Dr Justin Harris

A/Prof Justin Harris PhD (University of New South Wales)

Position: Associate Professor

Office: Rm 478, Griffith Taylor Building

Ph: +61 2 9351 2864
Fax: +61 2 9036 5223
Email: justinh
(Postfix email address with: @psych.usyd.edu.au)

Postal Address:
School of Psychology
Brennan MacCallum Building (A18)
The University of Sydney
NSW 2006
Australia

Research Interests

Publications

Research Interests:

My research is broadly concerned with the neural and behavioural mechanisms underlying learning, memory, and perception. These research programmes are run in close collaboration with Dr Ehsan Arabzadeh (HFSP postdoctoral fellow), Dr Evan Livesey (postdoctoral fellow), Thida Thein (PhD candidate), Nathan Holmes (PhD candidate), Saba Gharaei (research assistant), and Hannah Pincham (research assistant). They also form part of ongoing collaborations further affield with Fred Westbrook, Colin Clifford, Mathew Diamond, Carlo Miniussi, Adrienne Fairhall, and Bob Boakes.

Current issues in associative learning.

One major current interest concerns the nature of stimulus representation in Pavlovian conditioning. Learning about relations among events is crucial for the survival of any complex organism, allowing it to use the past to predict the future and adjust its behaviour accordingly. Pavlovian conditioning is an attempt to bring such relations into the laboratory in order to isolate those that produce learning, describe its contents, and specify its influences on behaviour. Most contemporary models of Pavlovian conditioning adopt the association as an explanatory construct and identify its formation with predictive error. But fundamental to the approach is an appropriate description of the stimulus representations that constitute the arguments of associations. My particular interest is whether these representations are more appropriately identified with the elemental features delivered by the sensory systems or with configural units that code for conjunctions of features.

Other areas of ongoing research include investigation of how animals use information about their physical context to regulate their responding in Pavlovian conditioning paradigms, and in particular how these relate to phenomena of extinction and latent inhibition. Also, we continue to investigate the nature of learned flavour preferences, and in particular their apparent resistance to extinction.

Tactile and visual perception and integration.

Measuring perceptual judgments about stimuli while manipulating their physical characteristics can unconver which aspects of the signal are relevant to perception and reveal the algorithms unerlying sensory processing. Our work addresses the nature of neural coding in the somatosensory system, and how this is affected by concurrent visual input. Specific research projects are directed at investigating the perceptual properties of simple tactile events (eg, vibrations and moving surfaces), and the relationship between conscious awareness of a stimulus and the sensory or behavioural response to that stimulus.

Publications: To request a reprint, please write to: justinhATpsych.usyd.edu.au

2008	Arabzadeh E., CLifford, C.W.G., & Harris, J.A. (2008).Vision merges with touch in a purely tactile discrimination. Psychological Science, in press. Harris, J.A., Livesey, E. J., Gharaei, S., & Westbrook, R. F. (2008). Negative patterning is easier than a biconditional discrimination. Journal of Experimental Psychology: Animal Behavior Processes, in press. Harris, J.A., Clifford, C.W.G., & Miniussi, C. (2008). The functional effect of transcranial magnetic stimulation: Signal suppression or neural noise generation? Journal of Cognitive Neuroscience, in press. Mitchell, C.J., Harris, J.A., Westbrook, R.F., & Griffiths, O. (2008). Changes in cue associability across training in human causal learning. Journal of Experimental Psychology: Animal Behavior Processes, in press. Harris, J.A., & Livesey, E. J. (2008). Comparing patterning and biconditional discriminations in humans. Journal of Experimental Psychology: Animal Behavior Processes, 34, 144-154. Thein, T., Westbrook, R. F., & Harris, J. A. (2008). How the associative strengths of stimuli combine in compound: Summation and overshadowing. Journal of Experimental Psychology: Animal Behavior Processes, 34, 155-166. Albertella, L., Harris, J. A., & Boakes, R. A. (2008). Acquired flavour preferences: Contextual control of adaptation-level effects. Quarterly Journal of Experimental Psychology, 67, 227-231. Livesey, E. J. , & Harris, J.A. (2008). What are flexible representations? Commentary on Melchers, Shanks and Lachnit. Behavioural Processes, 77, 437-439. Clifford, C.W.G., Arabzadeh, E., & Harris, J.A. (2008). Getting technical about awareness. Trends in Cognitive Sciences, 12, 54-58.
2007	Harris, J. A., Arabzadeh, E., Moore, C. A., & Clifford, C. W. G. (2007). Noninformative vision causes adaptive changes in tactile sensitivity. Journal of Neuroscience, 27, 7136-7140. Boakes, R. A., Albertella, L., & Harris, J. A. (2007). Expression of flavor preference depends on type of test and on recent drinking history. Journal of Experimental Psychology: Animal Behavior Processes, 33, 327-338.
2006	Harris, J. A. (2006). Elemental representations of stimuli in associative learning. Psychological Review, 113 (3), 584-605. Harris, J. A., Arabzadeh, E., Fairhall A. L., Benito, C., & Diamond, M. E. (2006). Factors affecting frequency discrimination of vibrotactile stimuli: Implication for cortical encoding. PLoS ONE, 1 (1), e100. doi:10.1371/journal.pone.0000100 Harris, J. A., Karlov, L., & Clifford, C. W. G. (2006). Localization of tactile stimuli depends on conscious detection. Journal of Neuroscience, 26, 948-952. Harris, J. A. (2006). Psychophysical investigations into cortical encoding of vibrotactile stimuli. In: R. Romo and M. E. Diamond (Eds). Percept, decision, action: bridging the gaps. Novartis Foundation: London, UK. (pp 238-245).
2005	Clifford, C. W. G. & Harris, J. A. (2005). Contextual modulation outside of awareness. Current Biology, 15, 574-578. Harris, J. A. & Thein, T. (2005). Interactions between conditioned and unconditioned flavor preferences. Journal of Experimental Psychology: Animal Behavior Processes, 31, 407-417.
2004	Harris, J. A., Shand, F. L., Carroll, L. Q., & Westbrook, R. F. (2004). Persistence of preference for a flavour presented in simultaneous compound with sucrose. Journal of Experimental Psychology: Animal Behavior Processes, 30, 177-189. Harris, J. A., Thein, T., & Clifford, C. W. G. (2004). Dissociating detection from localization of tactile stimuli. Journal of Neuroscience, 24, 3683-3693.
2003	Diamond, M. E., Petersen, R. S., Harris, J. A., & Panzeri, S. (2003). Investigations into the organization of information in sensory cortex. Journal of Physiology, Paris, 97, 529-536.
2002	Harris, J. A., Miniussi, C., Harris, I. M., & Diamond, M. E. (2002). Transient storage of a tactile memory trace in primary somatosensory cortex. Journal of Neuroscience, 22, 8720-8725. Harris, I. M., Harris, J. A., & Caine, D. (2002). Mental rotation deficits following damage to the right basal ganglia. Neuropsychology, 16, 524-537. Westbrook, R. F., Iordanova, M., McNally, G., Richardson, R., & Harris, J. A. (2002). Reinstatement of fear to an extinguished conditioned stimulus: Two roles for context. Journal of Experimental Psychology: Animal Behavior Processes, 28, 97-110. Diamond, M. E, Petersen, R.S., & Harris, J. A. (2002). Sensory learning and the brain's body map. In: R. J. Nelson (Ed.) The Somatosensory System: Deciphering the Brain's Body Image (pp 183-195). CRC Press: Boca Raton, Florida.
2001	Harris, J. A., Harris, I. M., & Diamond, M. E. (2001). The topography of tactile learning in humans. Journal of Neuroscience, 21,1056-1061. Harris, J. A., Petersen, R. S., & Diamond, M. E. (2001). The cortical distribution of sensory memories. Neuron, 30, 315-318. Harris, J. A., & Westbrook, R. F. (2001). Contextual control over the expression of fear in rats conditioned under a benzodiazepine. Psychopharmacology, 156, 92-97. Harris, I. M., Harris, J. A., & Caine, D. (2001). Object orientation agnosia: A failure to find the axis? Journal of Cognitive Neuroscience, 13, 800-812. Harris, J. A., Harris, I. M. & Diamond, M. E. (2001). The topography of tactile working memory. Journal of Neuroscience, 21, 8262-8269.
2000	Harris, J. A., Gorissen, M. C., Bailey, G. K., & Westbrook, R. F. (2000). Motivational state regulates the contents of odor-sucrose associations. Journal of Experimental Psychology: Animal Behavior Processes, 26, 15-30. Harris, J. A., & Diamond, M. E. (2000). Ipsilateral and contralateral transfer of tactile learning. NeuroReport, 11, 263-268. Westbrook, R. F., Jones, M. L., Bailey, G. K., & Harris, J. A., (2000). Contextual control over conditioned responding in a latent inhibition paradigm. Journal of Experimental Psychology: Animal Behavior Processes, 26, 157-173. Harris, J. A., Jones, M. L., Bailey, G. K., & Westbrook, R. F. (2000). Contextual control over conditioned responding in an extinction paradigm. Journal of Experimental Psychology: Animal Behavior Processes, 26, 174-185.
1999	Harris, J. A., & Westbrook, R. F. (1999). The benzodiazepine midazolam does not impair Pavlovian fear conditioning but regulates when and where that fear is expressed. Journal of Experimental Psychology: Animal Behavior Processes, 25, 236-246. Harris, J. A., Petersen R. S., & Diamond, M. E. (1999). Distribution of tactile learning and its neural basis. Proceedings of the National Academy of Sciences USA, 96, 7587-7591. Diamond, M. E., Petersen R. S., & Harris, J. A. (1999). Learning through maps: Functional significance of topographic organization in primary sensory cortex. Journal of Neurobiology, 41, 64-68.
1998	Harris, J. A. (1998). Using c-fos as a neural marker of pain. Brain Research Bulletin, 45, 1-8. Harris, J. A., & Westbrook, R. F. (1998). Benzodiazepine-induced amnesia in rats: Reinstatement of conditioned performance by noxious stimulation on test. Behavioral Neuroscience, 112, 183-192. Harris, J. A., & Westbrook, R. F. (1998). Retroactive revaluation of an odor-taste association. Animal Learning & Behavior, 26, 326-335. Harris, J. A., & Westbrook, R. F. (1998). Evidence that GABA transmission mediates context-specific extinction of learned fear. Psychopharmacology, 140, 105-115.
1997	Carrive, P., Leung, P., Harris, J., & Paxinos, G. (1997) Conditioned fear to context is associated with increased Fos expression in the caudal ventro-lateral region of the midbrain periaqueductal gray. Neuroscience, 78, 165-177.
1996	Harris, J. A., & Westbrook, R. F. (1996). Midazolam impairs the acquisition of conditioned analgesia if rats are tested with an acute but not a chronic noxious stimulus. Brain Research Bulletin, 39, 227-233. Harris, J. A. (1996). Descending antinociceptive mechanisms in the brainstem: Their role in the animal's defensive system. Journal of Physiology (Paris), 90, 15-25. Harris, J. A., Corsi, M., Quartaroli, M., Arban, R., & Bentivoglio, M. (1996). Upregulation of spinal glutamate receptors in chronic pain. Neuroscience, 74, 7-12. Harris, J. A., Guglielmotti, V., & Bentivoglio, M. (1996). Diencephalic asymmetries. Neuroscience and Biobehavioral Reviews, 20, 637-643.
1995	Harris, J. A., & Westbrook, R. F. (1995) Effects of benzodiazepine microinjection into the amygdala or periaqueductal gray upon the expression of conditioned fear and hypoalgesia in rats. Behavioral Neuroscience, 109, 295-304. Harris, J. A., Westbrook, R. F., Duffield, T. Q., & Bentivoglio, M. (1995). Fos expression in the spinal cord is suppressed in rats displaying conditioned hypoalgesia. Behavioral Neuroscience, 109, 320-328. Grassi-Zucconi, G., Harris, J. A., Mohammed, A. H., Ambrosini, M. V., Kristensson, K., Bentivoglio, M. (1995). Sleep fragmentation, and changes in locomotor activity and body temperature in trypanosome-infected rats. Brain Research Bulletin, 37, 123-129.
1994	Harris, J. A., & Westbrook, R. F. (1994). Effects of midazolam and naloxone in rats tested for sensitivity/reactivity to formalin pain in a familiar, novel or aversively conditioned environment. Psychopharmacology, 115, 65-72.
1993	Harris, J. A., McGregor, I. S., & Westbrook, R. F. (1993). Low and high doses of midazolam differentially affect hypoalgesia in rats conditioned to a heat stressor. Psychopharmacology, 111, 62-68.
1992	Westbrook, R. F., Harris, J. A., Good, A. J., & Paxinos, G. (1992). Effects of an infusion of morphine into the accumbens nucleus upon acquisition of hypoalgesic and fear responses in rats exposed to a heat stressor. Quarterly Journal of Experimental Psychology, 44B, 99-124.