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.

A blood test for dementia

Lauren Bartley is part of a team developing a blood test to detect dementia.

A blood test can reveal many things about your physical health, such as your blood glucose levels or an iron deficiency. But what if a simple blood test could reveal what’s happening inside your brain?

Blood 1 As the Biomarker Study Coordinator, I see each participant involved in frontotemporal dementia and Alzheimer’s disease research at NeuRA and take a sample of their blood for analysis.

At the moment, if your doctor suspects you have dementia, you are likely to undergo neuroimaging to look for changes to your brain structure and shape, as well as cognitive and behavioural assessments looking for changes in the way you think, act and process information. When people only have mild changes, it can be difficult to accurately predict the underlying disease process, which can be frustrating for the affected person and their families.

Developing a blood test

At NeuRA, we are currently investigating the concept of a blood test for dementia, with the hope that one day clinicians will be able to easily and quickly discriminate between frontotemporal dementia and Alzheimer’s disease, the two most common forms of younger onset dementia.

Our hope is that this test could further reveal if any medications or therapies might be effective in reducing symptoms and halting the progression of illness. This is important because a medicine that benefits someone with Alzheimer’s disease is unlikely to be effective for someone suffering from frontotemporal dementia.

Our blood test will screen for particular proteins in the blood associated with dementia: Beta Amyloid, Tau, TDP-43 and FUS. We know these proteins are responsible for causing the brain changes in both Alzheimer’s disease and frontotemporal dementia by having performed previous pathological studies on the brain tissue that has been generously donated by former research participants both in Australia and around the world.

These proteins are in everyone’s brains as they age and they carry out important functions in supporting the brain cells. But in some people, these proteins start aggregating in a harmful way that can kill the brain cells and cause the symptoms of dementia.

Our prediction is that a person who has pathological levels of protein massing in their brain will also have increased concentrations in their blood. It’s important for our study to screen the blood of a significant number of older healthy males and females to act as a comparison and help us understand what the respective protein concentrations are in people with no presentation of dementia symptoms.

The people attending the Frontier research clinic at NeuRA to volunteer for frontotemporal dementia research are generally aged between 50 and 75 when their symptoms begin, so we have a wide range of ages to match for. Often the supporting partners of our participants act as controls in the study, and are happy to be offered the opportunity to contribute to our research.

An update on our progress

Our study is a little more than half way through and so far I have collected blood samples from over 500 dementia-affected participants and controls. It’s important to obtain bloods from people with a variety of symptoms so that we can best correlate these symptoms to a protein profile.

I am also collecting further samples from participants at different in their illness to see if there are changes to this profile as the condition progresses.

The only way to quantify our study and determine the accuracy of our results will be to confirm the pathological protein at the end of the participant’s life through our brain donor program (see my previous blog post). In this way, we can ensure our results are meaningful.

The blood samples that I have collected are now in the very early stages of being analysed by the biomarker team, and over the next 18 months we will learn more about the feasibility of the blood test for dementia in everyday community healthcare. We want to be very certain of the accuracy of the test before its release.

Concerned about your memory?

In the meantime, anyone who has concerns about their memory, or who has had changes in their speech or ability to understand language should discuss them with their GP. Sometimes it’s easier for a loved one to recognise these symptoms, along with other clues like changes in personality or behaviour that might be more than just a ‘mid-life crisis’ or the general process of ageing.

‘Turning down’ voices and ‘turning up’ thinking in schizophrenia

We are calling for volunteers to take part in a new clinical trial that may help people with schizophrenia.

Many people with schizophrenia have residual symptoms in spite of treatment with antipsychotic medication. Auditory hallucinations (‘hearing voices’) are a symptom that is treatment-resistant in 25 to 30% of patients, and cause distress. Continue reading

Busy bee visits NeuRA

Australia’s brainiest teen shows off her trophy

NeuRA was lucky enough to host one of Australia’s brainiest teenagers, Uma Jha, when she visited last week for a work experience placement.

At just 14, the Perth native beat 3000 hopefuls to become the champion of the 2009 Australian ‘Brain Bee’; a neuroscience competition. As the sole representative of Australia, Uma continued to the international Brain Bee championships in San Diego and came head-to-head with students and high-school graduates as old as 18 from seven different countries.

“It was pretty incredible to be representing Australia. It was just good to be there,” she says. Continue reading