scholarly journals Visual Navigation in Nocturnal Insects

Physiology ◽  
2016 ◽  
Vol 31 (3) ◽  
pp. 182-192 ◽  
Author(s):  
Eric Warrant ◽  
Marie Dacke
Keyword(s):  
Visual Processing ◽  
Visual Navigation ◽  
Compound Eyes ◽  
Visual Landmarks ◽  
Processing Strategies ◽  
Straight Line ◽  
Highly Sensitive ◽  
Celestial Compass ◽  
The Brain

Despite their tiny eyes and brains, nocturnal insects have evolved a remarkable capacity to visually navigate at night. Whereas some use moonlight or the stars as celestial compass cues to maintain a straight-line course, others use visual landmarks to navigate to and from their nest. These impressive abilities rely on highly sensitive compound eyes and specialized visual processing strategies in the brain.

scholarly journals How dim is dim? Precision of the celestial compass in moonlight and sunlight

2011 ◽  
Vol 366 (1565) ◽  
pp. 697-702 ◽  
Author(s):  
M. Dacke ◽  
M. J. Byrne ◽  
E. Baird ◽  
C. H. Scholtz ◽  
E. J. Warrant
Keyword(s):  
Dung Beetle ◽  
The Sun ◽  
The Moon ◽  
Polarization Pattern ◽  
Animal Group ◽  
Straight Line ◽  
Celestial Orientation ◽  
Polarization Compass ◽  
Celestial Compass ◽  
Diurnal Species

Prominent in the sky, but not visible to humans, is a pattern of polarized skylight formed around both the Sun and the Moon. Dung beetles are, at present, the only animal group known to use the much dimmer polarization pattern formed around the Moon as a compass cue for maintaining travel direction. However, the Moon is not visible every night and the intensity of the celestial polarization pattern gradually declines as the Moon wanes. Therefore, for nocturnal orientation on all moonlit nights, the absolute sensitivity of the dung beetle's polarization detector may limit the precision of this behaviour. To test this, we studied the straight-line foraging behaviour of the nocturnal ball-rolling dung beetle Scarabaeus satyrus to establish when the Moon is too dim—and the polarization pattern too weak—to provide a reliable cue for orientation. Our results show that celestial orientation is as accurate during crescent Moon as it is during full Moon. Moreover, this orientation accuracy is equal to that measured for diurnal species that orient under the 100 million times brighter polarization pattern formed around the Sun. This indicates that, in nocturnal species, the sensitivity of the optical polarization compass can be greatly increased without any loss of precision.

Context-Dependent Modulation of Early Visual Cortical Responses to Numerical and Nonnumerical Magnitudes

2021 ◽  
pp. 1-12
Author(s):  
Joonkoo Park ◽  
Sonia Godbole ◽  
Marty G. Woldorff ◽  
Elizabeth M. Brannon
Keyword(s):  
Visual Processing ◽  
Context Dependency ◽  
Numerical Magnitude ◽  
Continuous Variables ◽  
Processing Stream ◽  
Cortical Responses ◽  
Early Visual Cortex ◽  
Context Dependent ◽  
Visual Cortical ◽  
The Brain

Abstract Whether and how the brain encodes discrete numerical magnitude differently from continuous nonnumerical magnitude is hotly debated. In a previous set of studies, we orthogonally varied numerical (numerosity) and nonnumerical (size and spacing) dimensions of dot arrays and demonstrated a strong modulation of early visual evoked potentials (VEPs) by numerosity and not by nonnumerical dimensions. Although very little is known about the brain's response to systematic changes in continuous dimensions of a dot array, some authors intuit that the visual processing stream must be more sensitive to continuous magnitude information than to numerosity. To address this possibility, we measured VEPs of participants viewing dot arrays that changed exclusively in one nonnumerical magnitude dimension at a time (size or spacing) while holding numerosity constant and compared this to a condition where numerosity was changed while holding size and spacing constant. We found reliable but small neural sensitivity to exclusive changes in size and spacing; however, changing numerosity elicited a much more robust modulation of the VEPs. Together with previous work, these findings suggest that sensitivity to magnitude dimensions in early visual cortex is context dependent: The brain is moderately sensitive to changes in size and spacing when numerosity is held constant, but sensitivity to these continuous variables diminishes to a negligible level when numerosity is allowed to vary at the same time. Neurophysiological explanations for the encoding and context dependency of numerical and nonnumerical magnitudes are proposed within the framework of neuronal normalization.

1. Observations on the Anatomy of the Rorqual (a Whalebone Whale of the largest magnitude), drawn up from the dissection of a specimen found dead off North Berwick

1845 ◽  
Vol 1 ◽  
pp. 14-15 ◽  
Author(s):  
Robert Knox
Keyword(s):  
Middle Part ◽  
Anatomical Structure ◽  
Entire Length ◽  
Straight Line ◽  
The Brain

This paper, composed ehiefly of anatomical details regarding the anatomical structure of the Rorqual, scarcely admits of abridgement. The author has described the skeleton of the cavity for receiving the brain and the mechanism of the larynx at greatest length. The entire length of the whale, measured by a straight line, drawn on the sand from the nose to the middle part of the tail, and making a slight allowance for the curved position in which the animal lay, was 80 feet. Length of the head 23 feet. The girth of the carcass at the pectoral extremities (though the animal had been ten days on the beach, and was much collapsed) 34 feet. Breadth of the tail from tip to tip' 20 feet. The author describes the appearance of the mouth, lined with whalebone, as very surprising.

Developmental Changes in Ambient and Focal Visual Processing Strategies

2017 ◽  
Vol 2017 (14) ◽  
pp. 224-229 ◽  
Author(s):  
Onkar Krishna ◽  
Toshihiko Yamasaki ◽  
Andrea Helo ◽  
Rämä Pia ◽  
Kiyoharu Aizawa
Keyword(s):  
Visual Processing ◽  
Developmental Changes ◽  
Processing Strategies

scholarly journals The relative coding strength of object identity and nonidentity features in human occipito-temporal cortex and convolutional neural networks

2020 ◽  
Author(s):  
Yaoda Xu ◽  
Maryam Vaziri-Pashkam
Keyword(s):  
Visual Processing ◽  
Visual Pathway ◽  
Feature Representation ◽  
Object Categorization ◽  
Object Identity ◽  
Visual Areas ◽  
Ventral Visual Pathway ◽  
Identity Representation ◽  
The Brain ◽  
Early Human

ABSTRACTAny given visual object input is characterized by multiple visual features, such as identity, position and size. Despite the usefulness of identity and nonidentity features in vision and their joint coding throughout the primate ventral visual processing pathway, they have so far been studied relatively independently. Here we document the relative coding strength of object identity and nonidentity features in a brain region and how this may change across the human ventral visual pathway. We examined a total of four nonidentity features, including two Euclidean features (position and size) and two non-Euclidean features (image statistics and spatial frequency content of an image). Overall, identity representation increased and nonidentity feature representation decreased along the ventral visual pathway, with identity outweighed the non-Euclidean features, but not the Euclidean ones, in higher levels of visual processing. A similar analysis was performed in 14 convolutional neural networks (CNNs) pretrained to perform object categorization with varying architecture, depth, and with/without recurrent processing. While the relative coding strength of object identity and nonidentity features in lower CNN layers matched well with that in early human visual areas, the match between higher CNN layers and higher human visual regions were limited. Similar results were obtained regardless of whether a CNN was trained with real-world or stylized object images that emphasized shape representation. Together, by measuring the relative coding strength of object identity and nonidentity features, our approach provided a new tool to characterize feature coding in the human brain and the correspondence between the brain and CNNs.SIGNIFICANCE STATEMENTThis study documented the relative coding strength of object identity compared to four types of nonidentity features along the human ventral visual processing pathway and compared brain responses with those of 14 CNNs pretrained to perform object categorization. Overall, identity representation increased and nonidentity feature representation decreased along the ventral visual pathway, with the coding strength of the different nonidentity features differed at higher levels of visual processing. While feature coding in lower CNN layers matched well with that of early human visual areas, the match between higher CNN layers and higher human visual regions were limited. Our approach provided a new tool to characterize feature coding in the human brain and the correspondence between the brain and CNNs.

Visual Processing of the River Cross-Sectional Data

2012 ◽  
Vol 204-208 ◽  
pp. 2726-2730
Author(s):  
Qi Qing Duan ◽  
Rui Hai Wu
Keyword(s):  
Data Processing ◽  
Cross Section ◽  
Visual Processing ◽  
Measurement Data ◽  
Measurement Process ◽  
Cross Section Data ◽  
Section Data ◽  
Section Line ◽  
Straight Line ◽  
The Cross

The cross-section of Hydraulic engineering (river, embankment) is a kind of cross section which is always perpendicular to the river direction. Section line is a straight line which is created by connecting two endpoint of the section. Cross-section measurements is that collecting a coordinate point (X, Y, H) on the section line every a certain distance. Field measurement, due to the influence of the external environment, especially when measured in the river, is difficult to ensure that the location of the measurement point exactly on the straight line shown in the section. The reason is that tracking ship traveling along with the section will be impacted by the water, resulting in the offset along the flow direction. Therefore we must to constantly adjust the direction of travel in the measurement process. For which the measurement data should be processed. So it is necessary to deal with the measurement data, and the idea of visual data was proposed in the paper, which is easier to analyze the accuracy of the measurement data. The BUFFER analysis method was used in the data processing, which effectively removed measurement invalid point that far away from the cross-section in measurement and improved the accuracy of the cross-section data processing. On the other hand, the effective pedal point coordinates was used in the calculation of the plane location of cross-section point. The coordinate which can make the cross-section data more realistic and different from the translation of point and uniform distribution algorithm closeted to the effective point of measurement. The method that the elevation of pedal point on the cross section calculated using the distance weighted interpolation method has been applied in the measurement process of several rivers. It is proved in practice that the method got good results and achieved the accuracy of the data and quality which the application sector requirements on.

scholarly journals Neuronal Correlates of Multiple Top–Down Signals during Covert Tracking of Moving Objects in Macaque Prefrontal Cortex

2012 ◽  
Vol 24 (10) ◽  
pp. 2043-2056 ◽  
Author(s):  
Ayano Matsushima ◽  
Masaki Tanaka
Keyword(s):  
Prefrontal Cortex ◽  
Object Tracking ◽  
Visual Processing ◽  
Moving Objects ◽  
Top Down ◽  
Selective Suppression ◽  
Internal Object ◽  
Object Segregation ◽  
Task Irrelevant ◽  
The Brain

Resistance to distraction is a key component of executive functions and is strongly linked to the prefrontal cortex. Recent evidence suggests that neural mechanisms exist for selective suppression of task-irrelevant information. However, neuronal signals related to selective suppression have not yet been identified, whereas nonselective surround suppression, which results from attentional enhancement for relevant stimuli, has been well documented. This study examined single neuron activities in the lateral PFC when monkeys covertly tracked one of randomly moving objects. Although many neurons responded to the target, we also found a group of neurons that exhibited a selective response to the distractor that was visually identical to the target. Because most neurons were insensitive to an additional distractor that explicitly differed in color from the target, the brain seemed to monitor the distractor only when necessary to maintain internal object segregation. Our results suggest that the lateral PFC might provide at least two top–down signals during covert object tracking: one for enhancement of visual processing for the target and the other for selective suppression of visual processing for the distractor. These signals might work together to discriminate objects, thereby regulating both the sensitivity and specificity of target choice during covert object tracking.

The brain behind straight-line orientation in dung beetles

2019 ◽  
Vol 222 (Suppl 1) ◽  
pp. jeb192450 ◽  
Author(s):  
Basil el Jundi ◽  
Emily Baird ◽  
Marcus J. Byrne ◽  
Marie Dacke
Keyword(s):  
Dung Beetles ◽  
Line Orientation ◽  
Straight Line ◽  
The Brain

An Electronic Model of a Neural Correlate to Experience Obtained When the Stimulus Object is a Straight Line or a Circle

1967 ◽  
Vol 25 (1) ◽  
pp. 189-202 ◽  
Author(s):  
Kristian Holt-Hansen
Keyword(s):  
Experimental Data ◽  
Brain Function ◽  
Stimulus Object ◽  
The Other ◽  
Neural Correlate ◽  
Close Analogy ◽  
Straight Line ◽  
Electronic Model ◽  
Close Relationship ◽  
The Brain

An attempt was made to present an electronic model of the neural correlate to the experiences of straightness and circularity on the basis of experimental data. Two sets of experiments were described. In one Ss had numerous kinds of experience when the stimulus object was a straight line or a circle. These experiments demonstrated a close relationship between a straight line and a circle in experience. The other set of experiments consisted of adjusting the electric voltages fed into a cathode ray oscilloscope so that the displays on the screen corresponded closely to some of the experiences reported by subjects in the first set of experiments. A plausible working hypothesis was put forward on the basis that the electronic functions underlying the working of a cathode ray oscilloscope suggest a close analogy with the brain function underlying the experiences obtained when the stimulus object is a straight line or a circle.

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