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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)
Local field potentials (LFPs) recorded from primary motor cortex (MI) have been shown to be tuned to the direction of visually guided reaching movements, but MI LFPs have not been shown to be tuned to the direction of an upcoming movement during the delay period that precedes movement in an instructed-delay reaching task. Also, LFPs in dorsal premotor(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)
437 problems raised by the initial formulation of ␶ and suggested that looming could provide a first-order approximation of ttc for use in fast interceptive actions, although ␶ 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,(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)
The primary motor cortex is arguably the first cortical area to be functionally examined in the history of neuroscience. Beginning with the early electrical stimulation experiments by Fritsch and Hitzig (1960) in 1870 and then the first electrophysiological recordings in awake, behaving primates by Evarts in the 1960s (Evarts 1968), numerous experiments(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)
The common marmoset has recently gained interest as an animal model for systems and behavioral neuroscience. This is due in part to the advent of transgenic marmosets, which affords the possibility of combining genetic manipulations with physiological recording and behavioral monitoring to study neural systems. In this review, they will argue that the(More)
Primary motor cortex has been studied for more than a century, yet a consensus on its functional contribution to movement control is still out of reach. In particular, there remains controversy as to the level of control produced by motor cortex ("low level" movement dynamics vs. "high-level" movement kinematics) and the role of sensory feedback. Here we(More)
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