Zone Preference in the Visual Water Maze
June 26, 2025
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Sonicators are high-frequency tools (20 kHz) that use ultrasonic energy to agitate particles in liquids. These devices are employed to facilitate a wide variety of processes, such as mixing, cleaning, degassing, cell disruption, and sample preparation.
Note that when sound travels through air, solids, and liquids in the form of sound waves, sound energy is manifested as vibration, with sound waves with higher frequency causing more vibrations. Vibrations in solutions, on the other hand, lead to cavitation – or the formation of vacuum bubbles – which allows sonicators to facilitate dissolution, homogenization, milling, cell lysis, chemical reactions, degassing, deagglomeration, and cleaning.
Sonication devices are indispensable in research and production settings. Note that such devices can be divided into bath sonicators and probe sonicators. Bath sonicators are ultrasonic tools that spread energy diffusely, making them invaluable for the processing of large volumes, cleaning, sterilizing, and degassing. As bath sonicators do not require a lot of power, they are more durable and affordable units. That said, bath sonicators can’t be employed for small particle sizes, and due to the uneven energy they produce, they do not support replication.
Probe sonicators, on the other hand, allow the particles around the probe to be blasted with high levels of energy, which is ideal for size reduction, cell disruption, emulsification, and dispersion of nanoparticles. Note that these devices are also called cell disruptors and ultrasonic homogenizers. Even though probe sonicators are highly sophisticated units (usually more costly than bath sonicators), we should note that erosion of the probe tip might lead to cross-contamination.
Probe sonicators and ultrasonic baths are invaluable scientific tools. Choosing a sonicator, however, can be a tricky task. Prospective buyers should consider three major aspects before purchasing a new unit: requirements, specifications, and total costs.
Requirements: Sonicators can be used for different purposes, such as degassing, cleaning, mixing, and cell disruption. Such instruments can be employed to substitute stirring; they can also provide the energy needed to catalyze chemical reactions and promote mixing and dissolution. As sonicators can disrupt cell membranes, they can be used in enhanced drug delivery and nanoparticle dispersion in liquids. Furthermore, sonicators can be employed to break adhesion bonds and clean instruments and lab equipment. Based on the specific research goals, experts can choose between probe and bath sonicators. As explained above, bath sonicators are ideal for cleaning and degassing, while probe sonicators are suitable for cell disruption and nanoparticle dispersion. Interestingly, ultrasonic baths can be used not only by professionals but hobbyists to clean jewelry, coins, and watches.
Specifications: Given their diverse applications, it’s no surprise sonicators come in all shapes and sizes. Yet, all sonication devices are based on the phenomenon of sonication or the use of sound energy to agitate particles. Probe sonicators, for instance, are made of three parts in order to agitate particles: 1) generator that provides electronic pulses; 2) converter that transforms the pulses into mechanical vibrations; 3) probe/horn that rests in the sample and transmits the vibrations to it. Note that sonication results in heat energy; thus, if samples are too fragile to stand sonication, experts can employ other processes (e.g., enzyme digestion).
Total costs: Many factors can add to the final price of a sonicator, including the type of the unit, its parameters, and additional features (e.g., digital timer). Note that bath sonicators are significantly more affordable than probe sonicators. When it comes to probe sonicators, users should consider buying different probe tips for different volumes. To be more precise, depending on the sample volume and the size and shape of the vessel, experts can choose from different probes. A ½-inch probe, for example, can process 20-250 ml, whereas microtips can be used for tiny vessels or samples of less than 50 ml. The type of the sample (e.g., aqueous samples) also has to be considered when choosing a probe (e.g., a solid tip for solvents). Additional parts, such as a booster horn that can increase the intensity of certain probes, should also be considered.
Sonicators are invaluable tools used in research and production settings. Given the wide applications of sonication, it’s no surprise there are many different types of probe sonicators, and ultrasonic baths experts can choose from. Based on different parameters and user reviews, here are the best bath and probe sonicators on the market:
Qsonica Q700-220 Sonicator with Touch Screen Control and Advanced Programming Features, 220V, 700W is one of the most advanced and reliable probe sonicators on the market. The unit comes with a touch-screen interface, which provides a user-friendly experience and easy-to-manage programming. Note that the applied energy is displayed in both Watts and Joules for convenience. Additionally, the unit’s internal circuitry guarantees efficient operation, sample-to-sample consistency, and reproducibility. With a power output of up to 700 Watts, a full amplitude control, and different features, this Qsonica unit is ideal for the processing of small and large samples across different settings.
Qsonica Q55-110 Q55 Sonicator Ultrasonic Processor, 110 VAC is another popular ultrasonic processor manufactured by Qsonica. This ultrasonic device is ideal for various applications, such as cell disruption, emulsions, and mixing. Note that the unit runs on 55 Watts. With its compact design, this sonicator is ideal for small volume processing and busy labs with limited floor space.
Qsonica Q500-220 Programmable Sonicator, Includes 1/2″ Probe with Replaceable Tip, 220V, 500W is a powerful ultrasonic processor that is equipped with a digital display, a 500 Watt generator, and set time and amplitude for hands-free processing. Given its high-level performance and versatile features, this sonicator is ideal for numerous applications, such as cell lysis, nanoparticle dispersion, and homogenization.
FS-1800N Ultrasonic Homogenizer/Sonicator/Processor/Disruptor/Mixer, 1800W, 100-3000 ml, 110V or 220V is an advanced ultrasonic unit with a novel design. Note that this sonicator comes with a large LCD display, as well as a temperature indicator and controller, in order to enhance user comfort and accurate use. From homogenization to mixing, this sonicator is ideal for various research and production settings.
BRANSON ULTRASONICS 101-063-199 Model S-450A Sonifier – Analog Cell Disruptor with 1/2″ Tapped Horn, 400W, 230V, 50/60 Hz, 7-3/8″ W x 17-5/8″ D x 9-5/8″ H is a versatile sonifier that comes with a range of accessories for customization. It provides quick control and access, as well as fully-automatic tuning (with stored frequency at the end of each cycle). The unit comes with a mechanical timer that can be set to continuous or timed (0-15 minutes) processing; it also has a pulsed mode to minimize heat generation and protect sensitive samples. With numerous features, this sonicator is one of the best models on the market.
Branson 101-063-969R SFX550 Sonifier Cell Disruptor with 1/2″ Tapped Probe, 20 kHz, 550W, 120V is one of the most advanced sonifiers manufactured by Branson Ultrasonics which comes with advanced energy model and temperature control. Note that the unit can handle high-volume processing with up to 550 Watts of output power. Given its high quality, this sonicator is ideal for experiments of all sizes and different applications.
CGOLDENWALL 2 in 1 Ultrasonic/Homogenizer/Sonicator/Processor/Lab Cell Disruptor/Mixer/Analysis of Ultrasonic Processor CE, 100-240V, 24 kHz, Integrated (800W, 100~1200 ml) is a great ultrasonic homogenizer suitable for different applications. This sonicator comes with an LCD screen that can store up to 10 sets of data and various parameters, such as display time, power, frequency, and temperature. It also has LED illumination, which facilitates monitoring. The unit has a unique design, including a soundproof box, making it highly popular in research.
Branson CPX-952-118R Series CPXH Digital Cleaning Bath with Digital Timer and Heater, 0.5 Gallons Capacity, 120V is a powerful digital ultrasonic bath. Note that experts can set temperatures from 20°C/68°F to 69°C/156.2°F. The unit is also equipped with programmable capabilities and self-adaptive technology. Note that all Branson ultrasonic baths can be used for different applications, such as cell separation, sample preparation, and degassing of liquids.
VEVOR Ultrasonic Homogenizer, 2-100 ml Lab Ultrasonic Sonicator Processor, 20KHz Cell Disruptor/Mixer is a great ultrasonic processor that can process 2-100 ml volume solution at a 20 kHz frequency. Note that its pulse timer is On/Off settable (from one second to 99 minutes). Additionally, this homogenizer has an LCD display to improve user experience. With different features, this unit can be used for different applications, such as cell disruption, as well as non-biological emulsions, mixing, homogenization, cleaning, and catalytic chemical reactions.
CO-Z 3L Professional Ultrasonic Cleaner with Digital Timer & Heater for Jewelry, Glasses, Watch, Dentures, Small Parts, Circuit Board, Dental Instrument, Industrial Commercial Ultrasound Cleaning Machine, 110V is a powerful ultrasonic cleaner ideal for oxidation, extraction, cleaning, and cavitation. Note that the unit comes with pre-set cleaning time options (1-30 minutes) for convenience. Its extra-thick tank (0.04 inches) made of stainless steel (with a 0.8Gal/3L volume) and its integrated cleaning basket (9.4 x 5.3 x 3.9 inches) are perfect for different products, such as jewelry, PC boards, razors, and laboratory equipment.
Taking care of sonicators is essential to guarantee long and accurate use. Always consult your instruction manual to ensure proper setup, maintenance, and storage! Note that high fluctuations of +/- 20 Watts may indicate a problem with the unit and its setup or the sample. Foaming is another problem that may occur with small samples (of less than 1 ml). Thus, always use a probe of the appropriate size to extend its lifetime and reduce processing times.
Safety is another major factor to consider. Note that although sonication uses ultrasound waves of above 20 kHz or 20,000 cycles per second, which is above what people can hear, ear protection is still recommended (sonicators may produce scraping noises). Additionally, never touch an ultrasonic probe as it can cause burns (note that often samples are chilled before and during ultrasonic processing).
Sonicators are vital lab tools used for a wide range of applications, such as degassing, mixing, cleaning, cell disruption, and dissolution. By using sound energy, sonicators allow no-touch manipulations of different samples. Before buying a sonicator, users should consider three major factors: requirements, specifications, and total costs. Here we should note there are two types of sonicators: bath sonicators that are ideal for cleaning and degassing, and probe sonicators suitable for cell disruption and nanoparticle dispersion, with probe sonicators being more costly than ultrasonic baths. When it comes to probe sonicators, users should consider purchasing different accessories, such as booster horns and different probe tips for different volumes and sample types. Maintenance and safety are also crucial to ensure a sonicator’s long life and accurate use.
To sum up, sonication or the use of sound energy to agitate particles in solutions is one of the most powerful phenomena employed to support research and production, with probe sonicators and ultrasonic baths being invaluable scientific tools.
In behavioral neuroscience, the Open Field Test (OFT) remains one of the most widely used assays to evaluate rodent models of affect, cognition, and motivation. It provides a non-invasive framework for examining how animals respond to novelty, stress, and pharmacological or environmental manipulations. Among the test’s core metrics, the percentage of time spent in the center zone offers a uniquely normalized and sensitive measure of an animal’s emotional reactivity and willingness to engage with a potentially risky environment.
This metric is calculated as the proportion of time spent in the central area of the arena—typically the inner 25%—relative to the entire session duration. By normalizing this value, researchers gain a behaviorally informative variable that is resilient to fluctuations in session length or overall movement levels. This makes it especially valuable in comparative analyses, longitudinal monitoring, and cross-model validation.
Unlike raw center duration, which can be affected by trial design inconsistencies, the percentage-based measure enables clearer comparisons across animals, treatments, and conditions. It plays a key role in identifying trait anxiety, avoidance behavior, risk-taking tendencies, and environmental adaptation, making it indispensable in both basic and translational research contexts.
Whereas simple center duration provides absolute time, the percentage-based metric introduces greater interpretability and reproducibility, especially when comparing different animal models, treatment conditions, or experimental setups. It is particularly effective for quantifying avoidance behaviors, risk assessment strategies, and trait anxiety profiles in both acute and longitudinal designs.
This metric reflects the relative amount of time an animal chooses to spend in the open, exposed portion of the arena—typically defined as the inner 25% of a square or circular enclosure. Because rodents innately prefer the periphery (thigmotaxis), time in the center is inversely associated with anxiety-like behavior. As such, this percentage is considered a sensitive, normalized index of:
Critically, because this metric is normalized by session duration, it accommodates variability in activity levels or testing conditions. This makes it especially suitable for comparing across individuals, treatment groups, or timepoints in longitudinal studies.
A high percentage of center time indicates reduced anxiety, increased novelty-seeking, or pharmacological modulation (e.g., anxiolysis). Conversely, a low percentage suggests emotional inhibition, behavioral avoidance, or contextual hypervigilance. reduced anxiety, increased novelty-seeking, or pharmacological modulation (e.g., anxiolysis). Conversely, a low percentage suggests emotional inhibition, behavioral avoidance, or contextual hypervigilance.
The percentage of center time is one of the most direct, unconditioned readouts of anxiety-like behavior in rodents. It is frequently reduced in models of PTSD, chronic stress, or early-life adversity, where animals exhibit persistent avoidance of the center due to heightened emotional reactivity. This metric can also distinguish between acute anxiety responses and enduring trait anxiety, especially in longitudinal or developmental studies. Its normalized nature makes it ideal for comparing across cohorts with variable locomotor profiles, helping researchers detect true affective changes rather than activity-based confounds.
Rodents that spend more time in the center zone typically exhibit broader and more flexible exploration strategies. This behavior reflects not only reduced anxiety but also cognitive engagement and environmental curiosity. High center percentage is associated with robust spatial learning, attentional scanning, and memory encoding functions, supported by coordinated activation in the prefrontal cortex, hippocampus, and basal forebrain. In contrast, reduced center engagement may signal spatial rigidity, attentional narrowing, or cognitive withdrawal, particularly in models of neurodegeneration or aging.
The open field test remains one of the most widely accepted platforms for testing anxiolytic and psychotropic drugs. The percentage of center time reliably increases following administration of anxiolytic agents such as benzodiazepines, SSRIs, and GABA-A receptor agonists. This metric serves as a sensitive and reproducible endpoint in preclinical dose-finding studies, mechanistic pharmacology, and compound screening pipelines. It also aids in differentiating true anxiolytic effects from sedation or motor suppression by integrating with other behavioral parameters like distance traveled and entry count (Prut & Belzung, 2003).
Sex-based differences in emotional regulation often manifest in open field behavior, with female rodents generally exhibiting higher variability in center zone metrics due to hormonal cycling. For example, estrogen has been shown to facilitate exploratory behavior and increase center occupancy, while progesterone and stress-induced corticosterone often reduce it. Studies involving gonadectomy, hormone replacement, or sex-specific genetic knockouts use this metric to quantify the impact of endocrine factors on anxiety and exploratory behavior. As such, it remains a vital tool for dissecting sex-dependent neurobehavioral dynamics.
The percentage of center time is one of the most direct, unconditioned readouts of anxiety-like behavior in rodents. It is frequently reduced in models of PTSD, chronic stress, or early-life adversity. Because it is normalized, this metric is especially helpful for distinguishing between genuine avoidance and low general activity.
Environmental Control: Uniformity in environmental conditions is essential. Lighting should be evenly diffused to avoid shadow bias, and noise should be minimized to prevent stress-induced variability. The arena must be cleaned between trials using odor-neutral solutions to eliminate scent trails or pheromone cues that may affect zone preference. Any variation in these conditions can introduce systematic bias in center zone behavior. Use consistent definitions of the center zone (commonly 25% of total area) to allow valid comparisons. Software-based segmentation enhances spatial precision.
Evaluating how center time evolves across the duration of a session—divided into early, middle, and late thirds—provides insight into behavioral transitions and adaptive responses. Animals may begin by avoiding the center, only to gradually increase center time as they habituate to the environment. Conversely, persistently low center time across the session can signal prolonged anxiety, fear generalization, or a trait-like avoidance phenotype.
To validate the significance of center time percentage, it should be examined alongside results from other anxiety-related tests such as the Elevated Plus Maze, Light-Dark Box, or Novelty Suppressed Feeding. Concordance across paradigms supports the reliability of center time as a trait marker, while discordance may indicate task-specific reactivity or behavioral dissociation.
When paired with high-resolution scoring of behavioral events such as rearing, grooming, defecation, or immobility, center time offers a richer view of the animal’s internal state. For example, an animal that spends substantial time in the center while grooming may be coping with mild stress, while another that remains immobile in the periphery may be experiencing more severe anxiety. Microstructure analysis aids in decoding the complexity behind spatial behavior.
Animals naturally vary in their exploratory style. By analyzing percentage of center time across subjects, researchers can identify behavioral subgroups—such as consistently bold individuals who frequently explore the center versus cautious animals that remain along the periphery. These classifications can be used to examine predictors of drug response, resilience to stress, or vulnerability to neuropsychiatric disorders.
In studies with large cohorts or multiple behavioral variables, machine learning techniques such as hierarchical clustering or principal component analysis can incorporate center time percentage to discover novel phenotypic groupings. These data-driven approaches help uncover latent dimensions of behavior that may not be visible through univariate analyses alone.
Total locomotion helps contextualize center time. Low percentage values in animals with minimal movement may reflect sedation or fatigue, while similar values in high-mobility subjects suggest deliberate avoidance. This metric helps distinguish emotional versus motor causes of low center engagement.
This measure indicates how often the animal initiates exploration of the center zone. When combined with percentage of time, it differentiates between frequent but brief visits (indicative of anxiety or impulsivity) versus fewer but sustained center engagements (suggesting comfort and behavioral confidence).
The delay before the first center entry reflects initial threat appraisal. Longer latencies may be associated with heightened fear or low motivation, while shorter latencies are typically linked to exploratory drive or low anxiety.
Time spent hugging the walls offers a spatial counterbalance to center metrics. High thigmotaxis and low center time jointly support an interpretation of strong avoidance behavior. This inverse relationship helps triangulate affective and motivational states.
By expressing center zone activity as a proportion of total trial time, researchers gain a metric that is resistant to session variability and more readily comparable across time, treatment, and model conditions. This normalized measure enhances reproducibility and statistical power, particularly in multi-cohort or cross-laboratory designs.
For experimental designs aimed at assessing anxiety, exploratory strategy, or affective state, the percentage of time spent in the center offers one of the most robust and interpretable measures available in the Open Field Test.
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