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A/Prof Justin Harris PhD (University of New South Wales) |
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Position:
Associate Professor Office: Rm 478, Griffith Taylor Building Ph:
+61 2 9351 2864 Postal
Address: |
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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 postdoctoral fellows Dr Evan Livesey and Dr Arman Abrahamyan, as well as current and recently completed PhD students Nathan Holmes and Thida Thein. They also form part of ongoing collaborations further affield with Dr Ehsan Arabzadeh, Fred Westbrook, Colin Clifford, Mathew Diamond, Carlo Miniussi, Irina Harris, 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: where available, PDFs can be downloaded
by clicking the relevant link.
2009 (and in press) |
Dwyer, D. M., Pincham, H. L., Thein, T., & Harris, J. A. (2009). A
learned preference based on orally consumed sucrose persisted despite
the extinction of conditioned palatability changes. Learning & Behavior. in press. Holmes, N., & Harris, J. A. (2009). The loss of latent
inhibition across compound conditioning. Journal
of Experimental
Psychology:
Animal Behavior Processes,
in press. Livesey, E. J., Harris, I. M., & Harris, J. A. (2009).
Attentional changes during implicit learning: Signal validity protects
a target stimulus from the attentional blink. Journal
of Experimental
Psychology: Learning, Memory, & Cognition, 35, 408-422. PDF Hart, G., Harris, J. A., Westbrook, R. F. (2009). Systemic
or
intra-amygdala injection of a benzodiazepine (midazolam) impairs
extinction but
spares re-extinction of conditioned fear responses. Learning & Memory, 16,
53-61. PDF Harris, J. A., Gharaei, S., & Moore, C. A. (2009). Representations of single and compound stimuli in negative and positive patterning. Learning & Behavior, 37, 230-245. PDF |
2008 |
Arabzadeh E., CLifford, C.W.G., & Harris, J. A.
(2008).Vision merges with touch in a purely tactile discrimination. Psychological Science, 19, 635-641. PDF 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, 34,
494-500. PDF 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, 20,
734-740. PDF 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, 34,
423-436. PDF Harris, J. A., & Livesey, E. J. (2008). Comparing
patterning and
biconditional discriminations in humans. Journal
of Experimental Psychology:
Animal Behavior Processes, 34,
144-154. PDF Thein, T., Westbrook, R. F., &
Harris, J. A. (2008). How
the associative strengths of stimuli combine in compound: Sum- mation
and
overshadowing.Journal
of Experimental Psychology: Animal Behavior Processes, 34,
155-166. PDF 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. PDF Livesey, E. J. , & Harris, J. A. (2008). What are flexible
representations? Commentary on Melchers, Shanks and Lachnit. Behavioural Processes, 77,
437-439. PDF Clifford, C.W.G., Arabzadeh, E., & Harris, J.A. (2008).
Getting technical about awareness. Trends
in Cognitive Sciences, 12,
54-58. PDF |
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. PDF 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. PDF |
2006 |
Harris, J.
A. (2006). Elemental representations of stimuli in
associative learning. Psychological
Review, 113 (3),
584-605. PDF 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 PDF Harris, J.
A., Karlov, L., & Clifford, C. W. G. (2006). Localization of
tactile stimuli depends on conscious detection. Journal
of Neuroscience, 26, 948-952. PDF 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:
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2005 |
Clifford,
CWG & Harris, JA (2005) Contextual modulation outside of
awareness. Current Biology,
15, 574-578. PDF Harris, J.
A. & Thein, T. (2005). Interactions between conditioned and
unconditioned flavor preferences. Journal
of Experimental Psychology: Animal Behavior Processes, 31, 407-417. PDF |
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. PDF Harris, J. A., Thein, T., & Clifford, C. W. G. (2004).
Dissociating detection from localization of tactile stimuli. Journal
of Neuroscience, 24, 3683-3693. PDF |
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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. PDF |
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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. PDF Harris, I. M., Harris, J. A., & Caine, D. (2002).
Mental rotation deficits following damage to the right basal ganglia. Neuropsychology,
16, 524-537. PDF 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. PDF 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. |
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Harris, J. A., Harris, I. M., &
Diamond, M. E. (2001). The topography of tactile learning in humans. Journal
of Neuroscience, 21,1056-1061. PDF Harris, J. A., Petersen, R. S., &
Diamond, M. E. (2001). The cortical distribution of sensory memories. Neuron,
30, 315-318. PDF Harris, J. A., & Westbrook, R. F.
(2001). Contextual control over the expression of fear in rats
conditioned under a benzodiazepine. Psychopharmacology, 156,
92-97. PDF 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. PDF Harris, J. A., Harris, I. M. &
Diamond, M. E. (2001). The topography of tactile working memory. Journal
of Neuroscience, 21, 8262-8269. PDF |
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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. PDF Harris, J. A., & Diamond, M. E.
(2000). Ipsilateral and contralateral transfer of tactile learning. NeuroReport,
11, 263-268. PDF 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. PDF 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. PDF |
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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. PDF 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. PDF 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. PDF |
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Harris, J. A. (1998). Using c-fos
as a neural marker of pain. Brain
Research Bulletin, 45,
1-8. PDF 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. PDF 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. PDF |
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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. PDF |
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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. PDF 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. PDF Harris, J. A., Corsi, M., Quartaroli,
M., Arban, R., & Bentivoglio, M. (1996). Upregulation of spinal
glutamate receptors in chronic pain. Neuroscience, 74,
7-12. PDF Harris, J. A., Guglielmotti, V., &
Bentivoglio, M. (1996). Diencephalic asymmetries. Neuroscience
and
Biobehavioral Reviews, 20, 637-643. PDF |
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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. PDF 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. PDF 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. PDF |
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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. PDF |
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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. PDF |
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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. |
©2009
School of Psychology, University of Sydney
Last update 3rd February 2006 webmaster@psych.usyd.edu.au