Attachment is the ability to form human relationship bonds. Individuals vary in their ability to develop social relationships. The ability to form secure human relationships plays a key role in successful personal and occupational development.Attachment theory evolved over 50 years ago. This theory proposes all humans have an innate biological mechanism that supports social engagement. This engagement is necessary during infancy to encourage nurturance and provision of a safe environment.Bowlby is credited with describing attachment theory and he proposed three developmental styles of attachment. These three attachment styles included:Secure attachment: an ability to easily seek and obtain support from others. This style promotes strong bonds with parents, siblings, friends and later in life allows for bonding with a mate.Anxious attachment: a insecure attachment style where emotional support has often been inconsistent during childhood. Individuals with anxious attachment develop hypersensitivity to interpersonal rejection and have anxiety in social environments. They may develop a needy approach to relationships constantly seeking reassurance of the strength of social supports.Avoidant attachment: an insecure attachment style that may have been characterized by early social adverse environments. Individuals with insecure attachment style built a wall around their life denying a need or interest in human interactions.Emerging research in social neuroscience is providing a better understanding of brain mechanisms related to human attachment. Vrticka and Vuilleumier of the University of Geneva in Switzerland recently published an excellent review of the neuroscience of human attachment in the journal Frontiers in Human Neuroscience.The authors of this review begin by noting research showing attachment has profound effects in the domains of emotion processing, selective attention and memory. Insecure attachment individuals are hypersensitive to changes in the expression of emotions in others. Anxious attachments individuals have enhanced attention to threatening cues. Avoidant attachment individuals inhibit the memory processing of distressful information.The authors note social approach behavior appears regulated in specific brain regions including the ventral tegmental area, pituitary, striatum and ventral medial orbitofrontal cortex. Social aversion appears to be regulated through the amygdala, hypothalamus, insula, anterior cingulate and anterior temporal poles.Social behavior appears to regulated through both affective evaluation (emotional mentalization) and cognitive control systems (cognitive mentalizations). These systems interact with hormonal and neurotransmitter domains in influencing social interactions.The neuroscience of human attachment includes emerging research showing the importance of mental state representation of others (theory of mind). Mothers with high sensitivity to the cries of their own infants during the post partum period show increased gray matter and fMRI BOLD responses in the prefrontal cortex, superior temporal sulcus and fusiform gyrus. These regions have been identified as key components engaged in being aware of the emotional states of others. The authors conclude that the neuroscience of human attachment is beginning to outline key common and distinct elements in avoidant and anxious attachment styles. Attachment styles appear to be influenced by both environmental history as well as neurobiological factors, some of which may have strong genetic contributions.Future neuroscience of research will need to move experiments into the "real world" and not be limited to task in brain scanners. Additionally, future research needs to target early intervention studies in children with attachment problems to find the most effective methods to improve social outcomes.Readers with more interest in this review are directed to the DOI link below where the free full text manuscript can be found.Photo of great white egret from the author's files.Vrtička, P., & Vuilleumier, P. (2012). Neuroscience of human social interactions and adult attachment style Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00212... Read more »
Vrtička, P., & Vuilleumier, P. (2012) Neuroscience of human social interactions and adult attachment style. Frontiers in Human Neuroscience. DOI: 10.3389/fnhum.2012.00212
by Thomas Shultz in Evolutionary Games Group
There is now evidence that the payoffs designed by researchers are not the only source of variation in human strategies in two-player symmetric games. In many cases, discrepancies from behavior predicted by variation in payoffs might be explained by social factors such as avoidance of inequality, desire for social harmony, or likability of the opponent. [...]... Read more »
Lee, D. (2008) Game theory and neural basis of social decision making. Nature Neuroscience, 11(4), 404-409. DOI: 10.1038/nn2065
I've long been fascinated by the idea that those feelings often attributed to 'intuition' or 'following your gut' might occur physiologically in the form of odor cues that we don't consciously register.Intuition or Olfactuation? (source)An example of this might me when you can just 'tell something is wrong' in a situation and decide to leave, and later found out that something bad happened later that evening. These sorts of stories are often used as evidence that people have psychic powers of some kind, and are equally often dismissed as just a coincidence.But another possibility is that humans communicate through scents more than we realize. Maybe you could actually 'smell something is wrong' rather than supernaturally 'tell something is wrong' in the above hypothetical situation.Researchers in the Netherlands tested whether the feelings of 'disgust' and 'fear' could be communicated through smell. They had guys watch scary parts of horror movies or disgusting graphic parts of MTV's Jackass while wearing 'sweat pads' in their armpits.Who knew this would contribute to SCIENCE?They then had female volunteers smell the sweat pads and measured their facial motions to see if the expressions they made were more like fear or disgust.Importantly the protocol was double-blind, so neither the experimenters handing out the sweat pad vials, nor the participants had any idea what 'emotion' was sweated into those pads.And they found what they thought they would find: the 'fear muscles' (Medial Frontalis) were most active for the women smelling the sweat of the horror-watching men, and the 'disgust muscles' (Levator Labii) were most active for the women smelling the sweat of the Jackass-watching men. In the authors words (stats taken out for readability):"Moreover, fear chemosignals generated an expression of fear and not disgust, disgust chemosignals induced a facial configuration of disgust rather than fear, and neither fear, nor disgust, were evoked in the control condition" de Groot et al. (2012)So at very very close range (like nose in armpit), it seems that emotional signals can be transmitted through scent.The smell of fear (source)A quick side note: the scent in this study was created by men and smelled by women. I wonder if this specific gender combination is necessary for the scent-based communication. You would think men smelling men and women smelling women would have the same effect, but they did not investigate other combinations.If you learn anything from this, let it be to not go see a disgusting movie on a first date, you might end up repulsing each other with your 'disgust sweat' later.© TheCellularScalede Groot JH, Smeets MA, Kaldewaij A, Duijndam MJ, & Semin GR (2012). Chemosignals communicate human emotions. Psychological science, 23 (11), 1417-24 PMID: 23019141... Read more »
You are hungry already and dinner is hours away. You’re getting irritable and making stupid decisions that you normally wouldn’t. Or maybe you just had a big meal and you’re sated. Your friend who is seated next to you turns and asks for a favor; you pleasantly agree and sink into your chair sleepily. What’s [...]... Read more »
Burghardt, P., Love, T., Stohler, C., Hodgkinson, C., Shen, P., Enoch, M., Goldman, D., & Zubieta, J. (2012) Leptin Regulates Dopamine Responses to Sustained Stress in Humans. Journal of Neuroscience, 32(44), 15369-15376. DOI: 10.1523/JNEUROSCI.2521-12.2012
Cocker, P., Dinelle, K., Kornelson, R., Sossi, V., & Winstanley, C. (2012) Irrational Choice under Uncertainty Correlates with Lower Striatal D2/3 Receptor Binding in Rats. Journal of Neuroscience, 32(44), 15450-15457. DOI: 10.1523/JNEUROSCI.0626-12.2012
Dunn, J., Kessler, R., Feurer, I., Volkow, N., Patterson, B., Ansari, M., Li, R., Marks-Shulman, P., & Abumrad, N. (2012) Relationship of Dopamine Type 2 Receptor Binding Potential With Fasting Neuroendocrine Hormones and Insulin Sensitivity in Human Obesity. Diabetes Care, 35(5), 1105-1111. DOI: 10.2337/dc11-2250
Starting a weekly journalistic-type blog is a daunting task, especially for someone who is holding down other jobs (as most bloggers do). But I can't be happier that I started down this path in order to share with you all these wonderfully quirky stories of animal behavior and physiology. This week, I am happy to announce that The Scorpion and the Frog turns 1! It has been a remarkable first year: We've covered topics from whale dialects, to birds that kill their "siblings", to steroids and dominance in rodents; We've learned more about the researchers that contribute this fascinating knowledge to our global society; We've had fantastic guest posts by student guest writers; We've been recognized in other blogs and with awards; But my favorite aspect of this endeavor is that we are developing a growing community of readers and animal enthusiasts from all backgrounds. So today, I would like to reflect back on how we began a year ago with a repost of the very first The Scorpion and the Frog post, The Same Clay. The Same Clay According to a Hopi creation myth, the world was once nothing but water and dry land. The Sun, in his daily travels across the dry land, noticed that he had not seen a single living being. The Sun mentioned this observation to Hurúing Wuhti of the east and Hurúing Wuhti of the west, the deities of all hard substances, and they decided they would make a little bird. Hurúing Wuhti of the east made a wren out of clay and covered it with a piece of native cloth. The deities then sang a song over it and the wren came to life. They sent the wren to fly all over the earth to search for anything living, which it did. When the wren returned and reported that no living being existed anywhere, Hurúing Wuhti of the west shaped the clay to form all kinds of birds and placed these clay birds under the native cloth. The deities sang over the clay birds, bringing them to life, and they taught each of them what sounds they should make and sent them to populate the earth. Hurúing Wuhti of the west then shaped the clay to form all kinds of other animals and placed these clay animals under the native cloth. The deities sang over the clay animals, bringing them to life, and they taught them each what sounds they should make and sent them to populate the earth. Hurúing Wuhti of the east then shaped the clay to form a woman and a man and placed these people under the native cloth. The deities brought them to life with their song, and they taught them language and sent them to populate the earth. I like this myth; in particular because it illustrates that despite the awesome diversity of the animals on our planet, we are all made of the same stuff and share many similarities. At first glance, we may be amazed by eels that resist eating prey fish who are providing a dental cleaning service (like the one on the left), or by snakes that eat animals larger than their own heads and toads that save themselves from the jaws of death by puffing up their bodies even larger than the snake can handle (like the snake and toad battling it out on the right), or by the elaborate displays of male birds in their attempts to woo females (like the golden pheasant below), or by kangaroo moms that guard their toddler-like young in their own bodies (like the one on the right). But at closer inspection, we realize that all of these animals are facing similar challenges: All animals are driven to eat and not be eaten, to stay healthy, to make babies, and to keep their babies alive. And animals have developed behavioral tools to achieve these goals, such as ways of finding or making food and a place to live, ways to defend these things, techniques for attracting the opposite sex, and parental methods. The details are extremely diverse across animal groups, but the ultimate goals and many of the strategies are common. And amazingly, the brain systems that regulate these behaviors are common too.In a new synthesis of decades of research spanning the field of behavioral neuroscience, researchers Lauren O’Connell and Hans Hofmann from the University of Texas at Austin show that despite our impressive diversity, mammals, birds, reptiles, amphibians and fish are all molded from the same metaphorical clay. They specifically focus on two brain systems, often called the social behavior network and the mesolimbic reward system.The social behavior network is a term first described in mammals by neuroscientist Sarah Newman to describe several brain regions that are all sensitive to steroid hormones (such as testosterone and estrogen), connect to each other, and are involved in many types of social behavior (including aggression, sexual behavior and parental behavior). We now know that reptiles, birds and fish also have brain areas that are similar in... Read more »
O'Connell, L., & Hofmann, H. (2011) The Vertebrate mesolimbic reward system and social behavior network: A comparative synthesis. The Journal of Comparative Neurology, 519(18), 3599-3639. DOI: 10.1002/cne.22735
O’Connell, L., & Hofmann, H. (2011) Genes, hormones, and circuits: An integrative approach to study the evolution of social behavior. Frontiers in Neuroendocrinology, 32(3), 320-335. DOI: 10.1016/j.yfrne.2010.12.004
(We're reporting from this month's Division of Occupational Psychology conference at the Digest. This post is by Dr Jon Sutton, Managing Editor of The Psychologist, and will also feature in that magazine's March issue. @jonmsutton / @psychmag)According to keynote speaker Gerard Hodgkinson (Professor of Strategic Management and Behavioural Science at Warwick Business School), ‘Descartes’s error is alive and well in the workplace’. In a bold and wide-ranging address, Hodgkinson made the case for why and how occupational psychology needs to connect with the social neurosciences.Hodgkinson is bringing psychology into the field of strategic management, trying to help decision makers become more rational. Take how organisations tend to respond to a major threat or opportunity (HMV and Blockbuster come to mind as I write this). Usually there are small, incremental changes, and when it becomes apparent this isn’t sufficient, what does the organisation do? Nothing. There is a period of ‘strategic drift’. Then there is a period of ‘flux’, which on Hodgkinson’s graphic representation looks rather like a tailspin. This is followed by ‘phase 4’, ‘transformational change’ or ‘complete demise’.But to what extent can psychology shed light on this process? Hodgkinson’s 2002 book ‘The Competent Organization’ argued the case for the centrality of the psychological contribution to organisational learning and strategic adaptation, yet 11 years on, he said, there was still only a passing consideration of affective and non-conscious cognitive processes. Why do we continue to sidestep it?Using examples from his practice, Hodgkinson demonstrated how strategising is both an inherently cognitive and affective process. Eliciting a cognitive taxonomy from senior figures in a UK grocery firm, he found that although the market conditions had changed dramatically, mental models – individually and collectively – had not. Decision makers were slaves to their basic psychological processes, for example still focusing on the ‘magic number’ of ‘7 plus or minus 2’ competitors.Hodgkinson showed how he confronts strategic inertia in top management teams, stimulating individual cognitive processes by scenario analysis. Some organisations excel at this: Hodgkinson claims that Shell closed all their facilities within 45 minutes of 9/11. While others were still struggling to comprehend what was happening, their scenario planning had allowed them to take quick and decisive action.Hodgkinson’s latest research draws on social cognitive neuroscience and neuroeconomics to develop a series of counterintuitive insights. His hope is that these can teach people to be more skilled in their control of their emotional, limbic system. True rationality, he concluded, is the product of the analytical and experiential mind.Further reading:Hodgkinson, G., & Healey, M. (2008). Cognition in Organizations Annual Review of Psychology, 59 (1), 387-417 DOI: 10.1146/annurev.psych.59.103006.093612Pdf freely available here.... Read more »
Why do smells bring back deep, emotional memories even when we're in unfamiliar places?... Read more »
Rabin, M., & Cain, W. (1984) Odor recognition: Familiarity, identifiability, and encoding consistency. Journal of Experimental Psychology: Learning, Memory, and Cognition, 10(2), 316-325. DOI: 10.1037/0278-7318.104.22.1686
It's not been a good few weeks for Adrian Owen and his team of Canadian neurologists.Over the past few years, Owen's made numerous waves, thanks to his claim that some patients thought to be in a vegetative state may, in fact, be at least somewhat conscious, and able to respond to commands. Remarkable if true, but not everyone's convinced.A few weeks ago, Owen et al were criticized over their appearance in a British TV program about their use of fMRI to measure brain activity in coma patients. Now, they're under fire from a second group of critics over a different project.The new bone of contention is a paper published in 2011 called Bedside detection of awareness in the vegetative state. In this report, Owen and colleagues presented EEG results that, they said, show that some vegetative patients are able to understand speech.In this study, healthy controls and patients were asked to imagine performing two different actions: moving their hand, or their toe. Owen et al found that it was possible to distinguish between the 'hand' and 'toe'-related patterns of brain electrical activity. This was true of most healthy control subjects, as expected, but also of some - not all - patients in a 'vegetative' state.The skeptics aren't convinced, however. They reanalyzed the raw EEG data and claim that it just doesn't prove anything.This image shows that in a healthy control, EEG activity was "clean" and generally normal. However in the coma patient, the data's a mess. It's dominated by large slow delta waves - in healthy people, you only see those during deep sleep - and there's also a lot of muscle artefacts which can be seen as 'thickening' of the lines.These don't come from the brain at all, they're just muscle twitches. Crucially, the location and power of these twitches varied over time (as muscle spikes often do).This wouldn't necessarily be a problem, the critics say, except that the statistics used by Owen et al didn't control for slow variations over time i.e. of correlations between consecutive trials (non-independence). If you do take account of these, there's no statistically significant evidence that you can distinguish the EEG associated with 'hand' vs 'toe' in any patients.However, in their reply, Owen's team say that:their reanalysis only pushes two of our three positive patients to just beyond the widely accepted p=0.05 threshold for significance - to p=0.06 and p=0·09, respectively. To dismiss the third patient, whose data remain significant, they state that the statistical threshold for accepting command-following should be adjusted for multiple comparisons... but we know of no groups in this field who routinely use such a conservative correction with patient data, including the critics themselves.I have to say that, statistical arguments aside, the EEGs from the patients just don't look very reliable, largely because of those pesky muscle spikes. However, a new method for removing these artifacts has just been proposed. I wonder if that could help settle this?Goldfine, A., Bardin, J., Noirhomme, Q., Fins, J., Schiff, N., and Victor, J. (2013). Reanalysis of "Bedside detection of awareness in the vegetative state: a cohort study" The Lancet, 381 (9863), 289-291 DOI: 10.1016/S0140-6736(13)60125-7... Read more »
Goldfine, A., Bardin, J., Noirhomme, Q., Fins, J., Schiff, N., & Victor, J. (2013) Reanalysis of "Bedside detection of awareness in the vegetative state: a cohort study". The Lancet, 381(9863), 289-291. DOI: 10.1016/S0140-6736(13)60125-7
It’s not been a good few weeks for Adrian Owen and his team of Canadian neurologists. Over the past few years, Owen’s made numerous waves, thanks to his claim that some patients thought to be in a vegetative state may, in fact, be at least somewhat conscious, and able to respond to commands. Remarkable if [...]... Read more »
Goldfine, A., Bardin, J., Noirhomme, Q., Fins, J., Schiff, N., & Victor, J. (2013) Reanalysis of "Bedside detection of awareness in the vegetative state: a cohort study". The Lancet, 381(9863), 289-291. DOI: 10.1016/S0140-6736(13)60125-7
Most people with synesthesia can't tell you exactly why they perceive the letter M as purple and not orange, or a high C-sharp as bright yellow and not blue. For one group of synesthetes, though, there appears to be an answer. For their green D's, red G's, and so on, they can thank the toy company Fisher-Price.
Stanford researchers Nathan Witthoft and Jonathan Winawer discovered, through word of mouth and from synesthetes contacting them online, a group of people who share a "startlingly similar" set of letter-color associations. Out of the eleven subjects, ten remembered owning (or still owned) a particular set of alphabet refrigerator magnets that was manufactured in the 1970s and 1980s.
The leftmost column below (labeled "set") shows the actual colors of this toy. The colors that the eleven subjects associate with the alphabet are listed as S1 through S11, in order of how well they match the magnetic letters. (And to the right are the magnets themselves.)
Subject S1 was carrying around mentally a perfect replica of the Fisher-Price letters, as the authors report in Psychological Science. The others had some differences—but were close enough to the toy's colors that, the researchers figure, it can't be a coincidence.
All eleven subjects also had number-color synesthesia. For the numerals 0 through 9, five of these people turned out to have color associations that matched sets of magnetic numbers sold along with some Fisher-Price alphabet sets.
Witthoft and Winawer don't think the magnets themselves made anybody synesthetic. But among this group of people who became synesthetic (and they may have been predisposed; it runs in families), many of the associations they learned came from a childhood toy.
Not that synesthesia should be confused with memory. Someone with synesthesia doesn't recall the color green when he sees the letter K the same way he sees Kansas and recalls that Topeka is the capital. Instead, synesthetes automatically experience that color when they read that letter or number (or experience a taste when they hear a sound, among other rarer combinations). Some even see the color on the page.
The authors say that the case of the Fisher-Price magnets shows synesthetic associations can be learned, rather than plucked from nowhere by the brain. "The idea that the colors would be learned has been around for a long time," Witthoft says, "but it has been difficult to turn up any examples." In this case, a mass-produced toy—combined with the powers of the Internet—helped.
But they don't think most synesthetes learn their associations from objects around them. These people appear to be, the researchers write, "anomalies among the anomalous."
When the colors of these subjects' mental alphabets differed from the Fisher-Price letters, it was often in ways that made them less anomalous—that is, more like the synesthetic population in general. "Color-grapheme synesthetes as a group have some shared tendencies," Witthoft says.
For example, 40 to 50 percent of English-speaking synesthetes associate the letter Y with yellow. Out of three subjects in this study who deviated from the red Y of the magnets, two went to yellow. It's also common to associate the letter X with black, as four subjects did (deviating from Fisher-Price purple).
Besides yellow Y's, studies have also found a lot of red R's, blue B's, and violet V's among synesthetes. These associations seem to come from language. The origin of most connections, though, is still mysterious.
One study, Witthoft says, argues that the brightness of a synesthetic color is related to how common that letter or number is. Other research "suggests that letters with similar shapes end up with similar colors." And in some types of synesthesia, he says, there are hints that the associations come from some basic way the brain is set up. For example, "pitch-color" synesthetes tend to see higher pitches as brighter colors. Non-synesthetes, if asked, make the same connection.
For now, childhood toys seem to be only a small part of the answer. To help dispel more of the mystery, you can take tests for synesthesia at synesthete.org—even if you weren't a Fisher-Price kid.
Witthoft, N., & Winawer, J. (2013). Learning, Memory, and Synesthesia Psychological Science DOI: 10.1177/0956797612452573
Images: Manon Paradis (Flickr); Witthoft & Winawer.
... Read more »
Today a new study appeared in Nature Scientific Reports claiming to show rhythmic entrainment (or spontaneous synchronization as the authors refer to it) in the Japanese macaque (Macaca Fuscata). Intriguing! However, reading the paper it becomes clear quickly that the results might not be what they seemed at first sight. ... Read more »
Nagasaka, Y., Chao, Z., Hasegawa, N., Notoya, T., & Fujii, N. (2013) Spontaneous synchronization of arm motion between Japanese macaques. Scientific Reports. DOI: 10.1038/srep01151
Honing, H., Merchant, H., Háden, G., Prado, L., & Bartolo, R. (2012) Rhesus Monkeys (Macaca mulatta) Detect Rhythmic Groups in Music, but Not the Beat. PLoS ONE, 7(12). DOI: 10.1371/journal.pone.0051369
While people of different beliefs from all over the world believe in an afterlife, many of them can’t seem to agree with each other or accept views other than their own. Yet, men have talked about the supernatural since the beginning of time. Recently, authors like Bill Guggenheim, Dr. Raymond Moody, and Dr. Eben Alexander [...]... Read more »
Mobbs D, & Watt C. (2011) There is nothing paranormal about near-death experiences: how neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them. Trends in cognitive sciences, 15(10), 447-9. PMID: 21852181
Feinsod M, & Langer KG. (2012) The philosopher's swoon--the concussion of Michel de Montaigne: a historical vignette. World neurosurgery, 78(3-4), 371-4. PMID: 22381306
Most athletes’ concussive symptoms are alleviated within 1 week; however, some athletes’ concussive symptoms may last longer. If we could identify risk factors for concussive symptoms that persists for over 1 week then this could lead to better evidence-based return-to-play policies since we could apply more cautious restrictions on patients with those risk factors. The purpose of this study was to determine the risk factors for concussive symptoms that persist for over 1 week among high school athletes. Additionally, the authors wanted to determine whether risk factors were different for football compared to other sports.... Read more »
Chrisman SP, Rivara FP, Schiff MA, Zhou C, & Comstock RD. (2013) Risk factors for concussive symptoms 1 week or longer in high school athletes. Brain Injury, 27(1), 1-9. PMID: 23252433
We know quite a bit about how long-term memory is formed in the brain - it's all about strengthening of synaptic connections between neurons. But what about remembering something over the course of just a few seconds? Like how you (hopefully) still recall what that last sentence as about?Short-term memory is formed and lost far too quickly for it to be explained by any (known) kind of synaptic plasticity. So how does it work? British mathematicians Samuel Johnson and colleagues say they have the answer: Robust Short-Term Memory without Synaptic Learning.They write:The mechanism, which we call Cluster Reverberation (CR), is very simple. If neurons in a group are more densely connected to each other than to the rest of the network, either because they form a module or because the network is significantly clustered, they will tend to retain the activity of the group: when they are all initially firing, they each continue to receive many action potentials and so go on firing. The idea is that a neural network will naturally exhibit short-term memory - i.e. a pattern of electrical activity will tend to be maintained over time - so long as neurons are wired up in the form of clusters of cells mostly connected to their neighbours: The cells within a cluster (or module) are all connected to each other, so once a module becomes active, it will stay active as the cells stimulate each other.Why, you might ask, are the clusters necessary? Couldn't each individual cell have a memory - a tendency for its activity level to be 'sticky' over time, so that it kept firing even after it had stopped receiving input?The authors say that even 'sticky' cells couldn't store memory effectively, because we know that the firing pattern of any individual cell is subject to a lot of random variation. If all of the cells were interconnected, this noise would quickly erase the signal. Clustering overcomes this problem. But how could a neural clustering system develop in the first place? And how would the brain ensure that the clusters were 'useful' groups, rather than just being a bunch of different neurons doing entirely different things? Here's the clever bit: If an initially homogeneous (i.e., neither modular nor clustered) area of brain tissue were repeatedly stimulated with different patterns... then synaptic plasticity mechanisms might be expected to alter the network structure in such a way that synapses within each of the imposed modules would all tend to become strengthened.In other words, even if the brain started out life with a random pattern of connections, everyday experience (e.g. sensory input) could create a modular structure of just the right kind to allow short-term memory. Incidentally, such a 'modular' network would also be one of those famous small-world networks.It strikes me as a very elegant model. But it is just a model, and neuroscience has a lot of those; as always, it awaits experimental proof.One possible implication of this idea, it seems to me, is that short-term memory ought to be pretty conservative, in the sense that it could only store reactivations of existing neural circuits, rather than entirely new patterns of activity. Might it be possible to test that...?Johnson S, Marro J, and Torres JJ (2013). Robust Short-Term Memory without Synaptic Learning. PloS ONE, 8 (1) PMID: 23349664... Read more »
We know quite a bit about how long-term memory is formed in the brain – it’s all about strengthening of synaptic connections between neurons. But what about remembering something over the course of just a few seconds? Like how you (hopefully) still recall what that last sentence as about? Short-term memory is formed and lost [...]... Read more »
There is a lively discussion going on right now in various forums on the incentives for scientists to publish their work in this venue or another. Some of these discussions cite our manuscript on the pernicious consequences of journal rank, others don't. In our manuscript, we speculate that the scientific community may be facing a deluge of fraud and misconduct, because of the incentives to publish in high-ranking journals, a central point of contention in the discussions lnked to above. An example of just how subtle these incentives may skew the scientific debate, even in the absence of any obvious misconduct, happened to land on my desk this morning in the form of a paper quite close to my own field of research, published in the (for our field) very highly ranked journal "Current Biology".This paper caught my attention not only because it concerned fly behavior or featured a colleague I happen to know quite well, but because it stated in the abstract that: "blocking synaptic output from octopamine neurons inverts the valence assigned to CO2 and elicits an aversive response in flight". We currently have a few projects in our lab that target these octopamine neurons, so this was a potentially very important finding. It was my postdoc, Julien Colomb, who spotted the problem with this statement first, in Fig. 3 (click for larger image):The important data to look at is in Fig. 3D. It shows an attraction for CO2 vs. air in wildtype flies (WT), but an aversion in the genetically manipulated flies (Tdc2-GAL4/UAS-TNT). This is what is stated in the abstract: wildtype flies are attracted to CO2 and flies where octopamine release is blocked, avoid CO2. However, the important control experiments, are those that test for off-target effects of the genetic manipulation. In other words, do the transgenes inserted into the fly genome have an effect of their own, independent of their combined effect on octopamine? In this case, there are two transgenes, a GAL4 transgene (the driver) and a UAS transgene (the effector). Their CO2 scores are shown at the end (Tdc2-GAL4/+ and UAS-TNT/+, respectively). Interestingly, these lines both show a strongly reduced preference for CO2. Their preference is so strongly reduced that it is not even different from that for air. To put it differently: neither of both control lines show normal, wild type behavior. They may not be able to detect CO2 any more, or have secondary alterations that simply reduce the preference for CO2, or a myriad of other explanations. Importantly, nobody can know if these two effects, which either alone already reduce the preference for CO2 dramatically, together could lead to an avoidance of CO2 that is completely independent of the targeted octopamine neurons.In this respect it is important to point out that the authors are not trying to hide this effect. In the text, in what appears to be a contradiction to the abstract, the authors write: We note that the Tdc2-GAL4/+ driver line does not spend a significantly greater amount of time in the CO2 plume by comparison to air, but this line, as well as the UAS-TNT/+ parent line, spends significantly more time in the CO2 plume in comparison to their progeny. Therefore, this experimental result cannot be fully attributable to the genetic background.The last sentence, of course, is incorrect: if both lines independently reduce the attractiveness of CO2, then it is very conceivable, one might even say straightforward, that both together might reduce it so much, that the resulting value of CO2 is negative, leading to an aversive response in the flies, irrespective of the involvement of octopamine.Given what is known about the action of octopamine in these processes, the hypotheses that the authors claim to have corroborated is beautiful, makes sense and is biologically plausible. So the result they present in the abstract "blocking synaptic output from octopamine neurons inverts the valence assigned to CO2" makes this a very sexy paper for the field that unites several disparate findings and puts a whole set of results in a broader perspective (and may well be correct!). Of course, these considerations are crucial for marketing your paper to one of the top journals in the field. Had the authors discarded the octopamine results from their paper, it is highly unlikely it would have been published in Current Biology.To be very clear: I can't find any misconduct in this paper, only clever marketing of the sort that occurs in almost every paper these days and is definitely common practice. This is precisely the kind of marketing we refer to in our manuscript and one wonders what the motivation of the authors might have been. The first author is a postdoc in Mark Frye's lab, so she needs to publish in top journals to get a job. The second author was an undergraduate, so likely less involved in the drafting and revising of the paper and the last author is a junior investigator for HHMI, so likely under enormous pressure to publish in top journals not only to justify his award, but also to do well in future evaluations.Obviously, this is just a case study, N=1, an anecdote, but I think it exemplifies the incentives and how they can distort the scientific debate. For instance, see the Tweet I sent around after I read the abstract (but before I had a look at the actual data:Octopamine reverses Carbon Dioxide preference in flies feedly.com/k/Upirw7— Björn Brembs (@brembs) January 25, 2013Wasserman, S., Salomon, A., & Frye, M. (2013). Drosophila Tracks Carbon Dioxide in Flight Current Biology DOI: 10.1016/j.cub.2012.12.038... Read more »
You can solve most problems in life by buying more computers – or grad students, or microscopes, or lasers for that matter. Some of Jack Gallant’s lab recent efforts in fMRI analysis are a good example of this approach. They published an interesting paper in Neuron last month about the representation of categories in cortex.
Objects can be classified by humans in thousands of different categories. How are those categories represented in cortex? How would you even try to locate where each of potentially thousands of categories are represented?... Read more »
Huth, A., Nishimoto, S., Vu, A., & Gallant, J. (2012) A Continuous Semantic Space Describes the Representation of Thousands of Object and Action Categories across the Human Brain. Neuron, 76(6), 1210-1224. DOI: 10.1016/j.neuron.2012.10.014
The recent paper "On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy" by Esther Krook-Magnuson and colleagues in Nature Communications (published online on January 22, 2013) applies the optogenetic approach to treat seizures in mice. The researchers used mice that had been genetically modified to express the inhibitory light sensitive protein halorhodopsin (normally only found in single cell organisms but not in mammals) in neurons. They placed an optical fiber to deliver the laser light to an area of the brain where they chemically induced a specific type of seizures (temporal lobe epilepsy or TLE) in the mice.... Read more »
Krook-Magnuson, E., Armstrong, C., Oijala, M., & Soltesz, I. (2013) On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy. Nature Communications, 1376. DOI: 10.1038/ncomms2376
There are many reactions that can be taken in response to the world going crazy on you, and depression is one of these. Even though it is (rightly) seen as perhaps not the greatest illness to have, there is a case to be made that depression is an energetically-efficient response to overwhelming stress; it can [...]... Read more »
Chaudhury, D., Walsh, J., Friedman, A., Juarez, B., Ku, S., Koo, J., Ferguson, D., Tsai, H., Pomeranz, L., Christoffel, D.... (2012) Rapid regulation of depression-related behaviours by control of midbrain dopamine neurons. Nature, 493(7433), 532-536. DOI: 10.1038/nature11713
Tye, K., Mirzabekov, J., Warden, M., Ferenczi, E., Tsai, H., Finkelstein, J., Kim, S., Adhikari, A., Thompson, K., Andalman, A.... (2012) Dopamine neurons modulate neural encoding and expression of depression-related behaviour. Nature, 493(7433), 537-541. DOI: 10.1038/nature11740
Warden, M., Selimbeyoglu, A., Mirzabekov, J., Lo, M., Thompson, K., Kim, S., Adhikari, A., Tye, K., Frank, L., & Deisseroth, K. (2012) A prefrontal cortex–brainstem neuronal projection that controls response to behavioural challenge. Nature. DOI: 10.1038/nature11617
Amat, J., Baratta, M., Paul, E., Bland, S., Watkins, L., & Maier, S. (2005) Medial prefrontal cortex determines how stressor controllability affects behavior and dorsal raphe nucleus. Nature Neuroscience, 8(3), 365-371. DOI: 10.1038/nn1399
Ever wonder why a perfume (or cologne) smells better on somebody else than on you? The reason lies in the interactions of our brains, immune system and nose. Our brains literally know exactly what we smell like and can set preferences based on that for associations with others (particularly sexual partners).... Read more »
Manfred Milinski, Ilona Croy,, Thomas Hummel, & and Thomas Boehm. (2013) Major histocompatibility complex peptide ligands as olfactory cues in human body odour assessment . Proc. R. Soc. B., 280(20122889). info:/10.1098/rspb.2012.2889
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