The Journal of Neuroscience, October 15, 2008, 28(42):10772-10780; doi:10.1523/JNEUROSCI.2468-08.2008
Previous Article | Next Article 
Behavioral/Systems/Cognitive
Neuronal Circuitry and Discharge Patterns Controlling Eye Movements in the Pigeon
Yang Yang,
Yan Yang, and
Shu-Rong Wang
Laboratory for Visual Information Processing, State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
Correspondence should be addressed to Shu-Rong Wang, Laboratory for Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, People's Republic of China. Email: wangsr{at}ibp.ac.cn
Horizontal eye movements in humans and other vertebrates are actuated by the lateral and medial rectus muscles that are innervated by the abducens and oculomotor nuclei. Here we show by single-cell recording in the pigeon that there exist three types of abducens neurons in terms of discharge patterns, which generate the shift and/or oscillation components of a horizontal saccadic eye movement. Shift-related neurons discharged sustained firing around saccadic shift, oscillation-related neurons produced several bursts accompanying saccadic oscillations, and saccade-related neurons discharged both sustained firing and several bursts perisaccadically. Oscillation- and saccade-related neurons were each divided into two groups according to their firing behaviors during nasotemporal saccades: bursting activity began before (leading) or after (lagging) the onset of saccades. Abducens neurons in the lagging group but not those in the leading group were activated by antidromic stimulation of the contralateral oculomotor nucleus. Blockade of the nucleus lentiformis mesencephali and the nucleus of the basal optic root, both of which are involved in optokinetic nystagmus, abolished sustained firing in abducens neurons and shift component of saccades, whereas blockade of the saccade-related raphe complex eliminated bursting activity in abducens neurons and oscillation component of saccades. The present study revealed oculomotor circuitry in the pigeon, in which the optokinetic nuclei and the raphe complex send differential signals to abducens neurons to generate three types of discharge patterns, and thereby initiate the shift and oscillation components of a horizontal saccade.
Key words: abducens nucleus; brainstem raphe complex; extracellular recording; eye movement; oculomotor circuitry; pigeon
Received June 2, 2008;
revised Aug. 18, 2008;
accepted Sept. 14, 2008.
Correspondence should be addressed to Shu-Rong Wang, Laboratory for Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, People's Republic of China. Email: wangsr{at}ibp.ac.cn