FY2016 Annual Report

Optical Neuroimaging Unit
Associate Professor Bernd Kuhn

Alisher Duspayev, Ray X. Lee, Bernd Kuhn, Hiroko Chinone, Shinobu Nomura, Christopher J. Roome, Sigita Augustinaite, Mohamed M. Eltabbal, Neil Dalphin, Leonidas Georgiou, Kazuo Mori
Photo by Emiko Asato

Abstract

In the FY 2016 the Optical Neuroimaging Unit continued several imaging projects. Most research projects focused on imaging neuronal activity in the mouse brain.

1. Staff

Dr. Bernd Kuhn, Associate Professor
Dr. Akihiro Funamizu, Postdoc (shared with Doya Unit)
Dr. Christopher J. Roome, Postdoc
Dr. Sigita Augustinaite, Postdoc
Dr. Shinobu Nomura, Postdoc
Ray X. Lee, Ph.D. student
Neil Dalphin, Ph.D. student
Leonidas Georgiou, Ph.D. student
Dr. Kazuo Mori, Technical Assistant
Hiroko Chinone, Research Unit Administrator

2. Collaborations

2.1 Neural substrate of dynamic Bayesian inference in the cerebral cortex

Dynamic Bayesian inference allows a system to infer the environmental state under conditions of limited sensory observation. We use in vivo two-photon calcium imaging and probabilistic population decoding to show that cortical neurons in layers 2, 3, and 5 implement the fundamental features (prediction and updating) of Dynamic Bayesian inference.
Type of collaboration: Joint research
Researchers:
- Professor Dr. Kenji Doya, Neural Computation Unit, OIST
- Dr. Akihiro Funamizu, Neural Computation Unit and Optical Neuroimaging Unit, OIST

3. Activities and Findings

3.1 Neural substrate of dynamic Bayesian inference in the cerebral cortex

Dynamic Bayesian inference allows a system to infer the environmental state under conditions of limited sensory observation. Using a goal-reaching task, we found that posterior parietal cortex (PPC) and adjacent posteromedial cortex (PM) implemented the two fundamental features of dynamic Bayesian inference: prediction of hidden states using an internal state transition model and updating the prediction with new sensory evidence. We optically imaged the activity of neurons in mouse PPC and PM layers 2, 3 and 5 in an acoustic virtual-reality system. As mice approached a reward site, anticipatory licking increased even when sound cues were intermittently presented; this was disturbed by PPC silencing. Probabilistic population decoding revealed that neurons in PPC and PM represented goal distances during sound omission (prediction), particularly in PPC layers 3 and 5, and prediction improved with the observation of cue sounds (updating). Our results illustrate how cerebral cortex realizes mental simulation using an action-dependent dynamic model. This paper was published in 2016.

3.2 Voltage imaging with two-photon microscopy

Many neurons have elaborate dendrites with a wide variety of ion channels governing their electric properties. Unfortunately, it is very difficult to record the voltage in dendrites due to their fine structure. At the same time dendritic voltage is a key to understand neuronal information processing and therefore also to understand brain function.

We develop tools to measure dendritic voltage changes in vivo. We use the pure electrochromic voltage sensitive dyes ANNINE-6 (Kuhn & Fromherz 2003) and ANNINE-6plus (Fromherz et al 2008). Pure electrochromic means that the change of fluorescence only depends on the electric field over the dye molecule and that there are no other, slower effects modulating the spectra.

We label single neurons in vivo through an access port in the chronic cranial window (Roome & Kuhn 2014). By excitation at the red edge of the a absorption spectrum we can reduce phototoxicity and increase voltage sensitivity dramatically (Kuhn et al 2004).

After filling a cell we can simultaneously electrically record from the soma and image dendritic voltage and calcium changes in awake animals. We study Purkinje neurons in the cerebellum. We can observe supra and subthreshold voltage changes.

Voltage measurement from Purkinje neuron dendrites in awake mice

3.3 Imaging thalamo-cortical interaction

Sensory information is relayed through the thalamus to cortex. At the same time, cortex is regulating thalamic activity by driving and modulatory feedback. We image layer 6 pyramidal neurons in primary visual cortex which send a feedback signal to primary visual thalamus during different behavioral states. This will allow us to better understand the thalo-cortical loop.

3.4 Imaging PKA activity in vivo

Protein kinase A (PKA) is an important enzym in the signaling cascade connecting neuronal activity and expression and modulation of proteins. We use genetically encoded indicators to image PKA activity in vivo.

3.5 Post-traumatic behavioral development in adult mice

PTSD is one of the most prevalent mental health disorders and has received serious clinical and research attention (DSM-III, 1980;DSM-5, 2013). Still, it remains as one of the most poorly understood and controversial presentations of psychiatric disorders. Here, we explore how bonding explains post-traumatic behavioral development in adult mice.

3.6 pH and Ca²⁺ measurement in nanopores of protein crystals

Protein crystals can be considered nano porous materials. We measure the conditions inside the nano pores with the help of molecular probes. We use pH-sensitive dyes, load them into the crystals, and record pH changes in response to pH changes of the bath. We find differences between the pH of the bath and the nano pores. We try to find a model that explains this difference.

4. Publications

4.1 Journals

A. Funamizu, B. Kuhn, and K. Doya* (2016) Neural substrate of dynamic Bayesian inference in the cerebral cortex, Nature Neuroscience 19: 1682-1689

4.2 Books and other one-time publications

Nothing to report

4.3 Oral and Poster Presentations

C.J. Roome, B. Kuhn (2017) In’s and Out’s of Neuronal Computation: Simultaneous Dendritic Voltage and Calcium Imaging and Somatic Recording from Purkinje Neurons in Awake miceGordon Conference ‚Dendrites‘, Lucca, Italy
R.X. Lee, G.J. Stephens, B. Kuhn (2017) Dynamics of somatic and dendritic populations in cerebral cortex during spontaneous movement onset, Computational and Systems Science (Cosyne) 2017, Salt Lake City, USA
K. Mori, B. Kuhn (2016) Optical measurement of diffusion and pH in nanopores of protein crystals, Annual Meeting of the Biophysical Society of Japan, Tsukuba, Japan
C.J. Roome, B. Kuhn (2016) In’s and Out’s of Neuronal Computation: Simultaneous Dendritic Voltage and Calcium Imaging and Somatic Recording from Purkinje Neurons in Awake mice, Society for Neuroscience Meeting, San Diego, USA
C.J. Roome, B. Kuhn (2016) In’s and Out’s of Neuronal Computation: Simultaneous Dendritic Voltage and Calcium Imaging and Somatic Recording from Purkinje Neurons in Awake mice, Champalimaud Neuroscience Symposium, Champalimaud Foundation, Lisbon, Portugal
A. Funamizu, B. Kuhn, K. Doya (2016) Neural substrate of dynamic Bayesian inference in posterior parietal cortex, The 39th Annual Meeting of the Japan Neuroscience Society, Yokohama, Japan
C.J. Roome, B. Kuhn (2016) Exploring input-output relations of neurons in vivo, The 39th Annual Meeting of the Japan Neuroscience Society, Yokohama, Japan
R.X. Lee, G.J. Stephens, B. Kuhn (2016) Neuronal Interaction Dynamics in the Neocortex during Spontaneous Locomotion Onsets, The Origin of Consciousness, ELSI, Tokyo Institute of Technology, Tokyo, Japan
The Seventh International Neural Microcircuit Conference: Recent advances in the analysis of cortical microcircuits “Neural substrate of dynamic Bayesian inference in the cerebral cortex”, Organizer: Prof. K. Kobayashi, Prof. Y. Kubota, (December 8-10, 2016), Okazaki Conference Center, Okazaki, Japan
Photonics Meeting, “Imaging neuronal activity in awake mice”, Organizer: Prof. K. Wakita, Chiba Institute of Technology (December 2-3, 2016), Okinawa Seinenkaikan, Naka, Japan
Biophysical Society Meeting of Japan Symposium “Advances in imaging neuronal activity: New tools and applications”, Exploring input-output relations of neurons in awake mice (November 25, 2016), Tsukuba, Japan
OIST-JST Presto Joint Symposium on Frontiers in Optics and Photonics (October 31, 2016), Organizer: Frontier-PJ, JST presto, OIST, OIST, Japan
OIST Mini Symposium “Science and Technology at the Interface of Bio-Nano-Systems: Challenges and Opportunities” (April 25-27, 2016), Organizer: Prof. Amy Shen, OIST, Japan

5. Intellectual Property Rights and Other Specific Achievements