A severe shortage of brains is hampering potentially groundbreaking research into the causes and nature of autism. Although funding from the charity Autistica is in place for the research, it is extremely difficult to get people to donate their brains after death. And while many are happy to sign up to the national organ donation registry, the separate process of committing to brain donation has encountered resistance. The UK Brain Bank for Autism has appealed for brains for four years, but so far only 22 have been donated, slowing down the pace of research at a time when there is growing interest in a condition affecting as many as one in 100 people.

"It is a matter of regret that we can't do it faster," says Professor Margaret Esiri, director of the initiative. She is optimistic that a clearer understanding of what happens to the brains of people with autism will lead to a faster development of interventions that could improve the quality of life of those affected by the condition. "This is a very positive thing to do, to help future generations. Those families who have done it have appreciated the opportunity. It gave some meaning to the awful experience of losing someone they loved," Esiri says. "We also need as many people as possible who don't have autism to consider donating because we need control tissue. People don't realise that a normal brain can really be valuable for research."

Donations for research purposes are not included in the NHS organ donation programme, which exists solely to organise transplants to keep people alive, and the Oxford-based brain bank has struggled to inform people about the scheme. This is partly because of cultural taboos around death, and a reluctance of medical staff and carers to approach the topic. "It is not a very easy conversation to have because it involves looking towards a death of a child, for example, when all the efforts on the part of the medical profession are looking to the future of the child, not their death," says Esiri. "The brain is so much the essence of who someone is; the idea of giving away the person themselves is difficult."

While appeals for donations from people with dementia for another research project at the John Radcliffe hospital in Oxford have been productive, finding families willing to support donation for autism research has been problematic. "Caring for people with dementia is a tremendous strain, so relatives are desperate that there should be a way to make it easier," says Esiri. "Autism is not always seen as something that would ideally be eradicated, in the same way as other diseases."

There is also hostility from some autism organisations to any research that could lead towards an in utero test for autism, which might lead to abortions, or any talk of a cure. "There is resistance to brain research in autism from the neurodiversity movement – who see autism as something which should be valued and celebrated," says Brenda Nally, the organisation's outreach worker, who meets all prospective donors. A "cure autism now" agenda in the US has "created a lot of antipathy and has led people to assume that the purposes of this research are eradication or a cure for autism", she says. However, the aim of the brain bank is not to find a cure, but to improve understanding of the condition. "We may perhaps be able to offer amelioration of some aspects of autism, for example severe social anxiety," Esiri says.

The developing brain is altered in autism but scientists do not yet know why or how. DNA research on blood samples has found some variant genes in autistic patients, particularly those known to be important in the development of connections between brain nerve cells. Analysis of the brain would allow greater understanding of whether this has a structural or chemical effect. Eventually, if for example it was discovered that there was a shortage of some kind of growth factor that might enable nerve cells to develop, scientists might be able to find a molecule that would mimic its effect and give it in tablet form.

Nicholas Riall, a historian and archaeologist who has autism and has also been diagnosed with incurable cancer, has pledged his brain to the project. "I talked to my wife after the diagnosis about trying to find something positive to come out of it," he says. He isn't hoping for a cure but wants to help promote better understanding. "I would be fascinated to find out what triggers it," he says.

"What makes me think in ways that are radically different to other people? Why does my brain tick a different way to the norm? It would probably have been helpful to me to have had an earlier diagnosis of my autism," he says. His condition wasn't formally diagnosed until he was in his 50s, and the failure to recognise it in him as a child caused real unhappiness.

"I have a see-saw intelligence. I am hopeless at maths but very bright in arts subjects. It was the bane of my life at school. In the 50s and 60s, if you didn't perform well, they beat you; I would get beaten a lot because I couldn't do maths and science. They thought they could beat it into you. I cannot learn a piece of text; I simply cannot do it, so I couldn't learn poetry by heart. As a little autistic boy, it made school absolutely hell," he says.

Esiri is hopeful that once people know about the work of her team, more individuals with autism will join the registry, or their families will sign up on their behalf. She hopes their relatives may also want to donate their brains, as well as people with no family connection to the condition. "If we could get 20 to 30 brains a year, that would be fantastic. A lot more could be done," Esiri says. "There is a vast amount that needs to be learned."

• If you are interested in being a donor, contact the UK Brain Bank for Autism by visiting: brainbankforautism.org.uk