Mirror Neurons in the Sociopath

Seriously Creepy Eyes

What is a sociopath? A killer? A raging lunatic?
Martha Stout has written a relatively short book (though not as short as it could have been) defining the sociopath and arguing that sociopaths are surprisingly common, 4% of the population in fact.

There are two things I liked about this book and two things I really did not like about this book.

First the good:

1. Dr. Stout effectively argues against the stereotype that sociopath=serial killer.  She defines a sociopath as someone without a 'conscience' who is incapable of real empathy. If this is combined with 'bloodlust' the person very well may turn out to be a serial killer. But if it is combined with 'preferring inertia', the person will manipulate their way into a situation where they are taken care of and don't have to do anything. 

2. A very powerful insight that Dr. Stout has is that the very fact of having a 'conscience' is what keeps 'normal' people from identifying and stopping sociopaths. A person with a 'conscience' will easily take the point of view of the sociopath and try to justify or explain their actions in terms of 'having a conscience'. "they are just depressed", "they didn't know this or that", "there must have been a miscommunication".  It is almost impossible for a person with a conscience to comprehend someone doing something manipulative or cruel for essentially no reason, so they try to invent a reason that would make the sociopath's actions comprehensible to them. The very thing that the sociopath is lacking: the ability to empathize and identify with the wants and needs of others, is the thing that prevents 'normal' people from identifying them. 


Now the bad:

1. What the heck is a 'conscience' anyway? Dr. Stout talks about the conscience like it is some brain structure that you either have or don't have. I wasn't convinced that people are either complete sociopaths or completely normal. I assume there is a continuum, and Dr. Stout does nothing to convince be otherwise, while at the same time constantly implying that it is an either/or situation.


2. I would have been much more interested if this book had delved into the possible neural underpinnings of conscience. It is getting a reward signal from the 'happiness' of others? Getting a pain signal from the pain of others?

An example that came to mind is a scene from the movie Pan's Labyrinth that will probably haunt me forever. A man has had his mouth slit and there is a very painful-to-watch scene where he sews up his own cheek, bandages it, and then takes a shot of vodka. The vodka seeps out his cheek into the bandage. I remember having a very physical reaction to this part of the movie, literally cringing and grabbing my own cheek. 

What I want to know is do sociopaths have this same physical reaction, or would the 'not having a conscience' or 'inability to empathize' prevent something so instinctual.

Well lucky for us, someone else is wondering this same thing something similar.  A 2008 paper tested healthy individuals for degrees of 'psychopathy' with a self-report questionnaire, and then measured their responses to transcranial magnetic stimulation (TMS) of the motor cortex during videos. They claim that this is somehow measuring mirror neuron activity, but I think that it going too far since they are not measuring individual neurons.  

Figure 1 Fecteau et al., 2008

They used a nice set of controls to specifically isolate the effect of watching something potentially painful. The videos were of a qtip touching a hand, a needle touching a hand and a needle touching an apple.  They also ran all the videos stopping them early (before the contact between the objects is made).

In 'normal' people, seeing a needle poking a hand causes a reduction in response to TMS stimulation. What this reduction in cortical excitability means is not clear, so any finding in this study will be hard to interpret. They found that the degree of response reduction was not correlated with the psychopathy index when taken as a whole, but when they isolate the 'coldheartedness' component, they find that the more cold-hearted a person reports they are, the stronger the signal reduction is during TMS. Despite the nice controls, this study leaves a lot to be desired.  They have a small sample size (n=18), and even their relatively mined correlation is not very strong (R=-0.58). In addition, the increase in signal reduction is 'supposed' to indicate 'more empathy', so the meaning of this study is basically ripe for the cherry-picking. Fortunately they don't spend a ton of time speculating wildly about what this reduction might mean, they simply say that their study finds a 'link' between motor empathy and cold-heartedness and end with the classic 'more studies need to be done'. 

Unfortunately the information that can be gleaned from this study is pretty limited, and the brain of the sociopath is still a mystery.

A caveat: I assume someone has studied whether the physical reaction that I describe above occurs in sociopaths or not, but I did not find a study testing it.  If you know of one, please send it my way. 

© TheCellularScale


Fecteau S, Pascual-Leone A, & Théoret H (2008). Psychopathy and the mirror neuron system: preliminary findings from a non-psychiatric sample. Psychiatry research, 160 (2), 137-44 PMID: 18599127

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15 Tips for Mental Fitness

1. Learn to Relax
Allow yourself to let go of inner tensions by giving yourself a “mini vacation.” Give your mind a break by becoming engrossed in a good book, watching a movie, listening to music, taking a walk, working on a hobby, meditating or similar activity that is relaxing for you.

2. Be Kind To Yourself
People are frequently too hard on themselves when things don’t go right. Tune into your self talk, and counteract your negative thoughts about yourself with positive statements.

3. Eat Properly
Nutrition has a direct impact on feeling mentally positive. Limit your intake of sugar, fat, salt, caffeine and alcohol and help yourself stay mentally fit.

4. Find A Friend
Friendships are very important to mental fitness. Working on developing and maintaining friendships is one of the best ways to continue growing as a person. Expressing feelings and ideas to another person can help us clarify what’s truly important to ourselves.

5. Learn to Say “No”
Often people feel the need to respond immediately when a friend or family member make a request. Help yourself set limits by avoiding the quick “knee jerk” response in the affirmative. Instead, let them know you will get back to them shortly. Then do a check of your schedule; ask yourself if you really want to add to your load. Give yourself permission to say “No” when you are too busy to take on additional commitments of your time or energy.

6. Exercise
Check with your doctor about what level is best for you. Even a brisk 15-minute walk, three times a week does wonders for how you think and feel.

7. Do It Now
Procrastination can lead to negative feelings about yourself. One doesn’t have to go to extremes, but it can feel very satisfying at the end of the day to have accomplished a hard task or met a difficult situation head-on.

8. Adapt To Rather Than Resist Change
Change is inevitable and is a necessary part of life. The important thing is to be patient with yourself when you are going through change, and to give yourself time to go through the phases of transition. Realize it takes time to let go of the old and embrace the new.

9. Test Your Assumptions
Sometimes in our interactions with other people, we make the most incredible assumptions and act as if they are true. Rather than assuming, it might be worth the risk to ask directly what was meant.

10. Express Your Feelings
Emotions are a natural response to life. It is important to find ways to express your feelings. Journaling your thoughts is one way that can help you clarify what you are feeling. Once you have identified your feelings, you may find it easier to share them with others.

11. Grieve Losses
Sadness and grief are natural and appropriate responses to the losses which we all experience. Grief over the loss of a love one can be very painful and may last for some time. By being kind and allowing ourselves the time to grieve, we have the potential to be stronger than ever

12. Rest
Get a good night’s sleep. Not everyone needs the same amount of sleep, but it should be restful sleep. There are many techniques available to help promote relaxation; or, you might want to check with your doctor rather than assuming your restless sleep is simply something you have to live with.

13. Review Your “Shoulds”
If you feel stuck by some things you “Should” be doing and aren’t, set a time limit by which you will either have them done or get rid of them. Staying stuck in the middle is a good way to punish yourself and cause mental anguish and stress.

14. Have A Laugh
Nurture your sense of humor, especially about yourself. Trying to see the humorous side of things makes even the most difficult situations easier to bear. Laughter is good medicine. Being too serious limits your ability to enjoy life.

15. Ask For Help
If you need emotional support or just someone to talk to, don’t be afraid to ask for it. There are times in life when everyone must look outside themselves for comfort and advice. If friends can do the job, ask them to help. If not, be assured that professional help is available through your employee assistance program.

I'd say I do about 13 of the 15.

How do you do with these?

Reference

University of Washington.

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Neuroscientists should study Zombie Ants

Zombie ant controlled by fungus (source)

The fungus-controlled zombie ant is one of nature's greatest wonders. A fungus (e.g. O. Unilateralis) is inhaled by an ant (e.g. Camponotus Leonardi), and begins to grow inside its body.  Eventually the fungus infests the brain of the ant, causing it to drunkenly wander, periodically convulse, climb up a leaf and clamp down on its ridge. Once the ant is securely in place, the fungus devours the brain and innards of the ant and grows out the back of its head often (but not always) releasing its spores onto the ground below. Un-freaking-believable, right?

As if this wasn't amazing enough, it's not like it is only one fungus species that infects only one ant species. There are many of these fungi and they infect many different kinds of insect, but somehow maintain a species specificity. In other words, fungus#1 can infect SpeciesX, but not SpeciesY, and Fungus#2 infects SpeciesY, but not SpeciesQ, and so forth. 


So WHY does this happen? and HOW has no one looked at the brain cells of these ants? 

Though no one has looked at the brains of these ants, Last year a paper painstakingly characterized their behavior under 'fungi control'. The most interesting characteristics are:

1. The ants display a 'drunkard's walk' (the author's words)
2. The ants periodically spasm and fall down (if they are above ground level)
3. The ants clamp down on the underside main vein of a leaf (never the side of the leaf, never the top) Interestingly they all bite down on the leaf around solar noon.

Figure 1, Hughes et al., 2011

This figure shows the behavior of several ants.  Each ant was observed during the time of the horizontal blue bar.  The black vertical lines and 'spasms' which caused the ants to fall down (gray stars), and the red triangles are when the ant bit down on the leaf ridge. 

Because we have no idea how the fungus is manipulating the ant, let's wildly speculate.

1. The Drunken Walk:
Why: The reason for this is not clear.  The ant doesn't go far, so the non-directional walking could be to keep it close to more ants.
How: The mechanism is also not clear, but usually an ants directional walking could be following a pheromone trail. The fungus could presumably cause random walking by confusing the ants ability to sense pheromones. It could possibly even cause 'hallucinatory' pheromone sensing.

2. The Periodic Spasms:
Why: The authors speculate that the purpose of these spasms is to keep the ant near the ground.  The infect ants spend much more time on the ground level than the uninfected ants, and the spasms are often followed by a fall.
How:A fungus could essentially cause a seizure in the ants brain by manipulating potassium or calcium channels. On the other hand, I suppose the fungus could be acting directly on the muscles, causing them to twitch in an uncontrolled way. 

3. The Clamping:
Why: This has an obvious function, to root the ant for ultimate fungal growth and dispersion. 
How: First of all, biting and even walking on leaves is not something these ants normally do. So the fungus isn't just hijacking a behavior that the ant already has, it's basically creating a new one.  The correlation with solar noon indicates that a light or heat signal could contribute to the trigger, but basically nothing else is known about it. Interestingly, the clamping does not always have to be one single event either.  A few of the ants clamped down on the leaf vein more than once. The authors of this paper spend time discussing fungi's direct effect on the mandible muscles of the ant.

Figure 3 Hughes et al., 2011

They show that the mandible muscles of the normal ant are fat and healthy (B), but the muscles of the infected ant are separated and reduced in size (C). Though this image is of an ant at the moment of biting, the authors suggests that the deterioration of the mandible muscle might be to prevent re-opening of the clamp. They do not speculate on how the clamp is initiated in the first place, or why it occurs at noon.

So please, fellow neuroscientists, somebody stain these brains! It's just too fascinating to resist exploration. What proteins are altered? What is the receptor composition of behaviorally-specific neurons? Are the dendrites differently shaped?
And who knows what sort of great advances might be hidden in these brain-controlling fungi. The magic of optogenetics comes from lowly light-sensitive bacteria, just think of the possibilities hidden in brain-controlling fungus. 

To be fair, some neuroscience has been done on parasitic brain control, but it is very limited.  In fact it is limited to basically one histological study about parasitic worms who infest crickets and cause them to drown themselves (the subject of a future blog post). However, suicide-crickets are no zombie-ants and the exact mechanisms of the interaction is not likely the same.

© TheCellularScale

Hughes DP, Andersen SB, Hywel-Jones NL, Himaman W, Billen J, & Boomsma JJ (2011). Behavioral mechanisms and morphological symptoms of zombie ants dying from fungal infection. BMC ecology, 11 (1) PMID: 21554670

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Hot Flashes after Menopause in Women | Causes

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What are hot flashes after menopause? You might know that hot flashes are one of common symptoms of menopause period in women. In the end of menopause period, they tend to be better and then usually gradually go away on their own.

You might also like to know more about hot flashes in men and post menopausal bleeding in women, before continuing!
But there are

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Neurons are like equations

The brain of the clock (I took this picture)

A computational model is a surrogate version of something usually made on a computer.  An example that most people are familiar with are the computational models used to predict the weather. If you know how low pressure and high pressure fronts interact, and you know where one is and how fast it is moving, you can program software to play the situation out in a simulation, predicting what will happen and how quickly. 

Computational neuroscience is more or less just like that and it can be used to investigate all levels of neuroscience. Here's a brief intro to three of the basic levels. There are other types of computational models in neuroscience, but these three make up most of them.

The Whole Brain
If you know how the thalamus, hippocampus, amygdala, and cortex all work together, you can simulate how inputs into one structure might influence the others. In this case each brain structure would basically be a 'black box' that received input and produced output based on known data.  To do this kind of simulation you wouldn't actually simulate the millions of neurons in each structure.

The Neural Network

(source)

On the next level down, you can make a computational model of a neural network inside a single brain structure. If you know the types of neurons in the amygdala and how they interact with each other, you can program those relationships in and test what might happen if one class of neurons fires too much or too little. You can test the effect removing one class of neurons has on the whole network and the output of that brain structure.  In this case you are simulating individual neurons, but you are probably not simulating the details of the neurons, such as their dendrites and their specific channel composition. In this kind of computational model, the neurons are the 'black box' which receive input and produce output based on pre-set equations.

The Cellular Scale
One level down from this is a computational model of an individual neuron. In this type of model, the neuron is simulated in detail, with its dendrites, soma, and sometimes the axon.  With this kind of model, you can test the effects of different dendrite shapes on the processing of the neuron. Usually the individual channels (such as calcium, potassium and sodium channels) in the neuron are programmed in and the electrical properties of the cells are calculated in detail. In this situation, the specific proteins and channels are the 'black boxes' computing ionic concentrations based on pre-set equations. A detailed tutorial on how to make a biophysically realistic model neuron can be found here.

a neuron can be simulated as a series of resistors and capacitors

Sidiropoulou et al., (2006) have an excellent review  of the neuroscience discoveries that have been made with this cellular level of computational modeling.

They start their paper highlighting the most interesting problem in cellular neuroscience.

"Understanding how the brain works remains one of the most exciting and intricate challenges of modern biology. Despite the wealth of information that has accumulated during the past years about the molecular and biophysical mechanisms that underlie neuronal activity, similar advances have yet to be made in understanding the rules that govern information processing and the relationship between the structure and function of a neuron." (Intro, Sidiropoulou et al., 2006) (red mine)

This paper directly argues against the idea that neurons are just 'on-off' switches, and illustrates the complex computational processes that occur in individual locations of the neuron. They cover computational studies analyzing the information processing that occurs in the dendrite, at the synapse, at the soma, and even in the axon. The details are to complicated to get into here, but the paper is free.

Finally, they end with a call to action for experimental and computational neuroscientists to work together to solve the really interesting problems in cellular neuroscience. 

"The following open questions could provide fertile ground for collaborations among molecular biologists, geneticists, physiologists, modellers and behaviourists for further explorations of the mysteries of the brain. Do specific behaviours require certain neuronal computational tasks? Which parts of the neural circuit or the neuron itself are responsible for these tasks? What are the underlying molecular mechanisms for the distinct operating modes of neuronal integration? Such holistic approaches should lend support to the growing idea reinforced by this review: that something smaller than the cell lies at the heart of neural computation." (Discussion, Sidiropoulou et al., 2006)

Just as computational models can predict weather patterns with some degree of accuracy, no model is perfect.  Similarly computational neuroscience is not going to lead to all the answers, but where it is particularly useful is in making very specific predictions about how certain aspects of a neuron or neural circuit might work. The insight gained from computational models can guide and focus experiments, making them more efficient. This saves time, money, energy, and animal lives.

© TheCellularScale


Sidiropoulou K, Pissadaki EK, & Poirazi P (2006). Inside the brain of a neuron. EMBO reports, 7 (9), 886-92 PMID: 16953202

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Hot Flashes in Men | Causes, Symptoms, and Treatment

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Did you know that there are also hot flashes in men? Hot flash is one of common menopause symptoms in women, but sometimes it also can occur in a man. It is also familiar known as a hot flush. It is a kind of momentary sensation of heat, and usually followed by a red, sweating, and flushed face. The exact cause of hot flush is still debatable, but many experts

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Signs and Symptoms of Emphysema | Treatment Options

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What are signs and symptoms of emphysema, and what are the currently treatments to treat this health condition? Well, emphysema is one of popular COPD (Chronic Obstructive Pulmonary Disease), which is usually pretty common in smoker. The disease can make patient be difficult to take a breath. Another popular type of COPD is chronic bronchitis which is

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