Mae'r Athro Halligan wedi ennill bri yn rhyngwladol am ei ymchwil, ac wedi bod yn rhan allweddol o nifer o ddatblygiadau arloesol gan gynnwys sefydlu Canolfan Delweddu Prifysgol Caerdydd er Ymchwil yr Ymennydd (CUBRIC), Canolfan Delweddu Tomograffeg Gollwng Positronau Cymru at ddibenion Ymchwil a Diagnostig (PETIC), Sefydliad Niwrowyddoniaeth Wybyddol Cymru (WICN), Cyfres o Ddarlithoedd Anrhydeddus Haydn Ellis a Sefydliadau Ymchwil Prifysgol Caerdydd.
Professor Halligan, who has secured international recognition for his research, has played a key role in a number of innovative developments including establishing the Cardiff University Brain Research Imaging Centre (CUBRIC), the Wales Research and Diagnostic Positron Emission Tomography Imaging Centre (PETIC), the Wales Institute of Cognitive Neuroscience (WICN), the Haydn Ellis Distinguished Lecture Series and Cardiff University Research Institutes.