Ridley's research career started with an investigation into cortical mechanisms of
visual perception followed by the delineation of the cortical areas involved in somatosensory discrimination learning. Her early career involved work on the role of
dopamine in cognitive
perseveration and motor
stereotypy, but her interests then extended to the role of the
hippocampus in simple and conditional learning. Much of her research effort was directed towards developing treatments for
Alzheimer's disease,
Parkinson's disease and
Huntington's disease. She and her research collaborators demonstrated that
acetylcholine was crucial for various types of
memory formation and established that transplantation of neural tissue into the brain could restore memory and learning ability. She also maintained an interest in the genetics of neurodegenerative diseases. Ridley was involved in early work on
transmissible spongiform encephalopathy (subsequently known as prion disease), particularly in the recognition that individual cases of human prion disease could be sporadic, familial or acquired and that familial cases were associated with mutations in the prion protein gene. She demonstrated the transmissibility of
bovine spongiform encephalopathy (BSE) and
scrapie to primates and argued that the evidence for BSE and scrapie being acquired by maternal transmission was also compatible with genetic susceptibility to disease. In experiments using data extending over 25 years, she demonstrated that the
amyloid proteins found in Alzheimer's disease were self-assembling and experimentally transmissible, establishing a link in pathogenesis between prion diseases and the other neurodegenerative proteinopathies Ridley's current research lies in aspects of cognitive psychology to be found in late nineteenth and early twentieth century books for children, especially the works of J. M. Barrie. ==Personal life==