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We present results of theoretical analysis and computational simulations of two models of the saccadic burst generator: the Scudder model and the Jurgens model. We used the experimental paradigm of prolonged stimulation in monkey superior colliculus (SC) to compare the performance of the two models. We excluded the Scudder model since it was not capable of reproducing the experimentally observed staircase movements. We modified the Jurgens model by replacing the originally proposed feedback integrator with an active reset mechanism by a leaky integrator. With this modification we have shown that the staircase movement elicited by prolonged stimulation in the SC can be modeled as a damped oscillatory step response of this model. Furthermore, to replicate the changes in the kinetic profiles of the staircase movements with increased stimulation we modified the functionality of the model. Our results suggest that prolonged stimulation of the SC dynamically changes the gains and time constant of the saccadic feedback. [ABSTRACT FROM AUTHOR]

We used prolonged stimulation of the monkey superior colliculus to elicit staircase eye movements. By changing the parameters of the stimulating current we were able to obtain movements with different dynamics. An increase in the current frequency resulted in the shortening of the intersaccadic interval and a decrease of the amplitudes in the staircase. In cases of high stimulation, after an initial saccade of fixed metrics, the eyes moved in an apparently smooth fashion. The movement was conjugate and in the same direction as the first saccade. By analyzing the velocity trace we found that the movement consisted of a chain of small saccades, each of which started before the previous one ended. We conducted a quantitative analysis of the staircase movements including the cases of apparently smooth movement of the eyes. We conclude that all of the movements elicited by prolonged SC stimulation were generated by the saccadic feedback circuitry. The dynamic profiles of the elicited movements changed continuously with the stimulating current parameters. On one end of the continuum we observed the classically described staircase movements with individual movements separated in time. On the other end of the continuum we saw the apparent smooth movement as the limit case produced by high stimulation of the SC. [ABSTRACT FROM AUTHOR]

The article presents views of the authors on the article 'Remote Control,' related to the state of neuroengineering research, published in the 2003 issue of the journal 'Nature.' The article discusses that any researcher who accepts funding from the U.S. Department of Defense without agreeing with the goals of the programme compromises his or her ethics. The authors say that the goal of the programme is the development of new computational and microsystem tools to study biological systems. However, looking beyond the officially stated goals of the programme to the broader issue of military funding, the article says that some scientists feel using money from the military is ethically problematic. The authors say that this view ignores the historical and social context of military research. If having a well-regulated U.S. military is both necessary and ethically sound, given the current state of the world, then there is no reason to believe that supporting this capacity in the form of basic research poses an ethical dilemma. The U.S. Defense Advanced Research Projects Agency (DARPA) is funding basic-science researchers in a non-classified capacity precisely because the principles on which a robust neural control signal might be based are not yet known. In the case of neuroengineering research, the knowledge being generated clearly has the potential for a large positive impact on society. Many technologies funded by the U.S. military have led to positive and even revolutionary changes in society. The neuroengineering community serves the best interests of society quite well and DARPA encourages a thorough and open debate of various applications built upon neuroengineering research.