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We describe a new, mostly software-based device for the sorting of waveforms in an extracellular multi-neuron recording situation. The sorting algorithm is largely unattended, and, after an initial 'learning' process, works in real time. Shape comparisons are based on up to 8 time points in the waveform; these points (the reduced feature set) are chosen… (More)
The companion paper has described a new, fully automatic device for the sorting of action potential waveforms in real time. We present here a brief comparison of performance between this new device and several of the older, more traditional devices used for this purpose. We include in the comparison the performance of 3 human observers.
The velocity-response curves of the cat's superior colliculus neurons responding to moving stimuli mere studied quantitatively. They were fitted by logarithmic Gaussian curves described by three parameters: optimal stimulus velocity, amplitude and dispersion of the curve. Since reversal of the stimulus movement direction changed neither optimal stimulus… (More)
Single unit responses in the superior colliculus of cats deprived of pattern vision from birth and of normally reared cats were studied in unanesthetized pretrigeminal preparations. Collicular units of deprived cats showed a diminished direction-selectivity but a somewhat better speed-selectivity compared to normals; they also preferred lowspeed stimuli,… (More)
The midbrain was isolated by two brainstem transections, pretrigeminal and premesencephalic. In the isolated midbrain, particularly within the reticular formation, EEG activity was greatly depressed. On the other hand, single-unit spike activity remained at a high level. The spatial density of active reticular units and the rate of their spontaneous… (More)
Spontaneous and evoked activities of nucleus interpositus neurons (IN) of the cerebellum were examined before and after cerebellar paravermal cortex lesions in cats anesthetized with alpha-chloralose. It was found that spontaneous activity increased dramatically following cortical ablation: before the lesion only 4% of cells encountered fired at a rate… (More)
Effects of a Nembutal upon responses of the superior colliculus neurons were analyzed in pretrigeminal cats. Most cells were studied during the spindly barbiturate pattern in the EEG. In this condition collicular neurons lose their spontaneous activity, become sluggish in their reactivity to stimuli moving at high velocity, and less sensitive to direction… (More)
Under different levels of Nembutal anesthesia the spatiotemporal characteristics of receptive fields of cells in the lateral geniculate nucleus were investigated. All units decreased their maintained activity and bursts of spikes occurred spontaneously after administration of the anesthetic. The excitatory domains of the receptive fields were also changed… (More)
A simple amplitude discriminator with two ways of triggering DC-level monitoring is described. This system is based on easily available inexpensive integrated circuits.