1. Honeybee as a model system in neuroscience

2. Bee navigation and cognition – the waggle dance
Lecture 08 - main goals:
Bee navigation and cognition – the waggle dance
Evidence for internal maps, i.e. representation of space
How do measure distance covered? How do they stay in the middle of a tunnel?
Associative memories in bees – what are the different paradigms
Associative recall
Simple brain – complex behaviors

3. Lecture 08 - circuit motif:
Simple brain – complex behaviors

4. The three levels by David Marr
Any machine carrying out an information-processing task must be understood at the following three levels:
Computational theory: What is the goal of the computation, why is it appropriate, and what is the logic of the strategy by which it can be carried out?
Representation and algorithm: How can this computational theory be implemented? In particular, what is the representation for the input and output, and what is the algorithm for the transformation?
Hardware implementation: How can the representation and algorithm be realized physically?
Marr - what systems neuroscience is all about.
What does it mean to understand the brain?
Computational theory – evolution of behavior (what’s the point, what’s the function)
Representation and algorithm – input, output and transformation function.
Hardware implementation – how do neurons/circuits carry out these computations?
Honeybees are good model system that allows systems neuroscientists to fulfill these criteria
(Marr, Vision, 1982)

5. Mandyan Srinivasan (lecture slides made by him)

6. Why are bees important. Pollination, including agricultural plants
Why are bees important? Pollination, including agricultural plants. Important for our food source. They are dying off. Microbes/parasites.
Stimulus to behavior (goal of systems neuroscience)
Stimulus
Behavior

7. Small brains - Big minds
1 million neurons – quite a lot for an insect. Smaller than the human retina!
Antenna lobe – equivalent to olfactory bulb
Bee brain: 1 g ; ~ neurons
Life span: ~2 months
Human brain: 1.4 kg ;
~ billion neurons
Compare to human retina:
~ neurons

8. Navigation “Cognition” Hive
Language that humans can understand – can report where they found the flower. Can tell them what kind of food (giving out samples), also where the source is (waggle dance – encodes direction/angle, distance, also how much food there is).
Hive

9. Karl VonFrisch (got Bobel prize with konrad laurenz) for insights into animal behavior.
Bees also have good color vision – test with associative reward learning. (discovered by VonFrisch).
But waggle dance was what he got the nobel prize for.
No visual cues in the bee hive – auditory or somatosensation used to understand the dance.
Video:
Waggle, turn, waggle (figure eight dance). Bees are female and sisters.
At different food source, students mark the bees with different colors. See how the dances are different for different positions.

11. Round dance Waggle dance (feeder distance < 50m)
Round dance (circle)
Waggle dance (figure eight)
Three variables in waggle dance:
– direction of the vector of the waggle dance (360 degrees)
Length of the vector
How many repetitions
Round dance
Waggle dance
(feeder distance < 50m)
(feeder distance > 50m)

12. Distance calibration
Mean waggling duration increases with distance of food source.

13. Direction is represented relative to the sun
Direction is represented relative to the sun. How about on a cloudy day? Use polarized UV light.
The bee signals 360 degrees orientations. Zero degrees is direction of sun projected on the horizon.
How does the waggle dance correspond to direction?
In the honeycomb, zero is vertical up. In this example, the bee is signaling 40 degrees. Note that while currently he is facing down, the direction of the vector is towards the top right corner (i.e. 40 degrees from vertical). So bee will use the sun as the zero reference, and then travel 40 degrees from where the sun is.
Amount of food – how often it repeats the waggle (how many cycles).
How do bees measure distance? Ants – counting steps
What do bees count?
Wingbeats (no)
Energy consumption (no)
Landmarks (no)
Time, sense of speed – vestibular system can measure acceleration (no)
Visual flow (yes). How about at night? Airflow over the body. Problem is wind.

14. Honeybee navigation: How does a bee work out how far she has flown?
Landmark count
Time of flight
Wingbeat count
Energy consumption
Airspeed integration
Integration of optic flow
Airspeed integration and optic flow are how they determine distance.

15. First experiment – just looking at behavior.
Dots are where the food is. Students are at the sources and mark the bee when they arrive.
As expected, waggle increases with distance (over land)
But what happens when the bee is flying over water? Not much optic flow if you are flying over water – so they won’t “notice” that they have traveled as far.

16. Over water – distance is underreported. Not much optic flow in water.
Distance (m)

17. How to get water data points? Little yellow rubber boat.

18. No recruits!
But bees don’t go when it is reported that there is food in the middle of the water.
They don’t believe.
So they have a cognitive map of outside space, with value added to it, so it knows the “water” region is probably not a credible report.
A control:
At night, they moved the hive inland without the bees’ knowledge. So now all the food sources are also translated. So basically, now all the food sources are inland. But no recruits ever go to the translated region that is supposed to be over water (bees don’t know their hives had been moved, and to them there shouldn’t be food where the water is). They still don’t believe, therefore it’s not just that they detect the water or have somehow received cues that suggest the food was over water. Also, only the bees who haven’t been outside to forage are the once that don’t “believe”, the ones that have been outside and experienced the food source over water will go to the boats (that have food on them) readily,

19. The bee goes with the flow! Distance is perceived in terms
of integrated optic flow
What is the relationship between optic flow and distance? Studying quantitatively in lab settings.

20. Honeybee odometry Bees are trained to find a food
source placed at a fixed location
inside a tunnel lined with a visual
texture
Food source at end of tunnel. See what the bee reports.

21. Honeybee odometry Bees can learn the location of a
food source placed inside a tunnel
lined with vertical stripes
They cannot learn the location if
the tunnel is lined with horizontal
stripes
Vertical vs horizontal stripes.
Bee is inaccurate when stripes are horizontal – no optic flow!
With vertical stripes, they are very sure.

23. Dance signal Feeder ~ 0 m 6 m Feeder ~ 200 m 6 m Feeder ~ 0 m 6 m Hive
Round dance
6 m
Hive
Feeder
~ 200 m
Waggle dance
6 m
Round dance – short distance – 0 m
Waggle dance – reporting 200m, but actual distance is 6m. There is much less optic flow in real life than what they experience in this tunnel. A lot of movement across their retina in the tunnel. So they overestimate how far they have flown. Angular speed of object on the retina is actually what is being detected.
If feeder is at the end of horizontal tunnel they do a round dance (no flow experienced!)
Hive
Feeder
Round dance
~ 0 m
6 m

24. How do the recruits respond to the dancing tunnel bees?
6 m
Recruits search
at ~200 m
Recruits actually go 200m. Food source is actually 6m.
Scouts returning from 6 m tunnel
signal a distance of ~200 m
Esch, Zhang, Srinivasan & Tautz
Nature (2001)

25. Visual calibration of the honeybee’s odometer and dance
1 msec of waggle corresponds to
18o of image movement in the eye during flight
18o
Angle of landmark –how much does it change over time. 1msec of waggle corresponds to 18 degrees of image movement.
Note that distance covered for a given angle of image movement depends on how far the bee is from the image (normally, the ground).
So bees must fly at a specific height to have an accurate gauge of distance. You can extract from this the height that bees fly. 7-8 ft. If they fly higher from ground, optic flow is very slow, and if they fly lower (closer to ground), optic flow is faster.

26. Bees negotiate narrow gaps by balancing the image velocities in the two eyes
How do bees fly in middle of tunnel (e.g between vegetation) – i.e. the centering response
What algorithm are they using to stay in the middle of the tunnel? If they are equidistance, speed of optic flow in both eyes are the same. If deviating, speed of optic flow will be higher to one eye. Which eye will perceive faster flow? The one closer to the wall! (E.g. on a train looking out of the window, things that are near are moving faster than things that are far away)
How to you test this prediction?
Change the speed of optic flow by moving the stripes. Can change the relative speed of optic flow.
If you pull on left wall in the direction of flight of the bee (DECREASE optic flow), they will think they are far from that wall and so move closer.
If you pull on left wall opposite to the direction of flight of the bee (INCREASE optic flow), they will think they are close to the wall and so move farther.
Note that spacing doesn’t actually make a difference. It’s the speed that they are paying attention to for this behavior.
When the grating isn’t moving, the speed of flow really depends on the speed of the bee, so it would be the same on both eyes even if the grating of one has larger spacing than the other. They are not trying to balance spatial frequencies!
Refer to this paper for more coverage on both distance gauging and the centering response.
HONEYBEE NAVIGATION EN ROUTE TO THE GOAL: VISUAL FLIGHT CONTROL
AND ODOMETRY
M. V. SRINIVASAN1, S. W. ZHANG1, M. LEHRER2 AND T. S. COLLETT3
The Journal of Experimental Biology 199, 237–244 (1996) 237

27. Bees negotiate narrow gaps by balancing the image velocities in the two eyes
How do bees fly in middle of tunnel (e.g between vegetation) – i.e. the centering response
What algorithm are they using to stay in the middle of the tunnel? If they are equidistance, speed of optic flow in both eyes are the same. If deviating, speed of optic flow will be higher to one eye. Which eye will perceive faster flow? The one closer to the wall! (E.g. on a train looking out of the window, things that are near are moving faster than things that are far away)
How to you test this prediction?
Change the speed of optic flow by moving the stripes. Can change the relative speed of optic flow.
If you pull on left wall in the direction of flight of the bee (DECREASE optic flow), they will think they are far from that wall and so move closer.
If you pull on left wall opposite to the direction of flight of the bee (INCREASE optic flow), they will think they are close to the wall and so move farther.
Note that spacing doesn’t actually make a difference. It’s the speed that they are paying attention to for this behavior.
When the grating isn’t moving, the speed of flow really depends on the speed of the bee, so it would be the same on both eyes even if the grating of one has larger spacing than the other. They are not trying to balance spatial frequencies!
Refer to this paper for more coverage on both distance gauging and the centering response.
HONEYBEE NAVIGATION EN ROUTE TO THE GOAL: VISUAL FLIGHT CONTROL
AND ODOMETRY
M. V. SRINIVASAN1, S. W. ZHANG1, M. LEHRER2 AND T. S. COLLETT3
The Journal of Experimental Biology 199, 237–244 (1996) 237

28. Honeybee “cognition”
Working memory

29. Delayed match-to-sample
Comparison stimuli A A’ B’
Indicator
stimulus
100%
Choice frequency
Relative
Indicator stimulus
Feeder either on left or right. Bee enters first chamber, there is a colored sign on the door. Feeder will be behind the next door with the SAME color. Rule is follow SAME color.

30. Delayed match-to-sample
Comparison stimuli
Indicator
stimulus
100%
Choice frequency
Relative A’ B’
Indicator stimulus A
Bees have been trained only on color. Now expose them to a different cue, which is stripes. They have never seen the stripes before. They will still choose the SAME pattern. They are abstracting the idea of “sameness”. Can transfer concepts from color to shape.

31. Delayed match-to-sample
Transfer across sensory
modalities
Now use odors instead of visual cue. They still go to the same odor. No other animals can do this. Transfer across modalities!

32. (Very) delayed match-to-sample
Comparison
stimuli
(Very) delayed match-to-sample
Indicator stimulus
Baffle 0%
10.2 sec
100%
Choice frequency **
0 m
2 m
3 m
4 m
1 m
7.8 sec
5.0 sec
3.1 sec
1.6 sec
Longer delay. Increase distance between cue and decision point. Test of memory! They have good working memory.

33. Delayed match-to-sample:
4 comparison stimuli
Give them a choice between 4 different colors. Match the one at the entrance with one of 4 choices.

34. An extension of the previously-described learning paradigm:
The entrance will be one image within one of the groups.
In the exit, they will be presented to one image of a DIFFERENT group. So they need to abstract which is most similar to the initial image.
This study shows that they can generalize within stimulus type (e.g. five petal flower, many petal flower, plant, landscape)

35. If indicator is 5 petal flower, they always still pick a five-petal flower at the exit (although it looks slightly different).

39. Associative recall
Manipulate the choice of an animal by inducing a memory of something it is associate with.

40. Initially, just show the same color at entrance to test chamber and entrance to feeder.
Now train association between color and odor.

42. Can scent trigger memories of locations?
Training paradigm
Rose-scented
feeder
Lemon-scented
feeder
At first, have scented feeders, Then, remove the scented feeders, but spray rose scent on the hive. They go to the former rose-scented feeder. They have a memory, linked location to scent.
If you spray lemon scent, they go to lemon feeder. 2m
21 individually marked bees
Hive

43. Can scent trigger memories of locations?
Test 40 5 4 41
Former “rose”
feeder
Former “lemon”
feeder 2m
Honeybees have evolved good memories, it is adaptive and essential for their survival and reproduction.
lemon
scent
rose
scent
21 individually marked bees
Hive

44. Can scent trigger memories of colours?
Training paradigm
Rose-scented
Yellow feeder
Rose-scented yellow feeder and lemon-scented blue feeder. Same location.
Next day, you have blue and yellow dummy feeder. Lemon scent – they go to the blue feeder. Completely different location, and doesn’t even smell like lemon. They still go to blue. Neither location nor scent links bees to the feeder, only color. 2m
25 individually marked bees
Hive

45. Can scent trigger memories of colours?
Training paradigm
Lemon-scented
Blue feeder 2m
25 individually marked bees
Hive

46. Can scent trigger memories of colours?
Test 39 12
Blue dummy feeder 37 14
Yellow dummy feeder 2m
lemon
scent
rose
scent
25 individually marked bees
Hive

47. Neural basis for learning in the honeybee
Proboscis extension reflex. Pair odor with sucrose. Eventually, odor itself can elicit the extension reflex. But it is a very simple form of learning. You can even do this in Drosophila.
Gap between neurophysiology and behavior.

48. Olfactory pathways in the honeybee
This is the paper we will be reading in section: How different odors get distinguished by honeybee brain.

49. The neural representation of rewarded and unrewarded odors changes with training

50. Papers
T. Faber, J. Joerges, and R. Menzel. Associative learning modifies neural representations of odors in the insect brain. Nat.Neurosci. 2:74-78, 1999.
M.Hammer. An identified neuron mediates the unconditioned stimulus in associative olfactory learning in honeybees. Nature , 1993.

51. Lecture 08 – Matlab problem:
How does neural activity relate to a stimulus or behavior?
Sniffing and olfactory bulb activity: cross correlation and autocorrelation
Simple brain – complex behaviors