Quantity as a Fish Views It: Behavior and Neurobiology

Abstract

An ability to estimate quantities, such as the number of conspecifics or the size of a predator, has been reported in vertebrates. Fish, in particular zebrafish, may be instrumental in advancing the understanding of magnitude cognition. We review here the behavioral studies that have described the ecological relevance of quantity estimation in fish and the current status of the research aimed at investigating the neurobiological bases of these abilities. By combining behavioral methods with molecular genetics and calcium imaging, the involvement of the retina and the optic tectum has been documented for the estimation of continuous quantities in the larval and adult zebrafish brain, and the contributions of the thalamus and the dorsal-central pallium for discrete magnitude estimation in the adult zebrafish brain. Evidence for basic circuitry can now be complemented and extended to research that make use of transgenic lines to deepen our understanding of quantity cognition at genetic and molecular levels.

Slowly walking down to the more food: relative quantity discrimination in African spurred tortoises (Centrochelys sulcata)

“…This area has been well-studied in mammals, birds, and fish, and their ability to discriminate depends on the ratio difference between the numbers (see Bryer et al 2021 for a recent meta-analysis). A similar pattern of responses has been observed in amphibians (Balestrieri et al 2019 ; Stancher et al 2015 ; Uller et al 2003 ), fish (see Messina et al 2022 for review), and also in invertebrates (see Bortot et al 2021 ; Gatto et al 2022 for review), suggesting that this ability may originate very early in evolution.…”

More than double the fun with two-photon excitation microscopy

“…TPE-LSFM further enhances imaging depth and SNR, while eliminating the need for visible excitation laser which can be a potential confounding factor in light-sensitive samples 50 or behavioral experiments. Recent notable applications have applied TPE-LSFM to light-sensitive behavioral studies that require imaging large regions such as the whole brain during seizure 51 , sleep 52 , phototaxis 53 and visual number sense 54 .…”

A Kaspar Hauser experiment for innateness of numerical cognition

“…Neurons selectively tuned to numerousness have been described in humans 6 , monkeys 6,7 and crows 8 , and some evidence for number selectivity has been reported also in zebrafish [9][10][11] .…”

“…Quantity discrimination is well-attested in vertebrates 1–4 and invertebrates 5 . Neurons selectively tuned to numerousness have been described in humans 6 , monkeys 6,7 and crows 8 , and some evidence for number selectivity has been reported also in zebrafish 9–11 .…”