Quantitative Analysis of the Retinal Ganglion Cell Layer and Optic Nerve of the Barn Owl &lt;i&gt;Tyto alba&lt;/i&gt;

Wathey, John C.; Pettigrew, John D.

doi:10.1159/000115936

Cited by 74 publications

(80 citation statements)

References 44 publications

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“…Since a complete CSF was not obtained for the little owl, a detailed comparison is not possible. The estimated acuity obtained in this experiment for barn owls (6.98 c/deg), however, is very close to the theorized acuity of 8.4 c/deg reported by Wathey and Pettigrew (1989), which they estimated from retinal ganglion cell density (12,500/mm 2 ) in this species.…”

Section: Barn Owlssupporting

confidence: 88%

“…35,714 (Northmore, personal communications) unknown (Wathey and Pettigrew, 1989) Eagle (Aquila audax) 290,000-550,000 (Reymond, 1985) 62,000 in both areas of Buteo fuscenses australis (Inzunza et al, 1991) Japanese quail (Coturnix coturnix japonica) 25,000 (Budnik et al, 1984) 35,600 area centralis (Ikushima, 1986); 36,500 area dorsalis (Budnik et al, 1984) Kestrel (Falco sparverius)…”

Section: Location Of the Csf On The Sf-axis And Physiologymentioning

confidence: 99%

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Spatial contrast sensitivity of birds

2006

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Contrast sensitivity (CS) is the ability of the observer to discriminate between adjacent stimuli on the basis of their differences in relative luminosity (contrast) rather than their absolute luminances. Prior to this study, birds had been thought to have low contrast detection thresholds relative to mammals and fishes. This was a surprising phenomenon because birds had been traditionally attributed with superior vision. In addition, the low CS of birds could not be explained by retinal or optical factors, or secondary stimulus characteristics. Unfortunately, avian contrast sensitivity functions (CSFs) were sparse in the literature, so it was unknown whether low contrast sensitivity was a general phenomenon in birds. This study measured CS in six species of birds The quail and pigeon data obtained in this experiment fit well with existing CS data for these species. The kestrel data were not similar to kestrel data in the literature; however the data in the literature were collected from a single subject. All of the birds studied had contrast sensitivities that were consistent with their retinal or optical morphologies relative to other birds (in species for which such data exists) and seem well suited for their natural environments. In addition, all of these birds exhibited low CS relative to humans and most mammals, which suggests that low CS is a general phenomenon of birds.Explanations for this avian low CS phenomenon include a possible trade-off between contrast mechanisms and UV mechanisms in cone systems, and lateral inhibitory mechanisms that are perhaps categorically different from mammals. Lateral inhibition affects contrast gain, and has been shown to differ according to ganglion cell types, which in turn will differ in vertebrate species.

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Section: Barn Owlssupporting

confidence: 88%

Section: Location Of the Csf On The Sf-axis And Physiologymentioning

confidence: 99%

Spatial contrast sensitivity of birds

2006

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“…Once anesthetized, the animal was positioned in a stereotaxic apparatus at the center of a double-wall, sound-attenuating booth. The head was fixed and aligned using the pecten oculi as a retinal landmark (Wathey and Pettigrew, 1989). Within the booth, isoflurane was removed and the bird was maintained on a fixed mixture of nitrous oxide and oxygen (4:5).…”

Section: Methodsmentioning

confidence: 99%

“…8). The pecten oculi is an apparent retinal landmark (Wathey and Pettigrew, 1989). Once the camera was positioned in place, the door of the booth was closed and video sequences (30 fps) were collected starting 500 ms before the onset of the stimulus and ending 3 s after.…”

Section: Methodsmentioning

confidence: 99%

Stimulus-Specific Adaptation: Can It Be a Neural Correlate of Behavioral Habituation?

Netser¹,

Zahar²,

Gutfreund³

2011

J. Neurosci.

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Habituation is the most basic form of learning, yet many gaps remain in our understanding of its underlying neural mechanisms. We demonstrate that in the owl's optic tectum (OT), a single, low-level, relatively short auditory stimulus is sufficient to induce a significant reduction in the neural response to a stimulus presented up to 60 s later. This type of neural adaptation was absent in neurons from the central nucleus of the inferior colliculus and from the auditory thalamus; however, it was apparent in the OT and the forebrain entopallium. By presenting sequences that alternate between two different auditory stimuli, we show that this long-lasting adaptation is stimulus specific. The response to an odd stimulus in the sequence was not smaller than the response to the same stimulus when it was first in the sequence. Finally, we measured the habituation of reflexive eye movements and show that the behavioral habituation is correlated with the neural adaptation. The finding of a long-lasting specific adaptation in areas related to the gaze control system and not elsewhere suggests its involvement in habituation processes and opens new directions for research on mechanisms of habituation.

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“…Once anesthetized, the animal was positioned in a stereotaxic apparatus at the center of a double-wall sound-attenuating chamber. The head was bolted to the stereotaxic apparatus and aligned using retinal landmarks (Wathey and Pettigrew, 1989). Within the chamber, isoflurane was removed and the bird was maintained on a fixed mixture of nitrous oxide and oxygen (4:5).…”

Section: Methodsmentioning

confidence: 99%

Interactions between Stimulus-Specific Adaptation and Visual Auditory Integration in the Forebrain of the Barn Owl

Reches¹,

Netser²,

Gutfreund³

2010

J. Neurosci.

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Neural adaptation and visual auditory integration are two well studied and common phenomena in the brain, yet little is known about the interaction between them. In the present study, we investigated a visual forebrain area in barn owls, the entopallium (E), which has been shown recently to encompass auditory responses as well. Responses of neurons to sequences of visual, auditory, and bimodal (visual and auditory together) events were analyzed. Sequences comprised two stimuli, one with a low probability of occurrence and the other with a high probability. Neurons in the E tended to respond more strongly to low probability visual stimuli than to high probability stimuli. Such a phenomenon is known as stimulus-specific adaptation (SSA) and is considered to be a neural correlate of change detection. Responses to the corresponding auditory sequences did not reveal an equivalent tendency. Interestingly, however, SSA to bimodal events was stronger than to visual events alone. This enhancement was apparent when the visual and auditory stimuli were presented from matching locations in space (congruent) but not when the bimodal stimuli were spatially incongruent. These findings suggest that the ongoing task of detecting unexpected events can benefit from the integration of visual and auditory information.

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Quantitative Analysis of the Retinal Ganglion Cell Layer and Optic Nerve of the Barn Owl <i>Tyto alba</i>

Cited by 74 publications

References 44 publications

Spatial contrast sensitivity of birds

Spatial contrast sensitivity of birds

Stimulus-Specific Adaptation: Can It Be a Neural Correlate of Behavioral Habituation?

Interactions between Stimulus-Specific Adaptation and Visual Auditory Integration in the Forebrain of the Barn Owl

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