Electrophysiology, the measurement of electrical properties of cells and tissues, is an important technique used in the department of Integrative Neurophysiology and across a breadth of research projects in collaboration with other departments in the CNCR. Usage of electrophysiology in our Institute ranges from measurements of specific ion channel and synaptic conductances, to neuronal network activity of hundreds of cells simultaneously.
Individual neurons and synaptic responses are recorded using the patch-clamp technique in acute brain slice preparations in many current CNCR research lines. Ten basic patch-clamp rigs are available, equipped with Luigs & Neuman manipulators and Olympus or Zeiss optics. Each is adapted with specialised modifications to suit the experimental needs, such as additional stimulation electrodes or UV fluorescence for targeted recordings of GFP-labelled neurons. Direct connectivity between multiple neurons can also be measured, using either the novel quadrapatch or hexapatch systems to record from 4 or 6 cells respectively in a slice preparation. Whole-cell patch-clamping techniques are also implemented in cell culture systems to test the role of specific proteins in synaptic vesicle release, often in combination with innovative imaging methodologies, such as the two Tandem-Illumination Microscopy (TIM) experimental rigs. Electrophysiology recordings are also integrated with non-linear imaging on both multi-photon microscopes within the department, run as part of a collaboration with the VU University Laser Centre.
The operation of neurons and their synaptic circuitry in intact brains is explored using two dedicated in vivo set-ups within the CNCR. Monitoring of local field potentials and juxtasomal recording techniques record both spontaneous and sensory-evoked events in cortical regions in both anaesthetised and awake rodents.
Neurons do not operate in isolation and thus, network properties of the brain are also studied, made possible using 64-channel multi-electrode MED and MEA recording systems. These enable the study of neuronal function at high temporal resolution across entire anatomical regions such as the hippocampal formation and play a key role in high throughput screening approaches for genetic and pharmacological assays.
Finally, the relationship between network activity in different brain regions and also with behavioural parameters is explored both in rodent models and also in humans within the Institute’s recently-opened EEG lab, involving collaboration between both clinical and neuro-informatics researchers.
These electrophysiology techniques all provide a high level of temporal resolution to study neuronal function from single ion channel to multiple neuronal networks across the brain. These recordings are frequently combined with other methodologies used in the CNCR, such as anatomical neuron reconstructions, computational modelling, live cell imaging and genetic studies in mouse models of disease. This combined approach is illustrated in recent publications from departmental teams and confirms the ongoing beneficial role of electrophysiology in research lines within the CNCR.
