Psychophysical investigation of vigilance decrement in jumping spiders: overstimulation or understimulation?

Independence and synergy of spatial attention in the two visual systems of jumping spiders

By selectively focusing on a specific portion of the environment, animals can solve the problem of information overload, toning down irrelevant inputs and concentrating only on the relevant ones. This may be of particular relevance for animals such as the jumping spider, which possess a wide visual field of almost 360 deg and thus could benefit from a low-cost system for sharpening attention. Jumping spiders have a modular visual system composed of four pairs of eyes, of which only the two frontal eyes (the anteromedial eyes, AMEs) are motile, whereas the other secondary pairs remain immobile. We hypothesised that jumping spiders can exploit both principal and secondary eyes for stimulus detection and attentional shift, with the two systems working synergistically. In experiment 1, we investigated the attentional responses of AMEs following a spatial cue presented to the secondary eyes. In experiment 2, we tested for enhanced attention in the secondary eyes' visual field congruent with the direction of the AMEs' focus. In both experiments, we observed that animals were faster and more accurate in detecting a target when it appeared in a direction opposite to that of the initial cue. In contrast with our initial hypothesis, these results would suggest that attention is segregated across eyes, with each system working on compensating the other by attending to different spatial locations.

The effect of interstimulus interval on sustained attention

The ability of nervous systems to filter out irrelevant and repetitive stimuli may prevent animals from becoming 'saturated' with excess information. However, animals must be particular about which stimuli to attend to and which to ignore, as mistakes may be costly. Using a comparative approach, we explored the effect of interstimulus interval (ISI) between repeated presentations of visual stimuli presented on a screen to test the decrease in responses (response decrement) of both Trite planiceps jumping spiders and untrained Columba livia pigeons, animals with comparable visual ability despite having structurally different visual systems and brain size. We used ISIs of 2.5 s, 5 s, 10 s, predicting that decreases in ISI would lead to progressively less responses to the stimuli. Following from previous work on T. planiceps, we also manipulated pigeon hunger level, finding that hungry birds were initially more responsive than sated pigeons, but the rate of decrease in responses to the stimulus did not differ between the two groups. While a clear response decrement was seen in both species across all conditions, shorter ISIs resulted in more dramatic response decrements, aligning with previous work and with the resource depletion theory posited in the human-based literature.

Long-range and cross-frequency neural modulation of gamma flicker on vigilance decrement

Vigilance decrement is a ubiquitous problem in attention-demanding tasks. Therefore, it is significant to develop neuromodulation methods to mitigate the negative neural effect of vigilance decrement. As one of the non-invasive brain stimulation techniques, visual flicker/rhythmic visual stimulation (RVS) has been proposed to entrain neural oscillations and thereby modulate cognitive processes supported by these brain rhythms, but its effects on vigilance decrement are still unclear. Here, we investigated the effect of gamma flicker on vigilance decrement and its underlying neural mechanism. Thirty participants were recruited to perform a 12-min vigilance task. They were required to discriminate the orientation of lateralized triangle targets with/without 40-Hz RVS background. As a result, it was found that 40-Hz RVS mitigated the decrease in perceptual sensitivity ( A ' ) with time-on-task, a typical adverse effect on behaviors caused by vigilance decrement. Electroencephalography (EEG) results showed that 40-Hz RVS could reduce the significant decline of post-stimulus theta-band inter-trial coherence (ITC) in the prefrontal cortex (PFC) with time-on-task. Regression analysis further revealed that the anterior theta-band ITC was significantly correlated to perceptual sensitivity ( A ' ) in a positive manner. These findings indicated that gamma flicker to the visual cortex had a cross-frequency neuromodulation effect on low-frequency EEG responses over the long-range PFC region. Furthermore, this study provides new insights into the neural effects of 40-Hz RVS, which could impact time-on-task effects on vigilance behaviors and alter the utilization of attentional resources.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-023-10008-6.

Will the real resource theory please stand up! Vigilance is a renewable resource and should be modeled as such

The vigilance decrement or decline in signal detection performance with time on task is one of the most reliable findings in the cognitive neuroscience and psychology literatures. The majority of theories proposed to explain the decrement are limited cognitive or attention resource based theories; the central nervous system is a limited capacity processor. The decrement in performance is then due to resource reallocation (or misallocation), resource depletion or some combination of both mechanisms. The role of resource depletion, in particular, is hotly debated. However, this may be due to a lack of understanding of the renewable nature of the vigilance resources and how this renewal process impacts performance during vigilance tasks. In the present paper, a simple quantitative model of vigilance resource depletion and renewal is described and shown to generate performance data similar to results seen in both humans and spiders. This model clarifies the role resource depletion and resource renewal may play in vigilance in both people and other animals.

When to Return to Normal? Temporal Dynamics of Vigilance in Four Situations

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation.

Perception of biological motion by jumping spiders

The body of most creatures is composed of interconnected joints. During motion, the spatial location of these joints changes, but they must maintain their distances to one another, effectively moving semirigidly. This pattern, termed "biological motion" in the literature, can be used as a visual cue, enabling many animals (including humans) to distinguish animate from inanimate objects. Crucially, even artificially created scrambled stimuli, with no recognizable structure but that maintains semirigid movement patterns, are perceived as animated. However, to date, biological motion perception has only been reported in vertebrates. Due to their highly developed visual system and complex visual behaviors, we investigated the capability of jumping spiders to discriminate biological from nonbiological motion using point-light display stimuli. These kinds of stimuli maintain motion information while being devoid of structure. By constraining spiders on a spherical treadmill, we simultaneously presented 2 point-light displays with specific dynamic traits and registered their preference by observing which pattern they turned toward. Spiders clearly demonstrated the ability to discriminate between biological motion and random stimuli, but curiously turned preferentially toward the latter. However, they showed no preference between biological and scrambled displays, results that match responses produced by vertebrates. Crucially, spiders turned toward the stimuli when these were only visible by the lateral eyes, evidence that this task may be eye specific. This represents the first demonstration of biological motion recognition in an invertebrate, posing crucial questions about the evolutionary history of this ability and complex visual processing in nonvertebrate systems.

Attention and distraction in the modular visual system of a jumping spider

Animals must selectively attend to relevant stimuli and avoid being distracted by unimportant stimuli. Jumping spiders (Salticidae) do this by coordinating eyes with different capabilities. Objects are examined by a pair of high-acuity principal eyes, whose narrow field of view is compensated for by retinal movements. The principal eyes overlap in field of view with motion-sensitive anterior-lateral eyes (ALEs), which direct their gaze to new stimuli. Using a salticid-specific eyetracker, we monitored the gaze direction of the principal eyes as they examined a primary stimulus. We then presented a distractor stimulus visible only to the ALEs and observed whether the principal eyes reflexively shifted their gaze to it or whether this response was flexible. Whether spiders redirected their gaze to the distractor depended on properties of both the primary and distractor stimuli. This flexibility suggests that higher-order processing occurs in the management of the attention of the principal eyes.

SPiDbox: design and validation of an open-source "Skinner-box" system for the study of jumping spiders

BACKGROUND

Skinner-box systems are fundamental in behavioural research. They are objective, reliable and can be used to carry out procedures otherwise impossible with manual methodologies. Recently, jumping spiders have caught the interest of scientists for their remarkable cognitive abilities. However, inquiries on their learning abilities are still few, since we lacked a proper methodology capable of overcoming the inherent difficulties that this family poses when carrying out a conditioning protocol.

NEW METHOD

In this paper, a new, automated, open-source Skinner-box, intended for the study of jumping spiders is presented. The system is 3d printable, cheap, fully open-source; is controlled with a Raspberry Pi Zero by a Python script. Since spiders are too lightweight to activate large physical object, the SPiDbox employs photo-sensors.

RESULTS

To validate the methodology, 30 Phidippus regius underwent a training procedure for a simple discrimination task to validate the effectiveness of the system. The spiders managed to learn the task, establishing the effectiveness of the SPiDbox.

COMPARISON WITH EXISTING METHODS

This automated training appears to be more reliable and effective than traditional methodologies. Moreover, its highly scalable, as many SPiDboxes could be used in parallel.

CONCLUSIONS

The SPiDbox appears to be an effective system to train jumping spiders, opening up the possibility to study learning in increasingly more complex tasks, possibly extending our understanding of jumping spiders' cognitive abilities.

Computational Modeling of the Effects of Sleep Deprivation on the Vigilance Decrement

OBJECTIVE

We developed a computational model of the effects of sleep deprivation on the vigilance decrement by employing the methods of system dynamics modeling.

BACKGROUND

Situations that require sustained attention for a prolonged duration can cause a decline in cognitive performance, the so-called vigilance decrement. One factor that should influence the vigilance decrement is fatigue in the form of sleep deprivation.

METHOD

We employed the methods of system dynamics modeling (numerical-integration techniques for modeling complex feedback systems) to create a computational model of the vigilance decrement. We then simulated the computational effects of sleep deprivation on the behavior of that model, using empirical data obtained from the literature for calibrating such effects.

RESULTS

Sleep deprivation of 2 hr over a 14-day period should produce an additional decline of 9% in detection performance over that found with the typical vigilance decrement, whereas 4 hr of sleep deprivation over 14 days should produce an additional decline of 14% in detection performance.

CONCLUSION

With respect to dual-process theory, it is through its deleterious effects on analytical cognition that sleep deprivation should impact the vigilance decrement.

APPLICATION

Such computational modeling may be advantageous for human-machine teaming by theoretically allowing a future autonomous software agent to anticipate the decline of human performance and compensate accordingly.