Zebrafish provide valuable insights into internal human processes through their behavior. The Multi-Camera Array Microscope (MCAM™) provides robust features and analysis capabilities that, combined with the suitability of zebrafish to serve as a model organism, can significantly advance zebrafish research. It streamlines acquisition-to-analysis pipelines, offering biologists seamless, end-to-end solutions for existing assays. This blog will specifically discuss how the MCAM™ can be uniquely leveraged for experiments measuring distance traveled in response to stimuli by optimizing workflows, ensuring consistent and precise results, and minimizing concerns about experimental details.

When researchers investigate distance traveled by zebrafish in a controlled environment, they are not just measuring how far they swim — they are looking into a window of their neural and sensory processing. Motion tracking provides a quantifiable measure of the zebrafish’s activity, which can be indicative of their health, stress levels, and even cognitive responses.

The key to conducting these experiments is in the stimuli. These are controlled variables introduced to elicit an observable reaction from the zebrafish. Three primary stimuli are often used: light flashes, vibrations and sounds. Meticulously timed and varied in intensity and/or chromaticity, these stimuli allow researchers to measure the effect sensory inputs have on zebrafish perception.

Diving into stimuli

Visual stimuli are used to reproduce the natural light-dark cycle of the environment. Abrupt, unexpected changes in environmental lighting or visual patterns elicit acute responses. Most living things, animals, plants, and even bacteria expect their environmental lighting to remain consistent with the diurnal cycle. Therefore, unexpected changes cause the zebrafish to be startled and swim around.

The sedative effects of anxiolytics (anxiety reduction drugs) could be tested using this paradigm. It would be expected that an effective sedative would reduce the capacity of visual stimuli to induce a startle response in fish (Maximino et al., 2010). Light phase experiments such as the Visual Motor Response (VMR) assay employ longer light phases rather than quick flashes.

Furthermore, the option of exposing the zebrafish to chromatic stimuli is also crucial for studying their behavior because zebrafish have polychromatic vision and rely heavily on color cues to guide their actions (de Abreu et al., 2021). By manipulating the color and intensity of light stimuli, researchers can investigate how zebrafish perceive and respond to different visual environments, providing insights into their neural and sensory processing.

So…why the MCAM™?

The Multi-Camera Array Microscope (MCAM™) facilitates acquisitions with not only all of the aforementioned visual stimuli but also auditory and mechanical stimuli. Using straightforward workflows, such as the one represented in Fig. 1, researchers can expose samples to vibration at different frequencies and impact stimuli, generating physical disruptions rather than visual ones. These stimuli can be varied and combined to generate desired experimental parameters (see Fig. 2 for an example). The MCAM™ can uniformly administer these stimuli and capture reactions synchronously across the entire well plate, then analyze this data to provide precise results and visualizations, such as the one in Fig. 1C, resulting from the assay depicted in Fig. 1B.

At the stimulus level, the MCAM™ offers precise control over the timing and specifics of all stimuli the samples are exposed to — a level of detail not always available with traditional imaging techniques. This capability allows researchers to go from acquisition to results with just a few clicks (Fig. 1).

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Moreover, the ability to record 96 fish simultaneously is crucial, as it ensures identical experimental conditions across multiple samples, enhancing the validity of findings. Additionally, the high resolution of the MCAM™ is essential for capturing biologically relevant features and behavioral processes across various spatial scales, enabling inferences at both individual and population levels that might otherwise be missed.

Combining precise stimulus control/variation with the capacity to record 96 fish at high resolution makes the MCAM™ a particularly powerful solution for propelling this type of research.

References

• Maximino, C., de Brito, T. M., da Silva Batista, A. W., Herculano, A. M., Morato, S., & Gouveia Jr, A. (2010). Measuring anxiety in zebrafish: a critical review. Behavioural brain research, 214(2), 157–171.
• de Abreu, M. S., Giacomini, A. C., Genario, R., Dos Santos, B. E., Marcon, L., Demin, K. A., Galstyan, D.S., Strekalova, T., Amstislavskaya, T.G. & Kalueff, A. V. (2021). Color as an important biological variable in zebrafish models: Implications for translational neurobehavioral research. Neuroscience & Biobehavioral Reviews, 124, 1–15.

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