N. Hatsopoulos

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An essential function of the brain is to detect threats, such as those posed by objects or predators on a collision course. A wide-field, movement-sensitive visual neuron in the brain of the locust was studied by presenting simulated approaching, receding, and translating objects. The neuron's responses could be described simply by multiplying the velocity(More)
The existence and role of fine-temporal structure in the spiking activity of central neurons is the subject of an enduring debate among physiologists. To a large extent, the problem is a statistical one: what inferences can be drawn from neurons monitored in the absence of full control over their presynaptic environments? In principle, properly crafted(More)
A novel statistical strategy, the spike jitter method, was developed to assess temporal structure in spike trains from neuronal ensembles. Its key feature is the introduction of a null hypothesis that assumes a uniform relative likelihood of observing a spike at one temporal location versus another within a small temporal window. We applied the method to(More)
1. The tonic responses of angular-position-sensitive afferents in the metathoracic chordotonal organ of the locust leg exhibit much hysteresis. For a given joint angle, the ratio of an afferent's tonic firing rate after extension to its firing rate after flexion (or vice versa) is typically between 1.2:1 and 3:1 but can be as large as 10:1. Spiking local(More)
problems raised by the initial formulation of t and suggested that looming could provide a first-order approximation of ttc for use in fast interceptive actions, although t alone could not possibly account for many of the accurate ttc judgements made by humans. If looming is not sufficient to account for the temporal precision of some human behaviour, what(More)
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