Fine structure of the optic fibre termination layers in the pigeon optic tectum: A golgi and electron microscope study

Angaut, P; Repérant, J

doi:10.1016/0306-4522(76)90003-8

Cited by 68 publications

(48 citation statements)

References 74 publications

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“…The avian tectum consists of well separated laminas that contain specific retinal afferents, interneurons, or projection neurons (Ramón y Cajal, 1911;Angaut and Reperant, 1976;Hunt and Künzle, 1976;Hardy et al, 1985;Luksch et al, 1998). Retinal afferents terminate in retinotopic organization in layers 2-7 with the exception of layer 6 (Hunt and Webster, 1975).…”

Section: Abstract: Visual System; Cellular Physiology; Optic Tectum;mentioning

confidence: 99%

Chattering and Differential Signal Processing in Identified Motion-Sensitive Neurons of Parallel Visual Pathways in the Chick Tectum

et al. 2001

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At least three identified cell types in the stratum griseum centrale (SGC) of the chick optic tectum mediate separate pathways from the retina to different subdivisions of the thalamic nucleus rotundus. Two of these, SGC type I and type II, constitute the major direct inputs to rotundal subdivisions that process various aspects of visual information, e.g., motion and luminance changes. Here, we examined the responses of these cell types to somatic current injection and synaptic input. We used a brain slice preparation of the chick tectum and applied whole-cell patch recordings, restricted electrical stimulation of dendritic endings, and subsequent labeling with biocytin. Type I neurons responded with regular sequences of bursts ("chattering") to depolarizing current injection. Electrical stimulation of retinal afferents evoked a sharp-onset EPSP/burst response that was blocked with CNQX. The sharp-onset EPSP/burst response to synaptic stimulation persisted when the soma was hyperpolarized, thus suggesting the presence of dendritic spike generation. In contrast, the type II neurons responded to depolarizing current injection solely with an irregular sequence of individual spikes. Electrical stimulation of retinal afferents led to slow and long-lasting EPSPs that gave rise to one or several action potentials. In conclusion, the morphological distinct SGC type I and II neurons also have different response properties to retinal inputs. This difference is likely to have functional significance for the differential processing of visual information in the separate pathways from the retina to different subdivisions of the thalamic nucleus rotundus.

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Section: Abstract: Visual System; Cellular Physiology; Optic Tectum;mentioning

confidence: 99%

Chattering and Differential Signal Processing in Identified Motion-Sensitive Neurons of Parallel Visual Pathways in the Chick Tectum

et al. 2001

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“…Layers 2Á/7 were grouped as those retinorecipient layers, where retinal fibers terminate [1]. Layers 8Á/12 were grouped as those retinoreceptive layers, which receive direct retinal input by ascending dendrites without projecting to the nucleus rotundus [19].…”

Section: Neuroanatomymentioning

confidence: 99%

Embryonic light stimulation induces different asymmetries in visuoperceptual and visuomotor pathways of pigeons

Skiba

Diekamp

Güntürkün

2002

Behavioural Brain Research

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In birds, visual object discrimination performance is lateralized with a dominance of the right eye/left hemisphere. This asymmetry is induced by embryonic light stimulation. However, visually guided behavior, even during simple object distinction tasks, is composed of different behavioral and neural modules. Therefore, the aim of the present study was to test whether all neural subsystems involved in visual discriminations are lateralized in a similar way after prehatch visual stimulation. To examine this question, two behavioral paradigms were used which reveal complementary aspects of visually guided behavior. The first was the grain Á/grit discrimination task in which no left Á/right differences in the number of pecks, but significant differences in the number of grains can be found. Therefore, grain Á/grit discrimination reveals visuoperceptual performance but not visuomotor speed. The contrary seems to be the case for a successive pattern discrimination with a VR32 schedule. Here, the hemispheres do not differ with respect to discrimination accuracy but with regard to the number of pecks emitted. Thus, successive pattern discrimination with lean VR schedules reveals hemispheric differences in visuomotor speed without testing visuoperceptual performance. Using these two paradigms a group of light and a group of dark incubated pigeons were tested. The results show that dark incubated birds evinced no asymmetry in any measure while light incubated ones were right-eye dominant in both variables. However, light incubation induced a visual left hemispheric dominance by modulating two different processes, a left-hemispheric increase of visuoperceptual processes; and a right-hemispheric decrease for visuomotor speed. Taken together these data show that embryonic light stimulation elicits visual lateralization by differently modulating visuoperceptual and visuomotor systems in both hemispheres. #

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“…In birds, the superficial layers of TeO contain a fine-grained map representing the visual field of the contralateral eye (Hunt and Webster, 1975;Angaut and Repérant, 1976) (for review, see, Luksch, 2003;Wylie et al, 2009). Tectal ganglion cells (TGCs) in deeper layers pool this precise retinotopy and project to the thalamic nucleus rotundus ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Attentional Capture? Synchronized Feedback Signals from the Isthmi Boost Retinal Signals to Higher Visual Areas

Marı́n

Durán²,

Morales³

et al. 2012

J. Neurosci.

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When a salient object in the visual field captures attention, the neural representation of that object is enhanced at the expense of competing stimuli. How neural activity evoked by a salient stimulus evolves to take precedence over the neural activity evoked by other stimuli is a matter of intensive investigation. Here, we describe in pigeons (Columba livia) how retinal inputs to the optic tectum (TeO, superior colliculus in mammals), triggered by moving stimuli, are selectively relayed on to the rotundus (Rt, caudal pulvinar) in the thalamus, and to its pallial target, the entopallium (E, extrastriate cortex). We show that two satellite nuclei of the TeO, the nucleus isthmi parvocelullaris (Ipc) and isthmi semilunaris (SLu), send synchronized feedback signals across tectal layers. Preventing the feedback from Ipc but not from SLu to a tectal location suppresses visual responses to moving stimuli from the corresponding region of visual space in all Rt subdivisions. In addition, the bursting feedback from the Ipc imprints a bursting rhythm on the visual signals, such that the visual responses of the Rt and the E acquire a bursting modulation significantly synchronized to the feedback from Ipc. As the Ipc feedback signals are selected by competitive interactions, the visual responses within the receptive fields in the Rt tend to synchronize with the tectal location receiving the "winning" feedback from Ipc. We propose that this selective transmission of afferent activity combined with the cross-regional synchronization of the areas involved represents a bottom-up mechanism by which salient stimuli capture attention.

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Fine structure of the optic fibre termination layers in the pigeon optic tectum: A golgi and electron microscope study

Cited by 68 publications

References 74 publications

Chattering and Differential Signal Processing in Identified Motion-Sensitive Neurons of Parallel Visual Pathways in the Chick Tectum

Chattering and Differential Signal Processing in Identified Motion-Sensitive Neurons of Parallel Visual Pathways in the Chick Tectum

Embryonic light stimulation induces different asymmetries in visuoperceptual and visuomotor pathways of pigeons

Attentional Capture? Synchronized Feedback Signals from the Isthmi Boost Retinal Signals to Higher Visual Areas

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