Michael Mangan PhD

Michael Mangan


Publications:
2017
  How Ants Use Vision When Homing Backward
Schwarz, S, Mangan, M, Zeil, J, Webb, B & Wystrach, A 2017, 'How Ants Use Vision When Homing Backward' Current biology : CB. DOI: 10.1016/j.cub.2016.12.019

Ants can navigate over long distances between their nest and food sites using visual cues [1, 2]. Recent studies show that this capacity is undiminished when walking backward while dragging a heavy food item [3-5]. This challenges the idea that ants use egocentric visual memories of the scene for guidance [1, 2, 6]. Can ants use their visual memories of the terrestrial cues when going backward? Our results suggest that ants do not adjust their direction of travel based on the perceived scene while going backward. Instead, they maintain a straight direction using their celestial compass. This direction can be dictated by their path integrator [5] but can also be set using terrestrial visual cues after a forward peek. If the food item is too heavy to enable body rotations, ants moving backward drop their food on occasion, rotate and walk a few steps forward, return to the food, and drag it backward in a now-corrected direction defined by terrestrial cues. Furthermore, we show that ants can maintain their direction of travel independently of their body orientation. It thus appears that egocentric retinal alignment is required for visual scene recognition, but ants can translate this acquired directional information into a holonomic frame of reference, which enables them to decouple their travel direction from their body orientation and hence navigate backward. This reveals substantial flexibility and communication between different types of navigational information: from terrestrial to celestial cues and from egocentric to holonomic directional memories.


General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Schwarz, Sebastian, Mangan, Michael, Zeil, Jochen, Webb, Barbara & Wystrach, Antoine.
Publication Date: 13 Jan 2017
Publication Information
Category: Article
Journal: Current biology : CB
ISSN: 0960-9822
Original Language: English
DOIs: 10.1016/j.cub.2016.12.019
2016
  Ant homing ability is not diminished when travelling backwards
Ardin, PB, Mangan, M & Webb, B 2016, 'Ant homing ability is not diminished when travelling backwards' Frontiers in behavioral neuroscience, vol 10, no. 69. DOI: 10.3389/fnbeh.2016.00069
Ants are known to be capable of homing to their nest after displacement to a novel location. This is widely assumed to involve some form of retinotopic matching between their current view and previously experienced views. One simple algorithm proposed to explain this behavior is continuous retinotopic alignment, in which the ant constantly adjusts its heading by rotating to minimize the pixel-wise difference of its current view from all views stored while facing the nest. However, ants with large prey items will often drag them home while facing backwards. We tested whether displaced ants (Myrmecia croslandi) dragging prey could still home despite experiencing an inverted view of their surroundings under these conditions. Ants moving backwards with food took similarly direct paths to the nest as ants moving forward without food, demonstrating that continuous retinotopic alignment is not a critical component of homing. It is possible that ants use initial or intermittent retinotopic alignment, coupled with some other direction stabilizing cue that they can utilize when moving backward. However, though most ants dragging prey would occasionally look toward the nest, we observed that their heading direction was not noticeably improved afterwards. We assume ants must use comparison of current and stored images for corrections of their path, but suggest they are either able to chose the appropriate visual memory for comparison using an additional mechanism; or can make such comparisons without retinotopic alignment.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Ardin, Paul Bjorn, Mangan, Michael & Webb, Barbara.
Number of pages: 8
Publication Date: 13 Apr 2016
Publication Information
Category: Article
Journal: Frontiers in behavioral neuroscience
Volume: 10
Issue number: 69
ISSN: 1662-5153
Original Language: English
DOIs: 10.3389/fnbeh.2016.00069
  Using an Insect Mushroom Body Circuit to Encode Route Memory in Complex Natural Environments
Ardin, P, Peng, F, Mangan, M, Lagogiannis, K & Webb, B 2016, 'Using an Insect Mushroom Body Circuit to Encode Route Memory in Complex Natural Environments' PLoS Computational Biology, vol 12, no. 2, e1004683. DOI: 10.1371/journal.pcbi.1004683
Ants, like many other animals, use visual memory to follow extended routes through complex environments, but it is unknown how their small brains implement this capability. The mushroom body neuropils have been identified as a crucial memory circuit in the insect brain, but their function has mostly been explored for simple olfactory association tasks. We show that a spiking neural model of this circuit originally developed to describe fruitfly (Drosophila melanogaster) olfactory association, can also account for the ability of desert ants (Cataglyphis velox) to rapidly learn visual routes through complex natural environments. We further demonstrate that abstracting the key computational principles of this circuit, which include one-shot learning of sparse codes, enables the theoretical storage capacity of the ant mushroom body to be estimated at hundreds of independent images.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Ardin, Paul, Peng, F., Mangan, Michael, Lagogiannis, Konstantinos & Webb, Barbara.
Number of pages: 22
Publication Date: 11 Feb 2016
Publication Information
Category: Article
Journal: PLoS Computational Biology
Volume: 12
Issue number: 2
ISSN: 1553-734X
Original Language: English
DOIs: 10.1371/journal.pcbi.1004683
2015
  How variation in head pitch could affect image matching algorithms for ant navigation
Ardin, P, Mangan, M, Wystrach, A & Webb, B 2015, 'How variation in head pitch could affect image matching algorithms for ant navigation' Journal of Comparative Physiology A, vol 201, no. 6, pp. 585-597 . DOI: 10.1007/s00359-015-1005-8

Desert ants are a model system for animal navigation, using visual memory to follow long routes across both sparse and cluttered environments. Most accounts of this behaviour assume retinotopic image matching, e.g. recovering heading direction by finding a minimum in the image difference function as the viewpoint rotates. But most models neglect the potential image distortion that could result from unstable head motion. We report that for ants running across a short section of natural substrate, the head pitch varies substantially: by over 20 degrees with no load; and 60 degrees when carrying a large food item. There is no evidence of head stabilisation. Using a realistic simulation of the ant's visual world, we demonstrate that this range of head pitch significantly degrades image matching. The effect of pitch variation can be ameliorated by a memory bank of densely sampled along a route so that an image sufficiently similar in pitch and location is available for comparison. However, with large pitch disturbance, inappropriate memories sampled at distant locations are often recalled and navigation along a route can be adversely affected. Ignoring images obtained at extreme pitches, or averaging images over several pitches, does not significantly improve performance.


General Information
Organisations: Neuroinformatics DTC.
Authors: Ardin, Paul, Mangan, Michael, Wystrach, Antoine & Webb, Barbara.
Pages: 585-597
Publication Date: 21 Apr 2015
Publication Information
Category: Article
Journal: Journal of Comparative Physiology A
Volume: 201
Issue number: 6
ISSN: 0340-7594
Original Language: English
DOIs: 10.1007/s00359-015-1005-8
  Optimal cue integration in ants
Wystrach, A, Mangan, M & Webb, B 2015, 'Optimal cue integration in ants' Proceedings of the Royal Society B: Biological Sciences, vol 282, no. 1816. DOI: 10.1098/rspb.2015.1484
In situations with redundant or competing sensory information, humans have been shown to perform cue integration, weighting different cues according to their certainty in a quantifiably optimal manner. Ants have been shown to merge the directional information available from their path integration (PI) and visual memory, but as yet it is not clear that they do so in a way that reflects the relative certainty of the cues. In this study, we manipulate the variance of the PI home vector by allowing ants (Cataglyphis velox) to run different distances and testing their directional choice when the PI vector direction is put in competition with visual memory. Ants show progressively stronger weighting of their PI direction as PI length increases. The weighting is quantitatively predicted by modelling the expected directional variance of home vectors of different lengths and assuming optimal cue integration. However, a subsequent experiment suggests ants may not actually compute an internal estimate of the PI certainty, but are using the PI home vector length as a proxy.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Wystrach, Antoine, Mangan, Michael & Webb, Barbara.
Number of pages: 6
Publication Date: 7 Oct 2015
Publication Information
Category: Article
Journal: Proceedings of the Royal Society B: Biological Sciences
Volume: 282
Issue number: 1816
ISSN: 0962-8452
Original Language: English
DOIs: 10.1098/rspb.2015.1484
  Route Following Without Scanning
Mangan, M & Khodshabashev, A 2015, Route Following Without Scanning. in Biomimetic and Biohybrid Systems. vol. 9222, pp. 199-210. DOI: 10.1007/978-3-319-22979-9_20
Desert ants are expert navigators, foraging over large distances using visually guided routes. Recent models of route following can reproduce aspects of route guidance, yet the underlying motor patterns do not reflect those of foraging ants. Specifically, these models select the direction of movement by rotating to find the most familiar view. Yet scanning patterns are only occasionally observed in ants. We propose a novel route following strategy inspired by klinokinesis. By using familiarity of the view to modulate the magnitude of alternating left and right turns, and the size of forward steps, this strategy is able to continually correct the heading of a simulated ant to maintain its course along a route. Route following by klinokinesis and visual compass are evaluated against real ant routes in a simulation study and on a mobile robot in the real ant habitat. We report that in unfamiliar surroundings the proposed method can also generate ant-like scanning behaviours.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Mangan, Michael & Khodshabashev, Aleksander.
Number of pages: 12
Pages: 199-210
Publication Date: 24 Jul 2015
Publication Information
Category: Chapter (peer-reviewed)
Original Language: English
DOIs: 10.1007/978-3-319-22979-9_20
2014
  Sky segmentation with ultraviolet images can be used for navigation
Stone, T, Mangan, M, Ardin, P & Webb, B 2014, Sky segmentation with ultraviolet images can be used for navigation. in Proceedings Robotics: Science and Systems.
Inspired by ant navigation, we explore a method for
sky segmentation using ultraviolet (UV) light. A standard camera
is adapted to allow collection of outdoor images containing light
in the visible range, in UV only and in green only. Automatic
segmentation of the sky region using UV only is signi?cantly more
accurate and far more consistent than visible wavelengths over
a wide range of locations, times and weather conditions, and can
be accomplished with a very low complexity algorithm. We apply
this method to obtain compact binary (sky vs non-sky) images
from panoramic UV images taken along a 2km route in an urban
environment. Using either sequence SLAM or a visual compass
on these images produces reliable localisation and orientation
on a subsequent traversal of the route under different weather
conditions.
General Information
Organisations: Neuroinformatics DTC.
Authors: Stone, Thomas, Mangan, Michael, Ardin, Paul & Webb, Barbara.
Number of pages: 9
Publication Date: 2014
Publication Information
Category: Chapter (peer-reviewed)
Original Language: English
  Still no convincing evidence for cognitive map use by honeybees
Cheung, A, Collett, M, Collett, TS, Dewar, A, Dyer, F, Graham, P, Mangan, M, Narendra, A, Philippides, A, Stürzl, W, Webb, B, Wystrach, A & Zeil, J 2014, 'Still no convincing evidence for cognitive map use by honeybees' Proceedings of the National Academy of Sciences, vol 111, no. 42, pp. E4396-E4397. DOI: 10.1073/pnas.1413581111
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Cheung, Allen, Collett, Matthew, Collett, Thomas S, Dewar, Alex, Dyer, Fred, Graham, Paul, Mangan, Michael, Narendra, Ajay, Philippides, Andrew, Stürzl, Wolfgang, Webb, Barbara, Wystrach, Antoine & Zeil, Jochen.
Keywords: (Animals, Bees, Cognition, Homing Behavior. )
Number of pages: 2
Pages: E4396-E4397
Publication Date: 21 Oct 2014
Publication Information
Category: Article
Journal: Proceedings of the National Academy of Sciences
Volume: 111
Issue number: 42
ISSN: 0027-8424
Original Language: English
DOIs: 10.1073/pnas.1413581111
2013
  Models of visual navigation in ants
Philippides, A, Wystrach, A, Mangan, M, Baddeley, B & Graham, P 2013, 'Models of visual navigation in ants' Frontiers in Psychology. DOI: 10.3389/conf.fphys.2013.25.00060
Here we present a model of visually guided navigation in ants that captures the known properties of real behaviour whilst retaining mechanistic simplicity and thus biological plausibility. For an ant, the coupling of movement and viewing direction means that a familiar view specifies a familiar direction of movement. Since the views experienced along a habitual route will be more familiar, route navigation can be re-cast as a search for familiar views. This search can be performed with a simple scanning routine, a behaviour ants have been observed to perform.

We test our model in a realistic simulation of a desert ant’s environment and also with images viewed by ants during behavioural experiments. Our results indicate that, not only is the approach successful, but also that the resultant behaviour shows characteristics of the paths of ants. As such, we believe the model provides a general demonstration that visually guided routes can be produced with parsimonious mechanisms that do not specify when or what to learn, nor separate routes into sequences of waypoints. Finally, we contrast our approach with the classical ‘snapshot’ model in which views are used as attractors to a point in space. This presentation summarises results from Baddeley et al. (2012) and Wystrach et al. (2013).
General Information
Organisations: Neuroinformatics DTC.
Authors: Philippides, Andrew, Wystrach, Antoine, Mangan, Michael, Baddeley, Bart & Graham, Paul.
Number of pages: 1
Publication Date: 2013
Publication Information
Category: Meeting abstract
Journal: Frontiers in Psychology
ISSN: 1664-1078
Original Language: English
DOIs: 10.3389/conf.fphys.2013.25.00060
  How active vision facilitates familiarity-based homing
Philippides, A, Dewar, A, Wystrach, A, Mangan, M & Graham, P 2013, How active vision facilitates familiarity-based homing. in Biomimetic and Biohybrid Systems: Second International Conference, Living Machines 2013, London, UK, July 29 – August 2, 2013. Proceedings. Lecture Notes in Computer Science, vol. 8064, Springer Berlin Heidelberg, pp. 427-430. DOI: 10.1007/978-3-642-39802-5_56
The ability of insects to visually navigate long routes to their nest has provided inspiration to engineers seeking to emulate their robust performance with limited resources [1-2]. Many models have been developed based on the elegant snapshot idea: remember what the world looks like from your goal and subsequently move to make your current view more like your memory [3]. In the majority of these models, a single view is stored at a goal location and acts as a form of visual attractor to that position (for review see [4]). Recently however, inspired by the behaviour of ants and the difficulties in extending traditional snapshot models to routes [5], we have proposed a new navigation model [6-7]. In this model, rather than using views to recall directions to the place that they were stored, views are used to recall the direction of facing or movement (identical for a forward-facing ant) at the place the view was stored. To navigate, the agent scans the world by rotating and thus actively finds the most familiar view, a behaviour observed in Australian desert ants. Rather than recognise a place, the action to take at that place is specified by a familiar view.
General Information
Organisations: Neuroinformatics DTC.
Authors: Philippides, Andrew, Dewar, Alex, Wystrach, Antoine, Mangan, Michael & Graham, Paul.
Number of pages: 4
Pages: 427-430
Publication Date: 2013
Publication Information
Category: Conference contribution
Original Language: English
DOIs: 10.1007/978-3-642-39802-5_56
  Snapshots in ants?
Wystrach, A, Mangan, M, Philippides, A & Graham, P 2013, 'Snapshots in ants?: New interpretations of paradigmatic experiments' Journal of Experimental Biology, vol 216, no. 10, pp. 1766-1770. DOI: 10.1242/jeb.082941

Ants can use visual information to guide long idiosyncratic routes and accurately pinpoint locations in complex natural environments. It has often been assumed that the world knowledge of these foragers consists of multiple discrete views that are retrieved sequentially for breaking routes into sections controlling approaches to a goal. Here we challenge this idea using a model of visual navigation that does not store and use discrete views to replicate the results from paradigmatic experiments that have been taken as evidence that ants navigate using such discrete snapshots. Instead of sequentially retrieving views, the proposed architecture gathers information from all experienced views into a single memory network, and uses this network all along the route to determine the most familiar heading at a given location. This algorithm is consistent with the navigation of ants in both laboratory and natural environments, and provides a parsimonious solution to deal with visual information from multiple locations.


General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Wystrach, Antoine, Mangan, Michael, Philippides, Andrew & Graham, Paul.
Keywords: (Animals, Ants, Memory, Models, Biological, Reproducibility of Results, Visual Perception. )
Number of pages: 5
Pages: 1766-1770
Publication Date: 2013
Publication Information
Category: Article
Journal: Journal of Experimental Biology
Volume: 216
Issue number: 10
ISSN: 0022-0949
Original Language: English
DOIs: 10.1242/jeb.082941
2012
  Spontaneous formation of multiple routes in individual desert ants (Cataglyphis velox)
Mangan, M & Webb, B 2012, 'Spontaneous formation of multiple routes in individual desert ants (Cataglyphis velox)' Behavioral Ecology, vol 23, no. 5, pp. 944-954. DOI: 10.1093/beheco/ars051
Desert ants make use of various navigational techniques, including path integration and visual route following, to forage efficiently in their extremely hostile environment. Species-specific differences in navigation have been demonstrated, although it remains unknown if these divergences are caused by environmental adaptation. In this work, we report on the navigational strategies of the European ant Cataglyphis velox, which inhabits a visually cluttered environment similar to the Australian honey ant Melophorus bagoti, although it is more closely related to other North African Cataglyphis species. We show that C. velox learn visually guided routes, and these are individual to each forager. Routes can be recalled in the absence of global path integration information or when placed in conflict with this information. Individual C. velox foragers are also shown to learn multiple routes through their habitat. These routes are learned rapidly, stored in long-term memory, and recalled for guidance as appropriate. Desert ants have previously been shown to learn multiple routes in an experimental manipulation, but this is the first report of such behavior emerging spontaneously. Learning multiple paths through the habitat over successive journeys provides a mechanism by which ants could memorize a series of interlaced courses, and thus perform complex navigation, without necessarily having a map of the environment.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Mangan, Michael & Webb, Barbara.
Number of pages: 11
Pages: 944-954
Publication Date: Sep 2012
Publication Information
Category: Article
Journal: Behavioral Ecology
Volume: 23
Issue number: 5
Original Language: English
DOIs: 10.1093/beheco/ars051
2009
  Modelling place memory in crickets
Mangan, M & Webb, B 2009, 'Modelling place memory in crickets' Biological Cybernetics, vol 101, no. 4, pp. 307-323. DOI: 10.1007/s00422-009-0338-1
Insects can remember and return to a place of interest using the surrounding visual cues. In previous experiments, we showed that crickets could home to an invisible cool spot in a hot environment. They did so most effectively with a natural scene surround, though they were also able to home with distinct landmarks or blank walls. Homing was not successful, however, when visual cues were removed through a dark control. Here, we compare six different models of visual homing using the same visual environments. Only models deemed biologically plausible for use by insects were implemented. The average landmark vector model and first order differential optic flow are unable to home better than chance in at least one of the visual environments. Second order differential optic flow and GradDescent on image differences can home better than chance in all visual environments, and best in the natural scene environment, but do not quantitatively match the distributions of the cricket data. Two models-centre of mass average landmark vector and RunDown on image differences-could produce the same pattern of results as observed for crickets. Both the models performed best using simple binary images and were robust to changes in resolution and image smoothing.
General Information
Organisations: Neuroinformatics DTC.
Authors: Mangan, Michael & Webb, Barbara.
Keywords: (Insect learning , Visual navigation , Place memory , Cricket , Homing models, , , . )
Number of pages: 17
Pages: 307-323
Publication Date: Oct 2009
Publication Information
Category: Article
Journal: Biological Cybernetics
Volume: 101
Issue number: 4
ISSN: 0340-1200
Original Language: English
DOIs: 10.1007/s00422-009-0338-1
2008
  Place memory in crickets
Wessnitzer, J, Mangan, M & Webb, B 2008, 'Place memory in crickets' Proceedings of the Royal Society B-Biological Sciences, vol 275, no. 1637, pp. 915-921. DOI: 10.1098/rspb.2007.1647
Certain insect species are known to relocate nest or food sites using landmarks, but the generality of this capability among insects, and whether insect place memory can be used in novel task settings, is not known. We tested the ability of crickets to use surrounding visual cues to relocate an invisible target in an analogue of the Morris water maze, a standard paradigm for spatial memory tests on rodents. Adult female Gryllus bimaculatus were released into an arena with a floor heated to an aversive temperature, with one hidden cool spot. Over 10 trials, the time taken to find the cool spot decreased significantly. The best performance was obtained when a natural scene was provided on the arena walls. Animals can relocate the position from novel starting points. When the scene is rotated, they preferentially approach the fictive target position corresponding to the rotation. We note that this navigational capability does not necessarily imply the animal has an internal spatial representation.
General Information
Organisations: Neuroinformatics DTC.
Authors: Wessnitzer, J., Mangan, Michael & Webb, B..
Keywords: (insect learning , visual navigation, place memory, cricket (Gryllus bimaculatus), homing algorithms, , , . )
Number of pages: 7
Pages: 915-921
Publication Date: Apr 2008
Publication Information
Category: Article
Journal: Proceedings of the Royal Society B-Biological Sciences
Volume: 275
Issue number: 1637
ISSN: 0962-8452
Original Language: English
DOIs: 10.1098/rspb.2007.1647
  Path Integration Using a Model of e-Vector Orientation Coding in the Insect Brain: Reply to Vickerstaff and Di Paolo
Wessnitzer, J, Haferlach, T, Mangan, M & Webb, B 2008, 'Path Integration Using a Model of e-Vector Orientation Coding in the Insect Brain: Reply to Vickerstaff and Di Paolo' Adaptive Behavior, vol 16, no. 4, pp. 277-280. DOI: 10.1177/1059712308094947
General Information
Organisations: Neuroinformatics DTC.
Authors: Wessnitzer, J., Haferlach, T., Mangan, Michael & Webb, B..
Keywords: (, , . )
Number of pages: 4
Pages: 277-280
Publication Date: Aug 2008
Publication Information
Category: Article
Journal: Adaptive Behavior
Volume: 16
Issue number: 4
ISSN: 1059-7123
Original Language: English
DOIs: 10.1177/1059712308094947
2007
  Evolving a Neural Model of Insect Path Integration
Haferlach, T, Wessnitzer, J, Mangan, M & Webb, B 2007, 'Evolving a Neural Model of Insect Path Integration' Adaptive Behavior, vol 15, no. 3, pp. 273-287. DOI: 10.1177/1059712307082080
Path integration is an important navigation strategy in many animal species. We use a genetic algorithm to evolve a novel neural model of path integration, based on input from cells that encode the heading of the agent in a manner comparable to the polarization-sensitive interneurons found in insects. The home vector is encoded as a population code across a circular array of cells that integrate this input. This code can be used to control return to the home position. We demonstrate the capabilities of the network under noisy conditions in simulation and on a robot.
General Information
Organisations: Institute of Perception, Action and Behaviour .
Authors: Haferlach, T., Wessnitzer, J., Mangan, M. & Webb, B..
Pages: 273-287
Publication Date: 1 Sep 2007
Publication Information
Category: Article
Journal: Adaptive Behavior
Volume: 15
Issue number: 3
ISSN: 1059-7123
Original Language: English
DOIs: 10.1177/1059712307082080

Projects:
Behavoural and robotic study of the function governing the generation of snapshots in foraging desert ants (PhD)