A Day in the Life of Gondi, the Little Toxoplasm

Hey there fellow organism! Yeah, I'm talking to you, bighead. Just because I am only a few micrometers long, doesn't mean you get to ignore me.

Look, I happen to be stuck – in you.
And it's really all your fault. You must have gotten yourself infected by eating uncooked meat or, if you happen to have a cat you probably got a little too close to its feces – either way, you're gross. Do you remember that flu you had a few weeks ago? That was me. Or rather that was your immune system trying to get rid of me, which by the way – rude! Others of my family have infected about half of your sorry population around the globe and most of them were doing fine, no symptoms whatsoever. The way a host should behave, if I may say so. So now, I am crammed into a cyst with who knows how many of my kind and have to lie around semidormant. I don't know if I will ever see the comfy squishy cells of a cat's intestine again, ergo I don't know if I will ever get to sexually reproduce again. Picture that! Sure, I could keep on merrily dividing in you but then your immune system would probably start going all rampage-y again on me, so no thanks. You are just seriously lacking as an intermediary host.

Dividing T. gondii, courtesy of Ke Hu and John M. Murray [1]

 
And this is not me whining – I happen to have been through a whole lot of intermediary hosts: mice, rats, once even a cow. I might be a small, arched parasite but I am capable of surviving in just about any warm-blooded animal. And outside of them, too! In fact, I have been told that I am very resilient to cold climates, thank you very much. Plus, in mice and rats I stand at least a fighting chance to get back into a cat. See, I happen to not only be resilient, highly international and wisely adjusting my proliferation rate so that hosts don't kick me out – I can tweak behaviour of animals who are ten thousand times my size. See, I propagate into my inter-host's brain, I fiddle about a little here and a little there, some hypomethylation of genes that are expressed in the amygdala, a bit of histone-lysine acetylation of astrocytes. And voilà: mice lose their fear of cat urine. Rats even find the smell more attractive! They stop avoiding marked territory and they become altogether less capable of escaping the cat they sniffed out. Isn't that just great?
But humans...pesky. There was a time when getting you eaten by a big cat, say a lion, was a real option. But nowadays you have become so cuddled away and safe with your sweet little overfed furballs. I mean, toxoplasma gondii is no quitter, mark my words! A toxoplasma infection is associated with some neat little behavioural changes in humans: Males show higher levels of testosterone, are more likely to disregard rules. Both of your sexes perform worse in respect to reaction time and concentration. We are associated with higher risks for schizophrenia, bipolar disorder, suicide and traffic accidents.
Still, getting out of a human and back into a cat is hard work. I'm a nice little fella, just wanting to get back to my favourite host.

So. About my being stuck – would you care to get eaten by your cat?

Malika Renz
MSc Student, MedNeuro

Want to know more?
[1]  Hu et al., PLoS pathog 2006
[2] Webster, Schizophrenia bull, 2007
[3] Flegr, Schizophrenia bull, 2007.
[4] Torrey et al., Schizophr res, 2012 
[5]  Hurley et al., J neuropsy clin neurosci, 2012 


This  article won the Best Contribution award for the  issue Brain Invasion  Thanks Malika for such a fun take on a complicated subject!

Like what you see? Interested in contributing? We are always looking for new authors and submission on anything related to the topic of neuroscience. Send us an article, some beautiful shots from your microscope, poems, short stories, critiques, reviews- anything to cns-newsletter@charite.de! 

New Issue Out Now: BRAIN INVASION

The brain is an amazing thing: it allows to think, feel, create and do lots of other less-glamorous things like breathe and digest your lunch. But what's even more amazing is the system that our body has involved to keep it that way. This issue of the newsletter is all about how things can find their way inside our heads- for better or for worse!

 

https://bit.ly/2LwCVRU

First off, have a look at our primer on the different ways in, intracortical implants to poorly cooked food (page 3), and learn more about the body's first line of defense (page 7-8). We also have a first-hand account of a particularly sneaky invader (page 4), as well as clinical reports of foreign objects turning up where they definitely shouldn't be (page 9)! But it's not all bad news! Recent developments have meant that our senses can be augmented (or even repaired, pages 5 and 10), and optogenetics has "illuminated" a whole new realm of experimental possibilities (page 13-14). Are we ready for blending our brains and technology? We have two stories examining the ways authors play with the idea of cyborgs (pages 11-12), as well as providing some thought-provoking watching material (page 7).
Of course, we also have stories from the here and now on campus. What's the point of publishing negative results (page 19)? Are MSc students treated fairly (page 18)? What is it like to work for a big pharma company (page 16)? And, most importantly: what the heck is going on with those yellow buses all over campus (page 21)?

Happy reading, dear readers! We hope that this issue will stick in your head.

Constance Holman and Claudia Willmes
Editors-in-Chief

Neuroscience Podcasts to Seriously Send Those Brain Cells Firing

There’s only so much time one can dedicate to surfing Netflix, listening to Spotify or watching reality TV. At some point, you are adamantly looking for intellectual forms of entertainment. Enter podcasts- the audible version of blogs.

Those with a story-telling flair can keep one indulged for hours. Others that present educational or scientific content keep you intellectually engaged and listening to them are by no means a passive activity. If the podcast’s host has a dulcet tone and knows how to keep things moving, even stuff that you probably couldn’t care less about will become potentially interesting. Which brings us to the million dollar question- with a plethora of science podcasts available, which ones should you listen to? More specifically, are there podcasts that deal with Neuroscientific topics? This was the quest I took two months ago.  Below are some of the Neuroscience podcasts, in no particular order, which might be the answer to your curiosity or intellectual thirst.

1. You are not so smart

Image courtesy: David McRaney, https://bit.ly/2yckkno

Host: David McRaney
Average length: 50-60 min.
How active? : very. uploads content every month, sometimes even twice a month.
The good: Compares different psychology/neurosci topics relevant to current topics and affairs in everyday world. His podcast episodes always leave you feeling sober or humbled by the fact that how subjective, unpredictable and sometimes fickle our human selves can be. Except for a few mins of ads in the beginning and centre, there are no distractions. He also has an excellent way of introducing his guests in that he first gives an overview of the topic and then lets his guest take centre stage. He also doesn’t ramble or try to chime in with his own opinions during the interviews. Plus his voice is deep and lucid which makes it easier to continue listening to him for extended periods of time.
Start where: Tribal Psychology; Selfie; The Dunning-Kruger effect (but really too many good episodes here)
What’s missing? The podcast is overall excellent and you are seriously missing out if you have not heard of YANSS before. Perhaps the only thing you might find lacking would be that this is not, strictly speaking, a Neuroscience specific podcast but borders around Psychology, Pop culture, Neuroscience and Behaviour [1].


2. Brain Science Podcast

Image courtesy: Virginia Campbell, https://bit.ly/1BtSxxs

Host: Ginger Campbell, M.D
Average length: 60 min
How active? : very. technical and less technical content uploaded regularly since 2008
The good: This one is for hard-core Neuroscience enthusiasts. If you are a grad student and are looking for something other than the oft-repeated topics such as reproducibility crisis, women/diversity in STEM than this IS the place for you. There are 100+ episodes available as Dr. Campbell’s podcast has been one of the longest running Neuroscience podcasts to date. She discusses really thought-provoking books that are related to different subdivisions of Neuroscience and has interviewed many leading experts in the field including Drs. Michael Gazzaniga, Christof Koch, Temple Grandin and György Buzsáki to name a few. Listening to Dr. Campbell is like having your extremely well-educated grandma let you in on the intellectual discussions she has with all of her guests.
Start where: Counting Neurons with Dr. Suzana Herculano-Houzel ; John Medina on Aging Well
What’s missing? Some of the older episodes require premium subscription (but full access is possible at 5 bucks a month) so listening to Dr. Koch or Dr. Gazzaniga comes at a small cost. However, you can listen to the more recent episodes uploaded after 2013 for free. All podcasts come with transcripts as well as links to discussed books and papers. Beware though as some of the links may not work due to website revamping [2].

3. Shrink Rap Radio

Image courtesy: David Van Nuys, https://bit.ly/2IxwBMF

Host: David Van Nuys, Ph.D
Average length: 60 min
How active? : very. There are almost 3-4 episodes posted every month.
The good: Dr. Van Nuys also has a talent of making his guests feel at ease and asks thought-provoking questions. There’s also a decent amount of content related to mind-body-soul science if you are into that stuff. Together with the Brain Science Podcast, this is one of the oldest running podcast I could find with quality content.
Start where: Quieting your inner critic and rising above social anxiety with Ellen Hendriksen; The Body of Sex with Sarah Byrden ; The Silent Epidemic of REM Sleep Loss with Rubin Naiman
What’s missing? This is more of a Psychology podcast but has close overlap with Cognitive Neuroscience because of the topics covered. Some episodes are longer than 60 mins so reserve this one for weekends [3].

  4.  A Neuroscientist Explains

Image courtesy: Max Sanderson, https://bit.ly/2Ilyx6M

Host: Daniel Glaser, Ph.D
Average length: 30-40 mins
How active? : Intermittent. Has two seasons out (1^st season: 8 episodes, 2^nd season: 7 episodes); one in 2017 and the other in 2018.
The good: This one’s for all the British accent lovers. The episodes have a very soothing background music so that it literally calmed my anxiety during stressful morning commutes. Quite accessible, user-friendly and the topics are quite relevant if you are interested in Neurosci but don’t know where to start
Start where: A Neuroscientist explains: how music affects the brain; A Neuroscientist Explains: is the internet addictive? ; A neuroscientist explains: how the brain stores memories
What’s missing? The podcast is not very active so if you are looking for interviews and bringing yourself up-to-date with current trends, this isn’t the one [4].

  5. Smart drug smarts

Host: Jesse Lawler (permission pending)

Average length: 40-60 min
How active? : very. Content updated religiously
The good: This podcast has one of the most amusing introduction out of all science podcasts. The episodes are quite fast paced so if you cannot stand slow discussions, go for this one. Lawler is a self-proclaimed science fan boy and is an excellent host. The voice quality is excellent and all the podcast episodes come with detailed transcripts as well as summary notes. The website overall is very decently designed which makes spending time here more fun.
Start where:     Brain Implants – Medical and Beyond with Dr. Brett Wingeier; Head in the Game with Dr. John Sullivan; Cognitive Fallacies with Dr. Richard E. Nisbett ; What are “Fast-Spiking Interneurons”?; Placebo: the Power of the Mind to Heal
What’s missing? Lawler is quite enthusiastic and throws in a lot of slangs and casual phrases so those looking for more serious style discussions may not agree with his hosting style (not that I’m complaining) [5].

  6.  Neurotransmissions

Image courtesy: Joe Schumacher, https://bit.ly/2KJQjlh

Host: Ben Scholl, Ph.D., Joe Schumacher, Ph.D., and Misha Smirnov, Ph.D.
Average length: 30-40 mins
How active? : post content every other month. Haven’t been very active for the last 2 months though.
The good: started by post-docs at Max Planck, Florida, this podcast discusses latest topics in Neuroscience in an almost jargon-free manner. Quite accessible for the general audience in terms of content. Voice quality decent and all of the hosts are quite adept at making things moving and not chiming in too often. The general mood of the podcast is academic style and formal. Go for it if you are into interviews or seeking some inspiration.
Start where: Science writing and life living with Dr. Brett Mensh; Sunposium 2017: Part 2, Technological innovation with Drs. Ed Boyden & Viviana Gradinaru; Live from Sunposium 2017: Part 1, The Value of Scientific Knowledge with Dr. Thomas Südhof
What’s missing? Could be a bit dry at times. Needs some light-hearted humor [6].

7. Neuroscientists Talk Shop

Image courtesy: Neuroscientists Talk Shop, https://bit.ly/2IDc5cJ

Host: various including Salma Quraishi,Ph.D, Alfonso Apicella,Ph.D, Charles Wilson,Ph.D (and others)
Average length: 40 min
How active? : usually post 2-3 episodes every month but have not been very active recently.
The good: started by a group of professors and graduate students at UT San Antonio, this podcast is more hinging on the technical side. Guest scientists are invited in each episode and talk about their research. The questions are more symposium-style and the atmosphere is quite academic and scholarly. If you are looking for some inspiration on someone who is working on a similar topic to yours, maybe look here for some inspiration. Although the podcast has many moderators, the questions never get jumbled up so that everything is easy to follow. Also the podcast has no ads which means no distractions.
Start where: (Interview with) Rusty Gage, PhD ; Ann Graybiel PhD ; Dwight Bergles PhD
What’s missing? Sometimes voice quality not as crisp as you’d like it to be. Could be a bit dry and information-heavy as the time duration is only 40 mins [7].

8. Honourable mentions:
These include Neuroscience podcasts that are no longer active. Neuropod (Nature podcasts on Neuroscience) which ran till late 2015 [8]. The Naked Scientists (Naked Neuroscience) which stopped updating after 2014 [9]. Note that the Naked Scientists podcast on other science disciplines such as Genetics, Astronomy and so on are still regularly updated.

Image courtesy: Chris Smith, https://bit.ly/2IDMkcw

Word to the wise: avoiding mindless media consumption does not mean that your ears have to be glued to scientific podcasts. Cut your poor brain cells some slack and have some time off to digest all the information.

Did we miss any cool podcasts that talk about science and especially all-things-brain? Give us a shout out at cns-newsletter@charite.de about any potential hidden gems that you know.

by Zara Khan, MSc Student MedNeuro

[1] https://bit.ly/2yckkno
[2] https://bit.ly/2jYSpCi
[3] https://bit.ly/2rGYGpK
[4] https://bit.ly/2Ilyx6M
[5] https://bit.ly/2rM38Ui
[6] https://bit.ly/2rNOSuf
[7] https://bit.ly/2IDc5cJ
[8] https://go.nature.com/2rJtyG9
[9] https://bit.ly/2IDMkc

Drug-induced mental disorders: a common reason for concern?

Most psychoactive drugs alter our cognitive and emotional states, but does chronic use implicate a pathological change in our mental condition?

If we chronically alter transmitter pathways, adaptations will certainly take place. Adaptations are expressed during addiction in sensitization and desensitization of transmitter pathways. This leads to an up- or downregulation of receptors and transporters and eventually to tolerance as well as craving when the drug is withdrawn. These adaptations originate out of natural compensation, but leave former drug users with an imbalanced brain chemistry and an increased risk for several mental disorders. Patients with substance disorders are twice as likely to suffer from mood and anxiety disorders (National Institute on Drug Abuse). Basically, all drugs alter dopaminergic regulation and consequently, our motivation and ability to experience pleasure is changed. Several drugs also cause neurotoxicity and can therefore easily lead to permanent damage, e.g. depression after prolonged ecstasy use due to serotonergic cell death. 
Apart from emotional disturbances, the most common drug-induced illness is psychosis; with alcohol (18%), cannabis (13%) and cocaine (18%) being the most common inducers [1]. One could blame everything on 'high risk drugs', yet, for many mental disorders susceptibility genes have been found, e.g. the VAL/VAL variant of the COMT-gene in cannabis users who go on to develop schizophrenia [2]. Other factors, such as food intake, can severely affect mental outcome after chronic drug use, for example vitamin b12 deficiency in alcoholics, which can lead to several mental disorders, including psychosis and depression.
Hence, aside from chronic substance use, our environmental and genetic conditions play a decisive role in the development of long lasting drug-induced mental pathologies.
  
[1] Drake et al., Am J Psychiatry, 2011
[2] Caspi et al., Biol Psychiatry, 2005

By Anne Schwerk, PhD Alumna, AG Neuronal Regeneration and Plasticity (Dr. med. Barbara Steiner)


This article originally appeared in CNS Volume 5, Issue 1, Mental Health Disorders

38% of Europeans affected by mental disease

Arguably, one of the most profound findings of 2011 was an epidemiological report on the mental health status of the European Union. Hans-Ulrich Wittchen and his international team of mental health experts have unraveled striking data on just how extensively disorders of the brain impact European society, and if the trend has been changing over the last three decades.   

With an initial goal to systematically assess the prevalence and burden of neurological and mental disorders in the European Union, experts from each disease category met and combined their data, only to find that it was difficult to segregate prevalence between mental and neurological disorders, due to significant overlap. However, it was possible to assess the burden of mental and neurological disease separately, when expressed as disability adjusted life years. Previous knowledge on this subject has been sparse - the World Health Organization reported an estimated 13% of global health burden to be from mental disorders. The World Mental Health Survey quotes that one in three adults suffers from a mental disorder.

Mental and Neurological Disorders Come to the Forefront: Significant Health Burden on Society

Wittchen and colleagues set out to sample all of the EU countries as well as Norway, Iceland, and Switzerland. The team combined retrospective studies, consistent reanalyses of existing epidemiological datasets and supplementary survey data from national experts to gather the best possible comprehensive dataset. 19 epidemiological panels were dispatched and at least one international expert was recruited per diagnostic group. Data was collected as far back as 1980, when the first diagnostic criteria were published on an international level (Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Statistical Classification of Diseases and Related Health Problems (ICD)).
The results were startling: 38% of all Europeans are affected by disorders of the brain. Combined, mental and neurological diseases comprise Europe's largest disease burden, in terms of disability adjusted life years. The highest proportion of this burden was due to anxiety disorder, unipolar depression and insomnia.
Previously, Wittchen and colleagues had published a similar report in 2005, where the numbers were significantly more conservative, citing that 27% of the EU population are affected by mental disorder. However, this study produced a much more restrictive estimate due to age restrictions of the sample (only adults and not kids nor elderly were included), and a much more limited set of criteria for mental disorders. This time around, the team decided to get an unrestricted estimate regardless of age range or disease type.

Wittchen et al., Eur. Neuropsychopharmacol, 2011
Wittchen and Jacobi, Eur. Neuropsychopharmacol, 2005
World Health Organization, The Global Burden of Disease, 2004 Update (WHO, 2008)


By Gina Eom, Alumna MedNeuro 

this article originally appeared in CNS Volume 5, Issue 1, Mental Health Disorders

Empirically Aesthetic? MPI Researchers Weigh In

It's fascinating to read about big concepts like philosophy and beauty, but what is it like to study them in your daily job? Malika Renz sat down with researchers from the Max Planck Institute for Empirical Aesthetics to find out.

Pauline Larrouy-Maestri

Pauline Larrouy-Maestri, you have a very diverse background – can you tell us how you got into neuroaesthetics?
Yes, I studied music, psychology and pedagogy and worked as a musician and a speech therapist. My PhD was in cognitive psychology, on the singing voice which is of course linked to aesthetics. But aesthetics wasn't my main focus then – it's more of a means of looking at how people interact with their environment, at auditory perception and processing. I've been working on this as a post-doc here at the MPI for 3 years now.

How do you start with something as vague and mysterious as beauty and end up learning about perception and processing mechanisms?
Suppose you start with the question: what makes something beautiful? Is it the same as being somehow correct? Or interesting? Recently, we've been working on pitch accuracy, so let's take that as an example. Beautiful singing voices or melodies are often associated with being "correct". Everyone can hear if a performance is in or out of tune – musicians, non-musicians, male, female, young and old – people usually agree on this. So what is it that makes all of us feel that one tone is correct and the other is not? It's hard to put a label on this, it just sounds right or wrong. Somehow, people must become sensitive to the criteria for a correct melody without ever being aware of it! And we know this holds true not only for music but also for other domains – we learn rules and we apply them to make an aesthetic judgment without even noticing.

But if we don't even notice it – how are we learning those rules?
The brain is made for taking in stimuli and building rules, and thus knowledge from it. It's similar to how children learn a language, a totally implicit process. To understand language you have to parse the auditory signal – you need to cut it into sensible units and concatenate them in a meaningful way. The same parsing and integrating of course happens in music appreciation as well and it is this process which I am interested in. Aesthetics is my vehicle to study how we learn auditory processing, what the minimal units and the rules of meaningful integration are.

How can you research music appreciation in the lab?
Me, I am doing psychophysics: I manipulate stimuli, I invite people to the lab and ask them to listen to these stimuli. We change single features of tones and ask something like “Which of these sounds is more in tune?”. The resulting data can tell us what differences are perceived and what magnitude of change is needed. That alone reveals a lot about the structure of sounds, its components and their relative importance. This was how we found out that the smallest meaningful units are not single notes –  it's the beginning and the end of a a note that matters. Once you find these units and confirm their discerning value, you can play with them: find out how the changes influence the perceived agreeableness or pitch accuracy. And whether people even agree on the direction of effect of a specific parameter.

Pardon my impoliteness, but apart from being fascinating, what use is there in all this?
Aesthetic appreciation of course is very fundamental. Many things are related to what you see and hear, all around you. Interaction with people is about tastes, preferences, about your appreciation of the environment. We all function with that all the time. But we don't understand the processes behind it very well: we know that the pleasure circuitry is based on automatic processes. For perceiving something as beautiful, however, indirect pathways, such as mediation by thought, are needed. Simply knowing how perception works has a clinical application. If someone has a speech impairment or a difficulty to understand language, is it because they cannot parse? Cannot concatenate? Didn't learn the appropriate rules? As soon as we have a working model we can tick which box is malfunctioning and focus training or treatment there.

To save the best for last: what was your personal research highlight?
I showed that we are all musicians. Let me explain. For decades, we had in the scientific literature a separation between musicians and non-musicians. It is categorical, but the idea has been around for a while – and it's nonsense! Take an opera performance. Who goes to the opera? No one does! Only a very small part of the general population, mostly educated people with a musical background or interest. And musicians agree to a very great extent on their judgment of what makes a beautiful opera voice. But here is what I found: people who have no idea what an opera voice is or should be apply the same criteria and come to the same conclusions. So, without ever going to the opera, without any explicit input, we build a representation that creates a link – between you and me, between people who are privileged enough to enjoy operas and those who aren't. Our learning mechanisms are fundamentally the same and they take whatever they can get from the environment.


 The interview was conducted by Malika Renz, MSc Student MedNeuro

Does Beauty Lie in the Face?

As the saying goes, ‘beauty is only skin-deep’. However, many times we cannot help but fall for an attractive face: the first impressions of a person do create an impact on our minds. What is considered ‘beautiful’? Are there features of faces across cultures that people find more attractive?

Facial Symmetry

According to researchers, a face is perceived as beautiful if it is symmetrical and represents the average traits of the population. Our eyes recognize symmetrical faces with similar proportions on left and right side of the face. The quest to define a golden standard for a facial feature - for example, the size or shape of the eyes or lips - dates back to antiquity. The Ancient Greeks believed that the essence of beauty lied in the golden ratio of 1:1.618. More recently, researchers have discovered that people find a female face attractive when the distance between the eyes is just under half of the width of the face. They also found that the eye-to-mouth distance should be just over one-third of the height of the face. These two ratios have been termed as the ‘golden ratios’, which correspond to that of an average face [1].

Example of faces with different length and width ratios. Boxes mark the optimal length and width ratios that people found attractive [1].

 

What is the reason behind the choice of such features? This can be explained by two existing theories: one is an evolutionary aspect where humans tend to choose healthy mates with physical characteristics resembling the average population. The other is a cognitive aspect where, due to repeated exposures, we tend to prefer prototypical facial features which are easier to process.

Golden ratio: can beauty be quantified? 

So, are facial preferences based on nature or nurture? Do we have a preference for certain faces as babies? The answer seems to be: yes! Babies of 2-3 months tend to look at attractive faces for longer time than unattractive ones [2]. The perception of attractiveness is also affected by familiarity: Hazda people, hunter-gatherers from Tanzania who have not been exposed to European faces, found the average face of a Hazda more attractive than an European face [3]. But spatial aspects of the face are not the only determinants of attractiveness - sexually dimorphic features like full lips and longer eyelashes also influence what people find attractive [1 ].

The Power of a Smile

A smile has more powerful influence on people’s perception than facial features or makeup, according to psychologists. People with genuine smiles were seen as healthier and more attractive by virtue of being optimistic and cheerful than people with blank expressions [4,5]. Thus, the secret to healthy appearance and being attractive? Smile!

For the evolutionary basis of beauty, check out Helge's article on page 5. Given the fact that there is an innate bias inside all of us towards 'beautiful' faces, it is even more important for us to think twice before making judgements on other people based just on their appearances!

How an average American woman will look like in 50 years
(Courtesy: National Geographic)

What will future humans look like?

It has been predicted that globalization, cultural diffusion and interracial marriages will eventually homogenize the human population, averaging out more and more people's traits such as hair, eye color, facial features, and eye shape. Dominant traits will be expressed more than recessive traits (which need not one but two copies of the gene to be expressed). In other words, we are going to become a huge amalgamated race!

by Aarti Swaminathan, PhD Student AG Schmitz

 [1] Pallett P.M, Link S, and Lee K. Vision Res. 2010.
 [2] Hoss R.A. and Langlois J.H. The Development of Face Processing in Infancy and Early Childhood: Current Perspectives. 2003.
 [3] Apicella C.L et al. Perception, 2007.
 [4] Golle et al. Cognition and Emotion, 2013
 [5] Jones A.L et al. Visual Cognition, 2017.