Oscillatory Bursts in the Optic Tectum of Birds Represent Re-Entrant Signals from the Nucleus Isthmi Pars Parvocellularis

Marı́n, Gonzalo; Mpdozis, Jorge; Sentis, Elisa; Ossandón, Tomás; Letelier, Juan-Carlos

doi:10.1523/jneurosci.1379-05.2005

Cited by 71 publications

(93 citation statements)

References 61 publications

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“…recording of simultaneous responses in all structures with a single moving stimulus. To investigate how the responses in the Rt were affected when the isthmic feedback shifted from one tectal location to another, bursting responses originating from Ipc axons (Marín et al, 2005) were recorded with two separate microelectrodes in the superficial layers of the TeO, such that their respective nonoverlapped RFs were also included within the RFs in the Rt. To trace the recording tracts in the Rt and E, the tungsten microelectrodes were immersed before recording in a 2% DiI and 95% ethanol solution, and allowed to dry for a few minutes.…”

Section: Methodsmentioning

confidence: 99%

“…These bursting events correspond to the bursting firing of the Ipc terminals in the TeO, and thus closely represent the local feedback signal (Marín et al, 2005). To compare the frequency rhythms of the Ipc feedback and the Rt responses, discrete and continuous auto-correlograms were computed for the TeO bursting responses and the Rt MUA, respectively, using the same 10 intervals selected above.…”

Section: Methodsmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

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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“…Among the indirect pathways to the OT, the extensively studied isthmotectal loop has been suggested to be involved in spatial attention (Marin et al, 2005). Nucleus isthmi, the homolog of the mammalian nucleus parabigeminalis (Diamond et al, 1992), receives auditory and visual afferents from tectal neurons, and send cholinergic projections back to the tectum (Maczko et al, 2006).…”

Section: Origin Of Ssamentioning

confidence: 99%

“…Nucleus isthmi, the homolog of the mammalian nucleus parabigeminalis (Diamond et al, 1992), receives auditory and visual afferents from tectal neurons, and send cholinergic projections back to the tectum (Maczko et al, 2006). This may constitute a winner-take-all network that enhances the sensitivity of tectal neurons to the location of the most salient stimulus (Marin et al, 2005;Wang et al, 2006;Knudsen, 2007). Adaptation in the isthmotectal loop has not been reported so far.…”

Section: Origin Of Ssamentioning

confidence: 99%

Stimulus-Specific Adaptations in the Gaze Control System of the Barn Owl

Reches¹,

Gutfreund²

2008

J. Neurosci.

111

133

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Abrupt orientation to novel stimuli is a critical, memory-dependent task performed by the brain. In the present study, we examined two gaze control centers of the barn owl: the optic tectum (OT) and the arcopallium gaze fields (AGFs). Responses of neurons to long sequences of dichotic sound bursts comprised of two sounds differing in the probability of appearance were analyzed. We report that auditory neurons in the OT and in the AGFs tend to respond stronger to rarely presented sounds (novel sounds) than to the same sounds when presented frequently. This history-dependent phenomenon, known as stimulus-specific adaptation (SSA), was demonstrated for rare sound frequencies, binaural localization cues [interaural time difference (ITD) and level difference (ILD)] and sound amplitudes. The manifestation of SSA in such a variety of independent acoustic features, in the midbrain and in the forebrain, supports the notion that SSA is involved in sensory memory and novelty detection. To track the origin of SSA, we analyzed responses of neurons in the external nucleus of the inferior colliculus (ICX; the source of auditory input to the OT) to similar sequences of sound bursts. Neurons in the ICX responded stronger to rare sound frequencies, but did not respond differently to rare ITDs, ILDs, or sound amplitudes. We hypothesize that part of the SSA reported here is computed in high-level networks, giving rise to novelty signals that modulate tectal responses in a context-dependent manner.

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“…The cholinergic input from NI is visually evoked and leads to oscillatory bursting potentials recorded across tectal layers. They are generated by the bursting firing of "paintbrush" axon terminals from the Ipc (Marin et al, 2005). Wide-field competition could be mediated by the diffuse GABAergic projection from the Imc to Ipc and the OT (Fig.…”

Section: The Bird Isthmotectal Network As a Spatial Attentional Mechamentioning

confidence: 99%

Influencing and Interpreting Visual Input: The Role of a Visual Feedback System

et al. 2006

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Vertebrates are able to visually identify moving objects and orient toward attractive ones or escape if the objects seem threatening. When there is more than one object in the visual field, they can attend to a particular object. The optic tectum (superior colliculus in mammals) (OT/SC) has long been known to mediate such functions (Schneider, 1969;Ingle, 1973a). Less well known is that the OT/SC is strongly affected by a smaller midbrain area called nucleus isthmi (parabigeminal nucleus in mammals) (NI/PB). We discuss how NI/PB influences OT/SC function and visual behavior.Anatomically, OT/SC makes reciprocal, topographic connections with ipsilateral NI/PB. Adjacent points in OT/SC project to adjacent points in NI/PB. The return projections from NI/PB terminate in many of the same superficial layers as retinotectal fibers, and their effects on tectal processing may facilitate selection of a single stimulus from an array of potential targets. In amphibians and mammals, NI/PB also project to the contralateral OT/SC (Fig. 1). Visual behavior and the frog NIWhen presented with a single prey stimulus anywhere in its visual field, a frog will approach and attack the stimulus. When presented with two prey stimuli, they will select one of the stimuli (Ingle, 1973b;Stull and Gruberg, 1998). After ablation of the optic tectum, frogs will not respond to prey stimuli (or to looming stimuli), although they retain other visual abilities, such as perceiving stationary objects (Ingle, 1973b).Other than the retina, the greatest input to the OT in frogs comes from NI. It can be divided into two functionally discrete regions: one region makes topographic reciprocal connections with the ipsilateral OT; the other region projects topographically to the contralateral tectal lobe. Unilateral ablation of NI results in a scotoma in the contralateral monocular visual field (Gruberg et al., 1991) that is similar to unilateral ablation of the OT. Partial ablation of NI results in a smaller scotoma that always includes the posteriormost part of the monocular field. Within the scotoma, the behavioral threshold to prey stimuli is considerably increased and resembles visual neglect.NI directly influences retinotectal transmission (King and Schmidt, 1991;Dudkin and Gruberg, 2003). Frog isthmotectal fibers are cholinergic (Desan et al., 1987;Wallace et al., 1990) and terminate in retino-recipient layers of the optic tectum. Retinal ganglion cell axons express nicotinic acetylcholine (ACh) receptors (Sargent et al., 1989). There do not appear to be conventional synapses between isthmotectal fibers and retinotectal axons (Gruberg et al., 1994). Nonetheless, by selectively filling retinotectal fibers with a fluorescent calcium-sensitive dye, NI influence on retinotectal fibers can be shown. Single-shock stimulation to the optic nerve causes a brief increase in fluorescence. Singleshock stimulation to NI causes no change in fluorescence. When single-shock stimulation of NI is paired with optic nerve stimulation, there is a greater than twofold incre...

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Oscillatory Bursts in the Optic Tectum of Birds Represent Re-Entrant Signals from the Nucleus Isthmi Pars Parvocellularis

Cited by 71 publications

References 61 publications

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

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

Stimulus-Specific Adaptations in the Gaze Control System of the Barn Owl

Influencing and Interpreting Visual Input: The Role of a Visual Feedback System

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