Shape selectivity in primate lateral intraparietal cortex

Nature ◽  
10.1038/26752 ◽  
1998 ◽  
Vol 395 (6701) ◽  
pp. 500-503 ◽  
Author(s):  
A. B. Sereno ◽  
J. H. R. Maunsell
Keyword(s):  
Shape Selectivity ◽  
Lateral Intraparietal Cortex

scholarly journals Comparison of Shape Encoding in Primate Dorsal and Ventral Visual Pathways

2007 ◽  
Vol 97 (1) ◽  
pp. 307-319 ◽  
Author(s):  
Sidney R. Lehky ◽  
Anne B. Sereno
Keyword(s):  
Population Level ◽  
Shape Selectivity ◽  
Visual Pathways ◽  
Neural Population ◽  
Inferotemporal Cortex ◽  
Lateral Intraparietal Cortex ◽  
Dorsal Pathway ◽  
Repetition Suppression ◽  
Shape Encoding ◽  
High Level

Ventral and dorsal visual pathways perform fundamentally different functions. The former is involved in object recognition, whereas the latter carries out spatial localization of stimuli and visual guidance of motor actions. Despite the association of the dorsal pathway with spatial vision, recent studies have reported shape selectivity in the dorsal stream. We compared shape encoding in anterior inferotemporal cortex (AIT), a high-level ventral area, with that in lateral intraparietal cortex (LIP), a high-level dorsal area, during a fixation task. We found shape selectivities of individual neurons to be greater in anterior inferotemporal cortex than in lateral intraparietal cortex. At the neural population level, responses to different shapes were more dissimilar in AIT than LIP. Both observations suggest a greater capacity in AIT for making finer shape distinctions. Multivariate analyses of AIT data grouped together similar shapes based on neural population responses, whereas such grouping was indistinct in LIP. Thus in a first comparison of shape response properties in late stages of the two visual pathways, we report that AIT exhibits greater capability than LIP for both object discrimination and generalization. These differences in the two visual pathways provide the first neurophysiological evidence that shape encoding in the dorsal pathway is distinct from and not a mere duplication of that formed in the ventral pathway. In addition to shape selectivity, we observed stimulus-driven cognitive effects in both areas. Stimulus repetition suppression in LIP was similar to the well-known repetition suppression in AIT and may be associated with the “inhibition of return” memory effect observed during reflexive attention.

scholarly journals Shape selectivity and remapping in dorsal stream visual area LIP

2014 ◽  
Vol 111 (3) ◽  
pp. 613-627 ◽  
Author(s):  
Janani Subramanian ◽  
Carol L. Colby
Keyword(s):  
Receptive Field ◽  
Information Transfer ◽  
Spatial Information ◽  
Dorsal Stream ◽  
Shape Selectivity ◽  
Visual Stream ◽  
Shape Information ◽  
Lateral Intraparietal Cortex ◽  
Shape Selective ◽  
Object Features

We explore the visual world by making rapid eye movements (saccades) to focus on objects and locations of interest. Despite abrupt retinal image shifts, we see the world as stable. Remapping contributes to visual stability by updating the internal image with every saccade. Neurons in macaque lateral intraparietal cortex (LIP) and other brain areas update information about salient locations around the time of a saccade. The depth of information transfer remains to be thoroughly investigated. Area LIP, as part of the dorsal visual stream, is regarded as a spatially selective area, yet there is evidence that LIP neurons also encode object features. We sought to determine whether LIP remaps shape information. This knowledge is important for understanding what information is retained from each glance. We identified 82 remapping neurons. First, we presented shapes within the receptive field and tested for shape selectivity in a fixation task. Among the remapping neurons, 28 neurons (34%) were selective for shape. Second, we presented the same shapes in the future location of the receptive field around the time of the saccade and tested for shape selectivity during remapping. Thirty-one (38%) neurons were selective for shape. Of 11 neurons that were shape selective in both tasks, 5 showed significant correlation between shape selectivity in the two tasks. Across the population, there was a weak but significant correlation between responses to shape in the two tasks. Our results provide neurophysiological evidence that remapped responses in area LIP can encode shape information as well as spatial information.

Shape selectivity of a metallo cavitand host allows separation of n ‐alkanes from isooctane

2021 ◽  
Author(s):  
Yun‐Hui Wan ◽  
Faiz‐Ur Rahman ◽  
Julius Rebek ◽  
Yang Yu
Keyword(s):  
Shape Selectivity

scholarly journals Pseudosparse neural coding in the visual system of primates

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sidney R. Lehky ◽  
Keiji Tanaka ◽  
Anne B. Sereno
Keyword(s):  
Neural Coding ◽  
Macaque Monkey ◽  
Implicit Assumption ◽  
Data Set ◽  
Efficient Coding ◽  
Population Responses ◽  
Lateral Intraparietal Cortex ◽  
Neural Populations ◽  
Neurophysiological Data ◽  
The Mean

AbstractWhen measuring sparseness in neural populations as an indicator of efficient coding, an implicit assumption is that each stimulus activates a different random set of neurons. In other words, population responses to different stimuli are, on average, uncorrelated. Here we examine neurophysiological data from four lobes of macaque monkey cortex, including V1, V2, MT, anterior inferotemporal cortex, lateral intraparietal cortex, the frontal eye fields, and perirhinal cortex, to determine how correlated population responses are. We call the mean correlation the pseudosparseness index, because high pseudosparseness can mimic statistical properties of sparseness without being authentically sparse. In every data set we find high levels of pseudosparseness ranging from 0.59–0.98, substantially greater than the value of 0.00 for authentic sparseness. This was true for synthetic and natural stimuli, as well as for single-electrode and multielectrode data. A model indicates that a key variable producing high pseudosparseness is the standard deviation of spontaneous activity across the population. Consistently high values of pseudosparseness in the data demand reconsideration of the sparse coding literature as well as consideration of the degree to which authentic sparseness provides a useful framework for understanding neural coding in the cortex.

Shape selectivity of zeolite EU-1 in reactions of aromatic hydrocarbons

1989 ◽  
Vol 49 (2) ◽  
pp. 307-318 ◽  
Author(s):  
G.N. Rao ◽  
R. Kumar ◽  
P. Ratnasamy
Keyword(s):  
Aromatic Hydrocarbons ◽  
Shape Selectivity

Epoxidation of olefins by cytochrome P-450 model compounds: kinetics and stereochemistry of oxygen atom transfer and origin of shape selectivity

1985 ◽  
Vol 107 (7) ◽  
pp. 2000-2005 ◽  
Author(s):  
James P. Collman ◽  
John I. Brauman ◽  
Bernard Meunier ◽  
Teruyuki Hayashi ◽  
Thomas Kodadek ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Shape Selectivity ◽  
Atom Transfer ◽  
Oxygen Atom Transfer ◽  
Model Compounds ◽  
Cytochrome P 450 ◽  
Epoxidation Of Olefins

scholarly journals Shape Selectivity in the Conversion of Methanol to Hydrocarbons: The Catalytic Performance of One-Dimensional 10-Ring Zeolites: ZSM-22, ZSM-23, ZSM-48, and EU-1

ACS Catalysis ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 26-37 ◽  
Author(s):  
Shewangizaw Teketel ◽  
Wegard Skistad ◽  
Sandrine Benard ◽  
Unni Olsbye ◽  
Karl Petter Lillerud ◽  
...  
Keyword(s):  
Shape Selectivity ◽  
Catalytic Performance ◽  
One Dimensional ◽  
Methanol To Hydrocarbons

Mo-modified ZSM-5 zeolite with intergrowth crystals for high-efficiency catalytic xylene isomerization

2021 ◽  
Author(s):  
Lei Miao ◽  
Zhe Hong ◽  
Guoqing Zhao ◽  
Fangtao Huang ◽  
Zhirong Zhu
Keyword(s):  
Hydrothermal Method ◽  
High Efficiency ◽  
Shape Selectivity ◽  
Reduction Procedure ◽  
Xylene Isomerization

Mo/ZSM-5 catalysts of xylene isomerization were prepared on the intergrowth ZSM-5 support by impregnation-calcination-reduction procedure. ZSM-5 zeolite with intergrowth crystals was prepared for high shape selectivity by the hydrothermal method....

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