skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: How cognitive and reactive fear circuits optimize escape decisions in humans
Flight initiation distance (FID), the distance at which an organism flees from an approaching threat, is an ecological metric of cost–benefit functions of escape decisions. We adapted the FID paradigm to investigate how fast- or slow-attacking “virtual predators” constrain escape decisions. We show that rapid escape decisions rely on “reactive fear” circuits in the periaqueductal gray and midcingulate cortex (MCC), while protracted escape decisions, defined by larger buffer zones, were associated with “cognitive fear” circuits, which include posterior cingulate cortex, hippocampus, and the ventromedial prefrontal cortex, circuits implicated in more complex information processing, cognitive avoidance strategies, and behavioral flexibility. Using a Bayesian decision-making model, we further show that optimization of escape decisions under rapid flight were localized to the MCC, a region involved in adaptive motor control, while the hippocampus is implicated in optimizing decisions that update and control slower escape initiation. These results demonstrate an unexplored link between defensive survival circuits and their role in adaptive escape decisions.  more » « less
Award ID(s):
1727007
PAR ID:
10120943
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
115
Issue:
12
ISSN:
0027-8424
Page Range / eLocation ID:
3186 to 3191
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Current Zoology)
    Zhi-Yun (Ed.)
    Abstract Escape theory has been exceptionally successful in conceptualizing and accurately predicting effects of numerous factors that affect predation risk and explaining variation in flight initiation distance (FID; predator–prey distance when escape begins). Less explored is the relative orientation of an approaching predator, prey, and its eventual refuge. The relationship between an approaching threat and its refuge can be expressed as an angle we call the “interpath angle” or “Φ,” which describes the angle between the paths of predator and prey to the prey’s refuge and thus expresses the degree to which prey must run toward an approaching predator. In general, we might expect that prey would escape at greater distances if they must flee toward a predator to reach its burrow. The “race for life” model makes formal predictions about how Φ should affect FID. We evaluated the model by studying escape decisions in yellow-bellied marmots Marmota flaviventer, a species which flees to burrows. We found support for some of the model’s predictions, yet the relationship between Φ and FID was less clear. Marmots may not assess Φ in a continuous fashion; but we found that binning angle into 4 45° bins explained a similar amount of variation as models that analyzed angle continuously. Future studies of Φ, especially those that focus on how different species perceive relative orientation, will likely enhance our understanding of its importance in flight decisions. 
    more » « less
  2. ; ; ; (, Animal Behaviour)
    The distance at which animals move away from threats, flight initiation distance (FID), is often used to study antipredator behaviour and risk assessment. Variation in FID is explained by a variety of internal and external biotic and physical factors, including anthropogenic activities. Most prior studies focused on unidentified individuals, so our understanding of the fitness consequences of FID is relatively limited. We asked whether consistent individual differences in variation in flight initiation distance is associated with variation in summer survival and/or winter survival in an individually marked population of yellow- bellied marmots. We found no clear association between flight initiation distance and summer sur- vival or winter survival. This suggests that FID decisions, while demonstrably optimizing current survival, may not have longer-term fitness consequences. Our results may be explained by the relatively modest repeatability of FID or it may have emerged from our attempt to explain longer-term measures of fitness. Future studies of the fitness consequences of personality traits should pay particular attention to the time interval between measuring the individuality of a trait and examining its fitness consequences. 
    more » « less
  3. ; ; (, Ecosphere)
    Abstract Shrub encroachment is transforming arid and semiarid grasslands worldwide. Such transitions should influence predator–prey interactions because vegetation cover often affects risk perception by prey and contributes to their landscape of fear. We examined how the landscape of fear of two desert lagomorphs (black‐tailed jackrabbit,Lepus californicus; desert cottontail,Sylvilagus audubonii) changes across grassland‐to‐shrubland gradients at Jornada Basin Long Term Ecological Research site in the Chihuahuan Desert of southern New Mexico. We test whether shrub encroachment shapes risk differently for these two lagomorphs because of differences in body size and predator escape tactics. We also examine whether an ecosystem engineer of grasslands (banner‐tailed kangaroo rat,Dipodomys spectabilis) mediates risk perception through the creation of escape refuge and whether trade‐offs exist between shrub encroachment and the local reduction of banner‐tailed kangaroo rats caused by shrub expansion. We measured perceived predation risk with flight initiation distances (FIDs) and then used structural equation modeling to tease apart the hypothesized direct and indirect pathways for how shrub encroachment could affect perceived risk. A total negative effect of shrub cover on FID was supported for jackrabbits and cottontails, suggesting both species perceive shrubbier habitat as safer. Increases in fine‐scale concealment also reduced risk for cottontails, but not jackrabbits, likely because cottontails rely on crypsis to avoid predator detection whereas jackrabbits rely on speed and agility to outrun predators. Perceived risk was reduced when individuals were near kangaroo rat mounds only for cottontails because the smaller species can use banner‐tailed kangaroo rat mounds as refuge. Shrub encroachment greatly reduced the availability of mounds. Thus, a trade‐off exists for cottontails in which shrub encroachment directly reduced perceived risk, but indirectly increased perceived risk through the local extirpation of an ecosystem engineer. Our work illustrates how the expansion of shrub encroachment can create a dynamic landscape of fear for populations of prey species involving direct and indirect pathways contingent on prey body size, escape tactics, and activities of an ecosystem engineer. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; (, Neurology)
    Background and Objectives The goal of this work was to determine the relationship between diffusion microstructure and early changes in Alzheimer disease (AD) severity as assessed by clinical diagnosis, cognitive performance, dementia severity, and plasma concentrations of neurofilament light chain. Methods Diffusion MRI scans were collected on cognitively normal participants (CN) and patients with early mild cognitive impairment (EMCI), late mild cognitive impairment, and AD. Free water (FW) and FW-corrected fractional anisotropy were calculated in the locus coeruleus to transentorhinal cortex tract, 4 magnocellular regions of the basal forebrain (e.g., nucleus basalis of Meynert), entorhinal cortex, and hippocampus. All patients underwent a battery of cognitive assessments; neurofilament light chain levels were measured in plasma samples. Results FW was significantly higher in patients with EMCI compared to CN in the locus coeruleus to transentorhinal cortex tract, nucleus basalis of Meynert, and hippocampus (mean Cohen d = 0.54; p fdr < 0.05). FW was significantly higher in those with AD compared to CN in all the examined regions (mean Cohen d = 1.41; p fdr < 0.01). In addition, FW in the hippocampus, entorhinal cortex, nucleus basalis of Meynert, and locus coeruleus to transentorhinal cortex tract positively correlated with all 5 cognitive impairment metrics and neurofilament light chain levels (mean r 2 = 0.10; p fdr < 0.05). Discussion These results show that higher FW is associated with greater clinical diagnosis severity, cognitive impairment, and neurofilament light chain. They also suggest that FW elevation occurs in the locus coeruleus to transentorhinal cortex tract, nucleus basalis of Meynert, and hippocampus in the transition from CN to EMCI, while other basal forebrain regions and the entorhinal cortex are not affected until a later stage of AD. FW is a clinically relevant and noninvasive early marker of structural changes related to cognitive impairment. 
    more » « less
  5. ; ; (, Journal of Zoology)
    Abstract Ecotourism provides an opportunity to experience nature that may promote its conservation. Ecotourists photograph wildlife, and photography plays an important role in focusing public's attention on nature. Although photography is believed to be a low‐impact activity, how the visual stimulus of cameras influences wildlife remains unknown. Since animals are known to fear eyes pointed towards them because of similarity to predator eyes, we predicted that cameras with zoom lens would increase vigilance. Using yellow‐bellied marmots (Marmota flaviventer) and adopting a behavioural approach to identify marmots' response to photography, we experimentally quantified proportion of time allocated to vigilance during foraging and flight initiation distance (FID, the distance at which a marmot started to flee from an approaching human) towards humans with and without a camera. We focused on time allocated to vigilance measured in three ways: the proportion of time when marmots moved their head and body towards observers (looking towards observer), the proportion of time when marmots moved their head away from observers (looking away from observer) and the total vigilance (sum of looking towards and away from observer). While a camera was pointed at a marmot, individuals allocated more time to looking towards the observer and less time to looking away from the observer than they did without a camera. However, the total proportion of time allocated to vigilance was not different when marmots were approached by humans with and without a camera. Additionally, whether or not an observer was carrying a camera had no effect on FID. Our results indicated that cameras distracted marmots but did not influence their subsequent risk assessment; marmots may be curious about cameras but were not threatened by them. However, capturing an individual's attention may reduce their ability to look out for predators and thus may increase vulnerability to predation. Regulating photography in locations where predation risk is high or vulnerable species ranges' overlap with humans may be required. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email