title: Selective IT neurons are selective along many dimensions.
abstract: Our visual abilities are unsurpassed because of a sophisticated code for objects located in the inferior temporal (IT) cortex. This code has remained a mystery because IT neurons show extremely diverse shape selectivity with no apparent organizing principle. Here, we show that there is an intrinsic component to selectivity in IT neurons. We tested IT neurons on distinct shapes and their parametric variations and asked whether neurons selective along one dimension were also selective along others. Selective neurons responded to fewer shapes and were narrowly tuned to local variations of these shapes, both along arbitrary morph lines and along variations in size, position, or orientation. For a subset of neurons, selective neurons were selective for both shape and texture. Finally, selective neurons were also more invariant in that they preserved their shape preferences across changes in size, position, and orientation. These observations indicate that there is an intrinsic constraint on the sharpness of tuning for the features coded by each IT neuron, making it always sharply tuned or always broadly tuned along all dimensions. We speculate that this may be an organizing principle throughout visual cortex.
authors.affiliation: Centre for Neuroscience, Indian Institute of Science, Bangalore, India.
authors.forename: Kalathupiriyan A
authors.initials: KA
authors.lastname: Zhivago
authors.affiliation: Centre for Neuroscience, Indian Institute of Science, Bangalore, India sparun@cns.iisc.ernet.in.
authors.forename: S P
authors.initials: SP
authors.lastname: Arun
mesh_terms: D000818:Animals; D005071:Evoked Potentials; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000145:classification / Q000166:cytology / Q000502:physiology*; D013702:Temporal Lobe / Q000166:cytology* / Q000502:physiology
keywords: inferotemporal cortex; monkey; object recognition; selectivity; shape coding
references.citation: Science. 2000 Feb 18;287(5456):1273-6
references.pmid: 10678835
references.citation: Cereb Cortex. 2001 May;11(5):384-99
references.pmid: 11313291
references.citation: Nat Neurosci. 2001 Dec;4(12):1244-52
references.pmid: 11713468
references.citation: J Physiol. 2004 Jun 15;557(Pt 3):923-33
references.pmid: 15090603
references.citation: Nat Neurosci. 2004 Aug;7(8):880-6
references.pmid: 15235606
references.citation: Proc Natl Acad Sci U S A. 2004 Oct 26;101(43):15524-9
references.pmid: 15483109
references.citation: Vision Res. 1982;22(5):545-59
references.pmid: 7112954
references.citation: Proc Natl Acad Sci U S A. 1983 Sep;80(18):5776-8
references.pmid: 6577453
references.citation: Science. 1993 May 14;260(5110):995-7
references.pmid: 8493538
references.citation: J Neurophysiol. 1994 Jun;71(6):2325-37
references.pmid: 7931520
references.citation: J Neurophysiol. 1995 Jan;73(1):218-26
references.pmid: 7714567
references.citation: Eur J Neurosci. 2005 Jul;22(1):212-24
references.pmid: 16029211
references.citation: J Neurosci. 2007 Nov 7;27(45):12292-307
references.pmid: 17989294
references.citation: Nat Neurosci. 2008 Nov;11(11):1352-60
references.pmid: 18836443
references.citation: Vision Res. 2010 Oct 28;50(22):2261-73
references.pmid: 20079759
references.citation: Neuron. 2012 Jun 21;74(6):1099-113
references.pmid: 22726839
references.citation: J Neurosci. 2012 Jul 25;32(30):10170-82
references.pmid: 22836252
references.citation: J Neurophysiol. 2012 Nov;108(10):2725-36
references.pmid: 22933717
references.citation: J Neurophysiol. 2014 Dec 1;112(11):2745-55
references.pmid: 25210165