Animal intermittent locomotion: A null model for the probability of moving forward in bounded space

Christensen, Kim; Cocconi, Luca; Sendova‐Franks, Ana B.

doi:10.1016/j.jtbi.2020.110533

Cited by 6 publications

(7 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These patterns inspired a stochastic model that is compatible with the observations of the rodent cautious walks. A central observation is that the animals slow down in order to re-evaluate the environment, with its potential danger and rewards (these stops might further develop into fear-or startle-induced behavioral arrests [33], or present as just a punctuation in the ongoing locomotor activity [32]). To describe this, we assumed the existence of two interfering processes: in addition to the impulses to move arriving at random times, continuous deceleration must be taken into account.…”

Section: Discussionmentioning

confidence: 99%

“…Since in our experiments the rodent pups (below the age of solid food ingestion) demonstrated velocity patterns similar to those in adult animals (figures 4, 6, 8), we could not ascribe the stops or lingering to putative foraging attempts. As the decelerated episodes were characterized by the lateral head scans [57] and used for reorientation [32], we hypothesize that they reflect the process of risk assessment, necessary for prey animals in the wild. One might attribute the animals' deceleration (i.e, action-stopping) behavior to the so called proactive inhibition [60][61][62], a condition where inhibition is strongly facilitated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Two modes in the velocity statistics in cautious walks of laboratory rodents

Midzyanovskaya,

Rebik,

Idzhilova

et al. 2024

Preprint

View full text Add to dashboard Cite

We have analyzed a large number of rodent tracks in open-field tests, in order to elucidate the statistics of their velocities. We found that the probability distribution of the absolute velocity of rodents can be approximated by a superposition of two Rayleigh distributions, with distinct characteristic velocities v1 and v2 with v1 < v2; this is in contrast to the single Rayleigh distribution for the velocity of a Brownian particle executing 2D random motion. We propose that the part of the distribution near the larger velocity, v2, characterizes rodents' progressions in space, while the part near v1 describes other types of motion, such as lingering and body micromovements. We observed that the animals switched randomly between these two modes. While both velocities, v1 and v2, increase with age, their ratio, v2/v1, also grows with age, implying an increased efficacy of switches between the two modes in older animals. Since the existence of the modes is observed both in pre- weaned, blind pups and in older animals, it cannot be ascribed to foraging, but instead reflects risk assessment and proactive inhibition. We called such motion "cautious walks". Statistical analysis of the data further revealed a biphasic decline in the velocity auto-correlation function, with two characteristic times, ts < tl, where ts characterizes the width of velocity peaks, and tl is associated with the timing of the switches between progression and lingering. To describe the motion, we propose a stochastic model, which assumes the existence of two interfering processes: impulses to move that arrive at random times, and continuous deceleration. Its 2D Langevin-like equation has a damping coefficient that switches between two values, representing mode switching in rodents. Techniques developed here may be applicable for locomotion studies in a wide variety of contexts, as long as tracking data of sufficient resolution are available.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Two modes in the velocity statistics in cautious walks of laboratory rodents

Midzyanovskaya,

Rebik,

Idzhilova

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Animals tend to display saltatory patterns of movements [O’Brien et al, 1990], with pauses punctuating the tracks. The pauses are used to rest, forage or make a decision about the next move [Christensen et al 2015; Hunt et al, 2016;Christensen et al, 2021]. The locomotor strategies of previsual pups in the present experiments looked like a superposition of simplified trips and extended stops.…”

Section: Discussionmentioning

confidence: 99%

“…The random walks of animals can be affected by geometry of the space and its boundedness [Christensen et al, 2021]. In rodents, the boundary effects are the most prominent, since they prefer to move thigmotactically minimizing the risk of predation and maximizing security [Nemati et al, 2013;Whishaw et al, 2006].…”

Section: Methodsmentioning

confidence: 99%

Locomotor strategies inside the blind walks: freely moving previsual rat pups in the open field test

Midzyanovskaya

Strelkov

2022

Preprint

View full text Add to dashboard Cite

Blind walks of previsual rat pups in the open field test were considered as a supposedly random process. At this age, immature rats should rely only on non-visual modalities for sampling a novel space and constructing putative cognitive maps. Spontaneous locomotion of outbred Wistar rat infants (n=51) on their 13th postnatal day was tracked for 2 minutes and analyzed offline for the presence of random components and/or strategies of locomotion. Three distinct patterns were observed. A large portion of the pups (n=22) performed sub-diffusive localized walks in the center. A smaller cohort (n=9) undertook almost immediate quasi-linear raids in a random direction, thus succeeding in reaching a shelter (i.e., a wall vicinity). The rest (n=20) demonstrated a mixed strategy: localized walks interspersed with quasi-linear raids. An algorithm for automated segmentation of the open field trajectories into the localized walks and quasi-linear fragments was developed; the fragments were analyzed separately. Statistical analysis shows the localized walks to be diffusive (i.e., Brownian) only within 2-3 seconds, but essentially sub-diffusive for longer time scales. The autocorrelation function shows that sub-diffusion was caused by the re-attraction of trajectories. Self-odor traces can be a physical cue ensuring the effect. Gender or body weights were not significant predictors for any locomotor parameters. The localized walks can be considered as a primary level of idiothetically-cued path integration in previsual pups, whereas the run trials can be a form of an active escape response. The applied method of space potentials avails the automated functional segmentation of locomotor tracks and thus brings advantages of big data analysis for studying non-visual navigation in animals.

show abstract

“…We consider the sampling area to be non‐confined so that individuals can move beyond this region or even return during the course of their movement. This is to avoid any unnecessary geometry‐specific biases, or any complexities that can arise due to individual interactions in the case a boundary was present (Bearup & Petrovskii, 2015; Christensen et al, 2021; Cocconi et al, 2021).…”

Section: Modelling Movement and Trapping Of Ground‐dwelling Arthropodsmentioning

confidence: 99%

Simulating capture efficiency of pitfall traps based on sampling strategy and the movement of ground‐dwelling arthropods

Ahmed,

Beidas,

Petrovskii

et al. 2023

Methods Ecol Evol

View full text Add to dashboard Cite

Pitfall traps are frequently used to capture ground‐dwelling arthropods, particularly beetles, ants and spiders. The capture efficiency of a pitfall trapping system strongly depends on the number and opening size of traps, how traps are distributed over the sampling area (spatial arrangement) and the movement characteristics of arthropods. We use numerical simulations for a single species to analyse the trap count patterns that emerge from these variables. Arthropod movement of individuals is modelled as correlated random walks, with multiple traps placed over an area, and catches are simulated as individual interaction with traps. We consider four different types of spatial arrangements of traps across a homogeneous landscape: grid (i.e. rectangular array), transect, nested‐cross and randomised. We contextualise our results by considering the locomotion of Pterostichus melanarius, a highly active carabid beetle often serving as a biocontrol agent for the suppression of pest insects and weeds. By simulating the trapping of randomly moving ground‐dwelling arthropods, we show that there is an optimal inter‐trap separation distance (trap spacing) that maximises captures, that can be expressed using exact formulae in terms of trap opening sizes, sampling area and trap number. Moreover, for the grid and nested‐cross arrangements, larger trap spacing to maximise spatial coverage over the whole sampling area is suboptimal. Also, we find that over a large sampling area, there is a hierarchical order for spatial arrangements in relation to capture efficiency: grid, randomised, transect, followed by the nested‐cross. However, over smaller sampling areas, this order is changed as the rate at which trap counts accumulate with trap number varies across arrangements—eventually saturating at different levels. In terms of movement effects, capture efficiency is maximised over a narrow diffusive range and does not depend strongly on the type of spatial arrangement—indicating an approximate optimal mode of arthropod activity, i.e. rate of spread. Our approach simultaneously considers several important experimental design aspects of pitfall trapping providing a basis to optimise and adapt sampling protocols to other types of traps to better reflect their various purposes, such as monitoring, conservation or pest management.

show abstract

Animal intermittent locomotion: A null model for the probability of moving forward in bounded space

Cited by 6 publications

References 34 publications

Two modes in the velocity statistics in cautious walks of laboratory rodents

Two modes in the velocity statistics in cautious walks of laboratory rodents

Locomotor strategies inside the blind walks: freely moving previsual rat pups in the open field test

Simulating capture efficiency of pitfall traps based on sampling strategy and the movement of ground‐dwelling arthropods

Contact Info

Product

Resources

About