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Goodhill, G.

Publications and source records attributed to Goodhill, G..

6 recordsLinked to original sources

A sensorimotor instability drives a locomotor transition during fish development

Animals rely on movement to survive -- to explore their environment, find food and mates and avoid danger. During development, changes in body shape, muscle strength and physiological needs drive the continuous adjustment of locomotor patterns. How these changes are orchestrated in a flexible and adaptive manner remains unknown. We explore this question in Danionella cerebrum, a miniature freshwater fish that is emerging as an important vertebrate model in systems neuroscience. We identify a clear transition in locomotion, from continuous to burst-and-coast swimming occurring around 3 weeks of age. We demonstrate that this transition is an energy saving strategy, and that it reflects an insta-bility in the sensorimotor process governing speed regulation. Rather than a preprogrammed developmental switch, it is therefore directly tied to the animal swimming strength. We confirmed this finding by manipulating sensory feedback in order to induce a similar transition at fixed developmental stages. Together, our results illustrate a dynamic interplay between body, brain, and environment during development, offering new insights into the principles governing adaptive locomotion.

biophysics↗

Zebrafish sleep displays distinct sub-states

Sleep is an essential and evolutionarily-conserved behavior. While mammals and several other species have been shown to exhibit well-defined sleep sub-states, some of which have been ascribed specific functions, it remains unclear to what extent such differentiation exists across the animal kingdom. Here we show, using long-term behavioral data combined with Hidden Markov Modeling, that larval zebrafish display distinct deep and light sleep sub-states. Although both states occur primarily at night, fish respond differently to sleep deprivation and arousing stimuli depending on which sleep sub-state they are in. Moreover, the proportions of deep and light sleep are selectively altered by genetic and pharmacological manipulations of melatonin, serotonin, and norepinephrine signaling, offering new insights into how these neuromodulators shape sleep architecture. These results support zebrafish as a tractable model for dissecting the regulation and function of sleep sub-states. More broadly, they demonstrate that structured, multi-state sleep is a conserved feature of vertebrate behavior.

neuroscience↗

Cortical activity emerges in region-specific patterns during early brain development

The development of precise neural circuits in the brain requires spontaneous patterns of neural activity prior to functional maturation. In the rodent cerebral cortex patchwork and wave patterns of activity develop in somatosensory and visual regions, respectively, and are present at birth. However, whether such activity patterns occur in non-eutherian mammals, as well as when and how they arise during development remain open questions relevant to understand brain formation in health and disease. Since the onset of patterned cortical activity is challenging to study prenatally in eutherians, here we offer a new approach in a minimally invasive manner using marsupial dunnarts, whose cortex forms postnatally. We discovered similar patchwork and travelling waves in the dunnart somatosensory and visual cortices at stage 27 (equivalent to newborn mice), and examined progressively earlier stages of development to determine their onset and how they first emerge. We observed that these patterns of activity emerge in a region-specific and sequential manner, becoming evident as early as stage 24 in somatosensory and stage 25 in visual cortices (equivalent to embryonic day 16 and 17, respectively, in mice), as cortical layers establish and thalamic axons innervate the cortex. In addition to sculpting synaptic connections of existing circuits, evolutionarily conserved patterns of neural activity could therefore help regulate early events in cortical development. Significance StatementRegion-specific patterns of neural activity are present at birth in rodents and are thought to refine synaptic connections during critical periods of cerebral cortex development. Marsupials are born much more immature than rodents, allowing the investigation of how these patterns arise in vivo. We discovered that cortical activity patterns are remarkably similar in marsupial dunnarts and rodents, and that they emerge very early, before cortical neurogenesis is complete. Moreover, they arise from the outset in different patterns specific to somatosensory and visual areas (i.e., patchworks and waves) indicating they may also play evolutionarily conserved roles in cortical regionalization during development.

neuroscience↗

fmr1 mutation interacts with sensory experience to alter the early development of behavior and sensory coding in zebrafish

While Autism Spectrum Disorders (ASDs) are developmental in origin little is known about how they affect the early development of behavior and sensory coding, or how this is modulated by the sensory environment. The most common inherited form of autism is Fragile X syndrome, caused by a mutation in FMR1. Here we show that zebrafish fmr1-/- mutant larvae raised in a naturalistic visual environment display early deficits in hunting behavior, tectal map development, tectal network properties and decoding of spatial stimuli. However when given a choice they preferred an environment with reduced visual stimulation, and rearing them in this environment improved these metrics. Older fmr1-/- fish showed differences in social behavior, spending more time observing a conspecific, but responding more slowly to social cues. Together these results help reveal how fmr1-/- changes the early development of vertebrate brain function, and how manipulating the environment could potentially help reduce these changes.

neuroscience↗

Behavioral signatures of a developing neural code

During early life neural codes must develop to appropriately transform sensory inputs into behavioral outputs. Here we demonstrate a direct link between the maturity of neural coding in the visual brain and developmental changes in visually-guided behavior. In zebrafish larvae we show that visually-driven hunting behavior improves from 4 to 15 days post-fertilization, becoming faster and more accurate. During the same period population activity in the optic tectum refines, leading to improved decoding and information transmission of spatial position, particularly in the representation of the frontal visual field. Remarkably, individual differences in decoding can predict each fishs hunting success. Together these results show how the neural codes required to subserve a natural behavior emerge during development.

neuroscience↗

Altered brain-wide auditory networks in fmr1-mutant larval zebrafish

Altered sensory processing is characteristic of several psychiatric conditions, including autism and fragile X syndrome (FXS). Here, we use whole-brain calcium imaging at cellular resolution to map sensory processing in wild type larval zebrafish and mutants for fmr1, which causes FXS in humans. Using functional analyses and graph theory, we describe increased transmission and reduced filtering of auditory information, resulting in network-wide hypersensitivity analogous to the auditory phenotypes seen in FXS.

neuroscience↗