Eulogy: Professor Adam Sillito

Adam M Sillito was born on 31 March 1944 in Tamworth, Staffordshire. He survived Polio as a child, missing several formative school years as a result. Nonetheless he went on to be one of the few in his village to pass the 11-plus exam, going on to attend Burton-on-Trent Grammar School. He enrolled at Birmingham University Medical School but switched tack after his BSc year to pursue neurophysiology, culminating in a PhD with Andrzej Zbrozyna on the neural organisation of the pupillary light reflex pathway - one of the techniques that he would continue to use throughout his career.  

His post-doctoral work included a period with Gian Poggio at Johns Hopkins University Medical School in Baltimore, recording from primary visual cortex to characterise the receptive fields of neurones, another technique that would become central to his later career.  

Adam then returned to a faculty position in Birmingham. From this point, Adam displayed a profound gift for innovative and lateral thinking which, in conjunction with his adoption of pioneering techniques, led to a number of seminal findings in the fields of neuroscience and visual processing which did not at the time have any place in the dominant theories of how the visual cortex processed information. According to those theories, the properties that determined the visual responses of neurones in primary visual cortex (such as the receptive field) were entirely sculpted by the pattern of excitation received by a neurone. By combining the application of GABA antagonists with visual neurophysiology, Adam identified the critical role played by inhibition in sculpting the responses of neurones in the visual cortex. In some cells, bicuculline abolished or reduced orientation selectivity, direction selectivity or size tuning. Bicuculline turn some monocular cells into binocular cells, even those rendered monocular by monocular deprivation during development (Nature, 1981). These discoveries changed the way that information processing in cortical regions was viewed, interpreted and studied from then on. 

In 1982 Adam was appointed to the Chair of Physiology and Head of the Department of Physiology at Cardiff University, where he incorporated studies of the role that inhibition plays in tuning the responses of neurones in the visual thalamus – the lateral geniculate nucleus, or LGN – before they relay information to the neocortex, revealing that, surprisingly, many receive binocular input.  Additional investigations identified an excitatory amino acid, either glutamate or aspartate, as the transmitter released at optic nerve synapses in the LGN – a critical finding at a time when the field of excitatory amino acid transmission was still in its infancy. 

Adam was also ahead of the field when he began studying the effects of neuromodulators, such as serotonin and acetyl choline, on the visual pathway. This is an area of intense research now but at that time, most attention was focussed on analysing the responses of neurones in the visual pathway. Importantly, in both the LGN and visual cortex, these neuromodulators altered the intensity of the response, with minimal influence on their selectivity. 

In 1987 Adam was appointed to the Chair of Visual Science at the Institute of Ophthalmology (at that time not part of UCL), where he remained until his retirement in 2014. In this period, his research focus switched to the role of feedback pathways and their link to the influence of stimulus context, and on the interplay between feed forward and feedback systems in visual processing. He showed that this feedback could synchronise the activity of LGN neurones, that it is spatially arranged according to the preferred orientation of the cortical cells, that it establishes the size turning of LGN neurones and that it enhances response precision. In one of his last studies, he demonstrated a possible cognitive role of the corticogeniculate pathway where the LGN neurones were modulated according to whether a visual stimulus appeared in the “figure” or “background”, a cognitive feature that could not be gauged directly from retinal inputs as it depends on the task that is being performed at the time. Adam’s studies of “size tuning”, once thought to be due to inhibition from the deep cortical layers that was activated by stimuli presented outside the neurone’s receptive field, also changed the way this neuronal response property was interpreted. He then linked size tuning to a more general phenomenon: neurones in visual cortex are not only selective for stimulus size but are sensitive to orientation discontinuities. These results were later replicated by other laboratories and have had a major impact on the field.  

Adam became Director of the institute in 1991, while it was still a constituent part of the British Postgraduate Medical Federation (BPMF). He remained Director throughout a period of great change until 2006. He was asked by Michael Peckham, who was then the Director of the BPMF, to take on the task of regenerating the institute, which he did. Adam delivered a dramatic change which in turn helped sustain the continuation and expansion of vision research in the UK. 

Strategic thinking is often discussed in academic institutions but rarely is it so clearly articulated and implemented. Adam identified the core components he thought were necessary and systematically recruited high-calibre heads of departments to take on the challenge. From the very outset, Adam brought a clear set of values about what research the then Institute of Ophthalmology should be pursuing - from liberal “blue skies” programmes straddling neurology and ophthalmology, through enhancement of the understanding of the visual system, and the application of vision research to clinical innovation (in collaboration with colleagues at Moorfields Eye Hospital).  

He fought courageously for the highest standards of vision research, for the staff he recruited and for the institution he led. His ethos was to give almost a luxurious freedom to the institute’s researchers, untrammelled by management responsibilities (which he considered he should shoulder) and heavy teaching loads (to maintain the original purpose of the BPMF research institutes).

He sustained that fight through all sorts of difficulties. He was driven, not by egocentric ambition, but by the aspiration to enable the institute’s researchers to have an environment that would maximise their success. The results speak for themselves. In successive Research Assessment Exercises (now the Research Excellence Framework system), the institute went from a low ranking to the highest possible ranking.

Adam oversaw a sustained building programme with the move from Judd Street to a HEFCE-funded new-build on the current site at Bath Street, adjacent to Moorfields Eye Hospital. A further two phases of construction expanded laboratory capacity and included a building dedicated to “translational research”, funded largely by the Wellcome Trust, that ultimately provided an internal link to Moorfields Eye Hospital once it completed development of a paediatric eye centre. This was all achieved with a remarkably lean management team and largely pre-merger with UCL.  

The merger with UCL by Act of Parliament in 1995, was part of the implementation of the Tomlinson plan and brought an interesting set of challenges. As ever, the primacy of the institute’s research mission drove Adam’s approach. He was determined that there should be net benefit to the institute and ring-fenced funding was maintained for some years. The other BPMF institutes (such as Cancer, Child Health, Neurology, National Heart and Lung, Psychiatry) merged in succession with components of the University of London; but at the vanguard of the process, Adam set the bar for everyone else, often fighting battles on their behalf. He developed close working alliances and rivalries with other Directors who merged their institutes with UCL, notably Roland Levinsky at Child Health and Roger Lemon at Neurology. The rapid expansion of the UCL Institute of Ophthalmology was costly, not only in terms of effort and bricks and mortar, but also the under-writing of salaries for new hires, including numerous recruits from the US and elsewhere in the late 1990s and early 2000s which was hailed as “a reverse brain drain”. Adam’s persuasive logic and remarkable advocacy for eye research drew on close alliances with Fight for Sight, which at that stage was an institute charity, as well as colleagues at Moorfields including the Special Trustees (which eventually evolved into Moorfields Eye Charity).  

The partnership between the institute and Moorfields was critical to the success of both organisations. While aspects of mission for both differed and this generated tension, Adam's leadership through many challenges was critical to that success.
But without his tenacity, the enduring legacy and benefit of a world-class eye research institute would not be here for patients and generations of researchers.   

In addition, Adam served as Chair of the British Neuroscience Association and of the Electrophysiology Panel of the ARVO Program Committee (the US-based, international Association for Research in Vision and Ophthalmology), as an editorial Board member of many highly ranked scientific journals, and panel member for numerous funding bodies. He was also a founding member of the European Vision Institute, a Fellow of the Academy of Medical Sciences, and was honoured by an invitation to give the Presidential lecture at the Society for Neuroscience. 

He was a complex man with wide-ranging interests that most working with him never saw. He was a remarkably talented fine art photographer and a lover of classical music, which was often playing in his office at the end of the day. He was exceptionally well read and appreciative of nature, a keen walker and a regular visitor to the Chelsea Flower Show. He fought for his cause, but away from that he was compassionate to a degree that often surprised those who had not been touched by it before. He would work quietly behind the scenes supporting, and in many instances, fighting for staff. What he rarely, if ever, did was pander to egos. For himself he sought very little external validation; it was all about doing a good job and taking pride in it. He expected others to do the same. He provided the environment for people to do great things.

To those who worked closely with him in the laboratory, Adam was a source of inspiration, a mentor and a friend. 

Adam was immensely proud of his children, Francesca and Rowland, and of his wife, Sharon. For all of us at the institute now, the work that it took to build such significant and sustained success is history. But we should all note, in Adam’s passing, that it is almost inconceivable that any other individual could have achieved what he did. We should take a moment to acknowledge his endeavours, and the wide-reaching impact on people’s lives that has been possible because of him.