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Neural Networks Research Group

The Retinal Microcircuits Laboratory

The Retinal Microcircuits Laboratory is interested in the cellular and molecular basis of synaptic transmission and synaptic integration in the central nervous system. Our main goal is to understand and characterize the synaptic and cellular mechanisms employed by identified neurons and specific microcircuits for signal processing.

Description of research interests:

Our lab is interested in the cellular and molecular basis of synaptic transmission and synaptic integration in the central nervous system. Our main goal is to understand and characterize the synaptic and cellular mechanisms employed by identified neurons and specific microcircuits for signal processing. The primary technique is that of  targeted patch-clamp recording of visually-identified neurons using voltage clamp, current clamp and dynamic clamp  recording configurations. This electrophysiological work is currently performed using an in vitro slice preparation of the rat retina, a preparation that offers the possibility to combine modern electrophysiological techniques with the use of natural stimuli to activate specific neuronal circuits.

 

Recently we have been:

1) performing combined multi-photon excitation imaging and patch-clamp recording to study healthy tissue and processes of neurodegeneration.

2) performing Ca2+-imaging in retinal slices.

3) performing quantitative morphological reconstructions of single neurons by computer-aided manual tracing of image stacks acquired with multi-photon excitation microscopy (after deconvolution).

4) performing simultaneous multi-electrode recordings from neurons in specific microcircuits within the inner retina;  

5) studying the location and functional properties of NMDA receptors in retinal microcircuits

6) utilizing dynamic clamp electrophysiology to artificially insert synapses and conductances into neurons, enabling us to study the mechanisms underlying the dynamic properties of neurons and microcircuits.

Additionally, morphological techniques such as immunocytochemistry and injection of fluorescent tracers in single cells are used, as well as compartmental modelling of reconstructed neurons.

 

Funding:

The research is supported by funds from the Norwegian Research Council, NevroNor, European Commission's Horizon 2020 programme Marie Curie Actions ITN (grant agreement No 674901).The University of Bergen, Helse Vest, Odd Fellow Medical-Scientific Research Fund, and INCF (Norwegian node).

 

Recent Publications:

Zandt BJ, Losnegård A, Hodneland E, Veruki ML, Lundervold A, Hartveit E. (2017). Semi-automatic 3D morphological reconstruction of neurons with densely branching morphology: Application to retinal AII amacrine cells imaged with multi-photon excitation microscopy. J Neurosci Methods. 279:101-118.

Zandt BJ, Liu JH, Veruki ML, Hartveit E. (2017). AII amacrine cells: quantitative reconstruction and morphometric analysis of electrophysiologically identified cells in live rat retinal slices imaged with multi-photon excitation microscopy. Brain Struct Funct. 222(1):151-182. 

Zhou Y, Tencerová B, Hartveit E, Veruki ML. (2016). Functional NMDA receptors are expressed by both AII and A17 amacrine cells in the rod pathway of the mammalian retina. J Neurophysiol. 115:389-403. 

Castilho Á, Madsen E, Ambrósio AF, Veruki ML, Hartveit E (2015). Diabetic hyperglycemia reduces Ca2+ permeability of extrasynaptic AMPA receptors in AII amacrine cells. Journal of Neurophysiology. 114: 1545-53.

Castilho Á, Ambrósio AF, Hartveit E, Veruki ML (2015).
Disruption of a neural microcircuit in the rod pathway of the mammalian retina by diabetes mellitus. Journal of Neuroscience. 35: 5422-33.

Hartveit E & Veruki ML (2012). Electrical synapses between AII amacrine cells in the retina: Function and modulation. Brain Research. 1487:160-72.

Freeman DK, Jeng JS, Kelly SK, Hartveit E, Fried SI (2011). Calcium channel dynamics limit synaptic release in response to prosthetic stimulation with sinusoidal waveforms. Journal of Neural Engineering. 8: 046005

Wang X, Veruki ML, Bukoreshtliev NV, Hartveit E, Gerdes HH (2010). Animal cells connected by nanotubes can be electrically coupled through interposed gap-junction channels. Proceedings of the National Academy of Sciences U S A. 107: 17194-9.

Oltedal L, Hartveit E (2010). Transient release kinetics of rod bipolar cells revealed by capacitance measurement of exocytosis from axon terminals in rat retinal slices. Journal of Physiology. 2010 May 1; 588: 1469-87.

Veruki ML, Oltedal L & Hartveit E (2010). Electrical coupling and passive membrane properties of AII amacrine cells. Journal of Neurophysiology 103: 1456-66.

Hartveit E & Veruki ML (2010). Accurate measurement of junctional conductance between electrically coupled cells with whole-cell voltage-clamp under conditions of high series resistance. Journal of Neuroscience Methods 187: 13-25.

 

Highlighted Publications:

Hartveit E & Veruki ML (2007). Studying properties of neurotransmitter receptors by non-stationary noise analysis of spontaneous postsynaptic currents and agonist-evoked responses in outside-out patches. Nature Protocols 2: 434-48.

Veruki ML, Mørkve SH & Hartveit E (2006). Activation of a presynaptic glutamate transporter regulates synaptic transmission through electrical signalling. Nature Neuroscience 9: 1388-1396.

Veruki ML & Hartveit E (2002). Electrical synapses mediate signal transmission in the rod pathway of the mammalian retina. Journal of Neuroscience 22: 10558-10566.

Veruki ML & Hartveit E (2002). AII (rod) amacrine cells form a network of electrically coupled interneurons in the mammalian retina. Neuron 33: 935-946.