Electrophysiology

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The electrophysiology platform provides our researchers with state-of-the-art electrophysiology systems and expert knowledge to support ongoing research projects.

 

Expertise

The electrophysiology expertise core can help formulate, design and execute electrophysiological experiments to resolve the functional physiological aspects within your research projects.

In addition, for projects that require extensive (time-consuming) electrophysiological contributions, we offer training and support to researchers, allowing them to conduct experiments independently.

For experimental research approaches that are not currently available within the facility, we will expedite collaborations with external labs and assist as intermediate spokesperson, if required.

Stakeholders

The electrophysiology expertise unit is currently a collaborative endeavour at our center, run by Keimpe Wierda.

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Tools & equipment

The electrophysiology expertise core helps to formulate, design and/or execute electrophysiological experiments to bring your research projects forward. For projects that likely need long standing electrophysiological involvement we offer training and support to researchers, allowing them to conduct experiments independently.

Our electrophysiology unit currently contains the following systems:

 

Two acute slice electrophysiology setups with scanner-based directed optogenetics (1P)

Systems are identical and allow double patch clamp recordings (Multiclamp 700B, Axon Instruments) in slices (upright microscope, Zeiss Axio Examiner A1) combined with extracellular stimulation systems (AM-systems, M2100) and site-directed, spot illuminated optogenetic manipulation of network activation (Rapp OptoElectronics, UGA-42 Combo scanner-based directed illumination, including Geo Module). Bath temperature control is available.

 

An acute slice electrophysiology setup with field-of-view-based optogenetics (1P)

Double patch clamp recordings (HEKA, Double EPC10 USB) in slices (upright microscope, Zeiss Axio Examiner A1) combined with an extracellular stimulation system (ISO-Flex) and LED-based (full field-of-view) optogenetic stimulation (Cairn Research). Bath temperature control is available.

A dissociated cell electrophysiology setup with rapid switching fluorescence imaging and fast local application system

Double patch clamp recordings (HEKA, Double EPC10 USB) of dissociated neurons (inverted microscope, Axio Observer D1) combinable with fast fluorescence-based imaging (rapid switching Lambda DG-4, Sutter Instruments and CMOS Andor Neo 5.5 camera). In addition, a fast, multibarrel application system (Warner Instruments, SF-77B) is available, allowing fast (millisecond) exchange/application of different external solutions.

A multi-photon setup (2P imaging, 2P excitation and 1P excitation) combined with acute slice electrophysiology

The two-photon system (VIVO 2-Photon platform, Intelligent Imaging Innovations GmbH) is designed for high-speed multiphoton fluorescence imaging and photo-excitation in live animals or acute slice tissue. A tuneable multiphoton laser is used for 2P fluorescence imaging (MaiTai, 690-1040 nm). For photo-excitation we use either a high power fixed wavelength 2P laser (FemtoTrain , 1040 nm) or an array of 1P solid-state lasers  excitation (currently 474 & 594 are available). For the available 1P solid-state lasers a holographic projection system (3i, Phasor™ 18D) is available for simultaneous multipoint and arbitrary pattern photostimulation and photoactivation. System is using a Zeiss Axio Examiner Z1 fully motorized fixed stage upright microscope (W Plan-Apochromat 20x/1.0NA, W Plan-Apochromat 40x/1.0NA). Signals are detected using two fast-gated GaAsP PMTs. In addition, this two-photon is upgraded with electrophysiology to allow simultaneous double patch clamp recordings (HEKA, Double EPC10 USB) and fluorescence imaging/excitation, in acute slices and (soon) also in vivo (anesthetized animals).
This system is only available for live tissue, no fixed tissue allowed!

All necessary peripheral equipment and tools are available:

  • Vibratome (VT1200, Leica Microsystems)
  • Pipette pullers (P-1000 Micropipette Puller, Sutter Instrument; PC-10, Narishige)
  • Water bath
  • Binocular microscope
  • Dissection tools
Leica VT2100 vibratome for acute brain slices

Research & development

We are exploring a medium-throughput screening method to study presynaptic calcium kinetics using imaging of genetically encoded calcium indicators (GECIs, e.g. GCaMP6f). In organotypic or acute slices expressing such GECIs, stimulation (using extracellular stimulation (AM-systems, M2100)) would be combined with a high sensitivity CMOS (ORCA-Flash4.0 V2) camera to detect individual presynaptic boutons.

We are testing a combined multi-electrode (MEA) array system. MEA systems allow recording (composite) electrical activity in biological samples, such as dissociated neuronal cultures or acute brain slices. The system currently tested allows MEA measurements of culture cells(multiwell MEA), acute mouse/rat slices (MEA2100) and drosophila fly brain extracts (CMOS MEA).

We work on spinning disc integration in our electrophysiology system. Combining spinning disc imaging with 1P optogenetics and electrophysiology allows to study network integration and function of individual cells in acute slices.

The 2P imaging/optogenetic stimulation system, for in vivo and ex vivo applications, is being complemented with multi patch clamp recordings to allow combinations of all three experimental approaches (2P imaging, optogenetic manipulation of network activity and electrophysiological recordings).

UGA-42 and Geo module combo

The UGA-42 and Geo module combo scanner-based directed illumination upgrade from Rapp OptoElectronics allows light induced excitation of cells expressing ChR2. Upon light exposure of predefined regions of interest, ChR2 channels will open and induce activation of expressing cells (left). For neurons this will lead to action potential generation and synaptic release, which can be recorded in postsynaptic partners using whole cell patch clamp electrophysiology (right).

Terms of use

There are two general options available, depending on the estimated workload.

  • For concise, directed experiments (assumed to be completed within < 3–4 months) it is most efficient to allow experienced personnel from the expert unit to execute the experiments. This is mostly due to a relatively extensive training period (2-3 months) before a new user will be able to work (semi) independently. During this period, the system used is unavailable for other applications and therefore decreases the overall output efficiency.
  • However, for projects that require extensive – and therefore time-consuming – electrophysiological contributions (>6 months), we can offer training and support to principle researchers/PhD-students, allowing them to conduct experiments (semi) independently. Keimpe Wierda will be responsible for training, hands-on assistance and troubleshooting.

 

Booking & cancellation

Due to the limited available slots for equipment and personnel we need to organize requests for reservations based on a first-come-first-serve policy. A queue list of requests is kept and allocation of available slots or personnel is assigned accordingly. For new research projects and further information on reservations please contact Keimpe Wierda.

Cancellations are permitted if notified >48 in advance. Cancellations are valid when (a) the reservation is removed from the online scheduler and (2) Keimpe Wierda was notified about the revocation via email. Cancellations 48-24 hours before reservation time will be charged at 50% and cancellations less than 24 h in advance will be charged 100%. This applies for all booked services.

New users will first need a mandatory training to acquire basic skills for operating electrophysiological setups, the 2P system and/or the peripheral equipment (see below for detailed pricing). Training is suggested only when (new) users are anticipated to make long-term use of the equipment within the unit (>6 months). Training for short-term projects will not be possible due to limited capacity and will be executed by electrophysiology unit personnel.

 

Pricing

Electrophysiology equipment

Training courses of new/inexperienced users (conduct experiments independently)

  • Basic (obligatory) training of new/inexperienced users to acquire basic skills for operating an electrophysiology system.
    ~ 4 weeks → € 3000
     
  • Basic (obligatory) training of new/inexperienced users to acquire basic skills for operating the 2P imaging system.
    ~ 3 days → € 450
     
  • Independent (obligatory) training of new/inexperienced users to acquire basic skills for operating (additional) peripheral equipment.
    ~ 1-5 days → €150/day

 

Experiments executed by experienced personnel from the ephys unit

  • Working days (9.00-18.00): € 150/day
  • Non-working days: € 300/day

These experiments need to be discussed well in advance (>3 weeks). We cannot guarantee availability of ephys unit personnel during non-working days.

 

Experiments executed by experienced/trained users or new user after training.

  • € 50/day (chemicals & maintenance)
  • Reservation of system only for full days

Two-photon/electrophysiology equipment

Training courses of new/inexperienced users (conduct experiments independently)

  • Basic (obligatory) training of new/inexperienced users to acquire basic skills for operating the 2P imaging system.
    ~ 3 days → € 450
     
  • For combined two-photon/electrophysiology applications, new/inexperienced users need to acquire the basic electrophysiology skills (see above).

 

Experiments executed by experienced personnel from the ephys unit

  • Working days (9.00-18.00): € 200/day
  • Non-working days: € 350/day

These experiments need to be discussed well in advance (>3 weeks). We cannot guarantee availability of ephys unit personnel during non-working days.

 

Experiments executed by experienced/trained users

Executed by experienced electrophysiologist or new user after training.

  • € 100/day (chemicals & maintenance)
  • Reservation of system only for full days

Peripheral equipment

  • Projects executed by experienced personnel from the ephys unit
    Working days (9.00-18.00): € 30/h
    Non-working days: € 60/h
  • Users who reserved electrophysiology setups always have priority in using the peripheral equipment
  • Projects executed by experienced/trained users
    Working days (9.00-18.00): € 20/h
    (Users who reserved electrophysiology setups always have priority in using the peripheral equipment)

Authorship policy

Generally, projects are conducted as a collaboration between users and the electrophysiology expertise unit. Academic, practical and facilitatory contributions from the electrophysiology expertise unit are expected to be recognized with appropriate (co)authorships. Active participation of technicians from the ephys unit should also be acknowledged in the manuscripts.

Accomplishments

Isolated neuron culture

Microdot glial islands are made using custom-made stamps (left). Isolated neurons make synaptic connections onto themselves, so called autapses. Using this culture system, we are able to study synaptic release from individual neurons using whole cell patch clamp electrophysiology (middle) and asses e.g. synaptic plasticity, synapse quantification (active vs total synapses) using synaptophysin-Phluorin (sypHy, right) and calcium imaging.

Multibarrel fast application system

Using a custom-made multi-barrel application system, it is possible to rapidly switch between different externally applied solutions to probe the effect of e.g. different (concentrations of) pharmacological compounds.