saccadic latency edit
The term "Saccade" originates from the french term saquer, meaning "jerk".[1] It describes the jerky, simultaneous movement of both eyeballs which is continuously being conducted to acquire visual information in mammals. The smaller movements of the eyes are necessary for scanning or redirecting our eyes over a small area such as a photograph or page of a book to "look" at it.[2][3] Saccadic initiation is increasingly being studied in SEF work to glean its role in the network of saccade initiation and vision. This work is conducted through use of monkeys asked to perform saccadic go/no-go tasks and tracking their eye movements.[4] These trained monkeys are to respond, or not respond, visually to the introduction of newly appearing targets. And as they perform these tasks, the initiation of a saccade is measured through microelectrodes implanted in the SEF. Using this technique, it is actually possible to monitor the time delay between the neuronal activation of saccade initiating neurons and the introduction of the target. The time delay is called Saccadic Latency.[5][6]
significance edit
The visual system is sensitive to sudden change.[7] If something distracting occurs while a person is performing a task--reading a newspaper, for example--this immediately captures one's attention. [8][9] While this sudden shift can be a distraction, it can also be thought to be a reflex of great importance as identifying and reacting to environmental changes quickly--when needed--can be imperative to survival. [10][11][12] Saccadic latency can then become a good parameter for learning which occulomotor neurons and structures of the brain play what specific roles in saccade initiation.[13][14]
references edit
- ^ Saccade. (n.d.). Merriam-Webster.com. Retrieved November 22, 2013, from http://www.merriam-webster.com/dictionary/saccade
- ^ Yarbus, A. L. (1967). Eye movements and vision (Vol. 2, No. 5.10). L. A. Rigss (Ed.). New York: Plenum press. Chicago
- ^ Pynte, J., & Kennedy, A. (2006). An influence over eye movements in reading exerted from beyond the level of the word: Evidence from reading English and French. Vision Research, 46(22), 3786-3801.
- ^ Halliday, J., & Carpenter, R. H. (2010). The effect of cognitive distraction on saccadic latency. Perception, 39(1), 41.
- ^ Bruce, C. J., & Goldberg, M. E. (1985). Primate frontal eye fields. I. Single neurons discharging before saccades. Journal of Neurophysiology, 53(3), 603-635.
- ^ Schiller, P. H., Sandell, J. H., & Maunsell, J. H. (1987). The effect of frontal eye field and superior colliculus lesions on saccadic latencies in the rhesus monkey. Journal of Neurophysiology, 57(4), 1033-1049.
- ^ Gottlieb, J. P., Kusunoki, M., & Goldberg, M. E. (1998). The representation of visual salience in monkey parietal cortex. Nature, 391(6666), 481-484.
- ^ Breitmeyer, B. G., & Ganz, L. (1976). Implications of sustained and transient channels for theories of visual pattern masking, saccadic suppression, and information processing. Psychological review, 83(1), 1.
- ^ Harel, J., Koch, C., & Perona, P. (2006). Graph-based visual saliency. In Advances in neural information processing systems (pp. 545-552).
- ^ Edelman, G. M. (1987). Neural Darwinism: The theory of neuronal group selection. Basic Books.
- ^ Morris, J. S., Friston, K. J., & Dolan, R. J. (1997). Neural responses to salient visual stimuli. Proceedings of the Royal Society of London. Series B: Biological Sciences, 264(1382), 769-775.
- ^ Elazary, L., & Itti, L. (2008). Interesting objects are visually salient. Journal of Vision, 8(3).
- ^ Gaymard, B., Ploner, C. J., Rivaud, S., Vermersch, A. I., & Pierrot-Deseilligny, C. (1998). Cortical control of saccades. Experimental Brain Research, 123(1-2), 159-163.
- ^ Grosbras, M. H., Leonards, U., Lobel, E., Poline, J. B., LeBihan, D., & Berthoz, A. (2001). Human cortical networks for new and familiar sequences of saccades. Cerebral Cortex, 11(10), 936-945.