SP Arun

Associate Professor

Phone : +91 80 2293 3436/3431
E-Mail : sparun[at]iisc.ac.in
VisionLab Website

Research Areas

Visual perception, object recognition

Research Details

We recognize objects easily every day, but object recognition is in fact a very difficult problem. Even leading computer algorithms do not match human performance today. Object recognition is not easy for the brain either: a series of cortical areas, taking up ~40% of the brain, is dedicated to vision. But we know very little about the rules by which the brain transforms what we see into what we perceive. What is the nature of this representation? What are the underlying rules?


Our approach to this problem is best understood through an analogy to colour. We see millions of colors but it is well known that color perception is three-dimensional – any color we perceive can be represented using three numbers. Can we do likewise for the millions of shapes we see? Do shapes also reside in a low-dimensional space?
To gain insight into these questions, we perform behavioral experiments in humans and record the electrical activity of neurons from the monkey visual cortex. In the human experiments, we probe the perceptual representation using behavioral tasks such as visual search or categorization. In the monkey experiments, we probe the representation at the level of single neurons in the inferotemporal cortex, an area critical for object recognition. We use both the behavioral and neuronal data to test and validate computational models of object recognition.


Ratan Murty NA & Arun SP, (2017), Seeing a straight line on a curved surface: Decoupling of patterns from surfaces by single IT neurons, Journal of Neurophysiology , 117: , 104-116

Ratan Murty NA & Arun SP, (2017), A Balanced Comparison of Object Invariances in Monkey IT Neurons, eNeuro, 4(2), e0333-16

Ratan Murty NA & Arun SP, (2017), Effect of silhouetting and inversion on view invariance in the monkey inferotemporal cortex, Journal of Neurophysiology

Vaidhiyan N, Sundaresan R & Arun SP , (2017), Neural dissimilarity indices that predict oddball detection in behaviour, IEEE Transactions on Information Theory,

Sunder S & Arun SP, (2016), Look before you seek: Preview adds a fixed benefit to all searches, Journal of Vision, 1-17

Ratan Murty NA & Arun SP, (2016), Seeing a straight line on a curved surface: Decoupling of patterns from surfaces by single IT neurons, Journal of Neurophysiology

Puneeth NC & Arun SP, (2016), A neural substrate for object permanence in monkey inferotemporal cortex, Scientific Reports, 6:30808

Pramod RT & Arun SP, (2016), Do computational models differ systematically from human object perception?, CVPR

Pramod RT & Arun SP, (2016), Object attributes combine additively in visual search, Journal of Vision, 1-29

Zhivago KA & Arun SP, (2016), Selective IT neurons are selective along many dimensions, Journal of Neurophysiology, 115: 1512-1520

Ratan Murty NA & Arun SP, (2015), Dynamics of 3d view invariance in monkey inferotemporal cortex, Journal of Neurophysiology, 113: 2180-94

Vighneshvel T & Arun SP, (2015), Coding of relative size in monkey inferotemporal cortex, Journal of Neurophysiology, 113: 2173-79

Zhivago KA & Arun SP, (2014), Texture discriminability in monkey inferotemporal cortex predicts human texture perception, Journal of Neurophysiology, 112: 2745-55

Pramod RT & Arun SP, (2014), Features in visual search combine linearly, Journal of Vision, 1-20

Vighneshvel T & Arun SP, (2013), Does linear separability really matter? Complex search is explained by simple search, Journal of Vision, 1-24

Mohan K & Arun SP, (2012), Similarity relations in visual search predict rapid visual categorization, Journal of Vision, 19

Vaidhiyan N, Arun SP & Sundaresan R, (2012), Active sequential hypothesis testing with application to a visual search problem, Proceedings of the 2012 IEEE Symposium on Information Theory, Cambridge MA

Arun SP, (2012), Turning visual search time on its head, Vision Research, 86-92

Kim SS, Sripati AP & Bensmaia SJ, (2010), Predicting the timing of spikes evoked by tactile stimulation of the hand. Journal of Neurophysiology, Journal of Neurophysiology, 1484-96

Sripati AP & Olson CR, (2010), Responses to compound objects in monkey inferotemporal cortex: The whole is equal to the sum of discrete parts, Journal of Neuroscience, 7948-60

Sripati AP & Olson CR, (2010), Global image similarity in monkey inferotemporal cortex predicts human visual search performance, Journal of Neuroscience, 1258-69