Brain and mind

The Physics of Neurons

jhalper — Mon, 30 May 2016 06:08:09 +0000

The Physics of Neurons

Does the brain really operate like some kind of extra-complex computer, with logic gates and circuits made of the synapses that connect one neuron to another?

In 2009, we wrote:

In the future, the interface between brain and artificial system might be based on nerve cells grown for that purpose. In research that was recently featured on the cover of Nature Physics, Prof. Elisha Moses of the Physics of Complex Systems Department and his former research students Drs. Ofer Feinerman and Assaf Rotem have taken the first step in this direction by creating circuits and logic gates made of live nerves grown in the lab.

In his latest research, Moses, together with neurobiologist Prof. Menachem Segal and postdoctoral fellow Dr. Yaron Penn, suggests that the communication between neurons is less logic circuit and more “synergy.” Their experimental artificial nerve cell network has now grown to several hundred neurons – enough to begin observing interesting phenomena.

Neurons in a lab dish act synergistically

Moses, Segal and Penn were looking for a “leader” – a neuron that would set off a chain of electric pulses running through the network. Instead, they found that neurons are naturally “nervous,” oscillating constantly. When a signal needs to be formed, the individual oscillations became synchronized, neighbors adjusting their wavelengths to one another until a group of neurons emits a single, coordinated pulse. This is an emergent phenomenon, like fireflies flashing in harmony, and it needs no leader to make it happen.

Do the neurons in our brains really work this way? There is some evidence that they do. If so, it could be one of those small but fundamental shifts in understanding that changes the way that experiments are conducted, data analyzed, and artificial intelligence designed. Penn reports that they were able to turn the oscillations up or down – basically by controlling the calcium intake of the cells, which led to more or less connectivity and more or less excitability. Connecting these two parameters, say the scientists, suggests new leads into such disorders as epilepsy, which looks a lot like an imbalance between the two.

Oscillations of an individual neuron in a calcium-free medium. At left - 110 minutes, at right 100 seconds. On top -firing rate (spikes/200msec), at bottom -FFT spectrogram

jhalper Mon, 05/30/2016 - 02:08

Tags

basic research

Biomedical

Biophysics

Brain and mind

neurobiology

Non-linear physics

scientific collaboration

Artificial neuron network

scientific collaboration

The 12th annual Ilan Ramon Space Olympics (Rehovot, we have a winner)

jhalper — Mon, 07 Mar 2016 12:51:55 +0000

The 12th annual Ilan Ramon Space Olympics (Rehovot, we have a winner)

Is this science writer jazzed that ninth-grade girls from a religious girls’ school in Jerusalem won a space/science contest? You bet your sweet solar-powered spacelab she is! It is not just that these girls beat out a lot of other classes (over 400), or that they break more than one stereotype. They also came up with a pretty clever idea for studying the Sun: Send a spacecraft to scatter assorted nanolabs all over an asteroid that is about to pass close to the Earth on its way to the Sun. The contest is held every year in memory of Israeli astronaut Ilan Ramon, who went down with the crew of the Columbia space shuttle in 2003. Middle-school classes all over the country vie to design space missions, and the top classes receive telescopes for their schools.

Korean astronaut Yi So-yeon with two members of the Ilan Ramon Space Olympics winning team

The top 12 classes, by the way, had a lecture from a female astronaut – South Korea’s Yi So-yeon. Women might not yet be set to take over the space program, but from where we are sitting, it looks like there is definite hope.

In other news from the Weizmann Institute, “over-generalization” – when your brain mistakes harmless stimuli for dangerous ones – is not only a real thing, in those who suffer from anxiety it can arise from patterns that become hardwired into the brain. Researchers found that attaching emotional stimuli, for example gaining or losing money, to hearing a tone can make a subject less able to later distinguish that tone from another, similar one. That was especially true for subjects who normally suffer from anxiety, and fMRIs of their brains showed that their response patterns work a bit differently, so they can’t help their seemingly irrational emotional responses to benign events.

Our brains may overgeneralize under stress; but we are actually pretty good at recognizing detail – better than a computer. In other research, scientists pitted 15,000 humans (hired from Mechanical Turk) against computers to see how well each is able to reconstruct a mental image from photos that had either been cropped or their resolution lowered. Humans beat computers hands down, but the interesting thing is that nearly all humans fail the test at the same point. Remove a couple of pixels, and suddenly most people are unable to name that image. This suggests several things. One is that our brains have some basic “atomic” unit of detail that we require to recognize an object. Another is that our brains process images in two ways at once, simultaneously constructing a whole from the details and comparing the images our eyes perceive to those in our memory banks. Computer vision – the ability of computers to identify objects in images – has come a long way in the last few years, thanks, in part, to work at the Weizmann Institute of Science. But it is still far from perfect, and this research points to possible improvements.

A small change in images at the minimal recognizable configurations (MIRC) level can cause a large drop in human recognition rate. MIRCs (top) and corresponding sub-MIRCs (bottom); numbers under each image indicate the human recognition rate

For more examples, check out their website: http://www.wisdom.weizmann.ac.il/~dannyh/Mircs/mircs.html

jhalper Mon, 03/07/2016 - 07:51

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Basic chemistry might keep brain cells healthy

jhalper — Wed, 27 May 2015 04:34:38 +0000

Basic chemistry might keep brain cells healthy

“Inclusion bodies – those clumps of protein that are found in the brain cells of Alzheimer’s patients – are, sadly, a product of aging,” says Dr. Maya Schuldiner. “They can form naturally in practically all cells, but when these cells get old, the mechanism for clearing them away starts to fail.”

That is not great news for those of us who are already seeing signs of incipient dementia every time we forget a name or misplace our keys. But of course there is good news too. Schuldiner has discovered a “detergent” that cells make to wash away those nasty protein clumps. And she believes that, in the future, this detergent could provide the basis of drugs to treat neurodegenerative diseases, among them Alzheimer’s and Parkinson’s.

We put the word “detergent” in quote marks, but the truth is that the basic chemistry is pretty much the same as that of laundry soap: The two-part molecules have a fatty, water-repelling end and a water-loving end. The fatty end can attach to molecules of grease or protein; the water-loving ends latch on to the nearest water molecules to whisk the “dirt” away. In scientific terms, the proteins in the inclusion body become soluble.

"Laundry soap" in human cells: The Inclusion bodies are in red, lipid droplets in green

Schuldiner and her team realized this detergent was being produced when they saw lipid droplets – “little lard balls,” in Schuldiner’s words – tethered to the inclusion bodies they were investigating in yeast cells. These little lard balls turn out to be a bit more complex than they look. They produce a special kind of fat that is similar to a sterol (related to cholesterol) – when and only when there is an inclusion body in the cell. This sterol is what forms the detergent.

She says that she and her team were amazed to find evidence of detergents inside a cell. Since detergent molecules are basically indiscriminate in their actions – capable of clearing away all sorts of proteins and fats – the cell would need to produce them carefully and deliberately in place. Hence the physical tethering.

Her lab mostly works with yeast cells, which have, says Schuldiner, “the same inclusion body issues as human cells. They contain a protein that is nearly identical to the human one for tethering the lipid droplets. And, like the human ones, they suck at the removal process once they get old.” The group did repeat their experiments on human cells in lab dishes, finding similar results to their yeast cell studies. And Schuldiner points out that other studies have noted the lipid droplets around inclusions in the nerve cells of Alzheimer’s patients, but mostly ignored the deceptive little “lard balls.”

What gives her hope for treatment is that the detergent production is really “basic chemistry.” Clearly any potential drugs based on her group’s findings are, for now, in the speculation stage, but we can all hope for rapid advances in this area.

jhalper Wed, 05/27/2015 - 00:34

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Guest Post: The Scent of a Handshake

jhalper — Tue, 03 Mar 2015 05:51:48 +0000

Guest Post: The Scent of a Handshake

Today's guest blogger is Idan Frumin, a student in the group of Prof. Noam Sobel in the Neurobiology Department. Their research on the transmission of odor compounds while shaking hands appears today in eLife.

It all started one day after lunch, sometime back in 2011. We sat in the lab’s living room (Yeah, we have a living room. And a bedroom. And a blind pet cat. But that’s a different story), when Noam asked – ever wonder why people shake hands?

– To show you don’t have a saber up your sleeve – I immediately retorted.
– But that seems odd, doesn’t it? After all, we’re not in the Middle Ages anymore, he responded.

Noam had just gotten back from an international conference, one of many, and did there what all better scientists do in their leisure time: observed.

– and what if I tell you people sniff their own hands right after they shake someone’s hand?
–You’re kidding right? what are we, rodents?!
–Well, you should know by now we’re not that far from that...

So we devised a simple paradigm to test this. Do people really sniff their hands following a handshake? And is it directly related to the handshake? And more importantly – is it related to our sense of smell?.. Which is our lab's frame of reference for, well, almost anything.

We already had most of what it takes – we have rooms where we can put human subjects and sit them relatively comfortably on a dentist-style chair (talk about comfortable…), we have CCTV cameras that only need to be set up, and plenty of subjects that come and go for the various experiments taking place in the lab. So off we went. We knew we needed a big sample of subjects to be able to say something meaningful, so we started with 60. The paradigm was pretty simple – A person was seated alone in the room, unaware at that point that they are being filmed. After three minutes of idle seating, one of my lab mates (or myself at times) would enter and either shake or not shake the subject’s hand, saying the same “greet” sentence. The subject thought they’re waiting for the “real” experiment to ensue, so we told them we are getting everything ready, and that the experiment will start momentarily. After an additional three-minute period, the experiment was essentially over.

Analysis of substances on the rubber glove after a handshake revealed that chemicals from human secretions were transmitted through handshake alone

Then the fun part started. Watching this quantity of videos could be "a bit" tedious, but it has its perks embedded - people do the most hilarious things when they are alone... the most interesting for us - they constantly touch their faces. Much as Noam and that late-90's song both foresaw - "you and me baby ain't nothing but mammals," and may we add - indeed not very far from rodents so it seems. We constantly "groom."

One of the more perplexing results was the "self-sampling" behavior after encountering another individual -- as if to assess or validate one’s own place within some sort of hierarchy.

But the jackpot was the statistics of before and after handshake - there was a significant and substantial increase if a handshake was involved!

After a handshake (left), a volunteer sniffs her “shaking” hand more (right) (photo illustration)

Though we got nice results with 60 subjects, and presented those in two international conferences, we wanted something more comprehensive to tell. Is this effect happening only between males and females? Is it gender specific at all? So up went the count - to 160 subjects, 20 in each possible combination of subject, experimenter and shake/no shake. And this number continued to swell as we added more conditions and more controls. You can check the article to see what we did there. Calvin Klein was unwittingly involved as well...

Along the way the paper got some pretty and colorful additions. One day Ofer came and asked - did you check and see WHERE people touch their faces? I replied "Well it's a very interesting question which I am not going to address, but feel free to check that". So he did just that, and the answer became figure 2C - which I must say is one of my favorite pieces of art since. Another day Yaara wondered what actual chemicals are transferred when we shake hands, and that’s Figure 1.

Heat map: The likelihood of people touching their faces close to the nose was highest (red, yellow) after a handshake (left)

When people ask why study such stuff, and what scientific field or discipline do such studies fall under anyway - we have several answers. First - because it's there - and it's interesting. Everyone shakes hands and if the common explanation as to why is partial - we need to amend it. We do basic science - and the notion of applicability is important but not the main thing. Second, this really serves a broader argument - in which our stand is quite obvious - there is no advantage for man over beast, and we're a part of the greater evolutionary tree.

So here you have it - a story that started off as a casual conversation in the living room of a lab, and 280 subjects / cups of coffee / new grey hair later became the paper you ought to read, if you haven’t done so already!

jhalper Tue, 03/03/2015 - 00:51

Tags

basic research

Brain and mind

Chemical communication

Im and throwed. I was studying in the library recently, and the guy who sat next to me had a friend come over and JUST shake his hand. He proceeded with his 'studying', but occasionally scratched his nose (which I noticed because moment generating functions were not generating ... 'moments'). I understand why now.

I personally think that people smell their hands because it way of know what the person you shake hands with have been touching or doing.

1520567

this is interesting,so i can basically get a person to sniff any substance i want by just applying it on my hand and then shake their hand...cool
u13412214

when I read the topic, I was expecting something to do with bacteria and what-so-not, interestingly enough I found something more interesting. I am so going to take note of this from now on. My question is now, does it come naturally or people do it deliberately or maybe it is the matter of the mind?

15166873

Definitely mind, and subconscious. If you tell people they have been sniffing their hands, they won't believe you.

I find it fascinating that most people actually smell their hands after a handshake. It could be because the subject was exposed to either familiar or unfamiliar smells that concern the subject from the person shaking hands with the subject. Then again it could also be a seasonal issue as in Winter people are more likely to touch their noses due to the common cold.

I do not think that people smell their hands after a handshake because I have never noticed it and I have never done that myself. I believe there is confusion between just touching your face and smelling your hands after a handshake.

Indeed, the scientists thought of that: They checked to see if the subjects inhaled more -- sniffing, on other words -- after the handshake.

I once read that people subconsciously choose partners according to their scent. This, apparently due to the fact that everybody's scent is unique to their genetics. People would then choose someone that smell completely different than they do. This it is a natural process to ensure stronger offspring due to genetic diversity. Maybe people identify possible partners by subconsciously smelling their hands after greeting someone? I do believe that many people may deny this because the cannot recall smelling their own hand after greeting someone by hand, but I also believe this is subconscious and not at all intentional.

15000983

Interesting, considering the fact that I may have also unconsciously touched my face after a handshake. Is there a mental shift in the way the individuals view the other person after they have sniffed their hands or is just simply an unconscious act?
15004407

This is very interesting and I'm not finding it hard to believe because I might have smelled my hand after a handshake more than once. It could have been subconsciously or it could have been out of curiosity. But I also think that people don't necessarily smell their hand but they do touch their nose with the hand they used to shake with. It is also interesting to find out what your hand smells like after a handshake and you identify that person by that particular smell.

This is very interesting and I’m not finding it hard to believe because I might have smelled my hand after a handshake more than once. It could have been subconsciously or it could have been out of curiosity. But I also think that people don’t necessarily smell their hand but they do touch their nose with the hand they used to shake with. It is also interesting to find out what your hand smells like after a handshake and you identify that person by that particular smell.
15030343

i think higher classes are the ones who do this to lower classes. what i have noticed is that rich people are the ones that tend to do this , since they think they are more clean that people at lower level and i think they do this knowingly and if you tell them after they just pretend they did not know to hide there snobbish behaviours
u15202722

Do you think we subconsciously form our first impressions of people based on the scent of a handshake? If so, would it not make sense that people with a heightened sense of smell have difficulty changing their first impressions of people? 15037780

What an interesting research task! This is definitely not something i would ever have noticed or looked into in the past, but now that it has drawn my attention ill be keeping an eye out as this may be very intriguing to witness. One has to consider that there could however be a clash between natural instinct for us humans to touch our faces regularly and the intention to smell our hands after a handshake. This could lead to a mistaken conclusion. This is still, undoubtedly a topic which grabbed my attention.
15102808

I have never really noticed this happen ever and maybe i should try and observe people's actions more but I don't necessarily think that people smell their hands each and every time they shake somebody's hand, they could have had an itch or something. In the blog it was not mentioned how successful the experiment was, did every single person experimented on smell their hands or just half? Please may you clarify on this

14111782

I live in a rural area and it is more common to greet people by a kiss than with a handshake, unless men greet each other or if you are German. I prefer to be greeted with a kiss as people's lips do not touch public toilet seat lids or shake other people's hands that did not wash their hands after they have been to the restrooms. Interesting enough, people that greet with a kiss also touch their faces, before and after the kiss.

If I meet a person for the first time I often touch my face because I feel nervous and uncomfortable. I researched this and found that people often touch their faces if they feel discomfort. This may be the reason people touch their faces after handshakes as they are meeting people for the first time.
To further this study it could be tested with people who already know each other.

It is interesting to see the natural animalistic behaviors that humans often exhibit. I am studying genetics and so topics on evolution fascinate me.

This is a very interesting study as most people can identify other individuals purely by smell. I have experienced this when walking into a strangers home. The smell of certain places can be remembered and associated with specific things, as with the unique smell of "home". I think the same science applies to the handshake experiment. Our instinct is to remember the smell and store it in our memory or to associate it with particular things.

I have noticed myself smelling my hand after a handshake...and thereafter quickly proceeding to the nearest tap. This was at an age of about 13 but as I became older I found myself becoming more and more against touching my face in public especially after being in contact with other people. How would this instinctive smelling of the hands explain that or am I just the excepting to the rule?

This is very interesting. I have always thought that most people avoid the handshake because of public health issues. Now i learn about smells and all. Its pretty simple to understand why most people avoid handshakes including myself after reading this. Too much goes on with hands!

15079148

This is a very fascinating study. Every person has a distinct scent and by subconscioulsy smelling one's hand after shaking another person's hand allows us to remember the other person's scent. i believe that once the body has recognised another person's scent, they can pick it up from far the next time they meet, however subconsciously. Does the scent recognised by the body resemble a specific personality trait and does it contain specific elements which allows the person to be attracted to another? u15007473

I agree as the specific smell can be associated with a specific person or even a group of individuals without you even seeing that person or that group. When your smell receptors pick up that specific smell it automatically associates it with the person or group of individual without you actually being able to see them.

I strongly agree with your statment. Alri because I too can identify my cousin and her family with just the scent they are giving off when ever they I near. I don't have to literally have to see them to know that they are here.

It's fascinating to observe the unconscious mind! Studies shown that people tend to touch their face even more often if they shaken their hands with someone with the same gender! It would be interesting to study the reason why we subconsciously do this?

This is something that I have never even noticed. So of course I just had to see it for myself. I was astonished by how many people sniff their hands after a handshake. I then started to wonder if I also have this strange habit and if I do, how have I never noticed it before?

Wow! And we thought we left the caveman behind. A very interesting study. I am not completely sure about the scientific significance of the information but will surely be watching closing the next time I greet anyone with a handshake. It would be interesting to find out if the different places touched on the face, could be linked to more than smell; like for instance an attraction or dislike towards a person depending on the place the person would touch their face and whether there would be a difference in the response between opposite genders. This could really give you an advantage in the dating game.

What amazes me about this article is that humans and animals, even rodents, subconsciously act the same in similar situations. The fact that most people would deny their actions, shows that it's not controlled and that it is done unwillingly. These types of researches intrigue me, as it seems simple and is unusual, but the results prove to be very useful and sheds light on other topics.

I agree with Alri Richter. The thought of entering a strange home and always noticing the smell also occurred to me when reading this article. It is interesting how big the role of smell is in our senses even though we do not always realize this. 15038336

I personally think the environment and situation in which people greet each other will have an influence on whether the person smells their hand after greeting another person. For example when you are at a fancy business dinner party you would act more professionally and therefor not smell your hands after greeting someone as it can easily come across as rude.
It would be interesting to further this study with testing the influence of the environment in which people greet each other as well as testing the influence it has when the people already know each other as Joanne Dilnot suggested.
15004512

This is very interesting. I have always thought people touch their faces after a handshake maybe as a reflex action, more like it just happens without really associating this behaviour with any thing peculiar. Could this also be due to man's curiosity or maybe people just trying to associate certain smells with something?

15079148

The concept of smelling my hands after a handshake is quite strange. Although not completely aware of what i do after a handshake i can not recall ever smelling my hands. For this experiment, i was wondering if you had considered that the subjects might have been touching their faces as either a nervous reaction for waiting alone or just some unconscious action that they might do?
(u15298622)

It’s fascinating to observe the unconscious mind! Studies shown that people tend to touch their face even more often if they shaken their hands with someone with the same gender! It would be interesting to study the reason why we subconsciously do this?

It is very interesting to see remnants of our evolutionary ancestors in modern humans. Of course they actually made practical use of this 'smelling' another person. What I want to know is whether our subconscious influences our opinion of a person based on his or her smell.
15007015

Well it is a very intriguing 'fact" if i may, I myself have never noticed this behaviour, but witnessing this would be very interesting.
15166873

Personally I think the environment and situation in which people shake hands and greet each other also has an effect on their behavior and the way they react after they shook hands, for example when a person is at a fancy business dinner party the chance of them smelling their hands would be less, because it can easily come across as unprofessional. But in a park while walking your dog it would not even be noticed if a person smells their hands or touches their face after greeting someone. Therefore I think to further the study they could place people in different situations to determine if the environment has an effect.
I also agree with Joanne Dilnot that it would be interesting to see whether people smell their hands after greeting someone they already know.
15004512

I've never noticed this before! Such an interesting experiment. I tried it with my aunt and uncle when they came to visit, shaking my uncle's hand and giving my aunt a hug. I watched their actions closely afterwards. My aunt fixed her clothes but never touched her face whereas my uncle rubbed his nose almost immediately after sitting down. Maybe just a coincidence but I'm definitely going to watch people more closely from now on after I've had interactions with them.

u15052576

Handshake greetings dated many years shows a symbol of solidarity and appreciation among people. That is why in most of the business meetings whereby a good conclusion is reached it must be ended with handshakes from both parties, but in case of disagreement handshakes are not applicable. Also it is not entirely true that people sniff their hands after a handshake in most of the cases. I

iIt’s fascinating to observe the unconscious mind! Studies shown that people tend to touch their face even more often if they shaken their hands with someone with the same gender! It would be interesting to study the reason why we subconsciously do this?

Wow! And we thought we left the caveman behind. A very interesting study. I am not completely sure about the scientific significance of this information, but I will surely be watching people very closely next time I greet them with a handshake. It would be interesting to find out if the different places touched on the face could be linked to more than a smell. For instance an attraction or a dislike towards a person depending on the place the person would touch their face; and if there would be a difference in the response between opposite genders. This could really give you a big advantage in the dating game.

I find this behaviour very interesting and something that I have never noticed myself, although I don't greet people with handshakes very often. This behaviour would be very interesting to test and observe in an uncontrolled environment. However, if I were to test it on myself the results would be unreliable because I am now aware of the behaviour of touching of one's face after shaking hands and would most likely make a conscious effort to avoid said behaviour. Therefore, I would only be able to observe other's reactions following shaking hands.
15170846

This is extremely interesting. I have never noticed it before but that shows how inattentive we are and how much we can improve on our observing skills. I think it is a an excellent way to remind us that we are only animals with basic instincts and we are subconsciously dependent on our senses. I have read an article that explains the connection between the smell of a person and his/her attraction. I would love to see results on male vs. female. Maybe we can change to 'love at first scent'.

The question I have now is whether a person's smell subconsciously influences our opinion of him or her?

I think that the research is very interesting but the results rather presumptuous. The fact that the experiment is based on a population of such magnitude or size and the fact that the very same experiment is conducted in a lab portray the idea of the substances used in a lab which everybody knows it is the practical nature of such an environment, and thus many individuals would naturally be eager to sniff anything they make contact with.(15142672)

I find this study very interesting. Growing up, I have developed three main ways of greeting people. When greeting friends, I generally hug them. For family it's usually a hug and a kiss on the cheek. Strangers I tend to greet with a handshake. The way a person shakes your hand gives you an immediate impression of them. It's interesting to learn that the smell and chemical transfer that occurs during the hand shake forms a subconscious part of that impression as well. It's also intriguing to learn that we have certain "habits" associated with the hand shake form of greeting. I wonder if that's the same with the other forms of greetings we have developed?

I find this extremely interesting. I have never noticed it before but it shows how inattentive we are and how much we can improve our observation skills. I read an article about the link between smell and attraction of a person. I would love to see the results of male vs. female. Maybe we can change to "love at first scent".
15004555

I is a very interesting fact that I have never known before. I would definitely pay more attention to notice it.

I think it is strange, but it is human nature.

Very interesting,I just released now that I do the same thing. To be honest, I don't think about it at all, it just happens. Which makes me wonder, did the research reveal whether it is voluntary or involuntary ?
15102778

I also the very same thing (touch my face a lot when alone), this is very interesting. This post is very scientific though people may think that it is not. It talks about our everyday lives and of what happens daily. According to me and to what I have seen shaking hands shows respect, and it is a way of welcoming the person greeting you.

Very remarkable observation made. It is astonishing what humans do involuntarily and have in common with each other and with other mammals such as rodents. Reading this however makes me ponder upon the fact that do humans do the same when greeting in other ways such as giving a peck on the cheek, or a hug greeting or by simply waving ?

One cannot help but wonder how many times they have observed the rather common tradition of shaking hands but never thought that due to several biological changes that are a result of chemicals being transferred during shaking hands would lead to the individuals sniffing their hands. this is quite intriguing that a simple hand gesture could be further explored and explained in such a scientific way rather than a social way.
(u14018676)

This information is very interesting...This makes me think who was the first human being who invented this revolution of this gesture

This information is very interesting…This makes me think who was the first human being who invented this revolution of this gesture??
u15341462

This is a really interesting observation! I always had a different approach on what a handshake told you about a person for example if someone had a firm handshake they would be more hard working and trustworthy.Since I've read this article I think I will be a lot more observant. The only problem I have with the experiment is that all the subjects were waiting, when you are not busy you have a habit of touching your face. Will they find the same results with subjects that shake hands before starting business?
u14224781

What an interesting read! I was compelled to observe the people in my surroundings and this has proven to be true most of the time. What's more is that I even caught myself out at some stage, that left me dumbfounded. Human are interesting beings, however it is the things we do when we are not even aware that make us fascinating to observe. What other unusual things have been dicovered about the human race?

what an interesting read! I was compelled to stop what i was busy with and observe the individuals in my surroundings and this theory has proven to be true majority of the time. I even caught myself out at some stage, what an eye-opener! Human beings are indeed an interesting race, but what makes us more fascinating is the things that we do unaware. Are there any more unusual things that humans have been said to do?

I would like to start off by saying that my comment is part of a research assignment that I have to complete for the University of Pretoria. I found this topic rather bizarre as I have never noticed that people smell their hands after a handshake. From personal experience I find I always touch my face when I'm feeling uncomfortable or shy, which brings me to the question of whether the smelling of the hand is based on behavioural and emotional feelings towards first introductions, rather than the remembrance and observation of someone.
U15004814

One cannot help but to think about the number of times they have observed the tradition of shaking hands and never attributed the sniffing of ones hand afterwards to biological changes due to a chemical change with the complex human body. It is quite intriguing that a simple hand gesture can be explored and defined to such scientific lengths.Guess there is never a dull moment when it comes to science.(u14018676)

This something I have also never really taken notice of. People have different ways of choosing who they associate themselves with. For example personality and similar interests. Maybe this is also another way of helping one decide whether they would consider being friends with someone or not. I think people tend to gravitate towards people with good body odour as opposed to people with bad body odour. How someone smells also forms part of the first Impression you have of them

I found this study very curious and fascinating, and so is the personalities and mindsets of scientists. Scientists always want to discover new and interesting facts, but also facts that refers to our daily lives. Handshake is so commonly seen in South Africa as a way of greeting that the study is so effective and let people rethink their reactions on certain actions. Danielle van Wyk I love your saying "love at first scent".

I do not readily agree with your theory A Potgieter. I feel as this is an act that people are not even aware that they are doing environment wouldn't be that great a factor.

One cannot help but wonder how many times they have observed the rather common tradition of shaking hands but never thought that due to several biological changes that are a result of chemicals being transferred during shaking hands would lead to individuals sniffing their hands. This is quite intriguing that a simple hand gesture could be further explored and explained in such a scientific.(u14018676)

One cannot help but wonder how many times they have observed the rather common tradition of shaking hands but never thought that due to several biological changes as a result of chemical being transferred from one individual to another this will lead the other individual to sniffing their hand. This is quite intriguing that a simple hand gesture could be further explored and explained in such a scientific way.(u14018676)

Sense Itmeleng Rapetsoa, I believe this is totally voluntary - I myself prefer to avoid smelling my hands (especially after a handshake). I do - though - find face touching the most contagious habit. I have also witnessed this plenty of times. We someone your are talking to touches their face, you immediately feel the need to do so too. Perhaps smelling your hand after a handshake is an individual's way of linking another individual to a specific scent, but then again - how much of their scent can your hand have?

I wonder if it could be related to a natural defence mechanism maybe? where your body is subconsciously checking if you have received any harmful chemicals or dangerous substances

it would be interesting to come across such behavior now that i have read this article.
u15156924.

Sleep Learning with Smell Could Reduce Addiction

jhalper — Wed, 12 Nov 2014 05:11:09 +0000

Sleep Learning with Smell Could Reduce Addiction

Get rid of your addictions while you sleep? Weizmann Institute researcher Dr. Anat Arzi is not promising this yet, but she and Prof. Noam Sobel have shown that changing bad habits through sleep conditioning could someday be possible. After just one session in the Neurobiology Department’s sleep lab, volunteers reported smoking on average 30% fewer cigarettes over the course of a week.

Volunteers given the same conditioning while awake did not reduce their nicotine consumption.

Arzi and Sobel had first demonstrated true sleep learning in 2012. This is the same conditioning that Pavlov discovered when he trained dogs to salivate at the sound of a bell: Teach the mind to subconsciously associate one sensation with another. Their twist was to use smell instead of the bell: We can register and even react to odors while we sleep without waking up. So when the volunteers were exposed throughout the night to the smell of cigarette smoke together with that of rotten fish, they did not remember it in the morning. And yet their need for a “ciggie” was not as strong as it had been.

Arzi and Sobel

The second trick was to monitor the sleepers’ brain waves and administer the smells at the right stage of sleep. The group’s previous research had suggested that the associations are formed and cemented in the brain during non-rapid-eye-movement (NREM) sleep – the stage in which researchers believe that memories from the previous day are being consolidated. The new study supported this finding quite strongly.

Arzi assiduously points out that the research has proven a point about the workings of the sleeping brain. She will be pleased, of course, if clinical researchers adopt the method and improve on it. She, herself, intends to use this window on the brain’s activity to keep investigating the mysterious phenomena of sleep and learning, and the apparently unique place of smell among our senses.

jhalper Wed, 11/12/2014 - 00:11

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microRNA Might Manage Mood Disorders

jhalper — Thu, 19 Jun 2014 14:00:56 +0000

microRNA Might Manage Mood Disorders

Since mental health problems are estimated to affect some 10% of the world’s population, it stands to reason that if you don’t suffer from depression, anxiety or bipolar disorder yourself, you are probably close to someone who does. So you might be pleased to read about a new finding that could eventually lead to a whole new approach to treating this group of common mood disorders.

The finding is that a tiny scrap of RNA – a microRNA that works in the brain – acts as a sort of mood regulator. It works something like the needle in a steam valve. Mice that had high levels of this particular molecule in one part of their brains were able to take the heat and remain calm. And those with the lowest levels were more quickly frazzled, acting depressed and anxious when exposed to stressful conditions. That second group also had a weaker response to antidepressant drugs than the average mouse – a possible clue as to why these drugs don’t really work for up to two thirds of the people who try them.

The microRNA “steam valve” Prof. Alon Chen and his group discovered regulates levels of the feel-good neurotransmitter serotonin in the brain. It turns out that people who suffer from depression have low levels of this microRNA in their blood, hinting that, at long last, we might have a standardized, quantifiable way to diagnose the disease – one that could be done in any clinic. But it also suggests we might find a way to adjust that needle up or down, to effectively treat mood disorders.

The Israeli firm miCure, which now has the license to develop a diagnostic test and drug based on these findings, was founded to develop two different microRNA applications, both stemming from Weizmann Institute research. The second is a possible ALS treatment based on the discovery of the role of certain microRNAs in the survival of motor neurons. The field of small RNA-based drugs is really in its infancy, so this development is somewhat daring. If it pays off, however, it could truly be part of a new era in treatment for any number of diseases. In other words, watch this space for future developments.

jhalper Thu, 06/19/2014 - 10:00

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Hello, I was upset by your claim that "these drugs don’t really work for up to two thirds of the people who try them.", after a bit of research, I found on medscape that, on the contrary :
"With appropriate treatment, 70-80% of individuals with major depressive disorder can achieve a significant reduction in symptoms, although as many as 50% of patients may not respond to the initial treatment trial.

Twenty percent of individuals with major depressive disorder untreated at 1 year will continue to meet criteria for the diagnosis, whereas an additional 40% will have a partial remission. Pretreatment irritability and psychotic symptoms may be associated with poorer outcomes. Partial remission and/or a history of prior chronic major depressive episodes are risk factors for recurrent episodes and treatment resistance."
Sincerely

Mice on Camera

jhalper — Mon, 17 Jun 2013 07:07:19 +0000

Mice on Camera

Take a bunch of peculiar individuals, put them all together in one setting; film their every move, every second of the day. Sound familiar? Dr. Tali Kimchi is explicit about the resemblance of her experiments to a well-known reality TV show. The difference, of course, is that Kimchi’s subjects are mice. She places large groups of animals in a common pen in her lab, which is fitted out with video cameras, infrared lighting for nighttime filming and electronics to continuously record information from the ID chips implanted in each mouse. And while no one can deny that our enjoyment at seeing people voted out reveals something about human nature, Kimchi’s mice are likely tell us much more about the way that our societies form and how different personality types find their places in human social structures.

Kimchi’s research takes place in that huge, messy gray area in which nature, nurture and culture overlap; where animals turn out to have unique personalities and human genes turn out to be more correlated with our behavior than we would like to believe. It’s also an area where mice can be bred to exhibit personality traits. Some of the mice used in the research team’s experiments were social animals; others had been bred to exhibit autistic-like activity – engaging in minimal social interaction and compulsive behavior patterns.

In contrast to the artifice of Big Brother-type situations, Kimchi and her team set out to create a semi-natural, yet controlled setting for observing mouse society. It turns out that mouse social structures are almost depressingly similar to human ones. Within 24 hours of coming together in one location, a social hierarchy begins to emerge. One alpha male mouse takes on the role of the house’s top banana (he has control over the movement of others, as well as first mating privileges). Sub-dominant male mice compete with the alpha male, waiting for a sign of weakness so they can capture the position of the alpha male; thus castes form within the groups. The mice have an intimate understanding of this structure: They know which of their fellow mice they can hang with, which to avoid and which they can pick on with impunity. Of course, that similarity is what makes these experiments compelling, on the one hand, and a useful model for further experimentation, on the other. Questions that still remain open: What are the factors that determine who will be the dominant and who will be the subordinate animal? How much of this nature (the genes, morphology, physiology we born with); how much is nurture (environmental factors affecting how we behave); and how much is just random occurrence?

But there is also a curious twist to the Big Brother: Mice! story. When just the autistic-type male mice were placed in the house, their society appeared to be relatively libertarian: Leaders did not tend to emerge or, if one did manage to set himself up at the top, he was quickly overthrown.

Mouse society, it seems, is both complex enough and human-like enough to provide real insight into how social structures and behaviors emerge from the collective drive to live and function in large, cooperative units. Even more interesting might be the suggestion that this type of set-up could be used to conduct experiments on neuropsychological disorders that have social aspects, for example, autism or schizophrenia.

http://www.youtube.com/watch?feature=player_embedded&v=xT0k68QerdE

jhalper Mon, 06/17/2013 - 03:07

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semi-natural lab setting

The Tao of Axon Pruning

jhalper — Tue, 28 May 2013 03:13:25 +0000

The Tao of Axon Pruning

To attain knowledge, add things every day. To attain wisdom, remove things every day.

Lao Tsu

Apparently our nervous systems develop according to the Chinese philosopher’s principle of being and not being. As our nerve cells grow, they send out long extensions – axons – throughout the developing tissues. And as they reach out, some are also pruned back. The configuration of nerve endings we finally possess depends on both what was added and what was removed.

Which axons will complete their developmental journeys and which will be pruned back? For some, it is simply a matter of fate.

But in the system studied by biochemist Dr. Avraham Yaron and his team, the sensory nerves in the skin, the decision arises from a limited number of neurotrophins – biological “beacons” in the target tissues that guide the growing nerve endings. Though the axons initially receive guidance to help them grow out in the right direction, at some point, they must compete for the scarce neurotrophin signals. Such a signal from a neurotrophin grants a developing axon the “knowledge” it needs to reach its final destination; lack of a signal initiates the “wise” path of pruning. So, what looks like a completely random process is, in fact, a method of attaining the proper, harmonious balance in our nervous systems.

This is the result when neuron pruning is induced in wild-type mice

And the nerve extensions, it turns out, carry the seeds of their own “enlightenment.” The researchers revealed the precise protein that mediates the pruning process. All the growing axons contain an inactive form of this protein; it is the addition of the neurotrophin signal that keeps it from activating.

Before we get carried too far into the realm of philosophical metaphors, we should point out the practical relevance of this research. Scientists refer to the axon pruning process as “remodeling.” In other words, it is not just the number of axons you end up with, but the shape of the nerve network that determines how efficiently communication takes place across that network. And a small but growing body of recent research suggests that such developmental disorders of the nervous system as autism may be tied to problems with the remodeling process. So understanding the exact mechanics of axon pruning could lead to better models of the disorder, better diagnostic tests and, eventually, possibly even treatments.

When the gene for one step in the pruning process is knocked out, this is what you get

jhalper Mon, 05/27/2013 - 23:13

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nerve growth and development

...it could also lead to understand what their differently remodeled network is trying to say :)

(Great post, thanks!)

What's that Smell?

jhalper — Thu, 22 Nov 2012 06:11:04 +0000

What's that Smell?

Weizmann Institute scientists have created a “white smell.” Think about white light or white noise: Each mixes a bunch of different waves together from various parts of the visual or audible spectrum. Those wavelengths combine such that we perceive that unobtrusive light or sound we call “white.”

How do smells fit into this scenario? Prof. Noam Sobel and his group have already shown that smells have their own spectrum – ranging from pleasant to unpleasant – and that this relates to the chemical structure of the odor molecules. Is this spectrum truly analogous to that of light or sound? That is, can one take bits from different parts of that spectrum, mix them together and come up with a convergent stimulus?

It turns out that if you take enough different and varied scents – at least 30 – dilute them all to the close to the same intensity and mix them together, you can produce a white smell. That is, those who smell it will perceive it to be neither pleasant nor unpleasant. And like white light or white sound, the exact mix doesn’t really matter, as long as the range is large enough and the intensities similar. The research team mixed up various versions of the odor blend and, past 30 different scents, the subjects who smelled them thought they smelled the same.

Aside from possible applications in the odor neutralization industry, the findings, says Sobel, reveal something very fundamental about our sense of smell. According to him, the smells we perceive are more than just the sensations from a lot of different smell receptors added together -- but it turns out they can also be less. As in vision and hearing, the mechanical receptors in our sense organs are tuned to specific stimuli, but when all of those stimuli come together, the sum of our perception can be simply “white.”

jhalper Thu, 11/22/2012 - 01:11

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interesting topics to read

This is really interesting given the relatively special nature of the sense of smell — it's a sensitivity to a very large number of specific molecules, not something closer to a general, abstracted physical phenomenon as in the case of hearing and vision. So you wouldn't necessarily expect there to be an analogous subjective experience as "whiteness".

That there is, hints at some of the tendencies in higher-level cognitive processing.

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A Computer That Learns to See Like a Baby

jhalper — Sun, 18 Nov 2012 12:14:11 +0000

A Computer That Learns to See Like a Baby

The idea of “seeing the world through the eyes of a child” takes on new meaning when the observer is a computer. Institute scientists in the Lab for Vision and Robotics Research took their computer right back to babyhood and used it to ask how infants first learn to identify objects in their visual field.

How do you create an algorithm that imitates the earliest learning processes? What do you assume is already hard-wired into the newborn brain, as opposed to the new information it picks up by repeated observation? And finally, how do you get a computer to make that leap from a data-crunching machine that “learns” from information that humans have already sorted, labeled and annotated to a true learning machine that can figure out how to make sense of visual input just by observing?

These researchers started with a basic theory and some fundamental knowledge of what attracts the attention of an infant. And they did manage to create an algorithm with which a computer could, just by watching videos, learn to identify a hand (and, without giving the whole story away, show that one, particular way of learning was much better than others). Then they extended their insight to direction of gaze – something an infant learns sometime between six months and a year – and the computer learned to tell where the person in a photo or video was looking as well as an adult human.

Computers (red arrows) detect the direction of a gaze about as well as humans (green)

To understand what an achievement this is, remember that just a few years ago, computer vision researchers were trying to get a computer to tell objects apart in images or, more recently, to be able to group together views of the same object seen from different angles (not that these are trivial, or have been fully resolved). Learning to identify a hand involves not only the ability to comprehend that the moving, changing object seen from various viewpoints is one thing, but to begin to grasp the concept of a “hand” long before the verbal skills to name it develop.

One of the nice things about these models is that they can be tested in real life. In fact, while they hold clear implications for the field of artificial intelligence, the researchers are quite jazzed that a computer model such as theirs has the potential to reveal something so basic about human development.

jhalper Sun, 11/18/2012 - 07:14

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Artificial Intelligence

object identification

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no twitter for the blog -- you can follow the Weizmann Institute on twitter. https://twitter.com/WeizmannScience

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