Biology subjects

Vega-Zuniga, T.

Publications and source records attributed to Vega-Zuniga, T..

4 recordsLinked to original sources

bioRxiv2026

Retinotopic organization of head-orienting vectors in the pigeon ventral lateral geniculate nucleus

The ventral lateral geniculate nucleus (GLv) is a conserved retinorecipient structure positioned between visual and premotor systems, yet its role in visuomotor transformations remains poorly understood. Here, we examined whether the pigeon GLv contains a spatially organized motor representation linking visual-field locations to orienting movements. Anatomical tracing identified descending projections from neurons in the GLv inner lamina (GLv-li) through pretectal and tegmental regions toward pontine targets. GLv-li projection neurons are GABAergic, yet electrical microstimulation of GLv-li in awake pigeons evoked rapid head movements followed by smaller eye movements. Each stimulation locus produced a reproducible characteristic motor vector whose direction and duration were largely insensitive to stimulation parameters, whereas movement amplitude and velocity approached site-specific plateaus. Movements initiated from different head positions were better explained by repetition of a fixed displacement than by convergence toward a common spatial goal. Critically, motor-vector direction was systematically related to the direction of the visual receptive field represented at the same GLv locus, while motor-vector amplitude covaried with receptive-field eccentricity. These defining features persisted after optic tectum ablation. Together, these findings reveal a retinotopically-organized map of fixed-vector head movements in the avian GLv and identify a tectum-independent route through which visual spatial representations can access descending orienting circuitry.

neuroscience↗

bioRxiv2025

Binocular vision emerges from the coordinated development of orbit convergence, eye orientation, and high-acuity retinal specializations

Binocular vision requires both eyes to be aligned such that their visual fields overlap. A long-standing premise derived from comparative studies is that the orientation of the orbits determines eye position, and thereby the extension of this overlap, the binocular field. In addition, to produce an accurate neural representation, the binocular field must integrate with the position of retinal high-acuity areas and with the extent of uncrossed retinal projections. It remains unknown, however, whether the binocular field is already formed at the time of eye-opening, as well as when and how it integrates with neuroanatomical visual traits during development. Using the diurnal rodent Octodon degus, a suitable animal model for visual neuroscience, we combined CT-based 3D cranial reconstructions, quantitative measurements of visual-field geometry, whole-mount retinal topography, neural tracing of retinal projections, and behavioral assays to reconstruct the postnatal assembly of the binocular visual system. We show that orbital and ocular orientations shift substantially after birth, broadening the dorsal binocular field; that retinal ganglion cell distributions sharpen into a horizontal visual streak and a defined area centralis; and that ipsilateral projections to the superior colliculus mature in parallel to binocular expansion. These changes coincide with the emergence of binocular-dependent behaviors such as depth discrimination and looming-evoked escape responses. Together, our findings demonstrate that binocular vision emerges through the coordinated alignment of multiple developmental processes across levels of organization.

neuroscience↗

bioRxiv2023

A thalamic hub of action cues coordinates early visual processing and perception

Distinguishing between sensory experiences elicited by external stimuli and an animals own actions is critical for accurate perception and motor control. However, the diversity of behaviors and their complex influences on the senses make this distinction challenging. Here, we uncover an action cue hub that coordinates both visual processing in the brains first visual relay and motor commands. We show that the ventral lateral geniculate nucleus (vLGN) acts as a corollary discharge (CD) center, integrating visual translational optic flow signals and motor copies from saccades, locomotion, and pupil dynamics. The vLGN relays these signals to correct action-specific visual distortions and refine perception, as shown for the superior colliculus and a depth estimation task. Simultaneously, brain-wide vLGN projections drive corrective actions necessary for accurate visuomotor control. Our results reveal an extended CD architecture that refines early visual transformations and coordinates actions via a distributed hub-and-spoke network enabling visual perception during action.

neuroscience↗

bioRxiv2022

Subcortical circuit dysfunctions delay perceptual decision-making in autism models

Despite the diverse genetic origins of autism spectrum disorders (ASDs), affected individuals share strikingly similar and correlated behavioural traits that include perceptual and sensory processing challenges. Notably, the severity of these sensory symptoms is often predictive of the expression of other autistic traits. However, the origin of these perceptual deficits remains largely elusive. Here, we show a recurrent impairment in visual threat perception that is similarly impaired in three independent models of ASD with different molecular aetiologies. Interestingly, this deficit is associated with reduced avoidance of threatening environments - a non-perceptual trait. Focusing on a common cause of ASDs, the Setd5 gene mutation, we define the molecular mechanism. We show that the perceptual impairment is caused by a potassium channel (Kv1) mediated hypoexcitability in a subcortical node essential for the initiation of escape responses, the dorsal periaqueductal grey (dPAG). Targeted pharmacological Kv1 blockade rescued both perceptual and place avoidance deficits, causally linking seemingly unrelated trait deficits to the dPAG. Our findings reveal a link between rapid perception controlled by subcortical pathways and appropriate learned interactions with the environment, and define a non-developmental source of such deficits in ASD.

neuroscience↗