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Professor Neil Harrison

Neil Harrison

Professor Neil Harrison (MB, BS, PhD, MRCP, MRCPsych)

Wellcome Clinician Scientist and Professor in Neuropsychiatry
T: +44 (0)1273 876657
Location: Room 208 Trafford Centre for Medical Research, University of Sussex, Brighton, BN1 9RY

DA: Christina Lee
T: +44 (0)1273 873833

Clinical Enquiries: Neurobehavioural Clinic, Sussex Partnership NHS Foundation Trust, East Brighton Community Mental Health Team, Brighton General Hospital, Brighton BN2 3EW
Tel: +44 (0)300 304 0096

Other roles: Research Lead for the Department of Neuroscience



Professor Neil Harrison is Research Lead for BSMS Neuroscience and Head of the Psychoimmunology Lab at Brighton and Sussex Medical School. Prior to moving to Sussex he completed a PhD in Neuroscience at the Wellcome Trust Centre for Neuroimaging (UCL), and psychiatry training at the Maudsley Hospital and National Hospital for Neurology, Queen Square. His research investigates how changes in bodily physiology particularly, infection/inflammation interact with the brain to modulate emotion, motivation and cognition and contribute to common mental illnesses such as depression, chronic fatigue and Alzheimer’s disease.

Key findings from his group include identification of a human pathway that rapidly communicates changes in peripheral inflammation to the brain. Activation of cortical components of which predict associated experience of fatigue.  His group has also demonstrated that inflammation impairs mood by changing the connection strengths of key components of the brain’s mood regulatory network and provided evidence that even mild inflammation can acutely impair human memory.

Recently, his group has also recently shown that small changes in bodily inflammation are even associated with subtle changes in brain microstructure. To paraphrase James from 1890 these findings continue to ‘make us realise more deeply than ever how much our mental life is knit up with our corporeal frame’.

Since 2005, his work has been funded through grants from the Wellcome Trust.



During his PhD, Professor Harrison pioneered the use of typhoid vaccination in conjunction with brain imaging as an experimental model of the mild systemic inflammation typically reported in depression. Using this approach he provided the first evidence for a human neurally mediated immune-brain communicatory pathway projecting to insula, a finding later replicated using fluorodeoxyglucose PET. He also provided some of the earliest evidence to suggest that inflammation-induced mood change recruits similar brain circuitry to that implicated in primary depressive disorder. This finding is highly cited and has made an important contribution to the evidence supporting a role for innate immune responses in depression aetiology.

During his current fellowship, Professor Harrison has expanded this work and demonstrated that systemic inflammation selectively impairs human spatial but not procedural memory (via actions on parahippocampal glucose metabolism) and shown that actions on ventral tegmental area (VTA) rather than hippocampus likely underlie impaired novelty processing. These findings are important as they suggest a potential mechanism for the observed epidemiologic link between inflammation and risk of age-related cognitive decline. By illustrating a role for the hippocampal-VTA loop they also provide insight into some of the paradoxical memory findings reported in mice.

Most recently Professor Harrison has applied computational modeling approaches to choice behaviour to show that inflammation-associated motivational reorientation is mediated via actions on ventral striatal and insula reward and punishment prediction error encoding.

In two recent studies Professor Harrison has identified quantitative magnetization transfer (qMT) MRI imaging as a promising clinical biomarker of the central effects of inflammation. This finding offers the opportunity of stratifying patients and monitoring response to immunotherapies in mental health and is being actively researched in depression.

More indirectly, these studies have contributed to an explosion of interest in the role of inflammation in mental illnesses including industry-funded trials of anti-IL-6 therapies in depression. 

Selected publications

Harrison N, Cooper E, Dowell N, Keramida G, Voon V, Critchley H et al. Quantitative Magnetization Transfer Imaging as a Biomarker for Effects of Systemic Inflammation on the Brain. Biological Psychiatry. 2015;78(1):49-57. 

Harrison N, Cercignani M, Voon V, Critchley H. Effects of Inflammation on Hippocampus and Substantia Nigra Responses to Novelty in Healthy Human Participants. Neuropsychopharmacology. 2014;40(4):831-838. 

Harrison N, Doeller C, Voon V, Burgess N, Critchley H. Peripheral Inflammation Acutely Impairs Human Spatial Memory via Actions on Medial Temporal Lobe Glucose Metabolism. Biological Psychiatry. 2014;76(7):585-593. 

Critchley H, Harrison N. Visceral Influences on Brain and Behavior. Neuron. 2013;77(4):624-638. 

Harrison N, Cooper E, Voon V, Miles K, Critchley H. Central autonomic network mediates cardiovascular responses to acute inflammation: Relevance to increased cardiovascular risk in depression?. Brain, Behavior, and Immunity. 2013;31:189-196. 

Harrison N, Gray M, Gianaros P, Critchley H. The Embodiment of Emotional Feelings in the Brain. Journal of Neuroscience. 2010;30(38):12878-12884. 

Harrison N, Brydon L, Walker C, Gray M, Steptoe A, Critchley H. Inflammation Causes Mood Changes Through Alterations in Subgenual Cingulate Activity and Mesolimbic Connectivity. Biological Psychiatry. 2009;66(5):407-414. 

Harrison N, Brydon L, Walker C, Gray M, Steptoe A, Dolan R et al. Neural Origins of Human Sickness in Interoceptive Responses to Inflammation. Biological Psychiatry. 2009;66(5):415-422. 

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