Encoding of global visual motion in the nidopallium caudolaterale of behaving crows

Abstract

Songbirds possess acute vision. How higher brain centres represent basic and parameterised visual stimuli to process sensory signals according to their behavioural importance has not been studied in a systematic way. We therefore examined how carrion crows (Corvus corone) and their nidopallial visual neurons process global visual motion information in dynamic random-dot displays during a delayed match-to-sample (DMS) task. The behavioural data show that moderately fast motion speeds (16° of visual angle/s) result in superior direction discrimination performance. To characterise how neurons encode and maintain task-relevant visual motion information, we recorded the single-unit activity in the telencephalic association area 'nidopallium caudolaterale' (NCL) of behaving crows. The NCL is considered to be the avian analogue of the mammalian prefrontal cortex. Almost a third (28%) of randomly selected NCL neurons responded selectively to the motion direction of the sample stimulus, mostly to downward motions. Only few NCL neurons (7.5%) responded consistently to specific motion directions during the delay period. In error trials, when the crows chose the wrong motion direction, the encoding of motion direction was significantly reduced. This indicates that sensory representations of NCL neurons are relevant to the birds' behaviour. These data suggest that the corvid NCL, even though operating at the apex of the telencephalic processing hierarchy, constitutes a telencephalic site for global motion integration.

A brain atlas of the carrion crow (Corvus corone)

“…In crows, the NCL has been shown to play an important role in cognitive control functions, a group of processes that direct, maintain, and manipulate information according to immediate task demands. NCL neurons respond to incoming sensory information (Veit et al., 2014; Wagener & Nieder, 2017) and signal the conscious perception of sensory stimuli (Nieder et al., 2020). NCL neurons classify sensory stimuli into behaviorally meaningful categories, such as numbers of items (Ditz & Nieder, 2015, 2016b, 2020; Ditz et al., 2022; Kirschhock et al., 2021).…”