scholarly journals Pattern and component responses of primate MT neurons recorded with multi-contact electrodes, stimulated with 1D and 2D noise patterns.

2021 ◽  
Author(s):  
Christian Quaia ◽  
Incheol Kang ◽  
Bruce G Cumming
Keyword(s):  
Type I ◽  
Motion Direction ◽  
Middle Temporal ◽  
Mt Neurons ◽  
Aperture Problem ◽  
The Past ◽  
Cortex Area ◽  
Pattern Motion ◽  
Alternative Measures ◽  
Contact Electrodes

Direction selective neurons in primary visual cortex (area V1) are affected by the aperture problem, i.e., they are only sensitive to motion orthogonal to their preferred orientation. A solution to this problem first emerges in the middle temporal (MT) area, where a subset of neurons (called pattern cells) combine motion information across multiple orientations and directions, becoming sensitive to pattern motion direction. These cells are expected to play a prominent role in subsequent neural processing, but they are intermixed with cells that behave like V1 cells (component cells), and others that do not clearly fall in either group. The picture is further complicated by the finding that cells that behave like pattern cells with one type of pattern, might behave like component cells for another. We recorded from macaque MT neurons using multi-contact electrodes while presenting both type I and unikinetic plaids, in which the components were 1D noise patterns. We found that the indices that have been used in the past to classify neurons as pattern or component cells work poorly when the properties of the stimulus are not optimized for the cell being recorded, as is always the case with multi-contact arrays. We thus propose alternative measures, which considerably ameliorate the problem, and allow us to gain insights in the signals carried by individual MT neurons. We conclude that arranging cells along a component-to-pattern continuum is an oversimplification, and that the signals carried by individual cells only make sense when embodied in larger populations.

Temporal Dynamics of 2D Motion Integration for Ocular Following in Macaque Monkeys

2010 ◽  
Vol 103 (3) ◽  
pp. 1275-1282 ◽  
Author(s):  
Fréderic V. Barthélemy ◽  
Jérome Fleuriet ◽  
Guillaume S. Masson
Keyword(s):  
Temporal Dynamics ◽  
Time Lag ◽  
Small Time ◽  
Open Loop ◽  
Dynamical Process ◽  
Motion Direction ◽  
Aperture Problem ◽  
Ocular Following ◽  
Pattern Motion ◽  
Line Ending

Several recent studies have shown that extracting pattern motion direction is a dynamical process where edge motion is first extracted and pattern-related information is encoded with a small time lag by MT neurons. A similar dynamics was found for human reflexive or voluntary tracking. Here, we bring an essential, but still missing, piece of information by documenting macaque ocular following responses to gratings, unikinetic plaids, and barber-poles. We found that ocular tracking was always initiated first in the grating motion direction with ultra-short latencies (∼55 ms). A second component was driven only 10–15 ms later, rotating tracking toward pattern motion direction. At the end the open-loop period, tracking direction was aligned with pattern motion direction (plaids) or the average of the line-ending motion directions (barber-poles). We characterized the dependency on contrast of each component. Both timing and direction of ocular following were quantitatively very consistent with the dynamics of neuronal responses reported by others. Overall, we found a remarkable consistency between neuronal dynamics and monkey behavior, advocating for a direct link between the neuronal solution of the aperture problem and primate perception and action.

Aging and the Visual Perception of Motion Direction: Solving the Aperture Problem

Perception ◽  
2018 ◽  
Vol 47 (7) ◽  
pp. 735-750 ◽  
Author(s):  
Lindsey M. Shain ◽  
J. Farley Norman
Keyword(s):  
Visual Motion ◽  
Motion Direction ◽  
Line Segments ◽  
Aperture Problem ◽  
Motion Signal ◽  
True Motion ◽  
Pattern Motion ◽  
Accurate Performance ◽  
Moving Line ◽  
True Direction

An experiment required younger and older adults to estimate coherent visual motion direction from multiple motion signals, where each motion signal was locally ambiguous with respect to the true direction of pattern motion. Thus, accurate performance required the successful integration of motion signals across space (i.e., accurate performance required solution of the aperture problem) . The observers viewed arrays of either 64 or 9 moving line segments; because these lines moved behind apertures, their individual local motions were ambiguous with respect to direction (i.e., were subject to the aperture problem). Following 2.4 seconds of pattern motion on each trial (true motion directions ranged over the entire range of 360° in the fronto-parallel plane), the observers estimated the coherent direction of motion. There was an effect of direction, such that cardinal directions of pattern motion were judged with less error than oblique directions. In addition, a large effect of aging occurred—The average absolute errors of the older observers were 46% and 30.4% higher in magnitude than those exhibited by the younger observers for the 64 and 9 aperture conditions, respectively. Finally, the observers’ precision markedly deteriorated as the number of apertures was reduced from 64 to 9.

scholarly journals 3O1145 Occlusion induced Motion : Type I Plaid Pattern Motion and barber pole effect

2002 ◽  
Vol 42 (supplement2) ◽  
pp. S202
Author(s):  
T. Nakamura ◽  
N. Saito
Keyword(s):  
Type I ◽  
Motion Type ◽  
Pattern Motion ◽  
Induced Motion

Area 17 lesions deactivate area MT in owl monkeys

1992 ◽  
Vol 9 (3-4) ◽  
pp. 399-407 ◽  
Author(s):  
Jon H. Kaas ◽  
Leah A. Krubitzer
Keyword(s):  
Visual Stimuli ◽  
Receptive Fields ◽  
Area 17 ◽  
Area Mt ◽  
Mt Neurons ◽  
Visual Hemifield ◽  
Cortex Area ◽  
Owl Monkeys ◽  
Evoked Activity ◽  
Visual Area Mt

AbstractThe middle temporal visual area, MT, is one of three major targets of the primary visual cortex, area 17, in primates. We assessed the contribution of area 17 connections to the responsiveness of area MT neurons to visual stimuli by first mapping the representation of the visual hemifield in MT of anesthetized owl monkeys with microelectrodes, ablating an electrophysiologically mapped part of area 17, and then immediately remapping MT. Before the lesions, neurons at recording sites throughout MT responded vigorously to moving slits of light and other visual stimuli. In addition, the relationship of receptive fields to recording sites revealed a systematic representation of the contralateral visual hemifield in MT, as reported previously for owl monkeys and other primates. The immediate effect of removing part of the retinotopic map in area 17 by gentle aspiration was to selectively deactivate the corresponding part of the visuotopic map in MT. Lesions of dorsomedial area 17 representing central and paracentral vision of the lower visual quadrant deactivated neurons in caudomedial MT formerly having receptive fields in the central and paracentral lower visual quadrant. Most neurons at recording sites throughout other parts of MT had normal levels of responsiveness to visual stimuli, and receptive-field locations that closely matched those before the lesion. However, neurons at a few sites along the margin of the deactivated zone of cortex had receptive fields that were slightly displaced from the region of vision affected by the lesion into other parts of the visual field, suggesting some degree of plasticity in the visual hemifield representation in MT. Subsequent histological examination of cortex confirmed that the lesions were confined to area 17 and the recordings were in MT. The results indicate that the visually evoked activity of neurons in MT of owl monkeys is highly dependent on inputs relayed directly or indirectly from area 17.

scholarly journals Sensitivity of Neurons in the Middle Temporal Area of Marmoset Monkeys to Random Dot Motion

2017 ◽  
Author(s):  
Tristan A. Chaplin ◽  
Benjamin J. Allitt ◽  
Maureen A. Hagan ◽  
Nicholas S. Price ◽  
Ramesh Rajan ◽  
...  
Keyword(s):  
Primate Species ◽  
Neural Basis ◽  
Temporal Area ◽  
Middle Temporal ◽  
Mt Neurons ◽  
Wide Range ◽  
Middle Temporal Area ◽  
Dot Motion ◽  
Marmoset Monkeys ◽  
Random Dot Motion

AbstractNeurons in the Middle Temporal area (MT) of the primate cerebral cortex respond to moving visual stimuli. The sensitivity of MT neurons to motion signals can be characterized by using random-dot stimuli, in which the strength of the motion signal is manipulated by adding different levels of noise (elements that move in random directions). In macaques, this has allowed the calculation of “neurometric” thresholds. We characterized the responses of MT neurons in sufentanil/nitrous oxide anesthetized marmoset monkeys, a species which has attracted considerable recent interest as an animal model for vision research. We found that MT neurons show a wide range of neurometric thresholds, and that the responses of the most sensitive neurons could account for the behavioral performance of macaques and humans. We also investigated factors that contributed to the wide range of observed thresholds. The difference in firing rate between responses to motion in the preferred and null directions was the most effective predictor of neurometric threshold, whereas the direction tuning bandwidth had no correlation with the threshold. We also showed that it is possible to obtain reliable estimates of neurometric thresholds using stimuli that were not highly optimized for each neuron, as is often necessary when recording from large populations of neurons with different receptive field concurrently, as was the case in this study. These results demonstrate that marmoset MT shows an essential physiological similarity to macaque MT, and suggest that its neurons are capable of representing motion signals that allow for comparable motion-in-noise judgments.New and NoteworthyWe report the activity of neurons in marmoset MT in response to random-dot motion stimuli of varying coherence. The information carried by individual MT neurons was comparable to that of the macaque, and that the maximum firing rates were a strong predictor of sensitivity. Our study provides key information regarding the neural basis of motion perception in the marmoset, a small primate species that is becoming increasingly popular as an experimental model.

scholarly journals Twenty years of observations of PM 1-188: Its chemical abundances and extraordinary kinematics

2021 ◽  
Author(s):  
Miriam Peña ◽  
Liliana Hernández-Martínez ◽  
Francisco Ruiz-Escobedo
Keyword(s):  
Chemical Composition ◽  
Planetary Nebula ◽  
Central Star ◽  
Emission Lines ◽  
Type I ◽  
Chemical Abundances ◽  
Line Intensities ◽  
Physical Conditions ◽  
The Past ◽  
Spectrophotometric Data

Abstract The analysis of 20 years of spectrophotometric data of the double shell planetary nebula PM 1-188 is presented, aiming to determine the time evolution of the emission lines and the physical conditions of the nebula, as a consequence of the systematic fading of its [WC 10] central star whose brightness has declined by about 10 mag in the past 40 years. Our main results include that the [O iii], [O ii], [N ii] line intensities are increasing with time in the inner nebula as a consequence of an increase in electron temperature from 11 000 K in 2005 to more than 14 000 K in 2018, due to shocks. The intensity of the same lines are decreasing in the outer nebula, due to a decrease in temperature, from 13 000 K to 7000 K, in the same period. The chemical composition of the inner and outer shells was derived and they are similar. Both nebulae present subsolar O, S and Ar abundances, while they are He, N and Ne rich. For the outer nebula the values are 12+log He/H = 11.13 ± 0.05, 12+log O/H = 8.04 ± 0.04, 12+log N/H = 7.87 ± 0.06, 12+log S/H = 7.18 ± 0.10 and 12+log Ar = 5.33 ± 0.16. The O, S and Ar abundances are several times lower than the average values found in disc non-Type I PNe, and are reminiscent of some halo PNe. From high resolution spectra, an outflow in the N-S direction was found in the inner zone. Position-velocity diagrams show that the outflow expands at velocities in the −150 to 100 km s−1 range, and both shells have expansion velocities of about 40 km s−1.

Direction- and Velocity-Specific Responses from beyond the Classical Receptive Field in the Middle Temporal Visual Area (MT)

Perception ◽  
1985 ◽  
Vol 14 (2) ◽  
pp. 105-126 ◽  
Author(s):  
John Allman ◽  
Francis Miezin ◽  
EveLynn McGuinness
Keyword(s):  
Receptive Field ◽  
Visual Area ◽  
Area Mt ◽  
Motion Cues ◽  
Middle Temporal ◽  
Global Context ◽  
Mt Neurons ◽  
Classical Receptive Field ◽  
Local Stimulus ◽  
Visual Area Mt

The true receptive field of more than 90% of neurons in the middle temporal visual area (MT) extends well beyond the classical receptive field (crf), as mapped with conventional bar or spot stimuli, and includes a surrounding region that is 50 to 100 times the area of the crf. These extensive surrounds are demonstrated by simultaneously stimulating the crf and the surround with moving stimuli. The surrounds commonly have directional and velocity-selective influences that are antagonistic to the response from the crf. The crfs of MT neurons are organized in a topographic representation of the visual field. Thus MT neurons are embedded in an orderly visuotopic array, but are capable of integrating local stimulus conditions within a global context. The extensive surrounds of MT neurons may be involved in figure–ground discrimination, preattentive vision, perceptual constancies, and depth perception through motion cues.

scholarly journals The Origin of the Idea That Herpes Labialis Is of Prognostic Importance in Bacterial Meningitis

2020 ◽  
Vol 83 (1) ◽  
pp. 105-110
Author(s):  
Peter J. Koehler
Keyword(s):  
Primary Infection ◽  
Meningococcal Meningitis ◽  
Type I ◽  
Herpes Labialis ◽  
The Past ◽  
Prognostic Importance ◽  
19Th And 20Th Century ◽  
Century Idea ◽  
Diagnostic Importance ◽  
Selection Of

Objective:The aim of the work was to study the origin of the idea that herpes labialis (HL) in patients with pneumonia and meningitis was believed to be of prognostic importance. Background:HL is caused by a primary infection or reactivation of herpes simplex type I. In the past, it has been related to pneumonia and meningitis; moreover, HL was believed to be of prognostic importance. Methods:A selection of 19th- and 20th-century textbooks and referred articles was consulted. The relation between meningitis and herpes, type of meningitis, and attributed diagnostic and prognostic importance were studied. In addition, the HL-pneumonia association was studied. Results:The Strasbourg physician Charles-Polydore Forget was the first to describe the HL-meningitis association in 1843. Tourdes (1843), Drasche (1859), and Salomon (1864) attributed a favorable prognostic importance to the HL-meningitis relation. In a comprehensive monograph (1866), August Hirsch, although confirming the association, denied the prognostic importance through critical analysis of the data. Few authors attributed a diagnostic importance to the occurrence of HL, suggesting meningococcal meningitis. Conclusions:The HL-meningitis relation, but not the prognostic importance, has been mentioned in most neurological textbooks since then. In contrast to meningitis, in which a prognostic attribution of HL was only a short-lived 19th-century idea, the favorable prognostic importance of HL in pneumonia continued to be described until the 1950s. A possible protective effect of herpesviruses has been found in recent years. One could speculate that the disappearance of the prognostic HL-pneumonia relation could be related to the introduction of antibiotics in the late 1940s.

scholarly journals Pattern Motion Processing by MT Neurons

2019 ◽  
Vol 13 ◽  
Author(s):  
Parvin Zarei Eskikand ◽  
Tatiana Kameneva ◽  
Anthony N. Burkitt ◽  
David B. Grayden ◽  
Michael R. Ibbotson
Keyword(s):  
Motion Processing ◽  
Mt Neurons ◽  
Pattern Motion

Study of the Anatomical Features of the Offending Arteries Involved in Glossopharyngeal Neuralgia

2020 ◽  
Vol 19 (3) ◽  
pp. E259-E268 ◽  
Author(s):  
Kohei Inoue ◽  
Toshio Matsushima ◽  
Shinji Ohara ◽  
Jun Masuoka ◽  
Tatsuya Abe
Keyword(s):  
Glossopharyngeal Nerve ◽  
Glossopharyngeal Neuralgia ◽  
Type I ◽  
Type Ii ◽  
Vagus Nerves ◽  
Anatomical Features ◽  
The Past ◽  
Different Types ◽  
Running Pattern ◽  
Surgical Videos

Abstract BACKGROUND The anatomic features of the posterior inferior cerebellar arteries (PICAs) and the anterior inferior cerebellar arteries (AICAs) as offending arteries involved in glossopharyngeal neuralgia (GPN) are important to dictate the best surgical approach. OBJECTIVE To study and classify the anatomic features of the offending arteries. METHODS All clinical data and surgical videos from 18 GPN cases that were surgically treated during the past 10 yr were retrospectively reviewed. RESULTS Among these 18 patients, the offending arteries involved were the PICA in 12 (66.7%), AICA in 4 (22.2%), and both PICA and AICA in 2 (11.1%). The PICA were then classified into the following groups based on their anatomic features: type I: the PICA formed an upward loop at the level of the glossopharyngeal nerve and passed between the glossopharyngeal and vestibulocochlear nerves; type II: the PICA formed an upward loop at the level of the glossopharyngeal nerve and passed between the glossopharyngeal and vagus nerves or between the rootlets of the vagus nerve; and type III: the PICA passed between the glossopharyngeal and vestibulocochlear nerves without forming a loop. The AICA had only one running pattern. CONCLUSION The offending arteries involved in GPN, mainly the PICA and/or AICA, were classified into 4 different types based on their anatomic features.

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