A new and effective automated procedure for mapping monkey V1 receptive fields built on induced responses V Gordillo-González, D Wegener, E Drebitz, F O Galashan, A K Kreiter |
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Theoretical Neurobiology, Institute for Brain Research, University of Bremen, Germany
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| Investigating the dynamic interactions in large populations of neurons requires recordings with many electrodes simultaneously. However, massive parallel recordings complicate the mapping of discrete receptive fields (RFs) and therefore critically depend on fast and reliable automated procedures. Such procedures usually utilize briefly flashed stimuli and rely on transient firing rate increases and evoked changes in the local field potential (LFP), even though experimental investigations often consider longer-lasting responses. We therefore tested a mapping protocol relying on the sustained, induced neuronal activity, using moving bars of different orientations. Based on chronic, intra-cortical recordings in primary visual cortex (V1) of macaque monkeys, we compare our bar mapping method with a standard ‘flashing dots’ procedure. We investigated RF properties from three different signals: spikes, the rectified and low-pass filtered multiunit signal, and the gamma-band LFP. The bar mapping procedure revealed RFs of similar size, position and signal-to-noise ratio as compared to RFs from the same recording site measured with the dot mapping technique. Furthermore, the bar mapping technique requires a smaller number of trials and provides information on direction and orientation selectivity of the individual units. |
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