Accession Number : ADA298760

Title :   Spatial Reference Frames for Object Recognition. Tuning for Rotations in Depth.

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB

Personal Author(s) : Logothetis, Nikos K. ; Pauls, Jon ; Poggio, Tomaso

PDF Url : ADA298760

Report Date : MAR 1995

Pagination or Media Count : 20

Abstract : The inferior temporal cortex (IT) of monkeys is thought to play an essential role in visual object recognition. Inferotemporal neurons are known to respond to complex visual stimuli, including patterns like faces hands, or other body parts. What is the role of such neurons in object recognition? The present study examines this question in combined psychophysical and electrophysiological experiments, in which monkeys learned to classify and recognize novel visual 3D objects. A population of neurons in IT were found to respond selectively to such objects that the monkeys had recently learned to recognize. A large majority of these cells discharged maximally for one view of the object, while their response fell off gradually as the object was rotated away from the neuron's preferred view. Most neurons exhibited orientation-dependent responses also during view-plane rotations. Some neurons were found tuned around two views of the same object. while a very small number of cells responded in a view-invariant manner. For five different objects that were extensively used during the training of the animals, and for which behavioral performance became view-independent, multiple cells were found that were tuned around different views of the same object. No selective responses were ever encountered for views that the animal systematically failed to recognize. The results of our experiments suggest that neurons in this area can develop a complex receptive field organization as a consequence of extensive training in the discrimination and recognition of objects. Simple geometric features did not appear to account for the neurons' selective responses.

Descriptors :   *SPATIAL DISTRIBUTION, *NERVE CELLS, *VISUAL PERCEPTION, *VISUAL CORTEX, *ELECTROPHYSIOLOGY, EXPERIMENTAL DATA, ELECTROOPTICS, ORIENTATION(DIRECTION), TEST METHODS, THREE DIMENSIONAL, AMINES, RESPONSE, IMAGES, TUNING, GEOMETRY, RECOGNITION, FRAMES, VISION, STIMULI, INVARIANCE, ROTATION, TRANSFORMATIONS, PSYCHOPHYSICS, MONKEYS.

Subject Categories : Anatomy and Physiology
      Electrooptical and Optoelectronic Devices
      Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE