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Several studies have shown that the precision of smooth pursuit eye speed can match perceptual speed discrimination thresholds during the steady-state phase of pursuit [Kowler, E., & McKee, S. (1987). Sensitivity of smooth eye movement to small differences in target velocity. Vision Research, 27, 993-1015; Gegenfurtner, K., Xing, D., Scott, B., & Hawken, M.(More)
Contemporary theoretical accounts of perceptual learning typically assume that observers are either unbiased or stably biased across the course of learning. However, standard methods for estimating thresholds, as they are typically used, do not allow this assumption to be tested. We present an approach that allows for this test specific to perceptual(More)
We have developed an analog very-large-scale integrated (aVLSI) electronic circuit that emulates a compartmental model of a neuronal dendrite. The horizontal conductances of the compartmental model are implemented as a switched capacitor network. The transmembrane conductances are implemented as transconductance amplifiers. The electrotonic properties of(More)
We describe an improved spiking silicon neuron (SN) [6] that approximates the dynamics of ionic currents of a real nerve cell. The improved version has less circuitry and fewer parameters than previous circuits thereby improving the spiking characteristics. We describe the differential equations governing the revised circuits and use them to explain the(More)
Retention of parameters and learnt synaptic weights is a central problem in the construction of neural networks. We have applied analog oating gate technology to solve these problems in the context of biologically real-istic`silicon neurons'. Parameters are stored on a novel oating gate array, and synaptic weights are retained by a oating gate learning(More)
Visual orienting has typically been characterized using simple displays--for example, displays with a static target placed on a homogeneous background. In the present study, visual orienting was investigated using a dynamic broadband (1/f) noise display that should mimic a more naturalistic setting and that should allow saccadic orienting experiments to be(More)
We describe a neuromorphic retina that signals a luminance edge as a spike. In a fast process, the luminance profile of the receptor layer determines the membrane potential of the ganglion cells and their individual, adjustable spiking thresholds. In a slower process, a wave-propagation process, the charge of ganglion cells with high membrane potential will(More)