The Social Brain

Dr Muireann Irish uncovers the part of the brain that underpins social cognitive deficits in semantic dementia, further unraveling mysteries behind the disease.

It may sound like the subject matter of a science fiction movie, but mind-reading is a process in which we regularly engage. On a daily basis, whenever we interact in social scenarios, we go beyond our own perspective to infer the thoughts, beliefs, and feelings of other people. This innate skill to appreciate perspectives distinct from our own allows us to function effectively within the social world. For example, we can instinctively understand how a colleague may feel when their latest publication is rejected, or we can intuitively place ourselves in a friend’s shoes when they experience a joyous event like the birth of a first child.

Theory of Mind

My latest study sheds light on the brain regions that need to be functional in order to support this ability to empathise with others. The study, published in the journal Brain, reveals that structures in the right hemisphere of the brain are essential to enable us to read the minds of others and to consider their beliefs and feelings. ‘theory of mind’ is the term used to refer to our uniquely human ability to make these inferences and is crucial for our successful functioning in the social world.

By understanding that other people think and feel in ways that are distinct from our own perspective, we can appreciate differences between individuals. This capacity to infer the mental state of others confers immense flexibility in our approach to various social scenarios. Without this ability, we would appear rigid, egocentric, and unfeeling towards others.

While appreciating the mental state of others may come relatively easy to us, the capacity for theory of mind relies upon a complex network of structures in the brain. Research on healthy individuals has revealed that when we successfully consider another person’s psychological perspective, regions in the frontal, temporal and parietal lobes of the brain activate. Such widespread brain activation reveals how complex this function truly is.

It follows that damage to any one of these brain regions will block the capacity to take another person’s perspective. Theory of mind abilities are disrupted across a number of clinical conditions such as traumatic brain injury, autism, and dementia.

Semantic dementia

In frontotemporal dementia, it is commonly reported that patients are unable to understand how their actions affect other people, or to consider that the reactions of others may differ from their own. However, up until recently, we knew relatively little regarding the capacity for theory of mind in the syndrome of semantic dementia. My recently published research reveals, for the first time, that individuals with semantic dementia experience severe difficulties in considering the mental states of others, and that such deficits are attributable to atrophy of structures in the right hemisphere of the brain.

Semantic dementia is a subtype of frontotemporal dementia, characterised by the progressive loss of general knowledge about the world. It is conceptualised as a language disorder whereby patients experience a profound loss of the meaning of words and concepts. The patient is unable to recall the names of objects, places, people, and experiences difficulties in correctly labeling popular musical tunes, or basic emotional expressions. While the predominant complaint of the patient is that of language disruption, carers of patients with semantic dementia report alterations in social functioning and interpersonal behaviour.

The Protocol

Images taken from Lough et al. (2006) Neuropsychologia,

Images taken from Lough et al. (2006) Neuropsychologia,

I used a new task to explore if patients with semantic dementia could infer the thoughts, beliefs, and feelings of the main characters in humorous cartoon scenarios. Patients were asked to describe why a selection of cartoon scenes were funny and their descriptions were analysed for language that reflected consideration of different mental states, for example “he thinks”, or “she feels”. In the cartoon scene to the left, a correct answer would be something like, “The gentleman thinks he is being held up. The lady is not aware that she is frightening the man.”

A patient with semantic dementia tended to respond as follows, “The woman is hitting the man in the back. He is putting his hands in the air”. These responses indicated that the ability to spontaneously consider the mental state of others was disrupted in semantic dementia. Importantly, I demonstrated that the failure to successfully appreciate the viewpoints of others was not a result of the language difficulties that are typically found in semantic dementia.

Using neuroimaging analysis of structural MRIs, I found that shrinkage of the right temporal lobe of the brain underpinned the theory of mind deficits in semantic dementia. This finding is surprising, as these patients are typified by damage to the left side of the brain. As the disease progresses however, pathology spreads from the left to the right hand side of the brain. The semantic dementia patient displays impairments across multiple domains, beginning with language disruption and gradually progressing to include social dysfunction.

Why is this important?

The findings of this study are unique as they reveal, for the first time, that degeneration of right temporal regions in the brain is associated with social dysfunction in semantic dementia. The right temporal lobes have been consistently implicated in studies of social functioning in healthy individuals.

Our study illuminates the complexity of social cognition and how we achieve sophisticated acts of social inference in our everyday lives. By incorporating brain mapping techniques with new experimental tasks, we can continue to unravel the mystery of mind-reading and build a coherent picture of how humans navigate within the social world.

Books For Brains

The NeuRA Foundation is looking to raise funds to support brain research via ‘Books for Brains’, which kicks off in October.

Sometimes an idea just ‘feels right’, and so it was when we conceived the idea for NeuRA’s Books for Brains event.

From the outset, it was clear to us that people who enjoy reading intuitively know that reading is good for their brains. And so the idea that people in book clubs would take a lively interest in the frontiers of knowledge about the brain, and how it works, was not a stretch.

Books for Brains is a NeuRA initiative calling on book clubs around Australia to put their heads together in the month of October and read a book with a focus on the brain and mind.

NeuRA’s Judy Dixon

The concept has received praise from a number of bestselling authors.

Norman Doidge, author of this year’s featured book, The Brain that Changes Itself, says:

“At this moment, while Australian neuroscience researchers are ‘punching well above their weight’ and making huge breakthroughs, so many Australians display an open-minded wonder about the brain. That’s why NeuRA’s initiative, Books for Brains, is such a wonderful idea. What could be more enlivening than digesting the meaning of new findings, which can so illuminate our lives, by getting together and discussing them within your book club – with the helpful, up-to-date comments on offer through Books for Brains from leading Australian researchers at NeuRA.

Ruby Wax, comedian and author of 2013’s bestseller, Sane New World, a story about what is it like to live with depression, says:

“The problem is in us; in our brains. The conflict is within ourselves. It’s those voices battering us and we project it out on the world. Inside our heads there is always war. I totally support NeuRA’s Books for Brains – unless we learn what’s in our heads, we will never resolve our own issues and the world’s.”

Peter FitzSimons, much-loved Australian author and social commentator, says:

 ”Books for Brains is a wonderful initiative to raise awareness about an issue growing in importance with every passing year. Once, while playing rugby in France, I was so badly eye-gouged I actually saw my own brain, and was satisfied it was big. But as time has gone on, I have become aware that none of us can take brain health for granted, and I fully support all efforts to make Australians aware of that very fact.”

Through NeuRA’s Books for Brains, we hope to encourage your book club to think about the importance of brain research. We want to encourage you to discuss one of our suggested books and hope that you find it stimulating, uplifting, funny or even moving.

To register and access this year’s book list, visit us here.

Beyond motor symptoms in MND

Motor neurone disease (MND), as discussed in previous posts, is not a disease of pure motor symptoms. MND can also affect one’s ability to perform complex judgments (e.g. financial decision-making) and leads to changes in behaviour (e.g. a person once very active and driven can become apathetic). These non-motor symptoms and behavioural changes often go unrecognised and underdiagnosed. In a recent study we investigated how these symptoms affect carers when compared to the more well-known motor symptoms of MND. Continue reading

Emotional control circuitry and schizophrenia

In addition to the ‘classic’ symptoms of psychosis which include delusions and hallucinations, people with schizophrenia often have problems with ‘executive functions’. This is a cognitive system that resides predominantly in the frontal lobes and regulates other cognitive processes. It is typically invoked when automatic processes need to be overruled to produce appropriate goal-directed behaviour. Another domain that is often affected in schizophrenia is emotional processing. Continue reading

Musical cognition: the demise of ‘left-brain right-brain’?

When looking at a human face we take it for granted that we can distinguish a happy face from a sad face and a scary face from a relaxed face. People with Alzheimer’s disease and other dementias often exhibit deficits in this area, and while this is interesting from a cognitive perspective, it has real world implications for the families of people with these diseases. Continue reading