EurekaMag.com logo
+ Translate

Spectral-response properties of optic-nerve fibers in the ground squirrel


, : Spectral-response properties of optic-nerve fibers in the ground squirrel. Journal of Neurophysiology 45(5): 891-902

The spectral-response properties of optic-nerve fibers were examined in anesthetized California ground squirrels. As defined by use of stimuli that were large relative to the spatial extent of the receptive-field centers, this optic nerve contains 3 types of units that give spectrally non-opponent responses, while 2 other types of units show evidence for spectral opponency. Of the non-opponent group, units were found to show either direction-selective responses, center-surround antagonism with both regions having the same spectral sensitivity (contrast-sensitive units), or center-surround antagonism with different spectral sensitivity in the 2 regions (BG/G units). The 2 classes of units showing spectral opponency give either an increase in firing rate for stimuli whose wavelength content is < 500 nm and a decrease in firing rate for longer test wavelengths (B/G units), or they show exactly the reverse response pattern (G/B units). In 963 units, about 75% were of the non-opponent varieties. The spectral sensitivities of the retinal mechanisms providing inputs to the optic nerve were determined for each of the various response classes by recording their spectral responses both with and without concurrent chromatic adaptation. Under conditions of light adaptation, 2 spectral mechanisms were isolated. After correction for preretinal filtering, these 2 mechanisms are shown to have sensitivity functions that correspond closely to those predicted by wavelength-dependent visual pigment nomograms with peak sensitivity at 440 and 525 nm. The 525 nm mechanism provides the sole input to the contrast-sensitive and direction-selective units, while the BG/G, B/G and G/B units receive inputs from both of these mechanisms. In addition to the 440 and 525 nm mechanisms, which presumably reflect the operation of cones, a 3rd mechanism having peak sensitivity at 500 nm provides input to some units under conditions of dark adaptation.

(PDF 0-2 workdays service)

Accession: 021786349

PMID: 7241175

Submit PDF Full Text: Here


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Jacobs G.H.; Tootell R.B.H., 1981: Spectral response properties of optic nerve fibers in the ground squirrel spermophilus beecheyi. The spectral-response properties of optic-nerve fibers were examined in anesthetized California ground squirrels. As defined by use of stimuli that were large relative to the spatial extent of the receptive-field centers, this optic nerve contains...

McCourt, M.E.; Jacobs, G.H., 1983: Effects of photic environment on the development of spectral response properties of optic nerve fibers in the ground squirrel. The California ground squirrel (Spermophilus beecheyi) has two classes of cone photopigments (lambda max = 440 and 525 nm). Under photopic conditions about 30% of all optic nerve fibers receives inputs from both cone classes, the remainder are dri...

Mccourt M.E.; Jacobs G.H., 1983: Effects of photic environment on the development of spectral response properties of optic nerve fibers in the ground squirrel spermophilus beecheyi. The California ground squirrel (S. beecheyi) has 2 classes of cone photopigments (.lambda.max = 440 and 525 nm). Under photopic conditions .apprx. 30% of all optic nerve fibers receive inputs from both cone classes, the remainder are driven solely...

Jacobs, G.H.; Blakeslee, B.; Tootell, R.B., 1981: Color-discrimination tests on fibers in ground squirrel optic nerve. The California ground squirrel (S. beecheyi) has dichromatic color vision. To determine which units in the optic nerve of this species transmit the information needed to support color vision, 2 tests were run on single units recorded from anesthet...

Jacobs G.H.; Blakeslee B.; Tootell R.B.H., 1981: Color discrimination tests on fibers in ground squirrel spermophilus beecheyi optic nerve. The California ground squirrel (S. beecheyi) has dichromatic color vision. To determine which units in the optic nerve of this species transmit the information needed to support color vision, 2 tests were run on single units recorded from anesthet...

McCourt, M.E.; Jacobs, G.H., 1984: Directional filter characteristics of optic nerve fibers in California ground squirrel (Spermophilus beecheyi). Directional units in the optic nerve of the California ground squirrel (Spermophilus beecheyi) were studied with respect to their response to diffuse light, preferred directions of motion, tuning for preferred direction, the relationship between s...

McCourt, M.E.; Jacobs, G.H., 1984: Spatial filter characteristics of optic nerve fibers in California ground squirrel (Spermophilus beecheyi). The spatial response properties of single optic nerve fibers in the California ground squirrel (Spermophilus beecheyi) were investigated. Results are reported for each of several response classes. Resolution limits determined for 165 spectrally no...

Jacobs, G.H.; Tootell, R.B., 1980: Spectrally-opponent responses in ground squirrel optic nerve. The spectral response patterns of single optic nerve fibers of the California ground squirrel (S. beecheyi) were determined in urethane-anesthetized and unanesthetized animals. Fibers showing spectrally-opponent responses were in about the same re...

Vaidya, P.G., 1964: The Retina And The Optic Nerve Of The Ground Squirrel Citellus Tridecemlineatus. Journal of Comparative Neurology 122: 347-353

Michael, C.R., 1966: Receptive fields of directionally selective units in the optic nerve of the ground squirrel. These units responded vigorously to stimuli moving entirely across their receptive field centers in one direction (preferred) and not at all when the direction of motion was reversed (null). The directional selectivity was the result of an inhibit...