Telencephalic Input to the Pretectum of Pigeons: An Electrophysiological and Pharmacological Inactivation Study

• Published in: Journal of neurophysiology Vol. 91; no. 1; pp. 274 - 285
• Main Authors: Crowder, Nathan A, Dickson, Clayton T, Wylie, Douglas R.W
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-01-2004
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Anesthetics, Local - pharmacology; Animals; Columbidae - physiology; Corpus Striatum - drug effects; Corpus Striatum - physiology; Electric Stimulation - methods; Electrophysiology; Lidocaine - pharmacology; Photic Stimulation - methods; Space Perception - drug effects; Space Perception - physiology; Superior Colliculi - drug effects; Superior Colliculi - physiology; Visual Cortex - drug effects; Visual Pathways - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00763.2003

1 Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
2 Centre for Neuroscience, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
Submitted 6 August 2003;
accepted in final form 20 September 2003
The pretectal nucleus lentiformis mesencephali (LM) and the nucleus of the basal optic root (nBOR) of the avian accessory optic system (AOS) are retinal-recipient visual nuclei involved in the analysis of optic flow that results from self-motion, and in the generation of the optokinetic response. Neurons in these nuclei show direction selectivity in response to large-field motion and are tuned in the spatiotemporal domain. In addition to retinal afferentation, both the nBOR and LM receive afferents from the Wulst, which is thought to be the avian homolog of the primary visual cortex. We examined the effects of Wulst electrical stimulation on the activity of LM neurons and recorded the directional and spatiotemporal tuning of LM neurons in pigeons before, during, and after the Wulst was temporarily inactivated by lidocaine injection. In response to Wulst electrical stimulation, LM neurons showed either short-latency excitation followed by longer-latency inhibition (W+ cells), or only a longer-latency inhibition (W– cells). The average response latencies for W+ and W– cells were 13.5 and 28.3 ms, respectively. The effects of Wulst stimulation did not correlate with either the directional or spatiotemporal tuning of the LM neurons. Injection of lidocaine into the nBOR reduced the longer-latency oscillations of W+ and W– cells. When the Wulst was temporarily inactivated by lidocaine neither the directional nor spatiotemporal response properties of LM neurons were affected. The possible functions of the projection from the Wulst to the LM are discussed.
Address for reprint requests and other correspondence: D. R. Wong-Wylie, Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada (E-mail: dwylie{at}ualberta.ca ).