Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models that rely on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by t...

We studied neurons in areas V1, V2, and posteromedial lateral suprasylvian area (PMLS) of anesthetized cats, assessing their speed tuning using steps to constant speeds and acceleration and deceleration tuning using speed ramps. The results show that the speed tuning of neurons in all three cortical areas is highly dependent on prior motion history, with early responses during speed steps tuned...

Database tuning is a common problem, but it requires much knowledge about the characteristics of the database system and the expected workload. Dynamically changing workload complicates the search for the perfect settings. In this contribution we present several approaches that autonomously examine the operations and adjust different parameters. Even though different tools for this task are ava...

in this study, a new approach for control (treatment) of aids based on patient entry drug. one of the main problems related to aids, is lack of control, lack of identification and early treatment of this disease. today physicians more than anything, control the disease relying on their experience and knowledge and time-consuming and complex experiments, nevertheless, human errors are inevitable...

this paper presents a self-tuning pid (proportional and integral and derivative) controller for regulating terminal voltage synchronous generators. in order to modify the system reponse and to overcome the difficulties of self tuning controllers, a dual rate sampling control system was used. system results demonstrated usfulness of the proposed regulator. the designed controller is simple and c...

362 NATURE | VOL 399 | 27 MAY 1999 | www.nature.com lateral interactions may allow basilar membrane motion to be selectively enhanced at a particular location where passive vibration is maximal. In nonlinear systems, 10% feedback can have enormous consequences. The likely increase in OHC coupling with increasing frequency, supported by morphological evidence, may explain the finding that tuning...

Unlike the quasitriangular frequency-tuning curves of peripheral neurons, pencil- or spindle-shaped frequency-tuning curves (excitatory areas) have been found in the central auditory systems of many species of animals belonging to different classes. Inhibitory tuning curves (areas) are commonly found on both sides of such "level-tolerant" sharp frequency-tuning curves. However, it has not yet b...

Neurons in primary visual cortex are highly sensitive to the contrast, orientation, and temporal frequency of a visual stimulus. These three stimulus properties can be varied independently of one another, raising the question of how they interact to influence neuronal responses. We recorded from individual neurons in ferret primary visual cortex to determine the influence of stimulus contrast o...