Do you remember the time when... How episodes shape our memories by Jai Yu!

Imagine sitting with your friends chatting about previous trips. You might mention the time when you went to a beautiful waterfall. You mention some details of the event, like the sun, weather and scenery. You can remember the activities from that day. But would you remember the exact duration you were at the waterfall, apart from a crude number? Or what you did the day earlier or the day later. Probably not so clearly. The event became fresh in your memory, but many details were lost to time. How does the brain retain this experience.

Jai and colleagues investigated the phenomena of coding experiences in the brain to understand how the mind recollects past experiences. They used an interesting model where a rat's behavior is monitored while it searches for a reward and then consumes it. The rat's activity gets divided into mobility (searching for reward) and immobility (consumption of reward). The rat's brain uses the changes in activity as switches to break time into discrete chunks. Each chunk becomes an episode and might be processed and saved differently. This way the brain could define interesting parts of experience and save them as separate memories, such as memories of experience on paths to reach rewards versus memories of being at those reward locations. To know more on how this happens, please listen to Jai.



To know more, please refer to:
Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility
eLife, Aug., 2017

The sugar deception! Interview with Maria Veldhuizen to know if our brain can tricked into uncoupling sweetness from calorie content.

We all know of diet drinks and sugar-free desserts. Such foods have ingredients that are sweet, but low in calorie. The temptation to savor and relish sweet foods without paying the price of high calorie intake is pretty tempting, isn't it? But does taking food items with a mismatch in sweetness and calorie content actually work on our brains? Can our brain detect the disparity?

Maria and colleagues wanted to understand the affect of discrepancy between the sweetness of the food and its calorie content on the brain's response and metabolism. By providing people drinks that were of the same nutritional value, but varying in calorie, they found that the body responded the best when the two things, sweetness and calories, matched. This suggested that calories are not the only factor that trigger metabolic and mental responses. It could be that the brain's reward circuits better register foods that match in their sweetness and nutritional content. This is of great importance because we live in a world where increasing amounts of food contain such mismatches. To know more, please listen to Maria.


To know more, please refer to:
Integration of Sweet Taste and Metabolism Determines Carbohydrate Reward
Maria et al., Current Biology, 2017

Don't judge a book by its cover. Different neural circuitry underlying similar behavior by Akira Sakurai!

It is assumed that similar behaviors are generated by similar neuronal mechanisms. If nature has found one way of doing things, it will reuse it again and again for the same purpose. Akira and colleagues wanted to investigate this phenomena in the swimming behavior of two closely related molluscs. The swimming behavior of the two species is generated by very similar neurons, yet when they looked closely, the connections between neurons differed drastically. This suggested that the swimming behavior used the same same blueprint, but different architecture. To know more, please listen to Akira.  


For more information, please refer to:
Artificial Synaptic Rewiring Demonstrates that Distinct Neural Circuit Configurations Underlie Homologous Behaviors
Akira Sakurai and Paul S. Katz, Current Biology, June 2017

How deep breaths help with relaxation -- Interview by Kevin Yackle!

The one advice for relaxation is to take deep breaths. Yoga practitioners and doctors alike give this age-old advice. But how does our body connect breathing with calmness? Or is this a placebo effect??

Kevin and colleagues wanted to understand the biological connection between breathing and relaxation. For this, they targeted a specific region in the brain that is involved in controlling breathing. They killed a small region within this special area. Surprisingly, and fortunately, the animal's breathing did not stop. But it was slower, and was connected to the animal being calm under normal conditions! This showed a link between deep, slow breaths and a relaxed state of mind. To know more, please listen to Kevin.



For more information, please refer:
Breathing control center neurons that promote arousal in mice
Yackle et al., Science, 2017

Listening with eyes! Interview with John Magnotti on deciphering McGurk effect!!

We all have tried to lip-read when we can't hear properly. We try to use visual cues to listen when the audio cue is missing or of bad quality. But did you know that our brain tries to use visual cues even when we can hear nicely. And if the two cues are not in sync, we can get confused. In-fact, we might 'hear' a different sound than what is falling on our ears! Our eyes change our audio perceptions! 

Have a look here:


John and colleagues wanted to understand why the effect occurs. And to do so, they generated a computational model which used an audio and visual cue to predict its perception. They found that an important step in correct perception is deciding if the cue arrives from one or two sources. Knowing the number of origins improves understanding. To know more, please listen to John.


To know more, please refer to:
A Causal Inference Model Explains Perception of the McGurk Effect and Other Incongruent Audiovisual Speech
Magnotti and Beauchamp.  PLoS Comput Biol 2017

Illuminating movements! Interview on motion control by optogenetics by Patrícia Correia.

Our brain controls our every behavior. This includes our simple everyday movements and our deepest thoughts and feelings. But are the mundane and complex processes connected in some way. Or are they processed in entirely different ways. Could there be a unified framework underneath the spectrum of behaviors.

Patricia and colleagues started by investigating the role of serotonin on mouse brain. Serotonin, a neuro-hormone, has been associated with mood and motivation within our brains. They wanted to understand the effect of providing increased amount of serotonin to mouse brain. They did this by using a technique called optogenetics, which is capable of using light to control cellular behavior. In their case, they used optogentics to increase serotonin levels in the brain. Upon doing this, they found a fascinating effect on the animal's locomotive behavior. This suggested that serotonin can controls our movements, possibly by affecting our motivations to carry them out! To know more, please listen to the interview with Patricia.


To know more, please refer to:

Transient inhibition and long-term facilitation of locomotion by phasic optogenetic activation of serotonin neurons.
Correia et al., eLife 2017;6:e20975

In addition, please have a look at wonderful fusion between art and science by Patricia, Roots of Curiosity, and her podcast, Creative Disturbance.

Mind reading! Interview on Brain-computer interface for the completely locked-in by Ujwal Chaudhary.

Stephen Hawkins uses a special computer technology which translates the movements of his cheek muscles to communicate with the outside world. His inability to move any other muscle is due to loss of muscular function from ALS (amyotrophic lateral sclerosis) disease. Unfortunately, some patients with ALS do not even retain a single musclular function, while retaining all mental functions; a state called locked-in syndrome. It would be great to help such people with a technology that could directly read the thoughts of the unfortunate patient.

With this inspiration, Ujwal and colleagues developed a brain-computer interface capable of reading simple 'yes' or 'no' thoughts of completely locked-in individuals. The interface is completely non-invasive and can be trained to read thoughts to any question. With this they can increase the interactions with the patients, stimulating and enriching their time, and increasing contact with the outside world.

This generates a nucleus that can be expanded to read full sentences, a technology out of sci-fi, but surely of great use to the unfortunately paralyzed. Please listen to Ujwal on this amazing technology.


To know further on the research, please read:
Brain–Computer Interface–Based Communication in the Completely Locked-In State.
Chaudhary et al., PLoS Biology, 2017

Sex is in the details! Interview with Esther Saiz on gender influencing neuronal circuitry.

'Men Are from Mars, Women Are from Venus.' But what differs between Mars and Venus. According to the author of the book, John Gray, the difference lies in the psyche. These differences could stem from different wiring inside the brain of individual sexes. With 100 billion neurons in the brain of typical human, and maybe as many as 1,000 trillion total connections, its a daunting task to answer this question.

Enter Esther and colleagues with their powerful model system C. elegans, which is a small transparent worm whose each and every cell in the body is accurately mapped along with most of cell's interacting partners. When they looked carefully at one neuron that differed between the sexes in C. elegans, they found a machinery that influenced the sex-specific maturation and behavior of that cell. Strikingly, this influence was not due to sexual hormones, but was wired inside the identity of the cell. So, just changing this one cell changed certain behaviors of the animal from one sex to another! To know more, please listen to Esther.


For further information, please refer to:
Sexually Dimorphic Differentiation of a C. elegans Hub Neuron Is Cell Autonomously Controlled by a Conserved Transcription Factor.
Saiz et al., Current Biology, 2017.
BioRxiv Link.

The Scent of Jealousy! Interview with Meghan Laturney on mate-guarding behavior!!

You know of Hollywood plots where a man comes smelling of another woman, and his wife suspects him of cheating on her. The woman is relying on olfactory cues for keeping a tab on the guy's sexual behavior. Does this soap-opera behavior also occur in other species? Is smell used as a tool to guard against promiscuous behavior??

Meghan and her colleagues try to tease apart such behavior in the fruit fly, Drosophila melanogaster. They see that the male deposits specific scents on the female's body and inside her reproductive tract. Both these olfactory cues decrease the female's attractiveness to future mating partners. This increases the chances of the male's sperm fertilizing the female. The female, on the other hand, might actively try to remove these marking scent in order to continuing mating, which gives her eggs better to survive. To know more about this exciting arms race between the sexes, please listen to Meghan!


To know more on the topic, please refer to:
Drosophila melanogaster females restore their attractiveness after mating by removing male anti-aphrodisiac pheromones.
Laturney & Billeter. Nature Communications.  7, 12322 (2016)

What did you have for dinner last night? Interview with Vishnu Sreekumar on memory formation in the real world!

Isn't is difficult to remember what you had for dinner two night ago, but so easy to remember your first kiss! Why is it difficult to remember few experiences while other stay etched in our memory forever. Of course, we have limited brain capacity, so few things are removed at the expense of others, but how do we evaluate that information; how much decision making goes into paying attention to important tasks for remembering them later onward.

Vishnu Sreekumar and his team work on memory formation in the real world. They utilize information gathering using contemporary technologies to come-up with models that can explain what we look for in experiences when memories are being formed. Their exciting work not only helps model our day-to-day working, but can also help people with better memory retention and improving attention span. To know more, please listen to Vishnu.


For further information please refer to the following publication:
The Episodic Nature of Experience: A Dynamical Systems Analysis.
Sreekumar et al., Cognitive Science, 23 July 2016.

Music to the heart! Interview with Troy Shirangi on development of neural circuitry for fly courtship behavior!!

You all must have seen a peacock dance. It's majestic, isn't it! The vibrant colors all moving in big waves, but for what?? The male peacock performs the majestic gesture to lure the female into mating. This is true for many species where the male makes ostentatious displays to entice the female. But how does the male develop the displays that the females respond to? Are there special neural circuitry controlling this behavior?? And if so, which genes are responsible for making them???


Troy and his colleagues dissect such machinery for the fruitfly, Drosophila melanogaster. They find the neurons and master transcription factor autonomously controlling the courtship behavior. They are able to specially pin-point the neuro-muscular apparatus underlying male singing. The study lays the platform for understanding sex-specific behaviors and the evolutionary forces underlying mate choice. To understand about the exciting work, please listen to the interview with Troy.


For further information, please refer the following study:
Doublesex Regulates the Connectivity of a Neural Circuit Controlling Drosophila Male Courtship Song
Shirangi et al., Developmental Cell, 20 June 2016.
   

Is to perceive to suffer? Interview with Anjali Krishnan on empathetic pain perception!

Imagine falling on the road and hurting yourself. Now imagine watching the same event happen to someone else. Would you react similarly to both these situations? Would your brain respond alike to your own pain vs. to other's pain. Aristotle once said, 'To perceive is to suffer'. According to him, your reaction would match. But is that true?!

Anjali Krishnan and her colleagues at University of Colorado Boulder set out to find answer to this question of similarities and differences in perceiving self and empathetic pain. Surprisingly, and excitingly, they found that our brain looks at these kinds of pain differently. Empathy for other people's pain involves the process of mentalization: imagining other's situation and condition. To know more about the interesting observation, please listen to interview with Anjali.



To know more, please read here:
Somatic and vicarious pain are represented by dissociable multivariate brain patterns.
Krishnan et al., eLife 2016;5:e15166.

A fat hope for autism! - Interview with Zhigang Xie on role of fatty acid metabolism in neuronal stem cells.

Autism is a distressful condition with impaired social interaction and communication. At its basis, it is a neurodevelopment disorder, with certain areas of the brain not developing properly. The burden of brain development falls on neural stem cells, which divide to generate functional neurons as well as maintaining their own numbers. Zhigang Xi and his colleagues show that fatty acid beta-oxidation seems to play a major role in maintaining the stem cells involved in autistic behavior. How is this achieved -- to know the answer, we call Zhigang Xi.


Please read the original article here:
Inborn Errors of Long-Chain Fatty Acid β-Oxidation Link Neural Stem Cell Self-Renewal to Autism
Xie et al., Cell Reports (2016). Volume 14, Issue 5, p991–999.

Give me food, give me sex; give me that which I desire -- Interview with Yi Li about reward sensing!!

Chocolate, chips, cigarettes, alcohol, sex; well, we all choose our sins. What is making us crave for such desires, and what happens when we finally achieve them. Yi Li in his exciting study published in Nature Communications shows that serotonergic neurons in the dorsal raphea nucleus in brain might be involved in reward and pleasure behavior. He did this by observing and recording neuronal activity in live, uninhibited mice while they seek food, sucrose, social interaction and even sex. We call him to hear more about this exciting study.   

You can read the original article here: 

Serotonin neurons in the dorsal raphe nucleus encode reward signals

Li et al., Nature Communications 7, 10503, January, 2016.