Timing of ascending and descending visual signals predicts the response mode of single cells in the thalamic nucleus rotundus of the pigeon (Columba livia)

2007 ◽  
Vol 1132 ◽  
pp. 100-109 ◽  
Author(s):  
Kristian Folta ◽  
Nikolaus F. Troje ◽  
Onur Güntürkün
Keyword(s):  
Thalamic Nucleus ◽  
Single Cells ◽  
Columba Livia ◽  
Response Mode ◽  
Visual Signals ◽  
Nucleus Rotundus

scholarly journals The Spectral Sensitivity of Single Units in the Nucleus Rotundus of Pigeon, Columba livia

1971 ◽  
Vol 57 (3) ◽  
pp. 363-384 ◽  
Author(s):  
A. M. Granda ◽  
S. Yazulla
Keyword(s):  
Spectral Sensitivity ◽  
Monochromatic Light ◽  
Columba Livia ◽  
Single Units ◽  
Response Functions ◽  
Light Stimulation ◽  
Sensitivity Functions ◽  
Nucleus Rotundus ◽  
Intensity Response ◽  
Changing Criterion

Responses to diffuse monochromatic light were recorded from single units in the diencephalon of pigeon. Units were both excited and inhibited by light stimulation. Intensity-response functions based on latency measures to the first spike after stimulation were used to generate action spectra. One class of spectral sensitivity functions presumably from rods, showed peak sensitivities near 500 nm: these functions were unaffected by changing criterion values used to generate the functions. A second class of cone functions showed multiple peak sensitivities at 540 nm and 600–620 nm. These units shifted their peak sensitivities with a change in criterion values. Unit response types tended to be localized differentially in the nucleus rotundus. Excitatory units were located in the dorsal half of the nucleus, while inhibitory units were located in the ventral half, with a few exceptions. An attempt was made to integrate the present findings with previous behavioral, electrophysiological, photochemical, and anatomical data in the pigeon.

Visual processing in pigeon nucleus rotundus: Luminance, color, motion, and looming subdivisions

1993 ◽  
Vol 10 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Yong-Chang Wang ◽  
Shiying Jiang ◽  
Barrie J. Frost
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Visual Information ◽  
Moving Objects ◽  
Single Cells ◽  
Central Zone ◽  
Avian Brain ◽  
Ambient Illumination ◽  
Motion In Depth ◽  
Nucleus Rotundus

AbstractThe responses of single cells to luminance, color and computer-generated spots, bars, kinematograms, and motion-in-depth stimuli were studied in the nucleus rotundus of pigeons. Systematic electrode penetrations revealed that there are several functionally distinct subdivisions within rotundus where six classes of visual-selective cells cluster. Cells in the dorsal-posterior zone of the nucleus respond selectively to motion in depth (i.e. an expanding or contracting figure in the visual field). Most cells recorded from the dorsal-anterior region responded selectively to the color of the stimulus. The firing rate of the cells in the anterior-central zone, however, is dramatically modulated by changing the level of illumination over the whole visual field. Cells in the ventral subdivision strongly respond to moving occlusion edges and very small moving objects, with either excitatory or inhibitory responses. These results indicate that visual information processing of color, ambient illumination, and motion in depth are segregated into different subdivisions at the level of nucleus rotundus in the avian brain.

scholarly journals Spatially Patterned Bi-electrode Epiretinal Stimulation for Axon Avoidance at Cellular Resolution

2021 ◽  
Author(s):  
Ramandeep S Vilkhu ◽  
Sasidhar S Madugula ◽  
Lauren E Grosberg ◽  
Alex R Gogliettino ◽  
Pawel Hottowy ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Ex Vivo ◽  
Single Cells ◽  
Electrode Array ◽  
Theoretical Work ◽  
Visual Signals ◽  
Artificial Vision ◽  
Cellular Resolution ◽  
Single Spike ◽  
Electrode Stimulation

Objective: Epiretinal prostheses are designed to restore vision to people blinded by photoreceptor degenerative diseases by stimulating surviving retinal ganglion cells (RGCs), which carry visual signals to the brain. However, inadvertent stimulation of RGCs at their axons can result in non-focal visual percepts, limiting the quality of artificial vision. Theoretical work has suggested that axon activation can be avoided with current stimulation designed to minimize the second spatial derivative of the induced extracellular voltage along the axon. However, this approach has not been verified experimentally at the resolution of single cells. Approach: In this work, a custom multi-electrode array (512 electrodes, 10 μm diameter, 60 μm pitch) was used to stimulate and record RGCs in macaque retina ex vivo at single-cell, single-spike resolution. RGC activation thresholds resulting from bi-electrode stimulation, which consisted of bipolar currents simultaneously delivered through two electrodes straddling an axon, were compared to activation thresholds from traditional single-electrode stimulation. Results: Across three retinal preparations, the bi-electrode stimulation strategy reduced somatic activation thresholds while increasing axonal activation thresholds, thus favoring selective somatic activation. Furthermore, individual examples revealed rescued selective activation of somas that was not possible with any individual electrode. Significance: This work suggests that a bi-electrode epiretinal stimulation strategy can reduce inadvertent axonal activation at cellular resolution, for high-fidelity artificial vision.

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