influence how sensory information is interpreted. Current research in the lab is focused on understanding how sensory information is processed by the brain in the context of behaviour, especially focusing on the role of thalamo-cortical and intracortical interactions. We are for instance interested in how different contextual signals are integrated with feed-forward visual information and how they influence perception, how such signals emerge during learning and by which pathways they are conveyed.  

To study these questions we use a wide range of multi-disciplinary methods: in vivo two-photon imaging and other imaging approaches, extracellular and intracellular electrophysiological recordings, animal behaviour and circuit modelling, together with molecular and genetic approaches to identify different cell types, record and manipulate their function and trace specific pathways.

Research Topics
What is the organization and function of higher-order thalamo-cortical circuits?

Contextual signals are typically attributed to ‘top-down’ projections from other areas of the neocortex. Yet higher-order sensory nuclei in the thalamus, such as the pulvinar, interconnect extensively with many cortical and subcortical areas, and could thus act as an internal reference to link sensory signals to the visual and behavioural context. The functions of sensory higher-order thalamic nuclei remain unclear and the nature of the signals they convey to cortex is poorly understood. We are studying the fine-scale organization of higher-order thalamo-cortical pathways, and what information they bring to different cortical areas. By combining in vivo two-photon imaging of axonal projections, anatomical tracing, in vivo electrophysiology, optogenetics, animal behaviour and in vitro circuit mapping, we aim to determine the role of these pathways during visual processing. Moreover, we are investigating the different sources of inhibition of thalamic pathways to test their role in regulating thalamo-cortical interactions and controlling sensory information flow.

How is the communication between cortical areas dependent on behavioural context?

Cortical areas are interconnected through long-range projections that are almost always reciprocal, forming feed-forward, feed-back and lateral pathways. These complex networks are thought to support the integration of diverse sensory, motor, and cognitive representations and to ultimately generate our vast cognitive and behavioural repertoire. However, while the anatomy of intra-cortical projections is relatively well described, for many of them we know little about what information they convey, what impact they have on the target region and how they are influenced by context. One aim in the lab is to study inter-areal communication and the flow of behaviourally relevant information between cortical areas. We want to understand how dynamic cortical information flow is, and how it is shaped by learning and behavioural demands. 

How is sensory processing changed during learning?

How a stimulus is perceived and what behaviour it triggers is strongly dependent on what prior knowledge is associated with it. However, it is still relatively unclear how learning the behavioural relevance and context of sensory stimuli changes their processing in the brain. How is the function of individual cells, their interactions and information flow through sensory and sensory-motor pathways changed by learning? To study this question, we are developing diverse behavioural paradigms for mice in which they have to learn visually-guided tasks. We are particularly interested in the following questions: How does synaptic and functional connectivity within and between different brain areas change with learning? Do primary sensory circuits change or are changes mainly expressed in top-down inputs from higher brain areas? How is the higher-order thalamus involved in the induction and expression of plasticity? How relevant are learning-related changes in sensory circuits for the behaviour of the animal? Is output connectivity from specific sensory circuits to motor-related areas changed by learning?  
 

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Sonja Hofer
Associate Professor of Neural Circuits and Behaviour
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Alex Fratzl
PhD Student
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Shohei Furutachi
Senior Research Fellow
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Michelle Li
Laboratory Manager
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Maxime Rio
Senior Research Fellow
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Antonin Blot
Senior Research Fellow
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Ioana Gasler
Research Fellow
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Mitra Javadzadeh No
PhD Student
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Andre Marques-Smith
Research Fellow
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Dulcie Vousden
Research Fellow
Selected publications

Distinct learning-induced changes in stimulus selectivity and interactions of GABAergic interneuron classes in visual cortex

Khan AG, Poort J, Chadwick A, Blot A, Sahani M, Mrsic-Flogel TD, Hofer SB
Published by:
Nature Neuroscience
21 June 2018

Synaptic organization of visual space in primary visual cortex

Iacaruso MF, Gasler IT, Hofer SB.
Published by:
Nature (547, 449–452) (doi 10.1038/nature23019)
27 July 2017

Thalamic nuclei convey diverse contextual information to layer 1 of visual cortex

Roth MM, Dahmen JC, Muir D, Imhof F, Martini FJ, Hofer SB.
Published by:
Nature Neuroscience (19 (2): 299-307) (doi: 10.1038/nn.4197)
21 December 2015

Functional organization of excitatory synaptic strength in primary visual cortex

Cossell L, Iacaruso MF, Muir DR, Houlton R, Sader EN, Ko H, Hofer SB, Mrsic-Flogel TD
Published by:
Nature
19 February 2015