Experience-dependent plasticity in the zebrafish retina

A fundamental challenge in neuroscience is understanding how sensory information is processed to create a specific behavioural output. Vision is crucial for organisms to interact with their environment. The process of visual perception begins in the neuralretina, consisting of five cell classes -photoreceptors, horizontal, bipolar, amacrine and retinal ganglion cells -before information is transmitted through the optic nerve to different visual targets (Marr et al, 2010; Rodieck et al, 1998). As well as capturing light stimuli, the retina pre-processes visual information and extracts salient visual features, such as contrast, direction, motion, and orientation selectivity. Specific circuits between the retina and visual brain targets then develop sensitives to define these features and encode information for sensory integration and predict responses (Masland et al, 2012). Visual processing is plastic and such experience-dependent plasticity allows the brain to adjust in accordance with changing environmental stimuli. Beginning with the work by Hubel and Wiesel (1963), visual plasticity has mainly focused on the primary and secondary visual cortex (Fox and Wong, 2009). Studies into understanding orientation selectivity explored ocular dominance columns and sharpening selectivity in functional circuits (Berry et al, 2020). Further studies for example in restricting visual input to a single orientation, through placing goggles on kittens while young, have shown a shift in cortical neural responses towards thisorientation (Lussiez et al, 2020; Tanaka et al, 2020; Sengpiel et al, 1999; Hirsch et al, 1970). However, orientation selectivity also occurs in the retina, and in zebrafish is dependent on type II and III amacrine cells (Antinucci et al, 2013, 2016; Antinucci and Hindges, 2018) and arises between 3-5dpf, which coincides with amacrine cell development. Although there is extensive evidence that the environment can change the properties of visual responses of neurons in cortical and subcortical brain areas (Fox and Wong, 2009), it is not clear if the detection and pre-processing of sensory information in the retina, the sensory organ itself, can also change upon exposure to different visual environments (Xie et al, 2019). This is the focus of the present project.