Dr Ian Johnston

A18 - Brennan MacCallum Building
The University of Sydney


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Research interests

Research in my laboratories involves projects spanning three fascinating areas:

1. Psychoneuroimmunology (PNI)

  • PNI is the study of the interactions between the central nervous system (CNS) and the immune system. Early work has shown that the CNS exerts considerable control over immune function, and these controls have significant contributions to the ability of an individual to survive disease and recover from injury. However, more recently it has been demonstrated that the immune system has powerful effects on cognition, affect and behaviour, and not only serves to signal the CNS that injury or infection has occurred, but also triggers self-care behaviours and motivates recuperation and rest. Moreover, glial cells - the major non-neuronal cell type in the CNS - release inflammatory molecules that are important in the development of major neuropathologies and cognitive and affective disorders.

2. Human and non-human spatial cognition

  • "Everything important in psychology … can be investigated in essence through the continued experimental and theoretical analysis of the determinants of rat behavior at a choice-point in a maze." EC Tolman, President of the APA, 1937.
  • “Everything important in psychology … can be investigated in essence through the continued experimental and theoretical analysis of the determinants of any individual’s behavior at a choice-point in a maze.” IN Johnston, 2017.
  • Spatial cognition involves memory (encoding and retrieval of the experience of exploring, recalling items within the space, and remembering where they are, etc), choice (where do I go?), motivation (which place would I prefer to go?), planning (what is the best path to take), planned vs habitual behaviour, the structure of knowledge about space (how is space represented?), and the interesting question of how the brain does all of these functions. This work is done with laboratory animals or with people in virtual reality environments. The human work is done in collaboration with the cool toys at the Sydney Human Factors Research laboratory.

3. The effects of food and exercise on the brain and behaviour

  • Obesity is, quite simply, a massive problem. At a very simple level, one’s bodyweight is determined by the decision to eat and/or to exercise. Most research focuses on how factors such as physiological energy demand, appetite and hunger, habit, preferences, tastes, and the environment determine patterns of eating, activity, and exercising. An important element of this is the idea of executive control of behaviour – the cognitive abilities required to control behaviour, plan ahead for future needs, and to control emotions and desires. Much work has shown that obesity is linked with poor executive function, and increasing executive control helps people lose weight and keep their weight down.
  • However, recent work in my lab has shown this is a bidirectional effect. Eating and exercising affects executive function:
    • Diets high in sugars and fats reduces executive function in rats and people.
    • More recently, we have shown that exercise increases executive function.
  • This is a new focus for my laboratory, and we are actively exploring the neurobiology of the effect of diet or exercise on executive function, and its relationship to obesity and dieting.

Teaching and supervision

PSYC2X10 (Brain and Behaviour).

Current research students

Project title Research student
Investigation of dairy cattle vocal behaviour and its application for the Australian dairy industry Ali GREEN

Current projects

1. The effect of High Fat and High Sugar diets on executive control of behaviour.

  • So far we have demonstrated that, after randomising rats to groups that either receive standard rat chow or to those that have 2-hr daily access to high-fat, high-sugar (HFHS) drinks (e.g., sweetened condensed milk) or a western cafeteria diet (e.g., cakes, biscuits, pies, etc), the HFHS diet condition show increased impulsivity compared to the control diet rats.
  • I would like to see this work expanded in several directions:
    • How does food affect the neurobiological mechanisms of executive function? What are the major histological or genetic changes?
    • What is the important component of the HFHS diet that causes these effects? Sugars? Fats? High palatability?
    • How might we reverse or prevent this effect?
    • How does this relate to obesity and consumption of obesogenic foods?
    • Is there a role for gut flora and the gut-brain axis?
    • What effect does HFHS diets have on the brains of rats at critical developmental periods?
  • I would like to see this work explored in human populations too:
    • What aspect of peoples' diets are associated with executive function?
    • Does this explain variance in human body weights?
    • Does this explain variance in dieting success?

2. Spatial cognition.

  • I am keen to supervise projects using virtual reality in rat mazes and with human participants to explore how individuals learn to navigate through environments, how they learn where things are within their environments, how they decide where they would like to go, and how they plan routes to get from their current position to their goal locations.
    • I have an immersive maze designed to project virtual cues and environments around the maze. We can study how freely exploring animals learn to use the virtual cues to find food while foraging in the maze.
    • Similarly, we can design vitual environments for people to examine questions of spatial cognition. We can use all the toys at the Sydney Human Factors Research laboratories.
  • I am also keen to supervise projects for students who would like to develop tests using new technologies (e.g., smart phones, augmented reality, virtual reality, avatars, etc.) to detect the early signs of cognitive impairment or to conduct cognitive rehabilitation training for people with impairments. This work will be done in conjunction with patients and clients from various clinical neuropsychologists within our School.

3. Neurotoxicities associated with cancer and cancer chemotherapy.

  • Survival from all cancers has increased dramatically over the years.
  • However, many survivors report that they suffer from neurocognitive and neurological impairments as a consequence of their treatments. These are expressed as:
    • Cognitive impairments - problems with memory, attention, processing speed.
    • Chronic pain (neuropathies) - problems with painful sensations from cold or touch.
  • These neurotoxicities reduce the quality of life of survivors, and make it difficult for them to return to work or assume their pre-disease roles and function. In extreme cases, these symptoms become severe enough that patients must discontinue potentially life-saving treatments.
  • As yet, the causes of the these neurotoxicities are poorly understood and there are no effective treatments.
  • I would like to supervise projects for students interested in:
    • Describing the neuropathologies associated with cancer or cancer treatments
    • Testing potential treatments to prevent or reverse these symptoms. We are currently testing anti-inflammatory agents, anti-ageing agents, cannabinoids, and exercise.

Selected grants

2016

  • The neurobiology of neuropathic pain-induced anxiety; Johnston I; Faculty of Science/Seed Funding.

2015

  • Cognitive ageing in cancer populations: a cohort study extension in colorectal cancer survivors; McLachlan A, Dhillon H, Vardy J, Waite L, Lagopoulos J, Mackenzie L, Johnston I, Clarke S, Cysique L; DVC Research/SPARC Implementation - Cancer.
  • Ibudilast as a therapy for chemotherapy-induced neuropathic pain and cognitive impairments; Johnston I, Graeber M, Hutchinson M, Vardy J, Dhillon H; Cancer Council New South Wales/Research Project Grants.

2006

  • Central nervous system cytokines and morphine analgesia; Johnston I; Australian Research Council (ARC)/Discovery Projects (DP).

2005

  • Modulation of opioid reward and analgesia by the immune system; Johnston I; University of Sydney/Early Career Researcher.

Selected publications

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Book Chapters

  • Shavit, Y., Wolf, G., Johnston, I., Westbrook, R., Watkins, L., Yirmiya, R. (2007). Proinflammatory cytokines modulate neuropathic pain, opioid analgesia, and opioid tolerance. In Linda S. Sorkin, Linda R. Watkins (Eds.), Immune and Glial Regulation of Pain, (pp. 361-384). United States: IASP PRESS.
  • Watkins, L., Wieseler-Frank, J., Milligan, E., Johnston, I., Maier, S. (2006). Contribution of glia to pain processing in health and disease. In Fernando Cervero (Eds.), Handbook of clinical neurology: Pain, (pp. 309-324). US: Elsevier - Health Sciences Division. [More Information]

Journals

  • Matsos, A., Loomes, M., Zhou, I., Macmillan, E., Sabel, I., Rotziokos, E., Beckwith, W., Johnston, I. (2017). Chemotherapy-induced cognitive impairments: White matter pathologies. Cancer Treatment Reviews, 61, 6-14. [More Information]
  • Johnston, I., Tan, M., Cao, J., Matsos, A., Forrest, D., Si, E., Fardell, J., Hutchinson, M. (2017). Ibudilast reduces oxaliplatin-induced tactile allodynia and cognitive impairments in rats. Behavioural Brain Research, 334, 109-118. [More Information]
  • Green, A., Johnston, I., Clark, C. (2017). Invited review: The evolution of cattle bioacoustics and application for advanced dairy systems. Animal, In Press, 1-10. [More Information]
  • Fardell, J., Vardy, J., Monds, L., Johnston, I. (2015). The long-term impact of oxaliplatin chemotherapy on rodent cognition and peripheral neuropathy. Behavioural Brain Research, 291, 80-88. [More Information]
  • Mullan, B., Allom, V., Fayn, K., Johnston, I. (2014). Building habit strength: A pilot intervention designed to improve food-safety behavior. Food Research International, 66, 274-278. [More Information]
  • Johnston, I. (2014). Chemotherapy-induced cognitive deficits, white matter pathologies and cytokines. Brain, Behavior, and Immunity, 35, 21-22. [More Information]
  • Fardell, J., Zhang, J., De Souza, R., Vardy, J., Johnston, I., Allen, C., Henderson, J., Piquette-Miller, M. (2014). The impact of sustained and intermittent docetaxel chemotherapy regimens on cognition and neural morphology in healthy mice. Psychopharmacology, 231(5), 841-852. [More Information]
  • Fardell, J., Vardy, J., Johnston, I. (2013). The short and long term effects of docetaxel chemotherapy on rodent object recognition and spatial reference memory. Life Sciences, 93(17), 596-604. [More Information]
  • Fardell, J., Vardy, J., Shah, J., Johnston, I. (2012). Cognitive impairments caused by oxaliplatin and 5-fluorouracil chemotherapy are ameliorated by physical activity. Psychopharmacology, 220(1), 183-193. [More Information]
  • Johnston, I., Maier, S., Rudy, J., Watkins, L. (2012). Post-conditioning experience with acute or chronic inflammatory pain reduces contextual fear conditioning in the rat. Behavioural Brain Research, 226(2), 361-368. [More Information]
  • Sharpe, M., Fardell, J., Vardy, J., Johnston, I. (2012). The chemotherapy agent oxaliplatin impairs the renewal of fear to an extinguished conditioned stimulus in rats. Behavioural Brain Research, 227(1), 295-299. [More Information]
  • Fardell, J., Vardy, J., Johnston, I., Winocur, G. (2011). Chemotherapy and Cognitive Impairment: Treatment Options. Clinical Pharmacology & Therapeutics, 90(3), 366-376. [More Information]
  • Fardell, J., Vardy, J., Logge, W., Johnston, I. (2010). Single high dose treatment with methotrexate causes long-lasting cognitive dysfunction in laboratory rodents. Pharmacology, Biochemistry and Behavior, 97(2), 333-339. [More Information]
  • Watkins, L., Hutchinson, M., Johnston, I., Maier, S. (2005). Glia: novel counter-regulators of opioid analgesia. Trends in Neurosciences, 28(12), 661-669. [More Information]
  • Johnston, I., Westbrook, R. (2005). Inhibition of morphine analgesia by LPS: role of opioid and NMDA receptors and spinal glia. Behavioural Brain Research, 156(1), 75-83. [More Information]
  • Johnston, I., Milligan, E., Wieseler-Frank, J., Frank, M., Zapata, V., Campisi, J., Langer, S., Martin, D., Green, P., Fleshner, M., et al (2004). A Role For Proinflammatory Cytokines And Fractalkine In Analgesia, Tolerance, And Subsequent Pain Facilitation Induced By Chronic Intrathecal Morphine. The Journal of Neuroscience, 24(33), 7353-7365. [More Information]
  • Johnston, I., Westbrook, R. (2004). Inhibition of morphine analgesia by lithium: Role of peripheral and central opioid receptors. Behavioural Brain Research, 151(1-2), 151-158. [More Information]
  • Johnston, I., Westbrook, R. (2003). Acute and conditioned illness reduces morphine analgesia. Behavioural Brain Research, 142(1-2), 89-97. [More Information]

2017

  • Matsos, A., Loomes, M., Zhou, I., Macmillan, E., Sabel, I., Rotziokos, E., Beckwith, W., Johnston, I. (2017). Chemotherapy-induced cognitive impairments: White matter pathologies. Cancer Treatment Reviews, 61, 6-14. [More Information]
  • Johnston, I., Tan, M., Cao, J., Matsos, A., Forrest, D., Si, E., Fardell, J., Hutchinson, M. (2017). Ibudilast reduces oxaliplatin-induced tactile allodynia and cognitive impairments in rats. Behavioural Brain Research, 334, 109-118. [More Information]
  • Green, A., Johnston, I., Clark, C. (2017). Invited review: The evolution of cattle bioacoustics and application for advanced dairy systems. Animal, In Press, 1-10. [More Information]

2015

  • Fardell, J., Vardy, J., Monds, L., Johnston, I. (2015). The long-term impact of oxaliplatin chemotherapy on rodent cognition and peripheral neuropathy. Behavioural Brain Research, 291, 80-88. [More Information]

2014

  • Mullan, B., Allom, V., Fayn, K., Johnston, I. (2014). Building habit strength: A pilot intervention designed to improve food-safety behavior. Food Research International, 66, 274-278. [More Information]
  • Johnston, I. (2014). Chemotherapy-induced cognitive deficits, white matter pathologies and cytokines. Brain, Behavior, and Immunity, 35, 21-22. [More Information]
  • Fardell, J., Zhang, J., De Souza, R., Vardy, J., Johnston, I., Allen, C., Henderson, J., Piquette-Miller, M. (2014). The impact of sustained and intermittent docetaxel chemotherapy regimens on cognition and neural morphology in healthy mice. Psychopharmacology, 231(5), 841-852. [More Information]

2013

  • Fardell, J., Vardy, J., Johnston, I. (2013). The short and long term effects of docetaxel chemotherapy on rodent object recognition and spatial reference memory. Life Sciences, 93(17), 596-604. [More Information]

2012

  • Fardell, J., Vardy, J., Shah, J., Johnston, I. (2012). Cognitive impairments caused by oxaliplatin and 5-fluorouracil chemotherapy are ameliorated by physical activity. Psychopharmacology, 220(1), 183-193. [More Information]
  • Johnston, I., Maier, S., Rudy, J., Watkins, L. (2012). Post-conditioning experience with acute or chronic inflammatory pain reduces contextual fear conditioning in the rat. Behavioural Brain Research, 226(2), 361-368. [More Information]
  • Sharpe, M., Fardell, J., Vardy, J., Johnston, I. (2012). The chemotherapy agent oxaliplatin impairs the renewal of fear to an extinguished conditioned stimulus in rats. Behavioural Brain Research, 227(1), 295-299. [More Information]

2011

  • Fardell, J., Vardy, J., Johnston, I., Winocur, G. (2011). Chemotherapy and Cognitive Impairment: Treatment Options. Clinical Pharmacology & Therapeutics, 90(3), 366-376. [More Information]

2010

  • Fardell, J., Vardy, J., Logge, W., Johnston, I. (2010). Single high dose treatment with methotrexate causes long-lasting cognitive dysfunction in laboratory rodents. Pharmacology, Biochemistry and Behavior, 97(2), 333-339. [More Information]

2007

  • Shavit, Y., Wolf, G., Johnston, I., Westbrook, R., Watkins, L., Yirmiya, R. (2007). Proinflammatory cytokines modulate neuropathic pain, opioid analgesia, and opioid tolerance. In Linda S. Sorkin, Linda R. Watkins (Eds.), Immune and Glial Regulation of Pain, (pp. 361-384). United States: IASP PRESS.

2006

  • Watkins, L., Wieseler-Frank, J., Milligan, E., Johnston, I., Maier, S. (2006). Contribution of glia to pain processing in health and disease. In Fernando Cervero (Eds.), Handbook of clinical neurology: Pain, (pp. 309-324). US: Elsevier - Health Sciences Division. [More Information]

2005

  • Watkins, L., Hutchinson, M., Johnston, I., Maier, S. (2005). Glia: novel counter-regulators of opioid analgesia. Trends in Neurosciences, 28(12), 661-669. [More Information]
  • Johnston, I., Westbrook, R. (2005). Inhibition of morphine analgesia by LPS: role of opioid and NMDA receptors and spinal glia. Behavioural Brain Research, 156(1), 75-83. [More Information]

2004

  • Johnston, I., Milligan, E., Wieseler-Frank, J., Frank, M., Zapata, V., Campisi, J., Langer, S., Martin, D., Green, P., Fleshner, M., et al (2004). A Role For Proinflammatory Cytokines And Fractalkine In Analgesia, Tolerance, And Subsequent Pain Facilitation Induced By Chronic Intrathecal Morphine. The Journal of Neuroscience, 24(33), 7353-7365. [More Information]
  • Johnston, I., Westbrook, R. (2004). Inhibition of morphine analgesia by lithium: Role of peripheral and central opioid receptors. Behavioural Brain Research, 151(1-2), 151-158. [More Information]

2003

  • Johnston, I., Westbrook, R. (2003). Acute and conditioned illness reduces morphine analgesia. Behavioural Brain Research, 142(1-2), 89-97. [More Information]

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