Author Archives: imranmitha

Can’t decide? Roll a die


Image source: Flickr commons; Uploader: neni d

Do you ever feel as though despite your experiences, you repeatedly make the same mistake? Most of the time, we center our decisions on logic and prior experience. But…  can we ever get the best outcome by simply making a random choice and ignoring what we already know?

(Click here for an awesome article about how our brain helps our reasoning and decision-making!)

Rats were monitored by a computer that tried to predict the rat’s decisions. Image Source: Howard Hughes Medical Institute (HHMI)

In a study recently published in Cell, scientists from Howard Hughes Medical Institute (HHMI) found that when faced with a challenging “opponent”, rats stopped using strategy to make decisions and made decisions randomly instead. In the experiment, rats were presented with two holes in a wall, one of which contained a sugary reward. Meanwhile, the rats were monitored by a computer-simulated opponent, which recorded the rats’ past choices so as to predict its future choices. To get the sugar, the rats had to choose the hole that was not predicted by the opponent. When faced with opponents that made weak predictions, the rats selected holes using strategy. However, when the computers used complex algorithms to predict the rats’ choices, the rats instead selected holes at random!

Are there advantages for animals to change behaviour from using logic to choosing randomly? Firstly, when animals encounter situations that are unpredictable in the wild, such as predators or prey that move erratically, it could be beneficial to move randomly to evade predation or capture prey. Moreover, random behaviour might be useful in the exploration of new environments. For example, a rat might find food in a place that it would not explore if it were making decisions based on past experience gained in a different environment.

The scientists from HHMI discovered that when the rats faced hard-to-beat opponents, the amount of a stress hormone (norepinephrine) increased in the rat’s brain. Furthermore, the rats continued to act randomly even after the opponent started to make weak predictions again! To free the rats from this state, the scientists suppressed the release of the stress hormone, causing rats to return to their strategic decision-making.

Further research into the role of hormones in the brain on decision-making may lead to novel treatments foe mental conditions. Image source: Flickr commons; Uploader: European Space Agency

This study may be a step in the right direction of developing a treatment for “learned helplessness” in people. Learned helplessness is a mental condition in which an individual becomes unwilling to avoid painful situations because they believe that they cannot control the outcome. The actions of people suffering from this disorder resemble that of the rats stuck in “random mode”, as their decision-making is impaired. Perhaps a treatment can be found in the near future for learned helplessness and other conditions, such as depression, with further research investigating the brain’s function in decision-making.

In the video below, uploaded to YouTube by LennyBound, an Oxford math professor participates in an experiment that aims to explain the brain’s role in decision-making:

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-Imran Mitha

Prosthetic Limbs approach the Natural kind

Advancements in the function of powered prosthetic limbs have been few and far between in the last 50 years. That is not to say that their structure and mechanical design have not improved, but current prostheses still limit the wearer’s motion control and sense of touch. Researchers at the Case Western Reserve University of Ohio recently performed a study in which they implemented pressure sensors to more closely mimic what a person with a normal arm would feel.

Prosthetic limbs aim to mimic real limbs by communicating directly with the brain. Image source: Gizmag

Touch perception, one of our five senses, is a critical part of the human experience and helps build our basic perception of the world around us. In humans, the somatosensory system (touch, or tactile perception) critically depends on the nervous system. When you touch a surface, for example placing your hand on a table, sensors on the skin’s surface initiate an electrical signal that is conducted to the brain via the spinal cord, and allows the impact to be felt by the hand. The term ‘stimulus’ simply refers to an electrical signal coursing through our body that is processed by our brain, and interpreted as an instruction for reaction. However, in individuals lacking normal limbs, this pathway cannot occur because the skin sensors are not present. In general, modern research in the field aims to improve two-way communication between the wearer and their prosthetic limb.


New technologies in prostheses aim to improve the communication between brain and limb. Image Source: Flickr commons; Uploader: U.S. FDA

Many people who currently wear prosthetic limbs complain that the appliances create unnatural sensations that are distracting and unpleasant. Moreover, current prosthetic limbs cannot directly convey stimulation to the wearers. Dr. Dustin Tyler and his colleagues at Case Western Reserve University proposed a solution for this problem. They hypothesized that if they could generate electrical signals in varying intensity to nerves (lying outside of the brain and spinal cord), this would produce sensory restoration. The team’s main improvements to the existing prostheses were as follows. Firstly, they created an ability for wearers to vary their grip strength, and secondly, they decreased the level of discomfort endured by the wearer.

In order to create a stimulation, the team connected electrodes that could create electrical impulses into the subjects’ upper limbs. Researchers also added pressure sensors to subjects’ artificial fingerprints that had the capacity to respond to varying stimulation patterns. Two parameters were tested. Firstly, by altering average signal intensity, researchers found that the wearer could precisely control the size of the area their hands were in contact with. Secondly, by changing signal frequency, researchers found that the wearer could control their finger strength. The combination of these two features gave wearers an enhanced ability to manipulate delicate objects. Also, users of the research team’s prosthetic limbs described the sensations as natural and comfortable.

The video below shows a prosthetic limb user performing the delicate task of removing a stem from a cherry. Those who were using nerve stimulation technology perform significantly better than those without it.

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-Imran Mitha


“Turbocharged” Photosynthesis – Wait what?!

Plants convert the sun’s energy into food. Source: Wikipedia Commons

Photosynthesis is a process that plants and other living organisms use to convert carbon dioxide, water and light energy into food. Sounds pretty amazing, right? But that’s only the start.  Photosynthesis single-handedly supplies all the organic compounds and nearly all the energy that is needed for life on Earth. Simply put, without photosynthesis we would not be alive today. In recent years, a question that has often been asked is whether photosynthesis can be tweaked such that the process becomes faster and more efficient.

-Click here for all the intricate details of photosynthesis! Also, the process is illustrated nicely in this short animated film:

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Micrograph of a cyanobacterial species; Synechococcus elongatus. Source: L.A. Sherman and D.M. Sherman, Purdue University

Crucial to photosynthesis is an enzyme called Rubisco. This enzyme is required in the conversion of carbon dioxide to sugar. However, the Rubisco found in plants is inefficient. And so, a team of American and British biologists came up with the idea to “borrow” genes for Rubisco from a cyanobacterial species, called Synechococcus elongates, and genetically engineer them into plants. Formerly known as blue-green algae, cyanobacteria specialize in photosynthesis. Consequently, researchers claim that by meddling with Rubisco in crops, photosynthesis can increase in efficiency by up to 60%.


In the aforementioned experiment, published in Nature, the team of researchers transferred bacterial genes and proteins, including Rubisco, into the tobacco plant, Nicotiana tabacum. As a result, this new hybrid plant could convert carbon dioxide to sugar faster than normal strains of the tobacco plant. When asked how her team of scientists was able to accomplish this feat where other teams had failed before, biochemist Maureen Hanson at Cornell University pointed to the fact that her team also transferrd additional proteins to assist the foreign Rubisco.


A bacterial enzyme was delivered to a sample of Tobacco Plant; Nicotiana tabacum. Source: Rothamsted Research

With crop production technology being a hot field of research, the implications of this study are immensely important. While human population continues to increase at staggeringly fast rates, there are continuously more mouths to feed. “Hacked photosynthesis” may be one way to alleviate the looming problem.

You may be wondering… when will these super-efficient plants be in crop fields near you? Not as soon as you might think. While turbocharged photosynthesis works great in theory, in reality there are a few setbacks. One issue is that cyanobacterial Rubisco has a tendency to react with oxygen. Bacteria deal with this problem by incorporating a protective capsule, called a carboxysome, to ward off oxygen. However, plants lack this defensive shell and so the tobacco plant with bacterial Rubisco wastes significant amounts of energy. Naturally, scientists are currently working on ways for plants to create structures resembling bacterial carboxysomes.


‘Turbo’ photosynthesis could redefine the way we farm crops. Source: Flickr commons, Uploader: Appe Plan

All in all, while the process of turbocharged photosynthesis has yet to be perfected, this scientific finding is a great leap in the direction of higher-yielding and faster-growing crops.

-Imran Mitha