The origins of empathy?

Neuroscience is uniquely suited to investigate the biological underpinnings of the features and traits that make us human, including morality, complex emotions and higher-order cognition. However, as we continually learn more about our behaviour and its origins, one unavoidable and startling possibility is frequently made clear; many quintessentially 'human' characteristics may not be unique to ourselves. One recent example is empathy, the experience of feeling and understanding the state of another agent. Empathy may cause one to respond altruistically; for example, to relieve the suffering or discomfort of another in unfortunate circumstances. Biologists have found evidence of altruistic behaviour across the animal kingdom, presumably due to evolutionary pressures favouring those behaviours that promote species survival and not due to active cognition. However, recent studies have raised the startling possibility that the experience of empathy may be older (evolutionarily) than we think, that we may not be alone in our understanding of the states of others, and that our own understanding of the mental states of animals may be even more primitive than we hold them to be.

Some of the recent evidence suggesting that rodents may have the capacity for empathy comes from pain research here at McGill. Mice in the presence of another mouse in pain are more sensitive to pain themselves, but only if the mouse is familiar (a 'roommate', essentially), and not if the alternate mouse is unfamiliar. To put it another way, if a mouse sees a 'friend' in pain, their understanding (such as it is) of the familiar mouse's experience can affect their own perception of pain, as part of a phenomenon termed “emotional contagion” that is believed to be a precursor to empathic behaviour.

A brand-new study has potentially added some exciting insight to the issue of empathy precursors in animals. A team from the University of Chicago developed a novel method of examining empathy-related behaviour, in which one rat is held in a restraining device that can be released by another rat. After learning how to open the restraining cage, the freely-moving rat chose to free its restrained companion, but not empty restrainers or those containing a toy rat. Notably, female rats seemed to show more altruistic behaviour than males. In a subsequent experiment, this team showed that if a second restrainer containing chocolate was placed alongside a trapped rat, the free rat was equally likely to initially open the chocolate restrainer (and enjoy the chocolate alone) or to open the rat restrainer and share the chocolate, suggesting that freeing the trapped companion is as motivating to the rat as a tasty treat. The authors of this study suggest that these results indicate empathy on the part of the freely-moving rat, in that it is highly motivated to rescue a companion animal that it perceives as distressed, even when doing so costs the rat resources (in terms of sharing the chocolate).

However, is this really the case? In the scant time since this article was published, alternative explanations for the rats' behaviour have arisen. One possibility is that the freely-moving rat becomes distressed by the trapped rat (either by their vocal cries, a released scent, or another signal), and the free rat is opening the restrainer to extinguish these cues and reduce its own distress, as opposed to 'helping' the other rat. Supporting this hypothesis, the animals emitted more frequent 'alarm calls' when an animal was trapped, explaining why the free animals were more motivated to open only those cages containing a trapped companion. This would not be empathic behaviour, as the freely-moving rat is merely acting to reduce its own distress, rather than altruistically 'rescuing' the trapped rat. In addition, the evolutionary advantages of empathic experiences in rodents are unclear.

So the animal empathy issue, new as it is, remains somewhat murky. It seems that rodents possess the capacity for emotional contagion, a primitive precursor for actual empathy. The more recent research raises the possibility for empathy underlying altruistic behaviour in rats, although the evidence so far is insufficient to conclude that this is the case. However, these studies provide clear research directions for future studies investigating the origins of our own uniquely human condition. We already know that human infants display empathy- and morality-related behaviour, as well as a basic understanding of the mental experiences of others (“theory of mind”), as early as one to two years of age. Taken together, these avenues of research bring us closer to understanding the evolutionary and developmental origins of those traits that make us human, to whatever extent we can say they remain uniquely ours.

[Adapted from a post originally posted here.]

Brains need love too

I recently saw the new ad campaign from the institute where I work (the Douglas Institute), ‘Brains need love too’. Seeing as the campaign touches on brain awareness-related topics (including the brain's involvement in psychiatric illness), as well as today being Valentine’s Day, I thought it deserved sharing. The video is extremely open-ended, with the actual message of the campaign open to the interpretation of the viewer, at least until they visit the campaign’s web site. Here are the initial interpretations I took away from it:

- Psychiatric conditions are neurobiologically based, as implied with the opening shots of brains labelled by psychiatric diagnosis. I’m assuming the reasoning behind this is that it has traditionally been believed that stigma against mental illness could be ameliorated in the general public if it was more widely known that mental illness is fundamentally due to the structure and function of the brain itself, as opposed to any personal weakness of afflicted persons themselves. Although it’s noble to attempt to combat stigma by replacing popular misconceptions with fact, however, recent studies showing that stigma against mental illness persists even in the face of improvement of the public’s understanding of the origins of mental illness sadly cast doubt on the effectiveness of this particular strategy.

- People are more than their labels, another anti-stigma message. Outside of its labelled container, the brain reveals it’s capable of experiencing life just like anyone else.

- Take care of your brain, not meant as an anti-stigma message but more of a suggestion that all of our brains, well, ‘need love too’. Speaking of which, Brain Awareness Week is coming up in the near future, so get involved if you need some spring brain-awareness-lovin’. I’m assuming the figurative message here is to be aware that your brain needs care, if not by skateboarding and psychedelic brain-tossing, then by nutrition, exercise, mental stimulation, paying attention to your mental and emotional functioning, and not-sniffing-glue-or-opening-doors-with-your-head-or-something. They’re pretty vague on this one.

Overall, it’s charming and cute, and I like the bold approach of using real (albeit calf) brains up-close and bloody to show that something that may seem disquieting to us (in this case, a bloody brain) is capable of experiencing cognition, emotions and the world around us. Similarly, although mental illness can be disquieting to those with a stigma against it, psychiatric patients are fully capable of these same experiences. Also, regarding the brain images, I feel obligated to point out that we’re talking about something we’ve all got, which is processing this sentence right now within your own head, and while you don’t necessarily have to realize how cool that is, you should at least try to get over your squeamishness over the look of your own brain. It is, after all, what ‘you’ really look like.

It’s a bit difficult to determine the overarching message of the campaign from the 62-second ad alone; it does seem to be necessary to go to the campaign website for clarification, where there’s a slightly vague description urging people to take care of their brains and, more usefully, a list of diverse resources for information on the brain as well as psychiatric disorders and treatment. However, despite this it’s a well-produced and genuinely endearing ad. So go love your brain.

-Ian Mahar

(Adapted from a post previously appearing here)

"Memory, Aging and Alzheimer's: When forgetting too much becomes a problem"

Although our brains produce new neurons throughout our lives, their overall number peaks in our early twenties and then gradually declines as we age. Certain forms of memory tend to get worse with age as a consequence. Episodic memory in particular is often weaker in the elderly, making it more difficult to remember where a car was parked, or what time a friend was supposed to arrive for dinner. The good news is that other types of memory such as semantic (remembering general facts and concepts) and procedural (remembering how to do something) memories remain robust in most people well into their later years.

Unfortunately this is not the case for people suffering from an increasingly well-known disorder called Alzheimer’s disease, which severely impairs normal memory. Alzheimer’s is the most common example of a spectrum of disorders known as neurodegenerative diseases, all of which cause neurons to die off more rapidly than they would with normal aging. The prevalence of Alzheimer’s increases dramatically with age, rising from just 3% in those aged 65-74 to almost 50% among those 85 years and older.

Currently available treatments tend to focus on minimizing the symptoms of Alzheimer’s by compensating for the loss of neurons. Some of these therapies can be helpful, but scientists have not yet found a ‘cure’ for Alzheimer’s, i.e. a treatment that would actually slow or halt the neuronal loss. This is because it’s still not entirely clear why neurons die in Alzheimer’s, although thousands of laboratories across the world are bringing us closer to the answer every day. We can hope that several of the many promising therapeutic avenues currently under investigation by scientists in Montreal and elsewhere will one day provide an effective means of combating the disease for both present and future generations. (Andrew Greene, McGill University)

All are welcome to join us on Wednesday, February 23rd, at 7:00 pm at La Sala Rossa (4848 boul. St-Laurent, Montreal, QC, H2T 1R6) for an evening of questions and answers, as we discuss memory and aging with world-class experts Andrea Leblanc, Ph.D., Serge Gauthier, M.D., F.R.C.P.C., and Judes Poirier, Ph.D., C.Q. Refreshments will be provided. This is a free event! We hope to see you there!

for more information: http://sfn-montreal.ca/baw/cafe/

http://www.facebook.com/#!/event.php?eid=183243215043955

hosted by BAW Montreal as part of our 2011 Brain Awareness Week public events. 

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*** Our popular Science Cafés offer the public the opportunity to meet and discuss various topics in Neuroscience in an informal setting. These Cafés feature a Question & Answer with three to four guest panelists who are experts in their fields, snacks and entertainment. Our Cafés are always free thanks to our sponsors. ***

What rodents are telling us about human behavior and autism

A tales of two voles

Prairie voles are extremely social creatures, preferring to spend the majority of their time with other prairie voles. In contrast, the closely related montane voles are extremely asocial creatures, choosing a solitary lifestyle over one where they’d have to be tied down. Eerily, prairie voles and humans share many other social behaviors: after a male and female prairie vole decide to spend the night together, they fall madly in love (called pair-bonding), move into a shared nest and raise their children together (‘Till death do us part: 75% of prairie voles stay together until one partner dies). Like with humans, affairs are fairly common, jealousy is rampant and some males (>40%) just never settle down (known in the field as “wanderers”). Prairie voles are even known to enjoy an alcoholic drink every once in a while. With these similarities, it’s no wonder the prairie vole has been the model system of choice to study the physiological basis of social behavior, and why the montane vole has served as the perfect “asocial” control.

Researchers have focused much of their attention on the role of two neuropeptide hormones, oxytocin and vasopressin, in mediating these social behaviors. Oxytocin and vasopressin are well-known regulators of peripheral tissues involved in birth, lactation and water homeostasis. However, their receptors (the cell-surface molecules which bind to these hormones and transmit their signals to the inside of cells) are also found scattered throughout the brain. Turns out, these hormones are also released by prairie voles when they “spend the night”, suggesting that these hormones may induce the post-mating behaviors of prairie voles: partner preference, aggression towards intruders and parental care (characteristics of social monogamy… referred to as monogamy for the rest of the article). Indeed, researchers can induce partner preference and aggression in virgin male prairie voles by injecting them with vasopressin and can block these behaviors by blocking the vasopressin receptor during mating. The same can be done in female prairie voles, except with oxytocin and an oxytocin receptor blocker, reflecting gender-specific differences in how these hormones affect social behaviors. Only thing is, montane voles also release oxytocin and vasopressin following mating and giving them additional vasopressin fails to induce monogamy—what then results in the difference in post-mating behaviors seen between prairie and montane voles? Surprisingly, when researchers looked at the brains of montane and prairie voles, they found striking differences in the location of vasopressin and oxytocin receptors. Prairie voles had more receptors in the ventral pallidum and nucleus accumbens, areas associated with reward and reinforcement, whereas montane voles lacked receptors in these areas. Importantly, other monogamous species, such as marmosets and California mice, show a similar distribution of receptors to the prairie voles. These results suggest that monogamous species may perceive social attachments as pleasurable and rewarding, therefore reinforcing these behaviors, whereas these behaviors are not reinforced in non-monogamous species.

Of course, the goal of all these studies is to understand and possibly treat some human behaviors. Autism can be a particularly devastating neurodevelopmental disorder characterized by severe social deficits such as lack of eye contact, empathy and social attachment. It is therefore not surprising that researchers are looking to see whether oxytocin and vasopressin are dysregulated in autistic patients. Indeed, some cases of autism are associated with reduced levels of circulating oxytocin or complete deletion or mutations in the oxytocin or vasopressin receptor genes. Can administration of oxytocin or vasopressin help with the symptoms of autism? Surprisingly, administration of oxytocin to humans increases social behaviors such as eye contact, trust and empathy and reduces social anxiety. Initial trials with oxytocin and high-functioning autistics showed improvements in their ability to make eye contact and other social behaviors. Therefore, although a link between autism and the oxytocin or vasopressin systems is tenuous and much research remains to be done, research on voles may surprisingly hold the key to understanding human social and asocial behaviors.

For more information:
Oxytocin, vasopressin and autism (free full-text): http://rstb.royalsocietypublishing.org/content/361/1476/2187.long

Those binge-drinking voles:
http://www.oregonlive.com/health/index.ssf/2010/07/voles_a_party_animal_sheds_lig.html