Fourier Descriptors Based on the Structure of the Human Primary Visual Cortex with Applications to Object Recognition

Most theories of visual processing propose that object recognition is achieved in higher visual cortex. However, we show that category selectivity for musical notation can be observed in the first ERP component called the C1 (measured 40–60 msec after stimulus onset) with music-reading expertise. Moreover, the C1 note selectivity was observed only when the stimulus category was blocked but not when the stimulus category was randomized. Under blocking, the C1 activity for notes predicted individual music-reading ability, and behavioral judgments of musical stimuli reflected music-reading skill. Our results challenge current theories of object recognition, indicating that the primary visual cortex can be selective for musical notation within the initial feedforward sweep of activity with perceptual expertise and with a testing context that is consistent with the expertise training, such as blocking the stimulus category for music reading.

Download Full-text

Haptic Shape Processing in Visual Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00548 ◽

2014 ◽

Vol 26 (5) ◽

pp. 1154-1167 ◽

Cited By ~ 19

Author(s):

Jacqueline C. Snow ◽

Lars Strother ◽

Glyn W. Humphreys

Keyword(s):

Visual Cortex ◽

Object Recognition ◽

Primary Visual Cortex ◽

Shape Recognition ◽

Visual Object ◽

Visual Object Recognition ◽

Object Shape ◽

Shape Processing ◽

Shape Selective ◽

Visual Cortical

Humans typically rely upon vision to identify object shape, but we can also recognize shape via touch (haptics). Our haptic shape recognition ability raises an intriguing question: To what extent do visual cortical shape recognition mechanisms support haptic object recognition? We addressed this question using a haptic fMRI repetition design, which allowed us to identify neuronal populations sensitive to the shape of objects that were touched but not seen. In addition to the expected shape-selective fMRI responses in dorsal frontoparietal areas, we observed widespread shape-selective responses in the ventral visual cortical pathway, including primary visual cortex. Our results indicate that shape processing via touch engages many of the same neural mechanisms as visual object recognition. The shape-specific repetition effects we observed in primary visual cortex show that visual sensory areas are engaged during the haptic exploration of object shape, even in the absence of concurrent shape-related visual input. Our results complement related findings in visually deprived individuals and highlight the fundamental role of the visual system in the processing of object shape.

Download Full-text

Recognition Model with Extension Fields

Perception ◽

10.1068/v970347 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 202-202

Author(s):

P Kalocsai ◽

W I Biederman

Keyword(s):

Visual Cortex ◽

Object Recognition ◽

Primary Visual Cortex ◽

Recognition Performance ◽

Recognition Rate ◽

Gabor Filters ◽

Shape Similarity ◽

Recognition Model ◽

Connectivity Patterns ◽

Human Object

A recognition model which defines a measure of shape similarity on the direct output of multiscale and multiorientation Gabor filters does not manifest qualitative aspects of human object recognition of contour-deleted images in that: (a) it recognises recoverable and nonrecoverable contour-deleted images equally well, whereas humans recognise recoverable images much better; (b) it distinguishes complementary feature-deleted images whereas humans do not. Adding some of the known connectivity patterns of the primary visual cortex to the model in the form of extension fields (connections between collinear and curvilinear units) among filters (a) increased the overall recognition performance of the model, (b) boosted the recognition rate of the recoverable images far more than of the nonrecoverable ones, (c) increased the similarity of complementary feature-deleted images, but not part-deleted ones. These correspond more closely to human psychophysical results. Interestingly, performance was approximately equivalent for narrow (±15 deg) and broad (±90 deg) extension fields.

Download Full-text