Adam Sillito, emeritus professor of visual science at the Institute of Ophthalmology in London, who has died aged 79, described one of his recreations in Who’s Who as “dreaming of better things”. A lateral thinker who grasped the bigger picture, he carried out research into the mechanics of visual perception that yielded vital knowledge for future treatments. As director of the institute from 1991 until 2006, he transformed it from a backwater on the verge of closure to a world-class centre of excellence, partnering with Moorfields eye hospital and attracting top scientists from all over the world.
In the 1970s, Sillito was a lecturer at the University of Birmingham and exploring an aspect of the intricate process of visual perception. In order to “see”, neurons must relay information from the eyes to the visual cortex in the brain, where it is interpreted as images. At the time researchers were mostly interested in how neurotransmitters have an “excitatory” effect on neurons, causing them to fire and transmit information to the next cell.
But Sillito was curious to know if the opposite happens: do neurotransmitters inhibit neurons from firing? He undertook a series of experiments in the 70s which proved that is the case: some neurotransmitters do have an inhibitory effect.
It was a fundamental discovery. His colleague Javier Cudeiro said: “Adam demonstrated that the inhibitory component was a key part of vision as we know it. It represented a paradigm shift in the conception of how the visual system works, which has proven to be fundamental for the modern understanding of visual neuroscience.”
In 1982, Sillito became professor of physiology and head of department at Cardiff University. Both there and later in London, he explored a key brain area involved in vision, the lateral geniculate nucleus, showing it had a role in inhibition and is involved in different functions, including helping us sense whether something is the focus of an image or is in the background.
He researched how vision is influenced by what the brain expects to see. Some vision happens through “bottom up processing”, meaning information comes in from the eyes and the brain has no expectations about what it is seeing. However, in “top down processing”, expectations are set up for what it might see.
An example of this is homing in on passers-by with hair or clothes similar to those of a friend you are waiting for to arrive. This type of visual processing involves many parts of the brain and Sillito’s research contributed key observations that opened up new avenues of research.
In a Guardian article in 2003, Our Lying Eyes , Sillito explained how the art of Bridget Riley – which has disorientating optical effects – offers a window on how visual perception works and how what we “see” can be framed by the brain’s expectations.
In 1987 he was appointed professor of visual science at the Institute of Ophthalmology, with the task of trying to turn it round, as it was likely to close. The Research Assessment Exercise (now Research Excellence Framework), which assesses research in the UK’s higher education institutions, had given it the lowest possible score because it had no significant academic output.
A logical, strategic thinker, Sillito knew that if he could recruit good scientists and raise the academic profile of the institute, funding would follow, transforming its fortunes. He encouraged researchers to do “blue skies” thinking, released them from teaching or management duties, and provided attractive conditions, such as good salaries and well-resourced laboratories.
He oversaw the institute’s merger with University College London in 1995 and its move to bigger premises in Bath Street, adjacent to Moorfields eye hospital, with which it had a close partnership. Funding flowed in from the Wellcome Trust and Sillito persuaded the charity Fight for Sight, which had hitherto supported medical projects, to support pure research as well.
It was not all plain sailing: decision-makers at the university and Moorfields did not always agree with him, but Sillito was tenacious. The institute’s score from the Research Assessment Exercise rose steadily and by 2008 it was rated “internationally excellent”.
Not long before she retired in 2018, his colleague Susan Lightman attended a meeting where staff at the institute spoke about their careers. Like most of her British contemporaries, she said she had spent time in the US, as it led the way in visual research at the time. The last speaker, however, was a new senior fellow at the institute, who said: “Well, I did not have to go abroad to succeed.” It was testament to Sillito’s work at the institute that young academics were now able to do world-class research in the UK.
Sillito was born in Tamworth, Staffordshire, the son of Adam Sillito, a dairy farmer, and his wife, Jean (nee Onion), who was a secretary at the Milk Marketing Board and kept the family farm accounts. The couple also had two daughters, Margaret and Susan.
From an early age Adam was interested in cars and anything mechanical, as well as in biology, keeping various pets, including a rescued magpie and jackdaw. Aged six, he contracted polio and had to spend two years in hospital, seeing his family only from the other side of a glass screen. The disease left its mark on his right arm and meant he did not start school until he was eight. A voracious reader, he caught up quickly, passing the 11-plus exam to attend Burton-on-Trent grammar school. He studied medicine initially at Birmingham University but switched to neurophysiology.
After his PhD, Sillito studied in Baltimore at Johns Hopkins University in 1970-71. He had met the physiotherapist Sharon Pascoe in Birmingham, when she signed up for a class he taught. She came out to be with him in the US and they had what she described as a “hippy wedding” in 1971 and went on a road trip to the west coast and back to celebrate. Returning to the UK, they made their home in Birmingham, where Sillito lectured and carried out research at the university.
In 2014 he retired from UCL, aged 70. He was diagnosed with bladder cancer in 2016, but nevertheless continued to enjoy a rich cultural life in London, which included poetry, chess, music, and visits to Seville and Italy.
He is survived by Sharon, his son, Rowland, daughter, Francesca, and grandchildren, Amelia and Laurie, and by his sisters.
• Adam Murdin Sillito, visual neuroscientist, born 31 March 1944; died 17 December 2023
