Zone Preference in the Visual Water Maze
June 26, 2025
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Spotting scopes are popular optical units that provide enlarged images of distant objects, ideal for large distance viewing and different activities, such as hunting, birding, camping, surveillance, and stargazing. Spotting scopes can also be defined as portable telescopes that present erected images in order to facilitate the observation of terrestrial objects.
Here we should note that it was spectacle-maker Hans Lippershey, who was credited as the inventor of the first refractor telescope in the 17th century, and Galileo Galilei, who pointed the telescope towards the skies. Over the years, advancements in lens technology led to the creation of reflecting and catadioptric telescopes. Interestingly, one of the main advancements that enhanced the creation of spotting scopes was the employment of prism-erecting systems to correct image orientation, launched in 1854 by Ignazio Porro and Jean Georges Hofmann.
Today, there are many telescopic units available on the market. While large-scale telescopes are the main optical instruments scientists utilize to study the universe, both seasoned users and enthusiasts can choose from a wide range of telescopes, spotting scopes, binoculars, and monoculars. Note that telescopes are the most powerful units that can be used for both terrestrial use and amateur astronomy. While there are numerous portable telescopes, spotting scopes and monoculars are also defined as portable telescopes that are ideal for terrestrial view and outdoor adventures. Spotting scopes often require the use of a tripod, just like telescopes, whereas monoculars are held in one’s hand like binoculars. Binoculars, on the other hand, require the use of both eyes and are defined as two telescopes mounted on a single frame. An interesting question is where a monocular ends and a telescope starts. Usually, telescopes and spotting scopes have high magnification rates of over 20X and an aperture between 50 mm and 90 mm, while popular parameters for monoculars and binoculars are 7×25, 8×30, 8×42, and 10×42, with monoculars being the smallest units on the market.
With a variety of optical units for sale, however, choosing a spotting scope can be a daunting task. Prospective buyers should consider three major factors: requirements, specifications, and total costs.
Requirements: Before purchasing a spotting scope, users should refine their goals. Buyers should decide what they’ll use the scope for (e.g., birding, hunting) and where they’ll be using it (e.g., low-light environments). Note that low-light performance can be improved by the use of bigger objective lenses. The size of the unit and its durability should also be considered, especially when choosing a hunting scope. Note that to improve usability outdoors, some spotting scopes can be quite small (8-35X) and held like monoculars. Waterproof units with durable armor, on the other hand, are required when hunting, camping, and hiking to resist harsh weather.
Specifications: Two of the main specifications to consider are magnification and lens diameter. Note that a high magnification level requires a large objective lens. To provide an example, a 60×80 unit (with 60X being the magnification level and 80 mm the aperture) is a highly-sufficient scope. The type of erecting system (roof or Porro prism) is also essential. Last but not least, the field of view and eye relief should be considered, especially by glasses wearers. Note that a large field of view is ideal for fast-moving targets (e.g., birds). That being said, the field of view decreases with magnification; thus, spotting scopes often have interchangeable eyepieces or a zoom system to provide different magnifications.
Total costs: Given the variety of units and competitors on the market, prices can vary significantly, with high-quality products being more costly. The materials used can also affect prices. Note that when it comes to prisms, BAK-4 glass prisms are considered as high-quality products. Additionally, coatings can affect costs; optics can be coated, fully coated, multi-coated, and fully multi-coated to prevent reflection and improve usability. Last but not least, from tripods to carrying bags, buying accessories is also essential.
Although there’s a wide range of units for sale, we should mention there are two main types of spotting scopes. Depending on the angle, the unit’s eyepiece forms with the scope’s body, there are straight-through (on the same axis as the scope) and angled (at an angle of 45 degrees to the scope) models. Based on different parameters and user reviews, here are the best spotting scopes on the market.
Gosky HD 15-45×60 Porro Prism Spotting Scope is a powerful spotting scope with a fully multi-coated 60 mm lens and a high-quality prism system. Note that the unit provides 15-45X magnification and a dynamic lens focusing system. This scope has a durable and waterproof design, which makes it ideal for outdoor activities and harsh weather. Furthermore, the unit comes with a digiscoping adapter, a carrying bag, a tripod, protection covers, and a manual.
Celestron 52249 65mm Ultima Spotting Scope – Straight is a compact spotting scope with a 65 mm lens and 18-55X zoom magnification. Note that the unit features a straight-through viewing angle, multi-coated optics, and a sight tube for fast targeting. Furthermore, this scope is waterproof and comes with a soft carrying case, which makes it ideal for hiking and other outdoor adventures.
Vanguard Endeavor XF Angled Eyepiece Spotting Scope is another powerful scope ideal for hunting, birding, and wildlife watching. The unit has fully multi-coated optics, BAK-4 roof prism, and a rubber-armored magnesium body. Note that it features 20-60X zoom magnification and an 80 mm aperture. With a long eye relief and an angled eyepiece, this water and fog-proof unit is simply an excellent gift choice, especially for glasses wearers.
BARSKA Colorado Waterproof Spotting Scope is a great unit with a 60 mm objective lens and 20-60X adjustable zoom magnification to deliver crisp images. Note that the set includes a pan-head tripod, a carry case, and a strap. With its high-quality rubber armoring and nitrogen purged construction, this spotting scope is ideal for hiking, targeting, hunting, astronomy, and marine observation.
Eyeskey Spotting Scope – Waterproof is a powerful spotting scope that offers excellent quality and crisp images. With 20-60X magnification and 80 mm aperture, as well as fully multi-coated optics and BK-7 prism, the unit is ideal for various settings, such as hunting, birding, and general observation. Note that this scope has a twist-up eyecup to improve user comfort.
Celestron 52257 Ultima 100 Straight Spotting Scope is a powerful and popular unit. This straight scope is ideal for outdoor enthusiasts as it features a 100 mm aperture and 20-60X magnification. Note that the set includes numerous accessories, such as an extended tripod mounting plate, a zoom eyepiece, an integrated T-adapter for digiscoping, a carrying case, protection caps, a lens cloth, and an instruction manual.
Bushnell Trophy Xtreme Spotting Scope is a compact spotting scope with 12-36X magnification and 50 mm aperture. Its multi-coated optics and waterproof design make it ideal for dusk conditions and harsh weather. Additionally, the scope comes with a compact tripod, a car window mount, a soft carrying case, as well as a premium hard-sided case.
Visionking 25-75×70 Maksutov Spotting Scope – 100% Waterproof Bak-4 with Tripod (Green) is a great 25-70×70 unit with sturdy armor. Note that the unit is equipped with a BAK-4 prism for better light transmission. This spotting scope is light and easy to operate, which makes it suitable for hunting, birding, and hiking.
Vortex Optics Viper HS-T 4-16×44 Second Focal Plane Riflescopes is a powerful rifle scope. With 4-16X zoom magnification and 44 mm aperture, this scope provides crisp images and high resolution. Furthermore, its VMR-1 reticle (MOA) is perfect for accurate holds and extended ranges, with a fast-focus eyepiece that allows users to adjust the reticle properly. With solid aircraft-grade aluminum construction, this unit is ideal for shooting and harsh conditions.
ROXANT High-Definition Ultra-Light Mini Monocular, Pocket Scope is a wonderful pocket scope. With its compact design, this 7×18 unit is perfect for climbing, traveling, boating, and people with impaired vision. Note that the unit features high-definition optical glass and multi-coated optics. Last but not least, this monocular scope comes with a carry pouch, a cleaning cloth, and a neck strap.
Spotting scopes are complex systems, so adequate maintenance is a must. Proper cleaning, transportation, and storage are essential. Note that cleaning should be done carefully, with a special cloth/brush, compressed air, or solution.
Storing units is also crucial to reduce possible adverse effects. Thus, always use protective lenses and dust caps and keep units in a moisture-free environment.
Spotting scopes are popular optical units that provide enlarged images of distant objects. While users can choose from a wide range of telescopes, monoculars, scopes, and binoculars, we should note that spotting scopes are among the most powerful units ideal for large distance viewing and different applications. To be more precise, scopes can be used for hunting, birding, camping, surveillance, shooting, and stargazing.
Before buying a spotting scope, however, users should consider three major factors: requirements, specifications, and costs. Note that aperture, magnification, eye relief, materials used, digital features, and accessories are all factors to consider. Usually, telescopes and spotting scopes have high magnification rates of over 20X and an aperture of 50-90 mm. Users should also remember that taking proper care of telescopic equipment is essential to guarantee long and accurate use.
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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