Research Methods
 
 

ORGANISMS INVESTIGATED:

Mice, rats, guinea pigs, cats & humans (EEG & anatomy)


RECORDING METHODS:

Macroelectrode registration:

cochlear microphonics, summating potentials, compound action potentials, brainstem response audiometry, electromyography; Electroencephalographic recordings with low-impedance electrodes and a high-density human EEG system (128 channels, BrainAmps)


Microelectrode registration:

multiunit & local field potentials registration with microelectrode arrays, single cell registration using glass microelectrodes of high impedance.


STIMULATION:

Auditory, visual & somatosensory stimulation, cochlear implant stimulation, laser stimulation; calibration of acoustic equipment


DATA ANALYSIS:

Recoding signal conditioning, unit activity analysis including spike sorting, peristimulus time analysis, interval histogram analysis, synchronization analysis (to stimulus and between recording sites), correlation analysis, frequency analysis of local field potentials (Fourier & wavelet), PCA & ICA, current source density analysis and many more.


HISTOLOGY:

Histological processing of nervous tissue and the cochlea, including standard staining techniques (Nissl, Golgi, COX), use of fluorescent tracers (DiI, DiO, fluoro ruby, fluoro emerald, diamino yelow) and immunohistochemistry (SMI-32, GFAP, parvalbumin). In vivo µCT (XtremeCT, Scanco Medical). 3D reconstructions using data obtained from serial sections, µCT imaging or grinding (using Amira and MatLab) .

 

 








Above: Multielectrode recordings allow registration of several neurons at the same time. Using that approach functional „couplings“ within a neuronal assembly can be investigated. Complex correlational analysis of neuronal activity are necessary to reveal such functional relations.





methods used in our laboratories:

Monoclonal antibody staining in the cortex.

3D reconstruction of an implanted guinea pig cochlea using the grinding technique. Scala tympani is shown in red, implant in blue. The implant is located in the  basalmost halfturn of the cochlea. Data from Burghard et al., 2014, 3D reconstruction by Peter Baumhoff.

Recording equipment includes three Neuralynx microelectrode amplifiers (two Cheetah 64-channel systems, one digital 128-channel, onother digital 256-channel system), two Alpha-Omega microelectrode amplifiers (128-channel and 32-channel) and three 4-channel auditory and 6-channel cochlear implant stimulation systems based on National Instruments MIO- and DIO-Boards controlled via CVI (Otoconsult Comp., Germany) and MatLab (programmed by P. Hubka, R. Land and A. Kral).

Multielectrode array recording in the auditory cortex shown as raster plots (left) and post-stimulus time histograms (right).