• Psychology
  • Back

    Dr Stephen Sawiak

    University Position
    Research Associate


    I am a physicist working with MRI. My primary research interest has been in morphometry, with structural imaging, diffusion tensor imaging and spectroscopy. I am particularly focussed on preclinical applications.

    Key Publications


    Cortical glutamate and GABA are related to compulsive behaviour in individuals with obsessive compulsive disorder and healthy controls.

    Journal: Nat Commun
    E-pub date: 27 Jun 2023
    Authors: M Biria, P Banca, MP Healy, E Keser, SJ Sawiak, CT Rodgers, C Rua, AMFLP de Souza, AA Marzuki, A Sule, KD Ersche, TW Robbins

    Early-life stress biases responding to negative feedback and increases amygdala volume and vulnerability to later-life stress.

    Journal: Transl Psychiatry
    E-pub date: 7 Mar 2023
    Authors: EG Dutcher, L Lopez-Cruz, EAC Pama, M-E Lynall, ICR Bevers, JA Jones, S Khan, SJ Sawiak, AL Milton, MR Clatworthy, TW Robbins, ET Bullmore, JW Dalley

    Sex-dependent effects of early life stress on reinforcement learning and limbic cortico-striatal functional connectivity.

    Journal: Neurobiol Stress
    E-pub date: 1 Jan 2023
    Authors: K Zühlsdorff, L López-Cruz, EG Dutcher, JA Jones, C Pama, S Sawiak, S Khan, AL Milton, TW Robbins, ET Bullmore, JW Dalley

    Over-activation of primate subgenual cingulate cortex enhances the cardiovascular, behavioral and neural responses to threat.

    Journal: Nat Commun
    E-pub date: 26 Oct 2020
    Authors: L Alexander, CM Wood, PLR Gaskin, SJ Sawiak, TD Fryer, YT Hong, L McIver, HF Clarke, AC Roberts

    Impulsivity and compulsivity are differentially associated with automaticity and routine on the Creature of Habit Scale.

    Journal: Pers Individ Dif
    E-pub date: 1 Nov 2019
    Authors: KD Ersche, LHE Ward, T-V Lim, RJ Lumsden, SJ Sawiak, TW Robbins, J Stochl

    Insula serotonin 2A receptor binding and gene expression contribute to serotonin transporter polymorphism anxious phenotype in primates.

    Journal: Proc Natl Acad Sci U S A
    E-pub date: 16 Jul 2019
    Authors: AM Santangelo, SJ Sawiak, T Fryer, Y Hong, Y Shiba, HF Clarke, PJ Riss, V Ferrari, R Tait, J Suckling, FI Aigbirhio, AC Roberts

    Fractionating Blunted Reward Processing Characteristic of Anhedonia by Over-Activating Primate Subgenual Anterior Cingulate Cortex.

    Journal: Neuron
    E-pub date: 16 Jan 2019
    Authors: L Alexander, PLR Gaskin, SJ Sawiak, TD Fryer, YT Hong, GJ Cockcroft, HF Clarke, AC Roberts

    Converging Prefronto-Insula-Amygdala Pathways in Negative Emotion Regulation in Marmoset Monkeys.

    Journal: Biol Psychiatry
    E-pub date: 15 Dec 2017
    Authors: Y Shiba, L Oikonomidis, S Sawiak, TD Fryer, YT Hong, G Cockcroft, AM Santangelo, AC Roberts

    Brain hypoxia mapping in acute stroke: Back-to-back T2′ MR versus 18F-fluoromisonidazole PET in rodents.

    Journal: Int J Stroke
    E-pub date: 1 Oct 2017
    Authors: U Jensen-Kondering, R Manavaki, S Ejaz, SJ Sawiak, TA Carpenter, TD Fryer, FI Aigbirhio, DJ Williamson, J-C Baron

    Behavior of Supramolecular Assemblies of Radiometal-Filled and Fluorescent Carbon Nanocapsules In Vitro and In Vivo

    Journal: Chem
    E-pub date: 14 Sep 2017
    Authors: H Ge, PJ Riss, V Mirabello, DG Calatayud, SE Flower, RL Arrowsmith, TD Fryer, Y Hong, S Sawiak, RMJ Jacobs, SW Botchway, RM Tyrrell, TD James, JS Fossey, JR Dilworth, FI Aigbirhio, SI Pascu

    Effects of hyperoxia on 18F-fluoro-misonidazole brain uptake and tissue oxygen tension following middle cerebral artery occlusion in rodents: Pilot studies.

    Journal: PLoS One
    E-pub date: 1 Aug 2017
    Authors: TD Fryer, S Ejaz, U Jensen-Kondering, DJ Williamson, S Sitnikov, SJ Sawiak, FI Aigbirhio, YT Hong, J-C Baron

    Normobaric hyperoxia markedly reduces brain damage and sensorimotor deficits following brief focal ischaemia.

    Journal: Brain
    E-pub date: 1 Mar 2016
    Authors: S Ejaz, JV Emmrich, SL Sitnikov, YT Hong, SJ Sawiak, TD Fryer, FI Aigbirhio, DJ Williamson, J-C Baron

    Serotonergic, brain volume and attentional correlates of trait anxiety in primates.

    Journal: Neuropsychopharmacology
    E-pub date: 1 May 2015
    Authors: Y Mikheenko, Y Shiba, S Sawiak, K Braesicke, G Cockcroft, H Clarke, AC Roberts

    Dissociable rate-dependent effects of oral methylphenidate on impulsivity and D2/3 receptor availability in the striatum.

    Journal: J Neurosci
    E-pub date: 4 Mar 2015
    Authors: D Caprioli, B Jupp, YT Hong, SJ Sawiak, V Ferrari, L Wharton, DJ Williamson, C McNabb, D Berry, FI Aigbirhio, TW Robbins, TD Fryer, JW Dalley

    Orbitofrontal dopamine depletion upregulates caudate dopamine and alters behavior via changes in reinforcement sensitivity.

    Journal: J Neurosci
    E-pub date: 28 May 2014
    Authors: HF Clarke, RN Cardinal, R Rygula, YT Hong, TD Fryer, SJ Sawiak, V Ferrari, G Cockcroft, FI Aigbirhio, TW Robbins, AC Roberts

    Translating positron emission tomography studies in animals to stimulant addiction: promises and pitfalls.

    Journal: Current Opinion in Neurobiology
    E-pub date: 1 Aug 2013
    Authors: D Caprioli, TD Fryer, SJ Sawiak, FI Aigbirhio, JW Dalley

    Baseline-dependent effects of cocaine pre-exposure on impulsivity and D2/3 receptor availability in the rat striatum: possible relevance to the attention-deficit hyperactivity syndrome.

    Journal: Neuropsychopharmacology
    E-pub date: 1 Jul 2013
    Authors: D Caprioli, YT Hong, SJ Sawiak, V Ferrari, DJ Williamson, B Jupp, T Adrian Carpenter, FI Aigbirhio, BJ Everitt, TW Robbins, TD Fryer, JW Dalley

    A comparison of four PET tracers for brain hypoxia mapping in a rodent model of stroke.

    Journal: Nucl Med Biol
    E-pub date: 1 Apr 2013
    Authors: DJ Williamson, S Ejaz, S Sitnikov, TD Fryer, SJ Sawiak, P Burke, J-C Baron, FI Aigbirhio

    Characterizing infarction and selective neuronal loss following temporary focal cerebral ischemia in the rat: a multi-modality imaging study.

    Journal: Neurobiol Dis
    E-pub date: 1 Mar 2013
    Authors: S Ejaz, DJ Williamson, T Ahmed, S Sitnikov, YT Hong, SJ Sawiak, TD Fryer, FI Aigbirhio, J-C Baron

    Validation and quantification of [18F]altanserin binding in the rat brain using blood input and reference tissue modeling.

    Journal: J Cereb Blood Flow Metab
    E-pub date: 1 Dec 2011
    Authors: PJ Riss, YT Hong, D Williamson, D Caprioli, S Sitnikov, V Ferrari, SJ Sawiak, J-C Baron, JW Dalley, TD Fryer, FI Aigbirhio