Technique Thursday: Microiontophoresis

In the brain, communication is both electrical and chemical. An electric impulse (action potential) propagates down an axon, and chemicals (neurotransmitters) are released. In neuroscientific research, the application of a neurotransmitter to a specific region may be necessary. One way to do this is via microelectrophoretic techniques like microiontophoresis. With this method, neurotransmitter can be administered to a living cell, and the consequent reactions recorded and studied.

Microiontophoresis takes advantage of the fact that ions flow in an electric field. Basically, during the method, current is passed through a micropipette tip and a solute is delivered to a desired location. A key advantage to this localized delivery and application is that very specific behaviors can be studied within context of location. However, a limitation is that the precise concentration of solute may sometimes be difficult to determine or control.

The main component of this technique is the use of electrical current to stimulate the release of solvent. In other words, it is an “injection without a needle.” The main driver of this electric current is galvanic current. The current is typically applied continuously. The solute needs to be ionic, and must be placed under an electrode of the same charge. That is, positively charged ions must be placed under the positive electrode (anode), and negatively charged ions must be placed under the negative electrode (cathode). This way, the anode will repel the positively charged ion into the skin, and the cathode will repel a negatively charged ion into the skin.

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Manic Monday: Eye of the Storm

A classic experiment on discrimination was Jane Elliott’s Blue eyes/Brown eyes experiment. Jane Elliott is a former third-grade teacher, with no research background to speak for. However, the day after Martin Luther King Jr. was shot, she decided to try a little experiment with her young, impressionable students.

What she did next was nothing short of fascinating.

On April 4, 1968, Jane Elliott was ironing a teepee for one of her classroom activities. On the television, she was watching news about the assassination of King. One white reporter mentioned something that shocked Elliott:

“When our leader [John F. Kennedy] was killed several years ago, his widow held us together. Who’s going to control your people?”

Elliott could not believe that the white reporter felt that because Kennedy was a “white-person’s leader”,  black people would now get out of control without a leader of their own.

So she decided to twist her little Native American classroom exercise and replace teepees and moccasins with blue-eyed and brown-eyed students.

On the first day of her experiment, Elliott decided that since she had blue eyes and was the teacher, blue-eyed students were superior. The blue-eyed and the brown-eyed children were consequently separated based on something as superficial as the color of their eyes.

Blue-eyed children were given brown collars to wrap around their brown-eyed peers–all the best to notice them with.

The blue-eyed children were then given extra helpings of food at lunchtime, five extra minutes at recess, and a chance to play at the new jungle gym at school. The brown-eyed children were left out of these activities. The blue-eyed children were also allowed to sit at the front of the class, while brown-eyed children were kept at the back.

Blue-eyed children were encouraged to play with other blue-eyeds, but told to ignore their brown-eyed peers. Further, blue-eyed students were allowed to drink at the water fountain, while the brown-eyed ones were prohibited from doing so. If they forgot, they were chastised.

Now, of course the children resisted the idea that the blue-eyed students were superior somehow. Elliott countered eloquently, and with a lie: melanin is linked to blue eyes, as well as to intelligence.

The students’ initial resistance wore out.

The blue-eyed “superior” students then became arrogant and bossy. They were mean, and excluded their brown-eyed peers. They thought themselves superior, simply on the basis of their eye color.

What’s even more interesting is that the blue-eyed students did better on some of their exams, and performed at a higher ability on math and reading than they previously had. Just believing they were superior affected their grades positively.

Even more interesting, but perhaps not surprising, was what happened to the brown-eyed students:

They became shy, timid, and frighteningly, subservient. They did poorer on their tests, and during recess, kept themselves away from the blue-eyed children. Each group effectually grouped themselves according to their eye color.

The next week, Elliott added another twist to the experiment: she made the blue-eyed students inferior, and made the brown-eyed ones superior. Brown collars for the blue-eyeds now.

The brown-eyeds then began to act meanly towards the blue-eyed kids, though at a lesser intensity.

Several days later, the blue-eyed students were told they could remove their brown collars. She then had the students reflect on the experiment by writing down what they thought and had learned from the experiment.

Needless to say, the experiment had a major impact on her students. Elliott continued the experiment with her students for years after, and has appeared on Oprah and other venues, promoting anti-discrimination.

What’s even more important is that her students, even when they became adults, continued to remember her lesson. They valued equality over racism, and continued to teach others against discrimination.

A documentary was filmed about her experiment, called Eye of the Storm.

A beautiful video about a modern re-enactment of the experiment can be found here.

The Pain in Brain Stays Mainly in the…Brain?

Pain is a major force of survival. Without pain, we would, simply, not survive. Of course, pain can be cumbersome, and unnecessary, at times. For example, when you stub your toe on your desk, do you really need that much pain for that long?

More importantly to this discussion, what do you do when you stub your toe? Probably do a bit of hopping, and you certainly grab that toe and squeeze or rub it.

Why do you do that? The Gate Control Theory of Pain can answer that.

At its basic, the Gate Theory of Pain dictates that non-painful input (like that rubbing) closes the gates to painful input. This results in the prevention of the sensation of pain from being fully perceived by the brain. Simply, when the painful stimulus is overridden by a non-painful stimulus, the pain sensation does not travel to the central nervous system (CNS).

Even more simply, non-painful stimuli suppress pain.

Why is that?

Collaterals, or processes, of large sensory fibers that carry cutaneous (skin) sensory input activate inhibitory interneurons. Now, inhibitory interneurons do just what their name implies: they inhibit. And what do they inhibit in this case? Pain sensory pathways. This therefore modulates the transmission of pain information by pain fibers. Non-painful input suppresses pain by “closing the gate” to painful input.

This happens at the spinal cord level: non-painful stimulation will result in presynaptic inhibition on pain (nociceptive) fibers that synapse on nociceptive spinal neurons. This inhibition, which is presynaptic, will therefore block any incoming painful stimuli from reaching the CNS.

More on this topic on this week’s Séance Sunday, coming up!

Monty Python’s influence in Neuroscience

Ever heard of the computer programming language called Python? Where do you think Python got its name from?

Monty Python!

Python programming has had an increasing effect on neuroscientific developments. In fact, with the growing field of computational neuroscience, Python programming has taken a role in how neuroscience research occurs.

Python itself is a high-level programming language. Its syntax is relatively straightforward, as one of its main philosophies is code readability. Therefore, coders can use fewer lines of code than they would in other programming languages.

In neuroscience, python is used in data analysis and simulation. Python is ideal for neuroscience research because both neural analysis and simulation code should be readable and simple to generate and execute. Further, it should be understandable xx time later, by xx people reading the code. That is, it should be timeless and should make sense to anyone who reads the code and tries to execute or replicate it.

Of course, MATLAB is good for neuroscience research purposes, but MATLAB is a closed-source, expensive product, where python is open-source and more readily available to the masses. In fact, you can download Python here. Further, there are a number of courses that can help a dedicated learner teach themselves Python.

Python also has science packages that allow for systems like algebra, packages specifically for neural data analysis and simulation packages to describe neuronal connectivity and function. Python can even be used for database management, which may be important when there are large amounts of data belonging to a given laboratory. Because Python combines features from other languages, it can be used in foreign code and other libraries beyond the ones it was developed in. This allows for effective sharing and collaboration between laboratories. SciPy is “a collection of open source software for scientific computing in Python.”

In relation to neuronal simulations, Python make sense because:

1. It is easy to learn. This is because is has a clear syntax, is an interpreted language (meaning the code is interactive and provides immediate feedback to the coder), and lists/dictionaries are built into the program itself.

2. It has a standard library, which therefore provides  built-in features important for  data processing, database access, network programming and more.

3. It is easy to interface Python with other programming languages, which means that a coder can develop an interface in Python, and then implement it in other fast programming languages, such as C and C++.

An example of Python being used as a neuronal simulator is NEURON. An example of code is the following:

>>> from neuron import h
>>> soma = h.Section()
>>> dend = h.Section()
>>> dend.connect(soma, 0, 0)
>>> soma.insert(’hh’)
>>> syn = h.ExpSyn(0.9, sec=dend)

(taken from Davison, et al., 2009).

Here, a neuron is “built”, with a dendrite, soma, dendrite all “created”, as well as channels. It is clear, then, how simple and straightforward Python code is, and how important it can then be in neuroscience.

Not quite Alibaba: Robber’s Cave Experiment

Muzafer Sherif, an American psychologist of Turkish heritage, made a contribution to psychology via his Realistic Conflict Theory. This theory states that group conflicts, stereotypes and prejudices are the result of competition for resources.

So it’s sort of caveman group 1 meets caveman group 2, all fighting for the same food and other resources, and deciding that the other group is the enemy and need to be hated on.

Sherif performed the famous Robber’s Cave experiment to support his theory.

Unfortunately, Robber’s Cave was not a pirate cove, or Alibaba’s hangout, but it was a state park in Oklahoma. The experiment itself involved two groups of 12-year-old boys, totaling 22 boys.

The boys were all from white middle-class backgrounds, from two-parent Protestant homes, and had no relation or connection to each other. In other words, they were all strangers to each other. The boys were randomly assigned to one of two groups, and each group was unaware of the other group’s existence.

Then, as separate groups, a bus picked them up in the summer of ’54 and took them to a fake summer camp at a 200-acre Boy Scouts camp in Robbers Cave State Park. Even at this state park, the groups were kept separate from each other, but were encouraged to get to know each other as two individual groups via common goals that required discussion, planning and execution.

During the first phase, the two groups did not know of the other group’s existence. Therefore, the boys developed an attachment to the group they belonged to during the first week of camp. They established their own cultural norms via activities such as hiking and swimming. They even chose names for their groups (The Eagles and The Rattlers), and had t-shirts and flags with their group name.

Then came the Competition stage. Over the course of 4-6 days, friction between the two groups was to occur. Basically, there was a turf war.

In this Competition stage, the two groups were brought into competition with each other, such as via baseball, tug-of-war, etc. with prizes like trophies. Individual prizes were also given out to the winning group.

Now, the Rattlers, confident boys that they were, were absolutely confident that they would be the victors. They spend a day discussing the contests, and improving their skills on the ball field, where they were bold enough to put up a “Keep Off” sign. In other words, they set up their own territory. The Rattlers even went so far as to make threatening remarks about what would happen if The Eagles bothered them.

Sherif built in situations that frustrated one group over the other, such as having one group get delayed going to a picnic so that by the time they arrived, the other group had eaten all the food.

Now of course, the prejudice began verbally, with name-calling and taunting. As the Competition phase continued, the verbal abuse became more physical, with The Eagles burning the flag of The Rattlers. The day after, The Rattlers retaliated by ransacking The Eagles’ cabin, stealing private property and overturning the beds. The researchers had to separate the boys because they became so violent with each other.

There was then a 2-day cooling off period, where the boys were instructed to characterize the two groups. Unsurprisingly, each boy described his own group in more favorable terms than the other group.

The results of this experiment indicated that Sherif’s Realistic Conflict Theory was correct; inter-group conflict can produce prejudice and negative behavior.

Now, a major ethical concern with the experiment was deception: the boys were not told of the nature of the experiment, nor were they protected from harm, either psychological or physical, to the best of the researchers’ abilities. The sample was also biased: middle-class, white, and young, the sample is hardly powerful enough to generalize to larger groups, such as nations.

The Three Christs of Ypsilanti

Because, apparently, one Jesus isn’t enough.

In the 1950’s, psychologist Milton Rokeach conducted an experiment where he brought together three psychiatric patients who all claimed to be Jesus.

These three patients were made to live together for two years, in an attempt to determine whether their beliefs would change.

Now, early on, there were heated exchanges. One patient would yell to another, “No, you will worship me!” to which he was replied, “No! I will not worship you!” and such things. You can imagine what kinds of exchanges would have occurred between these delusional Jesus Christs.

Now, Rokeach was no fool. He knew that the psychological traditions of his day did not probe well into individual identities. The stories of Secret Agents who felt that they had lost their identities were intriguing to Rokeach, as they would be to most anyone.

With these interests and experiences in mind, Rokeach set out to determine is a person’s self of self can be challenges in a controlled setting, such as a psychiatric hospital, under his eye. That is, if the Bible says there is only one Jesus, and a person believes themselves to be Jesus, what would happen to their self-identity if they are confronted with another who claims to also be Jesus.

It’s certainly a question to wonder. And Rokeach wrote all about it in his book, The Three Christs of Ypsilanti.

Rokeach was not the first to bring about this sort of Jesus get-together. In the 1660’s, Simon Morin, whom Voltaire wrote about in one of his essays, claimed to be Jesus. However, at one point, Morin had been committed to a psychiatric unit (or madhouse, as they were called), where he met with another man who also claimed to be Jesus. Morin deemed that other man to be ridiculous, and then recognized his own “ridiculousness”, and thus renounced his Jesus identity. However, this recognition did not last long, and Morin was thereafter burned at the stake.

Going back to Rokeach. He was rather humane with the patients, for that era, that is. He figured, smart man that he was, that a cure could not be had for these men. However, he also recognized that we draw our self-identities from rather weak foundations, and can build up beliefs that may not be grounded in a solid reality.

What was not so great, or smart, was how the researchers of the study manipulated the three men, simply out of curiosity. The three men, Clyde, Leon and Joseph, were, to put it mildly, manipulated. Leon, for example, received letters from a character he believed to be his wife. His “wife” professed her love to him, and also suggested small changes to Leon’s routine.

Joseph received false letters from the head of the hospital, suggesting changes to his (Joseph’s) routine that would lead to recovery.

In both these instances, the Jesus identity is progressively challenges, until things begin to get uncomfortable, and contact is cut off.

Interestingly, and perhaps unsurprisingly, the Jesus identities are not budged. The three Jesuses continue to argue and even fight, but their self-belief does not budge. Clyde claims that the other Jesuses are actually dead, and there are machines inside the bodies that are producing the false Jesus claims. Joseph and Leon claim that the others are crazy. Of course, they never claim the same about themselves, for the same Jesus-identity belief.

Even after two years, the Jesus identities do not shift. Rokeach eventually goes to Freudian lore, and states that perhaps the mistaken identities are due to some sort of sexual identity confusion. Rokeach, in a later edition to his book, apologized for the way he ran his experiment, stating that he had no right to interfere with the patient’s lives the way he did.

Rokeach, however, is still a fascinating man who contributed to psychology. He built the Rokeach Value System, which is used in empirical psychological work to classify people’s values. He also conducted a study where he determined that racial prejudice is due to people trying to make themselves feel better, to put it in simpler terms, and that the ones who are most prejudiced also tend to be lower in terms of their socioeconomic status (SES). That is, prejudice is inversely related to SES.

 

The Sentry (Bob Reynolds) and the Brain

Optogenetics. It sounds like genes being lit up in neon colors, like a flashy Las Vegas sign.

But what is it really?

Optogenetics is a technique that takes advantage of proteins found in certain algae species that respond to different wavelengths of light. This algal response to the wavelengths includes opening a channel (called a channelrhodopsin) in their cell membrane, allowing ions like NA+ and Cl to flow in/out of the cell.

Of course ,this is also how neurons operate: they work via the control of certain ions, such as NA+ and Cl-, in/out of the cell.

So, if you take a gene that encodes the light-sensitive channel of the algae, and force neurons to express that gene, what do you have?

Neurons that have been forced to become responsive to light! Therefore, shining a light on those neurons will force them to fire an action potential (nerve impulse). If you turn off the light, they stop firing. Then, if you use a different channel protein, you can silence those neurons, and they will no longer fire action potentials.

This then gives pointed and reversible control over the neuronal action potential activity patterns.

swert

Source: http://neurobyn.blogspot.se/2011/01/controlling-brain-with-lasers.html

The technique’s major asset is the specificity with which you can control gene expression and neuronal firing. This is possible because different types of cells express different sets of genes. Each gene has two major parts: one part encodes for a specific protein, and the other is a regulatory region which instructs the gene on when and where and how much of a certain protein is to be made. These two regions, the encoding one and the regulatory one, are separate from each other. In fact, the regulatory region is on a neighbouring segment of DNA.

Therefore, you can slice the DNA that makes up the regulatory region and splice it to the protein-encoding segment of another gene, like a channelrhodopsin protein, for example. Then, you can take that hybrid and stick it into a vector, that is, another organism. What do you think that organism wil now be able to do?

Express that protein, like the channelrhodopsin. And that organism will only express the new protein in the cell types directed by the regulatory segment of the DNA you chose in lab.

Now, biological research has a history of using light to control or interact with living systems. For example, a light-based technique called CALI is used to inhibit (by destruction) certain proteins. Lasers have also been used to destroy cells. UV light has also been used to activate a protein that regulates neurons.

In neuroscience, optogentics can be used to silence or activate neurons in different parts of the brain. For example, the amygdala is involved in fear. Of course, we can be conditioned to be fearful of certain things. Like a man who has a fear of driving over bridges because he was once on a bridge that was damaged, or the girl who has a fear of dogs because she nearly got bitten by one, our fear responses that be strong, and without intervention, permanent.

Optogenetics can step in and help us understand the workings of fear, and how it occurs.

For example, researchers conducted a study regarding the development of fear associations. Activation of lateral amygdala pyramidal neurons by aversive stimuli can drive the formation of associative fearful memories. This has been proven by taking channelrhodopsin proteins in lateral amygdala pyramidal neurons, and having an auditory cue paired with light stimulation of those neurons, rather than a direct aversive stimuli. After this experiment, it was found that presenting just the tone produced a fear response.

It is clear, then, that optogenetics can provide real-time information of what neurons are doing, and when. Further, it can also us to control the workings of neurons.

It is possible that optogenetics can get us to the point of not only understanding the brain, including dysfunction, but also offer a way for us to be able to solve problems, including epilepsy and depression. Maybe even schizophrenia.

http://video.mit.edu/watch/optogenetics-controlling-the-brain-with-light-7659/