Deciphering consciousness

In the new and rapidly expanding field of the science of consciousness, the Sackler Centre for Consciousness Science is  fulfilling its remit to bring together an interdisciplinary group of researchers from basic and clinical science and to develop an integrated approach to collaborative and cutting-edge research.

Anil Seth

Sackler Centre for Conciousness Science

The study of conscious experience has transformed in recent years from something that lay mainly within the realms of philosophy and religion into a rigorous scientific discipline encompassing a multitude of disciplines including neuroscience, cognitive science, psychiatry, psychology, computer science and mathematics.

The Sackler Centre, founded in 2010 with a generous donation from the Dr Mortimer and Theresa Sackler Foundation, was set up to provide a fertile and collaborative environment fostering an interdisciplinary approach to the science of consciousness, and to initiate research programmes that involved cross-over between basic and clinical research.

Three years on, the Sackler Centre, co-directed by Professors Anil Seth and Hugo Critchley, has produced over 130 prominent academic publications in peer-reviewed journals, and has implemented successful outreach programmes targeting both the academic community and the wider public.

Research at the Sackler Centre

One theme driving research at the Sackler Centre stems from the idea that the brain has no direct access to the world and so must infer its properties from the steady stream of sensory signals that it receives and the actions that it generates.

An important part of the world is the body, and evidence suggests that the experienced body is also the result of the brain making its best guess based on sensory data.

To study this, Professors Seth and Critchley have developed a framework called 'interoceptive predictive coding'; a theoretical idea that utilises sophisticated mathematical tools and insight into the neurophysiology of cognition and emotion – where 'interoception' means the sense of the internal state of the body. This concept informs and motivates several research projects at the Sackler Centre.

The brain and conscious sense

Three strands of this research are starting to shed new light on how our conscious sense of being an embodied self is generated by the brain.

The first – led by Professor Jamie Ward with research fellow Henning Holle – involved the study of 'contagious itch', a phenomenon where the sight of someone scratching can induce feelings of itchiness in another.

This study demonstrated a strong correlation between activity in particular brain regions known to be involved in interoception and the degree of perceived itchiness.

Recently published in the prestigious Proceedings of the National Academy of Sciences USA and picked up by a range of international media, this work may have clinical implications for debilitating itching conditions where there is no obvious underlying dermatological cause.

Conscious experience and the heartbeat

Two other research projects have explored the relationship between conscious experience and the timing of the heartbeat.

One, by postdoctoral fellow Dr Keisuke Suzuki, involved an adaptation of the famous 'rubber hand illusion' – where the brain is fooled into experiencing a fake hand as part of the person's body.

Using an elaborate 'augmented reality' setup, including an online 3D computer model of a person's actual hand, the timing of their heartbeat was used to visually alter the appearance of the hand.

Interestingly, the timing of the heartbeat subtly affected how and whether the virtual hand was experienced as part of the person's body.

Work along similar lines but with a more clinical focus, by Dr Sarah Garfinkel and Professor Critchley, showed that presenting visual stimuli at specific points during the heartbeat cycle determined whether the brain was more or less likely to notice them, ie whether or not they enter conscious awareness.

Crucially, many of these effects seem to be specific to stimuli associated with negative emotions like fear. Again, such work has potential clinical implications, for example in conditions like anxiety. Professor Critchley recently received a highly sought after European Research Council Advanced Investigator Award, worth over £1.4 million over four years, to develop new projects investigating clinical conditions using this type of approach.

Association for the Scientific Study of Consciousness

In 2012, the Sackler Centre hosted the 16th annual meeting of the Association for the Scientific Study of Consciousness (ASSC16), by far the most prestigious conference in the field.

The meeting was the largest yet, with over 500 attendees representing over 30 countries. It was widely regarded as the best in its 16-year series and provided an excellent opportunity to showcase the achievements of the Sackler Centre.

The ASSC16 was held in the heart of the city, at the Brighton Dome and Corn Exchange, and included a unique 'consciousness expo'.

This one-day expo, which relied on the dedicated help of over 40 student volunteers, was open to the general public, attracted over 1,800 people, and included talk programmes and a variety of consciousness experiments. Its outstanding success is a testament to the engagement of the general public in this research.

Looking to the future, the Centre's emphasis remains on combining basic science approaches with clinical applications.

Thanks to the Sackler Foundation, the Centre has purchased new cutting-edge equipment that allows simultaneous electroencephalography (EEG: measuring subtle changes in the brain's electrical activity) and transcranial magnetic stimulation (TMS: a technique that applies magnetic pulses in a controlled and harmless way to alter brain activity).

Investing in this equipment opens up a number of innovative experimental possibilities that rely on the precise stimulation of the brain while simultaneously recording its electrical responses.

It is a unique opportunity to test theoretical research experimentally, and in the end to ask how much of our conscious world is determined by what the brain expects and what happens when those expectations are violated.

Chris's perspective

Acer Chang who is an Associate Tutor in Informatics said: "I'm working on elucidating the relationship between conscious awareness and the process of predictive coding.

"Predictive coding is a growing research area on information processing in neuroscience. According to the concept of predictive coding, brains infer the external "causes" that give rise to the sensory input we receive. If brains can model the external causes well, we can make good predictions of the external events. This strategy lets us respond to outside events more quickly and decrease the information-processing load by passing on only "prediction errors" rather than the full sensory scene at any time.

"Recent physiological evidence suggests that some perceptual systems may rely on the predictive coding mechanism. This leads to a key question: how does information processed by predictive coding become conscious? Addressing this question, we manipulate prediction/expectation to see the changes of our conscious awareness of external events.

"Recently, my main work has been examining how cross-modal perceptual expectation influences conscious awareness. More specifically, if our brains receive available auditory information to predict future visual events, would those predicted events become conscious more quickly? In the near future, I hope to use computational modelling and neuroimaging techniques to clarify the role of predictive coding in conscious processing."