Analysis of extracellular spike waveforms and associated receptive fields of neurons in cat primary visual cortex

Key points Extracellular spikes recorded in the visual cortex (Area 17/18, V1) are commonly classified into either regular-spiking (RS) or fast-spiking (FS). Using multi-electrode arrays positioned cat V1 and a broadband stimulus, we show that there is also distinct class with positive-spiking (PS) waveforms. PS units were associated mainly non-oriented receptive fields while RS FS had orientation-selective fields. We suggest recordings of axons originating from thalamus. This conclusion was reinforced by our finding could record after cortical silencing, but not units. The importance findings able to correlate spike shapes field characteristics high precision using extracellular recording techniques. allows considerable increases amount information can be extracted future experiments. Abstract waveforms have been (FS) While both these types negative-dominant, classes Area 17/18 (V1) anaesthetised cats positive-dominant waveforms, which regularly reported. spatial (RFs) different waveform estimated, objectively revealed existence oriented RFs. found spikes, literature, mostly RFs (84%), similar centre-surround observed dorsal lateral geniculate nucleus (dLGN). Thus, hypothesise may dLGN afferents. before application muscimol (a silencer) remained cells did not. noted spiking normally (i.e. higher response rates, lower latencies proportion burst spikes). Our quantitatively it possible RF properties neurons particular has implications for how should interpreted complex experiments now contemplated would very challenging previously, such as assessing feedforward connectivity between brain areas same location tissue.