title: The Dynamic Multisensory Engram: Neural Circuitry Underlying Crossmodal Object Recognition in Rats Changes with the Nature of Object Experience.
abstract: Rats, humans, and monkeys demonstrate robust crossmodal object recognition (CMOR), identifying objects across sensory modalities. We have shown that rats' performance of a spontaneous tactile-to-visual CMOR task requires functional integration of perirhinal (PRh) and posterior parietal (PPC) cortices, which seemingly provide visual and tactile object feature processing, respectively. However, research with primates has suggested that PRh is sufficient for multisensory object representation. We tested this hypothesis in rats using a modification of the CMOR task in which multimodal preexposure to the to-be-remembered objects significantly facilitates performance. In the original CMOR task, with no preexposure, reversible lesions of PRh or PPC produced patterns of impairment consistent with modality-specific contributions. Conversely, in the CMOR task with preexposure, PPC lesions had no effect, whereas PRh involvement was robust, proving necessary for phases of the task that did not require PRh activity when rats did not have preexposure; this pattern was supported by results from c-fos imaging. We suggest that multimodal preexposure alters the circuitry responsible for object recognition, in this case obviating the need for PPC contributions and expanding PRh involvement, consistent with the polymodal nature of PRh connections and results from primates indicating a key role for PRh in multisensory object representation. These findings have significant implications for our understanding of multisensory information processing, suggesting that the nature of an individual's past experience with an object strongly determines the brain circuitry involved in representing that object's multisensory features in memory.
  
  
  CONCLUSIONS
  The ability to integrate information from multiple sensory modalities is crucial to the survival of organisms living in complex environments. Appropriate responses to behaviorally relevant objects are informed by integration of multisensory object features. We used crossmodal object recognition tasks in rats to study the neurobiological basis of multisensory object representation. When rats had no prior exposure to the to-be-remembered objects, the spontaneous ability to recognize objects across sensory modalities relied on functional interaction between multiple cortical regions. However, prior multisensory exploration of the task-relevant objects remapped cortical contributions, negating the involvement of one region and significantly expanding the role of another. This finding emphasizes the dynamic nature of cortical representation of objects in relation to past experience.
authors.affiliation: Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Ontario N1G 2W1, Canada.
authors.forename: Derek L
authors.initials: DL
authors.lastname: Jacklin
authors.affiliation: Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Ontario N1G 2W1, Canada.
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Cloke
authors.affiliation: Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Ontario N1G 2W1, Canada.
authors.forename: Alphonse
authors.initials: A
authors.lastname: Potvin
authors.affiliation: Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Ontario N1G 2W1, Canada.
authors.forename: Inara
authors.initials: I
authors.lastname: Garrett
authors.affiliation: Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Ontario N1G 2W1, Canada bwinters@uoguelph.ca.
authors.forename: Boyer D
authors.initials: BD
authors.lastname: Winters
mesh_terms: D000704:Analysis of Variance; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D046709:Pattern Recognition, Physiological / Q000187:drug effects / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000187:drug effects / Q000502:physiology*; D010775:Photic Stimulation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D021641:Recognition, Psychology / Q000502:physiology*; D014110:Touch / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D016760:Proto-Oncogene Proteins c-fos; D008012:Lidocaine
keywords: c-fos; cross-modal; multisensory integration; parietal cortex; perirhinal cortex
references.citation: Hippocampus. 1995;5(5):390-408
references.pmid: 8773253
references.citation: J Comp Neurol. 2001 Aug 13;437(1):17-41
references.pmid: 11477594
references.citation: J Neurosci Methods. 1980 Dec;3(2):129-49
references.pmid: 6110810
references.citation: Hippocampus. 2005;15(3):347-55
references.pmid: 15558543
references.citation: Behav Brain Res. 1998 Jun;93(1-2):99-105
references.pmid: 9659992
references.citation: Brain Res. 1979 Dec 14;178(2-3):363-80
references.pmid: 116712
references.citation: Cereb Cortex. 2012 Jun;22(6):1318-32
references.pmid: 21841156
references.citation: J Exp Biol. 2001 Jul;204(Pt 14):2439-46
references.pmid: 11511659
references.citation: Eur J Neurosci. 2010 Jan;31(1):134-47
references.pmid: 20092559
references.citation: Behav Neurosci. 1995 Apr;109(2):212-26
references.pmid: 7619312
references.citation: Hippocampus. 2007;17(9):898-908
references.pmid: 17636546
references.citation: Learn Mem. 2011 Jun 17;18(7):435-43
references.pmid: 21685150
references.citation: Exp Brain Res. 2005 Oct;166(3-4):559-71
references.pmid: 16028028
references.citation: Exp Brain Res. 1997 Oct;116(3):551-5
references.pmid: 9372304
references.citation: Trends Cogn Sci. 2008 Nov;12(11):411-7
references.pmid: 18805039
references.citation: Behav Brain Sci. 2007 Apr;30(2):189-201; discussion 201-39
references.pmid: 17705910
references.citation: J Neurosci. 1999 Feb 1;19(3):1142-8
references.pmid: 9920675
references.citation: J Neurosci. 2001 Dec 15;21(24):9824-36
references.pmid: 11739590
references.citation: Curr Opin Neurobiol. 2010 Jun;20(3):313-8
references.pmid: 20299205
references.citation: Brain. 2009 Mar;132(Pt 3):671-83
references.pmid: 19190042
references.citation: J Neurosci. 2007 Mar 7;27(10):2548-59
references.pmid: 17344392
references.citation: J Comp Neurol. 2004 May 3;472(3):371-94
references.pmid: 15065131
references.citation: Perception. 2007;36(10):1513-21
references.pmid: 18265834
references.citation: J Comp Neurol. 1998 Aug 24;398(2):179-205
references.pmid: 9700566
references.citation: J Comp Neurol. 1983 Oct 20;220(2):168-90
references.pmid: 6643724
references.citation: J Comp Neurol. 1994 Dec 22;350(4):497-533
references.pmid: 7890828
references.citation: Science. 1985 May 3;228(4699):604-6
references.pmid: 3983648
references.citation: J Neurosci. 2010 May 5;30(18):6253-61
references.pmid: 20445051
references.citation: Proc Natl Acad Sci U S A. 2006 May 23;103(21):8239-44
references.pmid: 16702554
references.citation: Trends Cogn Sci. 1999 Apr;3(4):142-151
references.pmid: 10322468
references.citation: Cereb Cortex. 2009 Dec;19(12):2993-3000
references.pmid: 19386635
references.citation: Learn Mem. 2007 Dec 17;14(12):821-32
references.pmid: 18086825
references.citation: Behav Neurosci. 2001 Apr;115(2):271-84
references.pmid: 11345954
references.citation: Trends Cogn Sci. 2006 Mar;10(3):100-7
references.pmid: 16469525
references.citation: J Neurosci. 2004 Jun 30;24(26):5901-8
references.pmid: 15229237
references.citation: Neurobiol Learn Mem. 2012 Oct;98(3):311-9
references.pmid: 22975081
references.citation: Annu Rev Neurosci. 2007;30:99-122
references.pmid: 17417938
references.citation: J Neurosci. 2005 Jan 5;25(1):52-61
references.pmid: 15634766
references.citation: Neurosci Biobehav Rev. 2008 Jul;32(5):1055-70
references.pmid: 18499253
references.citation: Behav Brain Res. 1987 Feb;23(2):95-107
references.pmid: 3566911
references.citation: Behav Brain Res. 1988 Nov 1;31(1):47-59
references.pmid: 3228475
references.citation: Cereb Cortex. 2014 Aug;24(8):2108-19
references.pmid: 23505287
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9777-82
references.pmid: 10944237
references.citation: Exp Brain Res. 1994;100(1):67-84
references.pmid: 7813654