scholarly journals An ideal observer analysis of variability in visual-only speech

2005 ◽  
Vol 5 (8) ◽  
pp. 883-883
Author(s):  
B. Conrey ◽  
J. M. Gold
Keyword(s):  
Ideal Observer ◽  
Ideal Observer Analysis

scholarly journals Ideal Observer Analysis of Overt Attention

2010 ◽  
Vol 10 (7) ◽  
pp. 12-12 ◽  
Author(s):  
W. S. Geisler
Keyword(s):  
Ideal Observer ◽  
Overt Attention ◽  
Ideal Observer Analysis

scholarly journals Cross inhibition from ON to OFF pathway improves the efficiency of contrast encoding in the mammalian retina

2012 ◽  
Vol 108 (10) ◽  
pp. 2679-2688 ◽  
Author(s):  
Zhiyin Liang ◽  
Michael A. Freed
Keyword(s):  
Spike Train ◽  
Ganglion Cells ◽  
Ideal Observer ◽  
Detection Accuracy ◽  
Low Contrast ◽  
Mammalian Retina ◽  
Ideal Observer Analysis ◽  
On And Off Pathways ◽  
Cross Inhibition

The retina is divided into parallel and mostly independent ON and OFF pathways, but the ON pathway “cross” inhibits the OFF pathway. Cross inhibition was thought to improve signal processing by the OFF pathway, but its effect on contrast encoding had not been tested experimentally. To quantify the effect of cross inhibition on the encoding of contrast, we presented a dark flash to an in vitro preparation of the mammalian retina. We then recorded excitatory currents, inhibitory currents, membrane voltages, and spikes from OFF α-ganglion cells. The recordings were subjected to an ideal observer analysis that used Bayesian methods to determine how accurately the recordings detected the dark flash. We found that cross inhibition increases the detection accuracy of currents and membrane voltages. Yet these improvements in encoding do not fully reach the spike train, because cross inhibition also hyperpolarizes the OFF α-cell below spike threshold, preventing small signals in the membrane voltages at low contrast from reaching the spike train. The ultimate effect of cross inhibition is to increase the accuracy with which the spike train detects moderate contrast, but reduce the accuracy with which it detects low contrast. In apparent compensation for the loss of accuracy at low contrast, cross inhibition, by hyperpolarizing the OFF α-cell, reduces the number of spikes required to detect the dark flash and thereby increases encoding efficiency.

scholarly journals Ideal observer analysis of crowding and the reduction of crowding through learning

2010 ◽  
Vol 10 (5) ◽  
pp. 16-16 ◽  
Author(s):  
G. J. Sun ◽  
S. T. L. Chung ◽  
B. S. Tjan
Keyword(s):  
Ideal Observer ◽  
Ideal Observer Analysis

scholarly journals An ideal observer analysis of visual working memory.

2012 ◽  
Vol 119 (4) ◽  
pp. 807-830 ◽  
Author(s):  
Chris R. Sims ◽  
Robert A. Jacobs ◽  
David C. Knill
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Ideal Observer ◽  
Ideal Observer Analysis

scholarly journals Adaptive shaping of cortical response selectivity in the vibrissa pathway

2015 ◽  
Vol 113 (10) ◽  
pp. 3850-3865 ◽  
Author(s):  
He J. V. Zheng ◽  
Qi Wang ◽  
Garrett B. Stanley
Keyword(s):  
High Energy ◽  
Cortical Response ◽  
Neuronal Firing ◽  
Ideal Observer ◽  
Moderate Amount ◽  
Spatial Spread ◽  
Processing Modes ◽  
Temporal And Spatial Characteristics ◽  
Stimulus Features ◽  
Ideal Observer Analysis

One embodiment of context-dependent sensory processing is bottom-up adaptation, where persistent stimuli decrease neuronal firing rate over hundreds of milliseconds. Adaptation is not, however, simply the fatigue of the sensory pathway, but shapes the information flow and selectivity to stimulus features. Adaptation enhances spatial discriminability (distinguishing stimulus location) while degrading detectability (reporting presence of the stimulus), for both the ideal observer of the cortex and awake, behaving animals. However, how the dynamics of the adaptation shape the cortical response and this detection and discrimination tradeoff is unknown, as is to what degree this phenomenon occurs on a continuum as opposed to a switching of processing modes. Using voltage-sensitive dye imaging in anesthetized rats to capture the temporal and spatial characteristics of the cortical response to tactile inputs, we showed that the suppression of the cortical response, in both magnitude and spatial spread, is continuously modulated by the increasing amount of energy in the adapting stimulus, which is nonuniquely determined by its frequency and velocity. Single-trial ideal observer analysis demonstrated a tradeoff between detectability and spatial discriminability up to a moderate amount of adaptation, which corresponds to the frequency range in natural whisking. This was accompanied by a decrease in both detectability and discriminability with high-energy adaptation, which indicates a more complex coupling between detection and discrimination than a simple switching of modes. Taken together, the results suggest that adaptation operates on a continuum and modulates the tradeoff between detectability and discriminability that has implications for information processing in ethological contexts.

scholarly journals Ideal observer analysis of the development of spatial contrast sensitivity in macaque monkeys

2003 ◽  
Vol 3 (10) ◽  
pp. 6 ◽  
Author(s):  
Lynne Kiorpes ◽  
Chao Tang ◽  
Michael J. Hawken ◽  
J. Anthony Movshon
Keyword(s):  
Contrast Sensitivity ◽  
Ideal Observer ◽  
Macaque Monkeys ◽  
Spatial Contrast Sensitivity ◽  
Ideal Observer Analysis
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