Formation of mnemonic neuronal responses to visual paired associates in inferotemporal cortex is impaired by perirhinal and entorhinal lesions.

AbstractEarly theories of efficient coding suggested the visual system could compress the world by learning to represent features where information was concentrated, such as contours. This view was validated by the discovery that neurons in posterior visual cortex respond to edges and curvature. Still, it remains unclear what other information-rich features are encoded by neurons in more anterior cortical regions (e.g., inferotemporal cortex). Here, we use a generative deep neural network to synthesize images guided by neuronal responses from across the visuocortical hierarchy, using floating microelectrode arrays in areas V1, V4 and inferotemporal cortex of two macaque monkeys. We hypothesize these images (“prototypes”) represent such predicted information-rich features. Prototypes vary across areas, show moderate complexity, and resemble salient visual attributes and semantic content of natural images, as indicated by the animals’ gaze behavior. This suggests the code for object recognition represents compressed features of behavioral relevance, an underexplored aspect of efficient coding.

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Dynamics of Neuronal Responses in the Inferotemporal Cortex Associated with 3D Object Recognition Learning

Neural Information Processing - Lecture Notes in Computer Science ◽

10.1007/978-3-642-42051-1_25 ◽

2013 ◽

pp. 193-199

Author(s):

Reona Yamaguchi ◽

Kazunari Honda ◽

Jun-ya Okamura ◽

Shintaro Saruwatari ◽

Jin Oshima ◽

...

Keyword(s):

Object Recognition ◽

3D Object Recognition ◽

Neuronal Responses ◽

Inferotemporal Cortex ◽

3D Object ◽

Recognition Learning

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Size and position invariance of neuronal responses in monkey inferotemporal cortex

Journal of Neurophysiology ◽

10.1152/jn.1995.73.1.218 ◽

1995 ◽

Vol 73 (1) ◽

pp. 218-226 ◽

Cited By ~ 235

Author(s):

M. Ito ◽

H. Tamura ◽

I. Fujita ◽

K. Tanaka

Keyword(s):

Anterior Part ◽

Single Cells ◽

Stimulus Size ◽

Long Term Memory ◽

Neuronal Responses ◽

Inferotemporal Cortex ◽

Size Dependent ◽

Neuronal Mechanisms ◽

Specific Manner

1. Object vision is largely invariant to changes of retinal images of objects in size and position. To reveal neuronal mechanisms of this invariance, we recorded activities from single cells in the anterior part of the inferotemporal cortex (anterior IT), determined the critical features for the activation of individual cells, and examined the effects of changes in stimulus size and position on the responses. 2. Twenty-one percent of the anterior IT cells studied here responded to ranges of size > 4 octaves, whereas 43% responded to size ranges < 2 octaves. The optimal stimulus size, measured by the distance between the outer edges along the longest axis of the stimulus, ranged from 1.7 to 30 degrees. 3. The selectivity for shape was mostly preserved over the entire range of effective size and over the receptive field, whereas some subtle but statistically significant changes were observed in one half of the cells studied here. 4. The size-specific responses observed in 43% of the cells are consistent with recent psychophysical data that suggest that images of objects are stored in a size-specific manner in the long-term memory. Both size-dependent and -independent processing of images may occur in anterior IT.

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Effect of silhouetting and inversion on view invariance in the monkey inferotemporal cortex

Journal of Neurophysiology ◽

10.1152/jn.00008.2017 ◽

2017 ◽

Vol 118 (1) ◽

pp. 353-362

Author(s):

N. Apurva Ratan Murty ◽

S. P. Arun

Keyword(s):

Object Representations ◽

Neuronal Responses ◽

Inferotemporal Cortex ◽

View Invariance ◽

Natural Objects ◽

Viewpoint Invariance ◽

And Inversion ◽

The Impact ◽

The Brain ◽

Coarse To Fine

We effortlessly recognize objects across changes in viewpoint, but we know relatively little about the features that underlie viewpoint invariance in the brain. Here, we set out to characterize how viewpoint invariance in monkey inferior temporal (IT) neurons is influenced by two image manipulations—silhouetting and inversion. Reducing an object into its silhouette removes internal detail, so this would reveal how much viewpoint invariance depends on the external contours. Inverting an object retains but rearranges features, so this would reveal how much viewpoint invariance depends on the arrangement and orientation of features. Our main findings are 1) view invariance is weakened by silhouetting but not by inversion; 2) view invariance was stronger in neurons that generalized across silhouetting and inversion; 3) neuronal responses to natural objects matched early with that of silhouettes and only later to that of inverted objects, indicative of coarse-to-fine processing; and 4) the impact of silhouetting and inversion depended on object structure. Taken together, our results elucidate the underlying features and dynamics of view-invariant object representations in the brain. NEW & NOTEWORTHY We easily recognize objects across changes in viewpoint, but the underlying features are unknown. Here, we show that view invariance in the monkey inferotemporal cortex is driven mainly by external object contours and is not specialized for object orientation. We also find that the responses to natural objects match with that of their silhouettes early in the response, and with inverted versions later in the response—indicative of a coarse-to-fine processing sequence in the brain.

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Texture discriminability in monkey inferotemporal cortex predicts human texture perception

Journal of Neurophysiology ◽

10.1152/jn.00532.2014 ◽

2014 ◽

Vol 112 (11) ◽

pp. 2745-2755 ◽

Cited By ~ 4

Author(s):

Kalathupiriyan A. Zhivago ◽

Sripati P. Arun

Keyword(s):

Firing Rate ◽

Neuronal Activity ◽

Array Size ◽

Neuronal Responses ◽

Inferotemporal Cortex ◽

Texture Perception ◽

Texture Discrimination ◽

Visual Objects ◽

Constituent Elements

Shape and texture are both important properties of visual objects, but texture is relatively less understood. Here, we characterized neuronal responses to discrete textures in monkey inferotemporal (IT) cortex and asked whether they can explain classic findings in human texture perception. We focused on three classic findings on texture discrimination: 1) it can be easy or hard depending on the constituent elements; 2) it can have asymmetries, and 3) it is reduced for textures with randomly oriented elements. We recorded neuronal activity from monkey inferotemporal (IT) cortex and measured texture perception in humans for a variety of textures. Our main findings are as follows: 1) IT neurons show congruent selectivity for textures across array size; 2) textures that were easy for humans to discriminate also elicited distinct patterns of neuronal activity in monkey IT; 3) texture pairs with asymmetries in humans also exhibited asymmetric variation in firing rate across monkey IT; and 4) neuronal responses to randomly oriented textures were explained by an average of responses to homogeneous textures, which rendered them less discriminable. The reduction in discriminability of monkey IT neurons predicted the reduced discriminability in humans during texture discrimination. Taken together, our results suggest that texture perception in humans is likely based on neuronal representations similar to those in monkey IT.

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