Connecting European Neuroscience

Imaging Neurons and Circuits in Neuroscience

Interview with Valentina Emiliani and Karel Svoboda, the two co-chairs of the upcoming Brain Conference 'The Brain in Focus: New Approaches to Imaging Neurons and Neural Circuits', about the achievements of optical microscopy in neuroscience.

FENS: The Brain Conferences have become well-loved events in Europe. What for you is special about the format?

VE & KS: The conference brings together researchers working in one field but with complementary expertise: tools developers and early adopters participate in this conference. The format of the talks (40 minutes for the invited talks and 20 minutes for the ‘short’ talks) provides sufficient time to introduce each topic and therefore to make the presentation accessible. The schedule provides ample time for poster sessions, general discussion and informal interactions, facilitating exchange of information on many levels. This is further helped by the beautiful and relaxed setting in Rungstedgaard.

FENS: Recent Brain Prizes have recognized new imaging technologies that have revolutionized neuroscience. In 2014, developers of optogenetics were honoured, and the 2015 Brain Prize (which Karel Svoboda shared with three others) was for two-photon microscopy. Do you anticipate further new technologies that could similarly revolutionize neuroscience [or will we now see incremental improvements]?

VE & KS: Two-photon microscopy and optogenetics have indeed revolutionized neuroscience by enabling spatially and temporally precise interrogation and control.

One important challenge is to combine these two approaches to achieve large-scale, all-optical recording of brain circuits with single-cell resolution.

Another important challenge is to map neural activity across the entire brains of non-transparent animals, using clever new optical approaches, possibly in combination with new molecular probes.

FENS: Cool imaging technologies need cool applications. Can you give a couple of examples of remarkable neuroscientific discoveries made with them in the last couple of years?

VE & KS: Perhaps the most impactful application of two-photon microscopy is mapping activity over multiple spatial scales. It is now possible to track signals as they propagate from one part of the brain to another at the level of individual synapses. At the other extremes it is possible to investigate large ensembles of neurons in multiple brain regions. These advances provide a fundamentally new view of neural circuits in action.

Optogenetics have revolutionized our understanding of specific neuron types in behaviour.

Optogenetics is even making its way into the clinic. Early applications are focusing on restoration of visual function and restoration of the function of the autonomous nervous system. 

FENS: What sort of new research applications are going to be discussed at the meeting?

VE & KS: This conference aims to bring together researchers and students with complementary fields of expertise including neurophysiology, physics, biophysics and molecular biology. The conference will be divided into three sections. Two sections will focus on describing advanced optical methods for brain imaging and photostimulation such as light-sheet microscopy, high-speed large-scale imaging, three-photon microscopy, light-field microscopy, phase conjugation, and 3D holographic light patterning. The third section will be dedicated to presenting exemplary experiments using cutting-edge technologies for the investigation of synaptic learning and plasticity, visual processing, dissection of neuronal circuits and optogenetics therapy for visual restoration.

FENS: In star-gazing mode: what might you anticipate to be the next big breakthrough in neuroscience in the next decade?

VE & KS: We anticipate many breakthroughs!

We should be able to reach brain regions inaccessible with conventional two-photon microscopy. This should be achievable by using new approaches that exploit ultra-sound-encoded light, phase conjugation and advanced computational approaches to enable the control of light propagation in multiple scattering regimes.

Molecules that sensitize neurons to mechanical deformation and magnetic fields will make it possible to manipulate neural circuits with ultrasound and magnetic fields much deeper in the brain than is possible with optogenetics.

A much-needed revolution in light-based neuroanatomy is on its way. Large-scale reconstruction of single neurons will reveal the basic cell types of the brain and how neural signals are routed across brain regions.

We anticipate an increasing role of advanced sequencing technologies and brain research. Deep sequencing will be used to interrogate neural activity and to measure neural connectivity at unprecedented scales. 

Get more information about The Brain Conference.