Aggregative mechanisms and behavior in ring-billed gulls departing from a colony

1985 ◽  
Vol 63 (12) ◽  
pp. 2767-2774 ◽  
Author(s):  
Roger M. Evans ◽  
Clive V. J. Welham

Departures of ring-billed gulls (Larus delawarensis) from a breeding colony were significantly clumped in time and space. Mean departure directions did not correlate among successive days, but were highly correlated with wind direction. Most gulls circling about the colony did not depart. Gulls that did depart typically flew directly away from the colony and approximately half emitted distinctive "contact" calls. Significantly more gulls departed when others were soaring on nearby thermals than at other comparable times. Playback experiments showed that contact calls and calls from thermal flocks attracted other gulls. A causal model of flock formation, derived from the assumption that temporal clumping arises from social facilitation superimposed upon random departure times, was supported by (i) random fly-up times by nondeparting gulls, (ii) demonstrated attractiveness of contact calls, (iii) characteristically direct flight paths of departing gulls, and (iv) by simulations of departing gulls. Social attraction, temporal and spatial grouping, wind, and visual contact between successively departing birds all appear to facilitate aggregation within localized regions of the habitat.

1982 ◽  
Vol 60 (6) ◽  
pp. 1388-1396 ◽  
Author(s):  
J. Brian E. O'Malley ◽  
Roger M. Evans

Observations of white pelicans commuting between nesting colonies and foraging areas revealed transitions from small, simple linear flock formations to larger, more complex vee and jay formations during departures, and the reverse during the return approach. Large, less-organized types of formations were relatively uncommon and short lived.Formation angles measured for filmed flocks ranged from 24° to 122° and were highly correlated with mean relative interbird distances within flocks. The number of wingbeats per hour, calculated from wingbeat frequency (beats per minute) and percent time flapping, was lowest in vee formation, progressively greater in jay, echelon, and column formation, and greatest for single birds. Wingbeats per hour decreased behind the lead bird, which usually had the highest rate, within each type of formation.Shifts between flapping and gliding were usually initiated by lead birds. Response times for these shifts were negatively related to flock size, and were shorter in vee and jay formations than in column and echelon formations.Our data suggests formation flight provides both aerodynamic–energetic and communication advantages over solitary flight.


2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Tianci Chu ◽  
Yi Ping Zhang ◽  
Zhisen Tian ◽  
Chuyuan Ye ◽  
Mingming Zhu ◽  
...  

Abstract Background The glial response in multiple sclerosis (MS), especially for recruitment and differentiation of oligodendrocyte progenitor cells (OPCs), predicts the success of remyelination of MS plaques and return of function. As a central player in neuroinflammation, activation and polarization of microglia/macrophages (M/M) that modulate the inflammatory niche and cytokine components in demyelination lesions may impact the OPC response and progression of demyelination and remyelination. However, the dynamic behaviors of M/M and OPCs during demyelination and spontaneous remyelination are poorly understood, and the complex role of neuroinflammation in the demyelination-remyelination process is not well known. In this study, we utilized two focal demyelination models with different dynamic patterns of M/M to investigate the correlation between M/M polarization and the demyelination-remyelination process. Methods The temporal and spatial features of M/M activation/polarization and OPC response in two focal demyelination models induced by lysolecithin (LPC) and lipopolysaccharide (LPS) were examined in mice. Detailed discrimination of morphology, sensorimotor function, diffusion tensor imaging (DTI), inflammation-relevant cytokines, and glial responses between these two models were analyzed at different phases. Results The results show that LPC and LPS induced distinctive temporal and spatial lesion patterns. LPS produced diffuse demyelination lesions, with a delayed peak of demyelination and functional decline compared to LPC. Oligodendrocytes, astrocytes, and M/M were scattered throughout the LPS-induced demyelination lesions but were distributed in a layer-like pattern throughout the LPC-induced lesion. The specific M/M polarization was tightly correlated to the lesion pattern associated with balance beam function. Conclusions This study elaborated on the spatial and temporal features of neuroinflammation mediators and glial response during the demyelination-remyelination processes in two focal demyelination models. Specific M/M polarization is highly correlated to the demyelination-remyelination process probably via modulations of the inflammatory niche, cytokine components, and OPC response. These findings not only provide a basis for understanding the complex and dynamic glial phenotypes and behaviors but also reveal potential targets to promote/inhibit certain M/M phenotypes at the appropriate time for efficient remyelination.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Colin A. Depp ◽  
Jesse Bashem ◽  
Raeanne C. Moore ◽  
Jason L. Holden ◽  
Tanya Mikhael ◽  
...  

Abstract Mobility is an important correlate of physical, cognitive, and mental health in chronic illness, and can be measured passively with mobile phone global positional satellite (GPS) sensors. To date, GPS data have been reported in a few studies of schizophrenia, yet it is unclear whether these data correlate with concurrent momentary reports of location, vary by people with schizophrenia and healthy comparison subjects, or associate with symptom clusters in schizophrenia. A total of 142 participants with schizophrenia (n = 86) or healthy comparison subjects (n = 56) completed 7 days of ecological momentary assessment (EMA) reports of location and behavior, and simultaneous GPS locations were tracked every five minutes. We found that GPS-derived indicators of average distance travelled overall and distance from home, as well as percent of GPS samples at home were highly correlated with EMA reports of location at the day- and week-averaged level. GPS-based mobility indicators were lower in schizophrenia with medium to large effect sizes. Less GPS mobility was related to greater negative symptom severity, particularly diminished motivation, whereas greater GPS mobility was weakly associated with more community functioning. Neurocognition, depression, and positive symptoms were not associated with mobility indicators. Therefore, passive GPS sensing could provide a low-burden proxy measure of important outcomes in schizophrenia, including negative symptoms and possibly of functioning. As such, passive GPS sensing could be used for monitoring and timely interventions for negative symptoms in young persons at high risk for schizophrenia.


2019 ◽  
Vol 31 (2) ◽  
pp. 233-269 ◽  
Author(s):  
Christophe Gardella ◽  
Olivier Marre ◽  
Thierry Mora

The principles of neural encoding and computations are inherently collective and usually involve large populations of interacting neurons with highly correlated activities. While theories of neural function have long recognized the importance of collective effects in populations of neurons, only in the past two decades has it become possible to record from many cells simultaneously using advanced experimental techniques with single-spike resolution and to relate these correlations to function and behavior. This review focuses on the modeling and inference approaches that have been recently developed to describe the correlated spiking activity of populations of neurons. We cover a variety of models describing correlations between pairs of neurons, as well as between larger groups, synchronous or delayed in time, with or without the explicit influence of the stimulus, and including or not latent variables. We discuss the advantages and drawbacks or each method, as well as the computational challenges related to their application to recordings of ever larger populations.


2021 ◽  
Author(s):  
Natalia Popa ◽  
Angela C Roberts ◽  
Andrea M Santangelo ◽  
Eduardo Gascon

Background: Neuroimaging studies have consistently reported that stress-related disorders such as depression and anxiety impinge on the activity of emotion regulation networks, namely in the ventromedial prefrontal cortex (vmPFC). This circuitry is known to be extensively modulated by serotonin and it has been long shown that genetic polymorphisms in the serotonin transporter gene (SLC6A4) are linked to anxiey and depression. vmPFC encompasses different brain regions in terms of cytoarchitecture, activity and connectivity. However, molecular heterogeneity within the vmPFC and how these differences affect emotional regulation and behavior have not been elucidated. Methods: Here, we took advantage of recently described polymorphisms in marmoset SLC6A4 gene linked to alter threat responses. Using FACS-sorted cells from different brain areas of genotyped marmosets, we tested the hypothesis that specific molecular changes in precise regions of the vmPFC underlie the behavioral differences and can be associated with high anxiety-like trait. Results: miRNA analysis of FACS-sorted cells from marmoset cortex revealed that clear miRNA profiles can be identified for different cell subsets (NeuN+ versus NeuN- cells) or cortical regions (visual cortex versus vmPFC). More importantly, marmosets bearing different SLC6A4 polymorphisms show distinct miRNAs signatures specifically in vmPFC area 32 neurons but not in the closely related vmPFC area 25 neurons. Finally, levels of these miRNAs were highly correlated to the anxiety-like score in a test of uncertain threat. Conclusions: These data demonstrate that molecular changes within area 32 likely underlie the differential anxiety-like responses associated with SLC6A4 polymorphisms.


2021 ◽  
Author(s):  
Anne Draelos ◽  
Maxim Nikitchenko ◽  
Chaichontat Sriworarat ◽  
Daniel Sprague ◽  
Matthew D. Loring ◽  
...  

AbstractNeuroscientists now routinely record the activity of large numbers of neurons at high temporal and spatial resolution. With these capabilities comes the promise of causally intervening during these recordings by perturbing neurons or changing experimental conditions, requiring tight integration between data acquisition, analysis, and manipulation. Unfortunately, solutions for real-time interventions are rare, difficult to design and implement, and remain largely unused. Here, we introduce improv, a software platform that allows users to flexibly specify and manage adaptive experiments to integrate data collection, preprocessing, visualization, and user-defined analytics. Using improv for streaming data analysis for two photon calcium imaging and behavior we demonstrate how access to online information can be used for automated, integrated experimentation.


Behaviour ◽  
2021 ◽  
pp. 1-20
Author(s):  
Estelle Meaux ◽  
Chao He ◽  
Luying Qin ◽  
Eben Goodale

Abstract Vocalizations that signal predation risk such as alarm calls provide crucial information for the survival of group-living individuals. However, alarm calling may attract the predator’s attention and, to avoid this cost, animals can opt for alternative strategies to indicate danger, such as ‘adaptive silence’, which is the cessation of vocalizations. We investigate here whether abrupt contact call cessation would provoke alarm responses, or would reinforce the signal given by an alarm call. In an aviary setting, we conducted playback experiments with a group-living passerine, the Swinhoe’s white-eye, Zosterops simplex. We found that birds did not respond to a sudden call cessation, nor did they have a stronger response to alarm calls followed by silence than to alarm calls followed by contact calls. Confirming previous work investigating contact call rate, it appears that in this species contact calls encode information about social factors but not environmental conditions.


2017 ◽  
Vol 14 (7) ◽  
pp. 546-551 ◽  
Author(s):  
Greg Welk ◽  
Youngwon Kim ◽  
Robin P. Shook ◽  
Laura Ellingson ◽  
Roberto L. Lobelo

Background:The study evaluated the concurrent and criterion validity of a new, disposable activity monitor designed to provide objective data on physical activity and energy expenditure in clinical populations.Methods:A sample of healthy adults (n = 52) wore the disposable Metria IH1 along with the established Sensewear armband (SWA) monitor for a 1-week period. Concurrent validity was examined by evaluating the statistical equivalence of estimates from the Metria and the SWA. Criterion validity was examined by comparing the relative accuracy of the Metria IH1 and the SWA for assessing walking/running. The absolute validity of the 2 monitors was compared by computing correlations and mean absolute percent error (MAPE) relative to criterion data from a portable metabolic analyzer.Results:The output from 2 monitors was highly correlated (correlations > 0.90) and the summary measures yielded nearly identical allocations of time spent in physical activity and energy expenditure. The monitors yielded statistically equivalent estimates and had similar absolute validity relative to the criterion measure (12% to 15% error).Conclusions:The disposable nature of the adhesive Metria IH1 monitor offers promise for clinical evaluation of physical activity behavior in patients. Additional research is needed to test utility for counseling and behavior applications.


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