Björn Brembs

*[During my [flyfishing vacation last
year](http://blogarchive.brembs.net/comment-n862.html), pretty much
nothing was happening on this blog. Now that I've migrated the blog to
WordPress, I can actually schedule posts to appear when in fact I'm not
even at the computer. I'm using this functionality to re-blog a few
posts from the [archives](http://blogarchive.brembs.net) during the
month of august while I'm away. This post is from [February 9,
2011](http://blogarchive.brembs.net/comment-n704.html):]{style="font-size: 12px;"}  
*

 

In this week's journal club, we talked about an old paper from 1918!
"[The reactions to light and to gravity in Drosophila and its
mutants](https://onlinelibrary.wiley.com/doi/10.1002/jez.1400250103/abstract){target="_blank"
rel="external"}" by Robert McEwen, in the *Journal of Experimental
Zoology*.

As the title says, the author studied how the fruit fly
*[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"}* responds to light and gravity. He tested this in
walking flies and compared flies both with intact wings and clipped
wings, wing mutations, clipped antennae, glued wings or clipped middle
legs. He discovered that flies without wings or with mutated wing shape,
show less movement towards light (i.e., less phototaxis). This finding
was later confirmed by one of the founders of modern neurogenetics,
Seymour Benzer
([1967](https://www.pnas.org/content/58/3/1112.full.pdf+html?sid=a682d90d-38bb-468e-a0fe-516988a69491){target="_blank"})
and we also find this in our experiments. We have now set out to find
out which neuronal mechanisms are involved in this drastic change in
behavior.

In order to get the flies to show phototaxis, McEwen developed a machine
to gently tap the tube in which the flies were placed, to get them to
walk. He described the necessity for flies to be active in order to show
a consistent orientation towards a light source: without walking
behavior being either initiated spontaneously or by the tapping machine,
flies would not walk towards the light themselves. If the flies were at
rest, light was not an orienting stimulus for them. This key insight was
formulated by McEwen at the very end of the paper:

> <div>
>
> Lastly, it may be well to emphasize the peculiar relation which exists
> in
> [Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
> rel="external"} between general activity and phototropism. This
> phenomenon has been clearly recognized by Carpenter and in general I
> agree with this author's conclusions. The fact seems to be that this
> insect is not phototropic unless it is in a certain physiological
> state brought on by, or at least accompanied by, activity. When the
> fly reaches a certain degree of activity, induced by various means, it
> suddenly becomes phototropic. When it quiets down, however, it may
> still crawl about but ceases to be phototropic. Thus, when an insect
> has been exposed to constant illumination for some time, it no longer
> orients to light but wanders aimlessly up and down the tube.
> Eventually such an animal may even come to rest with its head away
> from the source of light.
>
> </div>

The technique described mimics what other colleagues have later
developed in other fly paradigms based on vision and walking, such as
the
"[fly-stampede](https://www.landesbioscience.com/journals/fly/article/9139){target="_blank"}"
paradigm. But the insight reaches much further than that. More recent
research has shown that the state of the animal has minute control over
how the environment is processed. For instance, leeches respond with
various behaviors to local mechanosensory stimulation (i.e., touch).
However, when they feed, the biogenic amine serotonin is released and
prevents the mechanosensory neurons from transmitting the stimuli -- the
animal becomes unresponsive when it feeds ([Gaudry & Kristan,
2009](https://www.nature.com/neuro/journal/v12/n11/full/nn.2400.html){target="_blank"}).
Another study showed that motion-sensitive neurons in the optic lobes of
the fly brain increase their gain when the fly is flying, as opposed to
when it is not flying ([Maimon et al.,
2010](https://www.nature.com/neuro/journal/v13/n3/abs/nn.2492.html){target="_blank"}).
Analogous results were obtained when walking vs. sitting flies were
compared ([Chiappe et al.
2010](https://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VRT-50KKY4V-4&_user=4113557&_coverDate=08%2F24%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_rerunOrigin=scholar.google&_acct=C000047720&_version=1&_urlVersion=0&_userid=4113557&md5=587c1ad8c1256e6f1543427990606546&searchtype=a){target="_blank"}).
In another, also very sophisticated study, Haag et al.
([2010](https://www.pnas.org/content/107/46/20104.full){target="_blank"})
showed how an identified motor neuron responds more strongly to visual
input when the animal is flying than when it is at rest. Finally, Tang
and Juusola
([2010](https://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0014455))
report evidence that the direction in which a fly attempts to turn
changes the way in which the optic lobes process the visual information
on the side towards the fly attempts to turn, compared to the
contralateral side.

All these groups have, largely independently of each other, discovered
the biological mechanisms for something that already McEwen (and
Carpenter, cited there) had understood: animals don't just respond to
stimuli in always the same, stereotypical way: all animals have many
different ways to treat and evaluate the incoming sensory stream,
depending on what they are doing at the moment. The decisive factor for
understanding animal behavior is not the environment, or the sensory
organs, it is the animal itself. Apparently, this profound insight was
known long ago and we're just rediscovering it now, in various places,
all over the world.

Something *was* new in all the recent studies, though: they all provide
first mechanistic insight into how brains balance internal and external
processing. All these studies show that there seems to be a smooth
gradient between decision-making and attention-like processing, even in
invertebrates: Gaudry and Kristan call it decision-making, when their
leeches 'decide' to ignore stimuli while they feed, even though the
incoming sensory stimuli are blocked already at the very first synapse.
Chiappe et al., on the other hand, relate their phenomenon to attention
and Haag et al. also mention attention in their paper, with their
effects being observed many synapses downstream of the sensory neurons
-- the word 'decision' does not occur in either of the two papers. It
appears as if future neurophysiological research is bound to show that
the distinction between attention-like mechanisms and decision-making,
which seems so intuitive and clear-cut, may dissolve when we start to
unravel how brains actually do it. Now when will we come accross the
ancient text that already pre-empts that insight?
![nuetral.png](http://blogarchive.brembs.net/e107_images/emotes/yellow/nuetral.png){decoding="async"}

References:

------------------------------------------------------------------------

McEwen, R. (1918). The reactions to light and to gravity in
[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"} and its mutants Journal of Experimental Zoology, 25 (1),
49-106 DOI:
[10.1002/jez.1400250103](https://dx.doi.org/10.1002/jez.1400250103){rev="review"}  
Zhu, Y., & Frye, M. (2009). Neurogenetics and the "fly-stampede":
dissecting neural circuits involved in visual behaviors Fly, 3 (3),
209-211 DOI:
[10.4161/fly.3.3.9139](https://dx.doi.org/10.4161/fly.3.3.9139){rev="review"}  
Gaudry, Q., & Kristan, W. (2009). Behavioral choice by presynaptic
inhibition of tactile sensory terminals Nature Neuroscience, 12 (11),
1450-1457 DOI:
[10.1038/nn.2400](https://dx.doi.org/10.1038/nn.2400){rev="review"}  
Maimon, G., Straw, A., & Dickinson, M. (2010). Active flight increases
the gain of visual motion processing in
[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"} Nature Neuroscience, 13 (3), 393-399 DOI:
[10.1038/nn.2492](https://dx.doi.org/10.1038/nn.2492){rev="review"}  
Chiappe, M., Seelig, J., Reiser, M., & Jayaraman, V. (2010). Walking
Modulates Speed Sensitivity in
[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"} Motion Vision Current Biology, 20 (16), 1470-1475 DOI:
[10.1016/j.cub.2010.06.072](https://dx.doi.org/10.1016/j.cub.2010.06.072){rev="review"}  
Haag, J., Wertz, A., & Borst, A. (2010). Central gating of fly optomotor
response Proceedings of the National Academy of Sciences, 107 (46),
20104-20109 DOI:
[10.1073/pnas.1009381107](https://dx.doi.org/10.1073/pnas.1009381107){rev="review"}  
Tang, S., & Juusola, M. (2010). Intrinsic Activity in the Fly Brain
Gates Visual Information during Behavioral Choices [PLoS
ONE](https://plosone.org){target="_blank" rel="external"}, 5 (12) DOI:
[10.1371/journal.pone.0014455](https://dx.doi.org/10.1371/journal.pone.0014455){rev="review"}


<em>
 During my flyfishing vacation last year, pretty much nothing was happening on this blog. Now that I’ve migrated the blog to WordPress, I can actually schedule posts to appear when in fact I’m not even at the computer. I’m using this functionality to re-blog a few posts from the archives during the month of august while I’m away. This post is from February 9, 2011:
</em>

Flashback: Nothing new in science?

[*During my [flyfishing vacation last
year](http://blogarchive.brembs.net/comment-n862.html), pretty much
nothing was happening on this blog. Now that I've migrated the blog to
WordPress, I can actually schedule posts to appear when in fact I'm not
even at the computer. I'm using this functionality to re-blog a few
posts from the [archives](http://blogarchive.brembs.net) during the
month of august while I'm away. This post is from [April 28,
2011](http://blogarchive.brembs.net/news734.html):  
*]{style="font-size: 12px;"}

<div>

It turns out, [operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"} is very different from other forms of learning, all the
way from the genes up. When I started my research on [operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"} in 1995, I did so with the opposite hypothesis, namely
that the underlying mechanism of all learning processes was always
[synaptic
plasticity](https://en.wikipedia.org/wiki/Synaptic_plasticity){target="_blank"
rel="external"} with the well-known molecular pathway: Ca^++^, cAMP,
PKA, CamK, CREB and so on. After all, wasn't that pathway conserved all
the way from flies, snails and mice to humans? By the time I finished by
PhD in 2000, [Eric
Kandel](https://en.wikipedia.org/wiki/Eric_Kandel){target="_blank"} had
received the Nobel prize for exactly these learning mechanisms -- he
wouldn't have gotten the prize if the pathways had not been so
conserved. In principle, changing the weight of the synapses is all you
need to do to store whatever information you want. There is no a priori
need to have several different mechanisms by which neural networks are
modified.

</div>

A few years ago, I started getting data from fruit flies (
*[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"}*) that were exactly the opposite of what my initial
hypotheis was: the genes required for standard synaptic plasticity (such
as the [*rutabaga*](https://en.wikipedia.org/wiki/Rutabaga_%28gene%29)
adenylyl cyclase) were not required in our form of [operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"}. In contrast, a gene which had previously been shown not
to be involved in [classical
conditioning](http://brembs.net/learning/classical.html){target="_blank"
rel="external"}, protein kinase C (PKC) turned out to be crucial for
[operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"}. What made the whole story even more intriguing was that
the same evidence started to show up in the lab where I did my postdoc,
using the marine snail
*[Aplysia](http://brembs.net/learning/aplysia/){target="_blank"
rel="external"}* as a model system: PKC was required, but the
*rut*-cyclase was not.

Why had nobody discovered this dichotomy between the learning mechanisms
before us? It turned out that the crucial experimental advance was to
prevent the animals from learning about anything else besides their
behavior. As soon as we let the animals learn about any external cues in
addition to their behavior, the results go back to the expected
canonical pathways being required and PKC not. Obviously, nobody had
been able to completely isolate [operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"} to the extent that was required. Because all our
experiments were operant in nature, but only differed in whether or not
the animals were able to learn about environmental cues or not, we
called the PKC-dependent learning mechanism operant self-learning and
the other, well-described form, operant world-learning.

How far is this new form of plasticity (in
*[Aplysia](http://brembs.net/learning/aplysia/){target="_blank"
rel="external"}* it is a form of 'intrinsic plasticity' modifying the
entire neuron and not just the synapse; in
*[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"}* we don't know) conserved? We are currently in the
process of writing up our experiments on the 'language gene'
[FoxP2](https://en.wikipedia.org/wiki/FOXP2){target="_blank"}.
*[Drosophila](http://brembs.net/learning/drosophila/){target="_blank"
rel="external"}* has an orthologue of this gene and if we mutate it (or
knock it down with RNAi), we find that it is required for operant
self-learning, but not for operant world-learning, paralleling the
results we had for PKC. This means we now have a new learning mechanism
at hand that is clearly distinct from the well-known synaptic plasticity
pathway, but is equally conserved among invertebrates and vertebrates.
These results suggest an ancient evolutionary origin for operant
self-learning, possibly at the root of the bilaterian branch, and a
complementary role to world-learning.

I have summarized these results in an [invited
review](https://dx.doi.org/10.1016/j.beproc.2011.02.005) on occasion of
the 2010 conference of [SQAB](https://www.sqab.org/){target="_blank"} in
the journal "Behavioural Processes". Unfortunately, there are a few
mistakes in the copy available from the publisher. Some spaces are
missing between words and the references Brembs 2009a and Brembs 2009b
are mixed up. I've notified the publisher, but they said it was too late
to fix. I've now fixed the [HTML version of my local
copy](http://brembs.net/learning/drosophila/behavproc11/index.html){target="_self"},
but I can't fix [my PDF
copy](http://blogarchive.brembs.net/request101.html){target="_self"} as
they use a font that is not freely avaliable. So if anybody knows how I
can fix my own PDF copy, please let me know!

------------------------------------------------------------------------

<div>

Brembs, B. (2011). Spontaneous decisions and [operant
conditioning](http://brembs.net/learning/operant.html){target="_blank"
rel="external"} in fruit flies Behavioural Processes DOI:
[10.1016/j.beproc.2011.02.005](https://dx.doi.org/10.1016/j.beproc.2011.02.005){rev="review"}

</div>


<em>
 During my flyfishing vacation last year, pretty much nothing was happening on this blog. Now that I’ve migrated the blog to WordPress, I can actually schedule posts to appear when in fact I’m not even at the computer. I’m using this functionality to re-blog a few posts from the archives during the month of august while I’m away.
</em>

Flashback: The neurobiology of operant conditioning

[[![ResearchBlogging.org](https://www.researchblogging.org/public/citation_icons/rb2_mid.png){decoding="async"
style="border: 0;"}](https://www.researchblogging.org)]{style="float: left; padding: 5px;"}Until
1986, it was thought that so-called [optomotor
responses](https://en.wikipedia.org/wiki/Optomotor_response){target="_blank"},
i.e., the tendency of all animals and humans to follow moving visual
stimuli with their eyes or their bodies, were a prerequisite for gaze or
trajectory stabilization: whenever the scenery in your gaze moves, you
adjust gaze or body orientation to compensate for the shift. The main
concept was that these behaviors were responses to external stimuli,
e.g., shift to the left elicits a counter movement to compensate for the
shift. Without such simple input-output processes, it was thought, it
would be impossible to maintain course or gaze. However, in 1986, [Wolf
and
Heisenberg](https://www.nature.com/nature/journal/v323/n6084/abs/323154a0.html){target="_blank"}
reported on experiments in *Drosophila* fruit flies with drastically
reduced optic lobes, the primary visual processing centers of insects.
These flies with the double mutation *rol* (reduced optic lobes) *sol*
(small optic lobes, see figure 1) were incapable of performing optomotor
responses to rotating stimuli, but nevertheless fixated a stripe in
their frontal visual field if they were allowed to control the position
of that stripe with turning maneuvers that were simultaneously recorded.
In other words, the flies could not see in which direction the stripe
was moving, but nevertheless managed to move the stripe in a way that
fixated it preferentially in front of the flies. Further experiments
showed that the only way the flies could possibly accomplish this feat
is by 'trying out' which turning maneuver led to the stripe staying in
the frontal part of their visual field -- an operant (or, as one would
also say today, goal-directed) behavior. For more details on this and
two related classic experiments from the Heisenberg lab see "[The
Importance of Being
Active](https://bjoern.brembs.net/downloads/?download=16 "The importance of being active")".

::: {#attachment_133 .wp-caption .alignright style="width: 160px"}
[![rolsol](https://bjoern.brembs.net/wp/wp-content/uploads/2013/05/rolsol-150x150.jpg){.size-thumbnail
.wp-image-133 decoding="async" aria-describedby="caption-attachment-133"
width="150"
height="150"}](https://bjoern.brembs.net/wp/wp-content/uploads/2013/05/rolsol.jpg)

Fig. 1: Side by side comparison of the brains of wild type (WT) and rol
sol double mutant flies (click to enlarge).
:::

Now [Bahl *et
al.*](https://www.nature.com/neuro/journal/v16/n6/full/nn.3386.html){target="_blank"}
in the lab of [Alexander
Borst](https://www.neuro.mpg.de/borst){target="_blank"}
[(](https://www.neuro.mpg.de/borst){target="_blank"}a [graduate student
of
Heisenberg](https://neurotree.org/neurotree/tree.php?pid=8061){target="_blank"}'s
from 1982-84) have not only replicated this seminal study, they have
done so in an impressively sophisticated and meticulous manner, avoiding
many if not all of the methodical problems of the original experiments
and adding exciting new findings to our body of knowledge along the way.
Their fabulous publication constitutes a shining example of the power of
combining today's genetic technology with state-of-the-art behavioral
physiology and computational modeling. Technically, it doesn't get any
better than that in our field today. A major procedural concern with the
1986 Wolf & Heisenberg paper had always been that none of the potential
side-effects of the drastic double mutation *rol sol* were known.
Granted, the optic lobes were vanishingly tiny in these mutants (see
figure 1) and almost any visual capability seemed like a surprise, but
which other processes were affected and in what way was completely
unknown. Rather than almost ablating the entire optic lobes of the
flies, Bahl *et al.'*s genetic manipulations specifically affected only
two sets of interneurons, T4/5, in the flies' visual system which the
[Borst lab had previously
reported](https://dx.doi.org/10.1007/s00359-012-0716-3){target="_blank"}
as abolishing all optomotor responses. Not only was it known that these
highly specific manipulations abolished optomotor responses, it was also
known why this happened: these neurons are a crucial component of the
fly's visual motion detector. Thus, these flies were exclusively
motion-blind and all other faculties were unaltered. Amazingly, despite
this highly specific manipulation, these flies behaved exactly like the
*rol sol* flies: they did not respond to moving visual cues, but when
allowed to control a black stripe with turning maneuvers, they kept the
stripe in their frontal visual field. The authors not only replicated
this aspect of the flies' behavior, they also did so using walking
flies, while the original study had examined flying flies, thus
extending and generalizing the findings of Wolf and Heisenberg.
Moreover, the authors found out, by careful and detailed dissection of
the flies' behavior, that optomotor responses improve fixation by
increasing the tendency of the fly to move the stripe to the front of
its visual field. For more details see the original publication or an
[excellent news-type article by Masson &
Goffard](https://dx.doi.org/10.1038/nn.3411){target="_blank"}. This
news-article also emphasizes, btw, the relevance of fly work for our
general understanding of gaze stabilization even in vertebrate systems.

::: {#attachment_134 .wp-caption .alignleft style="width: 160px"}
[![Fig. 2: "Inverting goggles" experiment. Whenever the tethered fly
attempts a turning maneuver, the fly\'s visual panorama is rotated in
the same direction. In the depicted example, a right turning maneuver
leads to a rotation of the panorama to the right. In this situation, any
attempts of the fly to follow the stripe will lead to a catastrophic
feedback of increasing speed of the stripe and yaw torque of the fly in
the same direction. Nevertheless, flies learn to generate turning
maneuvers in the opposite direction in order to establish a zero net
rotation of the stripe (optomotor balance). Fly drawing courtesy of
Reinhard
Wolf.](https://bjoern.brembs.net/wp/wp-content/uploads/2013/05/inversegoggles-150x150.jpg){.size-thumbnail
.wp-image-134 decoding="async" aria-describedby="caption-attachment-134"
width="150"
height="150"}](https://bjoern.brembs.net/wp/wp-content/uploads/2013/05/inversegoggles.jpg)

Fig. 2: "Inverting goggles" experiment. Whenever the fly attempts a
turning maneuver, the fly's visual panorama is rotated in the same
direction. Fly drawing by R. Wolf.
:::

Very much like Wolf & Heisenberg in 1986, Bahl *et al.* come to the
conclusion that there is, in addition to the well-studied optomotor
system, a less well-studied position system that acts in parallel during
object fixation/course control. Specifically, and this is where they
differ markedly from Wolf & Heisenberg, the authors assume that both
systems operate according to more or less fixed input-output rules,
i.e., "turn left on stimuli moving to the left" or "turn right if the
bar is on the right". However, the single most critical condition in the
experiments by Wolf & Heisenberg was the one where a right turn of the
fly led to a rotation of the visual field to the right, instead of to
the left (the '[inverting
goggles](https://www.grand-illusions.com/acatalog/Reversing_Goggles.html){target="_blank"}'
experiment, see figure 2). The *rol sol* flies showed no difference in
stripe fixation between both conditions, whereas control flies took much
longer to fixate the stripe under 'inverting goggles' conditions. This
decisive experiment showed that "turn right when the stripe is on the
right" (i.e., the conclusion Bahr *et al.* arrive at) cannot explain
fixation in these motion blind flies. Had the *rol sol* flies performed
this function exclusively, they would not have been able to fixate the
stripe. The same then also holds for the flies from Bahr *et al.*: if
their flies also fixate the stripe equally well in the regular as well
as the inverted situation, their entire explanation for their results
falls apart. Regrettably, Bahl *et al.* did not perform this very
crucial, essential experiment, not in their flies, nor in the computer
model they derived from their data. Hopefully, their next publication
will contain these exciting experiments.

**UPDATE**: I have visited Axel Borst's lab yesterday and they are
working on the inverting goggles experiment. For now, the flies have
trouble stopping the stripe from rotating at all, so there may be some
technical problems using walking flies instead of flying flies for this
kind of experiment, or simply the right parameters have not been found,
yet. Either way, as I speculated, they are working on it!

------------------------------------------------------------------------

[Bahl, A., Ammer, G., Schilling, T., & Borst, A. (2013). Object tracking
in motion-blind flies [Nature Neuroscience,
16]{style="font-style: italic;"} (6), 730-738 DOI:
[10.1038/nn.3386](https://dx.doi.org/10.1038/nn.3386){rev="review"}]{.Z3988
title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.jtitle=Nature+Neuroscience&rft_id=info%3Adoi%2F10.1038%2Fnn.3386&rfr_id=info%3Asid%2Fresearchblogging.org&rft.atitle=Object+tracking+in+motion-blind+flies&rft.issn=1097-6256&rft.date=2013&rft.volume=16&rft.issue=6&rft.spage=730&rft.epage=738&rft.artnum=http%3A%2F%2Fwww.nature.com%2Fdoifinder%2F10.1038%2Fnn.3386&rft.au=Bahl%2C+A.&rft.au=Ammer%2C+G.&rft.au=Schilling%2C+T.&rft.au=Borst%2C+A.&rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CNeuroscience%2CBehavioral+Biology%2C+Ecology%2C+Evolutionary+Biology%2C+Genetics%2C+Zoology%2C+Behavioral+Biology%2C+Computational+Biology%2C+Genetics+%2C+Zoology%2C+Behavioral+Neuroscience%2C+Computational+Neuroscience"}  
[Wolf, R., & Heisenberg, M. (1986). Visual orientation in motion-blind
flies is an operant behaviour [Nature, 323]{style="font-style: italic;"}
(6084), 154-156 DOI:
[10.1038/323154a0](https://dx.doi.org/10.1038/323154a0){rev="review"}]{.Z3988
title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.jtitle=Nature&rft_id=info%3Adoi%2F10.1038%2F323154a0&rfr_id=info%3Asid%2Fresearchblogging.org&rft.atitle=Visual+orientation+in+motion-blind+flies+is+an+operant+behaviour&rft.issn=0028-0836&rft.date=1986&rft.volume=323&rft.issue=6084&rft.spage=154&rft.epage=156&rft.artnum=http%3A%2F%2Fwww.nature.com%2Fdoifinder%2F10.1038%2F323154a0&rft.au=Wolf%2C+R.&rft.au=Heisenberg%2C+M.&rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CNeuroscience%2CBehavioral+Biology%2C+Genetics%2C+Zoology%2C+Behavioral+Neuroscience%2C+neurogenetics"}


Until 1986, it was thought that so-called optomotor responses, i.e., the tendency of all animals and humans to follow moving visual stimuli with their eyes or their bodies, were a prerequisite for gaze or trajectory stabilization: whenever the scenery in your gaze moves, you adjust gaze or body orientation to compensate for the shift.

Postagens de Rogue Scholar

Flashback: Nothing new in science?

Flashback: The neurobiology of operant conditioning

Dissecting a fly’s course control system