Neuronal responses to frontal binocular and lateral monocular visual stimuli in the crow nidopallium caudolaterale

In birds, visual information from the binocular-frontal and monocular-lateral fields is processed through multiple lateralized pathways that converge in associative telencephalic areas, where sensory inputs are integrated to guide behavior. How these initially separated inputs are represented in such higher areas remains unclear. We recorded single-unit activity in the left nidopallium caudolaterale (NCL), a higher-order associative area, in two passively viewing carrion crows (Corvus corone). The crows were presented with static and moving sine-wave gratings of varying parameters, and colored natural images, in the frontal binocular and lateral monocular visual fields. About 40% of units were strongly modulated by stimulus position (frontal, left, right), with subpopulations distinguishing frontal versus lateral inputs or left-eye versus contralateral right-eye inputs. Nearly 30% of neurons responded selectively to colored images, whereas only ∼10% discriminated between grating parameters, favoring higher spatial frequencies. Stimulus content interacted with position, showing stronger selectivity for frontal and right-eye inputs, consistent with contralateral processing. These results demonstrate that left NCL integrates inputs from both eyes to represent visual information across the visual fields.NEW & NOTEWORTHY Single-unit activity recorded in the left associative nidopallium caudolaterale (NCL) of awake crows was modulated by the position of stimuli across the visual field. Distinct subpopulations of visually responsive neurons distinguished both frontal binocular versus lateral monocular inputs and contralateral right-eye versus monocular left inputs. Stimulus content was more consistently encoded in the contralateral half-field, revealing that stimulus processing in left NCL differs across the visual field.