Carbonation is an important quality of favorite drinks like beer and soda. In addition to the feel of bubbles bursting on the tongue, the flavor of CO2 adds to the fizz experience. Researchers have just identified the taste cells and a membrane-bound receptor responsible for tasting CO2. Using genetically-engineered mice that lack one of the sets of cells required for each of the five taste sensations– sweet, sour, salty, bitter, or umami– the researchers discovered that sour-tasting cells are necessary for mice to perceive the flavor of CO2. The researchers then looked through genes expressed in sour-tasting cells to find the particular receptor that is activated by CO2. A gene encoding a carbonic anhydrase, an enzyme that catalyzes the breakdown of CO2, stood out to the researchers. They then treated mice with a drug that inhibits this enzyme and found that CO2 detection in treated mice was greatly reduced. Furthermore, knocking-out the carbonic anhydrase gene also greatly reduced the ability of mice to taste CO2. Interestingly, neither treatment completely abolished the ability of mice to taste CO2, so there are likely other ways that mice detect CO2.
For more than 100 years we have known of the “fifth” taste- that savoury numminess that is found in protein-rich foods. But we have not been able to define the specific receptor to the core of that flavour: glutamate. Many of the GPCR’s in taste buds are activated by amino acids in conjunction with nucleotides. This would be the primary component of the ‘soup’ derived from boiling down meats or legumes or, in the original case of Umami, seaweed.
Recently, however, the glutamate-specific receptor has been identified. This detects MSG that is found naturally in foods such as tomatoes and aged cheeses; giving them their distinctive flavour.
(submitted by AJ) Colour blindness can cause mild perturbation in a person’s daily life, but there are cases where it has led to fatal mistakes. However, there are degrees to colour blindness, and many are unaware that they are failing to see certain hues at all. Mark Twain and Bill Clinton are examples of famous people that were/are colour blind. In a recent release, scientists were able to correct colour blindness in monkeys using a transgene delivered by a virus. The gene was for L-opsin, the protein in the retinal receptors that responds to long wave-lengths of light. This allowed the monkeys to distinguish reds from oranges and yellows more accurately. More than two years after the treatment, there appear to be no problematic side-effects and the monkeys can still distinguish the colours. This is tested by rewarding the subjects with juice if they can spot a pattern on a display. This of course, may lead to a treatment for human colour blindness– or monkeys getting driver’s licenses. There is also a nifty TED talk (submitted by BM) that describes how we perceive the world around visually.
“Researchers at Stanford engineered mice to carry light-sensitive proteins in the brain’s reward center, which responds to drugs of abuse. Using pulses of light delivered directly to the brain, researchers were able to induce a druglike state, ultimately conditioning the mice to behave like drug-addicted animals.” To read the rest of the article click here.
When Bob went out to the beach, he couldn’t stop oogling Hilda in the yellow polka dot bikini. They were both attending a steamy neurobiology conference. With his heart beating rapidly, he decided to ask her out to a gourmet meal at Chipotle. Lucky for Bob, she was hungry after surfing all day so she said “sure-rritos.” Hilda’s puns only reinforced Bob’s initial attraction. “What a woman!” Bob thought. They walked to his car. She reached over to hold his hand, at which point his stomach flipped with nervousness. They both smiled.
He leaned over and whispered
“Hilda, it’s about time I let you know how I feel. You light up my ventral tegmental area, nucleus accumbens, ventral pallidum and raphe nuclei.”
Hilda was so touched, she screamed out “I love you too Bob!”
Your brain has a circuit for snuggling with schnookums. You might have expected that being in love activates a reward pathway.
But here is one surprising detail: heartache is akin to “craving”…the kind of craving seen in drug addiction.
Some of you have mastered the art of cramming for exams. But what really happens when we store a thought for a very short period of time? What are memories made of? We’ve come a long way in our understanding since Dean Martin’s 1955 hit song. After looking at single neurons in the prefrontal cortex of mice, researchers at UT Southwestern have identified a specific receptor that drives short-term memory storage. Even more interestingly, they used dopamine and cocaine to simulate the effects of addiction on momentary recall. Curious about what happened? This article gives a great summary of their recently published findings in Nature Neuroscience.
Speaking of memory…do you remember our lecture on the hippocampus? Another study at the University of California looked at long-term recall and the involvement of specific brain structures. In light of what we learned in class, try to reason through their results.
One powerful aspect of neurobiology is the wide range of approaches we can use to answer key questions. Both of these research teams wondered “how do we store memories?” While the first study chose to look at single cells, the latter looked at whole brains. Integrating both micro and macro results gives us a more accurate depiction of how our brains are processing information.
This is yet another great piece on the topic of memory. A group of German researchers noticed that particular patterns of brain waves predict which memories you will remember, and which you will forget.
Do these lines look like they extend away from you at different angles? Actually, they’re exactly the same. You brain is fooling you…again! For more information and a few other examples of this illusion, click here.
Still trust your perception? Maybe this will change your mind. Here is the 2009 winner of the Best Visual Illusion of the Year Contest.
The placebo effect has been observed for centuries. Patients given nothing more than sugar pills are able to alleviate their own pain, anxiety and depression. In one case, a terminal cancer patient shrunk his own tumors when he believed in the power of a sham treatment.
This is a very well-written article that links the placebo effect with conditioning. Just like Pavlov’s dogs were conditioned to salivate at the ring of a bell, your immune system can be conditioned to start the healing process at the sight of a doctor’s coat.
Has someone just been watching too many sci-fi movies on Hulu? Doctors at Geneva University Hospital disagree. This is a special case of a supernumerary phantom limb. After suffering a stroke, the 64-year old woman says she can see and feel the “presence of a pale, milky-white and translucent third arm.” More surprisingly, she even uses it to scratch other parts of her body! When neurologists gave her an MRI, they found activity in her motor and visual cortices. Even though the arm does not physically exist, her brain responds as if it’s really there.
Did you know that your brain is made up of more than just neurons? In reality, it’s a mix of many different types of cells. Glial (housekeeper) cells are the most common cell type in the CNS. These have endless functions, from providing nutrients, to repairing damaged tissue, to physically keeping neurons in place.
It would be an oversimplification to think that neurons get all the action. Sure, they’re the jocks of your brain. But don’t overlook the guys in the background. You know…the geeky glial cells. They can surprise you! Research on these supporting cells is turning up some interesting results. One particularly cool discovery: when it comes to lulling you to sleep after a long day, astrocytic glial cells steal the spotlight.
For more than 100 years we have known of the “fifth” taste- that savoury numminess that is found in protein-rich foods. But we have not been able to define the specific receptor to the core of that flavour: glutamate. Many of the GPCR’s in taste buds are activated by amino acids in conjunction with nucleotides. This would be the primary component of the ‘soup’ derived from boiling down meats or legumes or, in the original case of Umami, seaweed.
(submitted by AJ) Colour blindness can cause mild perturbation in a person’s daily life, but there are cases where it has led to fatal mistakes. However, there are degrees to colour blindness, and many are unaware that they are failing to see certain hues at all. Mark Twain and Bill Clinton are examples of famous people that were/are colour blind. In a recent 
Some of you have mastered the art of cramming for exams. But what really happens when we store a thought for a very short period of time? What are memories made of? We’ve come a long way in our understanding since Dean Martin’s 1955 hit song. After looking at single neurons in the prefrontal cortex of mice, researchers at UT Southwestern have identified a specific receptor that drives short-term memory storage. Even more interestingly, they used dopamine and cocaine to simulate the effects of addiction on momentary recall. Curious about what happened? This 
The placebo effect has been observed for centuries. Patients given nothing more than sugar pills are able to alleviate their own pain, anxiety and depression. In one case, a terminal cancer patient shrunk his own tumors when he believed in the power of a sham treatment.
