scholarly journals Facilitation of neural responses to targets moving against optic flow

2021 ◽  
Vol 118 (38) ◽  
pp. e2024966118
Author(s):  
Sarah Nicholas ◽  
Karin Nordström
Keyword(s):  
Optic Flow ◽  
Target Motion ◽  
Human Observer ◽  
Neural Responses ◽  
Response Facilitation ◽  
Descending Neurons ◽  
The World ◽  
Background Clutter ◽  
Spatial Window ◽  
Target Pursuit

For the human observer, it can be difficult to follow the motion of small objects, especially when they move against background clutter. In contrast, insects efficiently do this, as evidenced by their ability to capture prey, pursue conspecifics, or defend territories, even in highly textured surrounds. We here recorded from target selective descending neurons (TSDNs), which likely subserve these impressive behaviors. To simulate the type of optic flow that would be generated by the pursuer’s own movements through the world, we used the motion of a perspective corrected sparse dot field. We show that hoverfly TSDN responses to target motion are suppressed when such optic flow moves syn-directional to the target. Indeed, neural responses are strongly suppressed when targets move over either translational sideslip or rotational yaw. More strikingly, we show that TSDNs are facilitated by optic flow moving counterdirectional to the target, if the target moves horizontally. Furthermore, we show that a small, frontal spatial window of optic flow is enough to fully facilitate or suppress TSDN responses to target motion. We argue that such TSDN response facilitation could be beneficial in modulating corrective turns during target pursuit.

scholarly journals Facilitation of neural responses to targets moving in three-dimensional optic flow

2020 ◽  
Author(s):  
Sarah Nicholas ◽  
Karin Nordström
Keyword(s):  
Biological Sciences ◽  
Opposite Direction ◽  
Optic Flow ◽  
Three Dimensional ◽  
Target Motion ◽  
Human Observer ◽  
Spatio Temporal ◽  
Small Targets ◽  
Target Pursuit ◽  
Temporal Profiles

AbstractFor the human observer, it can be difficult to follow the motion of small objects, especially when they move against background clutter. However, insects efficiently do this, as evidenced by their ability to capture prey, pursue conspecifics, or defend territories, even in highly textured surrounds. This behavior has been attributed to optic lobe neurons that are sharply tuned to the motion of small targets, as these neurons respond robustly even to a target moving against background motion. However, the target selective descending neurons (TSDNs), that more directly control behavioral output, do not. Importantly, though, the backgrounds used previously not only lacked 3D motion cues, but also high-contrast features, both of which would be encountered during natural behaviors. To redress this deficiency, we here use backgrounds consisting of many targets moving coherently to simulate the type of 3D optic flow that would be generated by an insect’s own motion through the world. We show that hoverfly TSDNs do not respond to this type of optic flow, even though it contains features with spatio-temporal profiles similar to optimal targets. However, TSDN responses are inhibited when this optic flow is shown together with a target. More surprisingly, TSDNs are facilitated by horizontal, frontal optic flow in the opposite direction to target motion. We show that these interactions are likely inherited from the pre-synaptic neurons, and argue that the facilitation could benefit the initiation of target pursuit.Significance statementTarget detection in visual clutter is a difficult computational task that insects, with their poor resolution compound eyes and small brains, do successfully and with extremely short behavioral delays. We here show that target neurons do not respond to widefield motion consisting of a multitude of “targets”, suggesting that the hoverfly visual system interprets coherent widefield motion differently from the motion of individual targets. In addition, we show that widefield motion in the opposite direction to target motion increases the neural response. This is an incredibly non-intuitive finding, and difficult to reconcile with current models for target selectivity, but has behavioral relevance.ClassificationBiological sciences: Neuroscience

Something Rich and Strange

2020 ◽  
pp. 207-252
Author(s):  
Philip Kitcher
Keyword(s):  
John Dewey ◽  
William James ◽  
Human Observer ◽  
Multiple Perspectives ◽  
The World ◽  
Narrative Techniques ◽  
Moral Attitudes

Ulysses presents its central figures from many perspectives. Joyce’s proliferation of stylistic devices enables readers to view Leopold Bloom, Stephen Dedalus, and Molly Bloom from different angles. Although confused and irritated readers might take the profusion of styles as a showy display of erudition, or, at best, as creating opportunities for humor, this chapter argues that the multiplication of narrative techniques serves important novelistic purposes. They enable Joyce to provoke revisions of our conventional values and to recognize the extraordinary in the commonplace. The chapter suggests broadening David Hayman’s seminal concept of “the Arranger” to consider arrangements, ways of reordering and restructuring the world that transcend the perspective of any potential human observer. Joyce’s multiple perspectives are akin to the worlds of experience favored by pragmatists like William James and John Dewey. They enable us to recognize the heroism in Bloom and to reflect on moral attitudes we take for granted.

scholarly journals Impact of visual motion adaptation on neural responses to objects and its dependence on the temporal characteristics of optic flow

2011 ◽  
Vol 105 (4) ◽  
pp. 1825-1834 ◽  
Author(s):  
Pei Liang ◽  
Roland Kern ◽  
Rafael Kurtz ◽  
Martin Egelhaaf
Keyword(s):  
Optic Flow ◽  
Visual Motion ◽  
Induced Response ◽  
Neural Responses ◽  
Neuronal Responses ◽  
Motion Adaptation ◽  
Preferred Direction ◽  
Pure Rotation ◽  
Normal Behavior ◽  
Natural Dynamics

It is still unclear how sensory systems efficiently encode signals with statistics as experienced by animals in the real world and what role adaptation plays during normal behavior. Therefore, we studied the performance of visual motion-sensitive neurons of blowflies, the horizontal system neurons, with optic flow that was reconstructed from the head trajectories of semi-free-flying flies. To test how motion adaptation is affected by optic flow dynamics, we manipulated the seminatural optic flow by targeted modifications of the flight trajectories and assessed to what extent neuronal responses to an object located close to the flight trajectory depend on adaptation dynamics. For all types of adapting optic flow object-induced response increments were stronger in the adapted compared with the nonadapted state. Adaptation with optic flow characterized by the typical alternation between translational and rotational segments produced this effect but also adaptation with optic flow that lacked these distinguishing features and even pure rotation at a constant angular velocity. The enhancement of object-induced response increments had a direction-selective component because preferred-direction rotation and natural optic flow were more efficient adaptors than null-direction rotation. These results indicate that natural dynamics of optic flow is not a basic requirement to adapt neurons in a specific, presumably functionally beneficial way. Our findings are discussed in the light of adaptation mechanisms proposed on the basis of experiments previously done with conventional experimenter-defined stimuli.

scholarly journals MEG activity of the dorsolateral prefrontal cortex during optic flow stimulations detects mild cognitive impairment due to Alzheimer’s disease

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259677
Author(s):  
Moeko Noguchi-Shinohara ◽  
Masato Koike ◽  
Hirofumi Morise ◽  
Kiwamu Kudo ◽  
Shoko Tsuchimine ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Cognitive Impairment ◽  
Prefrontal Cortex ◽  
Mild Cognitive Impairment ◽  
Optic Flow ◽  
Dorsolateral Prefrontal Cortex ◽  
Brodmann Area ◽  
Maximum Power ◽  
Neural Responses ◽  
Dorsolateral Prefrontal

Dorsal stream, which has a neuronal connection with dorsolateral prefrontal cortex (DLPFC), is known to be responsible for detection of motion including optic flow perception. Using magnetoencephalography (MEG), this study aimed to examine neural responses to optic flow stimuli with looming motion in the DLPFC in patients with mild cognitive impairment due to Alzheimer’s disease (AD-MCI) compared with cognitively unimpaired participants (CU). We analyzed the neural responses by evaluating maximum source-localized power for the AD-MCI group (n = 11) and CU (n = 20), focusing on six regions of interest (ROIs) that form the DLPFC: right and left dorsal Brodmann area 9/46 (A9/46d), Brodmann area 46 (A46) and ventral Brodmann area 9/46 (A9/46v). We found significant differences in the maximum power between the groups in the left A46 and A9/46v. Moreover, in the left A9/46v, the maximum power significantly correlated with the Wechsler Memory Scale-Revised general memory score and delayed recall score. The maximum power in the left A9/46v also revealed high performance in AD-MCI versus CU classification with the area under the ROC curve of 0.90. This study demonstrated that MEG during the optic flow task can be useful in discriminating AD-MCI from CU.

scholarly journals Cardiac motion estimation using multi-scale feature points

2008 ◽  
Author(s):  
Alessandro Becciu ◽  
Hans C. van Assen ◽  
Luc Florack ◽  
Bart J. Janssen ◽  
Bart Ter haar romeny
Keyword(s):  
Magnetic Resonance ◽  
Optic Flow ◽  
Causes Of Death ◽  
Cardiac Motion ◽  
Feature Points ◽  
Aperture Problem ◽  
Multi Scale ◽  
Harmonic Phase ◽  
The World ◽  
Suitable Framework

Heart illnesses influence the functioning of the cardiac muscle and are the major causes of death in the world. Optic flow methods are essential tools to assess and quantify the contraction of the cardiac walls, but are hampered by the aperture problem. Harmonic phase (HARP) techniques measure the phase in magnetic resonance (MR) tagged images. Due to the regular geometry, patterns generated by a combination of HARPs and sine HARPs represent a suitable framework to extract landmark features. In this paper we introduce a new aperture-problem free method to study the cardiac motion by tracking multi-scale features such as maxima, minima, saddles and corners, on HARP and sine HARP tagged images.

scholarly journals Popularity is linked to neural coordination: Neural evidence for an Anna Karenina principle in social networks

2021 ◽  
Author(s):  
Elisa C Baek ◽  
Ryan Hyon ◽  
Karina López ◽  
Emily S. Finn ◽  
Mason A. Porter ◽  
...  
Keyword(s):  
Social Networks ◽  
Social Cognition ◽  
Network Analysis ◽  
Brain Regions ◽  
Social Connections ◽  
Degree Centrality ◽  
Neural Responses ◽  
Anna Karenina ◽  
The World ◽  
High Level

People differ in how they attend to, interpret, and respond to their surroundings. Convergent processing of the world may be one factor that contributes to social connections between individuals. We used neuroimaging and network analysis to investigate whether the most central individuals in their communities (as measured by in-degree centrality, a notion of popularity) process the world in a particularly normative way. More central individuals had exceptionally similar neural responses to their peers and especially to each other in brain regions associated with high-level interpretations and social cognition (e.g., in the default-mode network), whereas less-central individuals exhibited more idiosyncratic responses. Self-reported enjoyment of and interest in stimuli followed a similar pattern, but accounting for these data did not change our main results. These findings suggest an “Anna Karenina principle” in social networks: Highly-central individuals process the world in exceptionally similar ways, whereas less-central individuals process the world in idiosyncratic ways.

scholarly journals Persistent Firing and Adaptation in Optic-Flow-Sensitive Descending Neurons

2020 ◽  
Vol 30 (14) ◽  
pp. 2739-2748.e2
Author(s):  
Sarah Nicholas ◽  
Karin Nordström
Keyword(s):  
Optic Flow ◽  
Descending Neurons ◽  
Persistent Firing

scholarly journals Examining the relationship between social cognition and neural synchrony during movies in children with and without autism

2020 ◽  
Author(s):  
KM Lyons ◽  
RA Stevenson ◽  
AM Owen ◽  
B Stojanoski
Keyword(s):  
Social Cognition ◽  
Conscious Experience ◽  
Autistic Traits ◽  
Autism Spectrum ◽  
Social Impairment ◽  
Neural Synchrony ◽  
Neural Responses ◽  
The World ◽  
Marked Deficit ◽  
The Relationship

AbstractChildren who have been diagnosed with autism spectrum disorder (ASD) often show a marked deficit in measures of social cognition. In autistic adults, measures of social cognition have been shown to relate to differences in brain synchronization (as measured by fMRI) when individuals are processing naturalistic stimuli, such as movies. However, whether children with social impairments, with or without a diagnosis of ASD, differ in their neural responses to movies has not yet been investigated. In the current study, neural synchrony, measured using fMRI, was examined in three groups of children aged 7 to 12, who differed with respect to scores on a measure of autistic traits associated with social impairment and whether or not they had been diagnosed with ASD. While watching the movie ‘Despicable Me’, those diagnosed with ASD had significantly less neural synchrony in areas that have been previously shown to be associated with social cognition (e.g. areas related to ‘theory of mind’), and plot following (e.g. the lateral prefrontal cortex), than those who did not have an ASD diagnosis. In contrast, two groups who differed in their degree of social impairment, but did not have a diagnosis of ASD, showed no significant differences in neural synchrony across the whole brain. These results shed some light on how autistic traits may contribute to an individual’s conscious experience of the world, and how, for children with ASD, that experience may differ markedly from that of those without ASD.

scholarly journals Implicit Agency in Observed Actions: Evidence for N1 Suppression of Tones Caused by Self-made and Observed Actions

2015 ◽  
Vol 27 (4) ◽  
pp. 752-764 ◽  
Author(s):  
Simandeep K. Poonian ◽  
Jessica McFadyen ◽  
Jessica Ogden ◽  
Ross Cunnington
Keyword(s):  
Interval Estimation ◽  
The Self ◽  
Sense Of Agency ◽  
Neural Responses ◽  
Top Down ◽  
Intentional Binding ◽  
Visual Events ◽  
Neural Processes ◽  
The World ◽  
Sensory Consequence

Every day we make attributions about how our actions and the actions of others cause consequences in the world around us. It is unknown whether we use the same implicit process in attributing causality when observing others' actions as we do when making our own. The aim of this research was to investigate the neural processes involved in the implicit sense of agency we form between actions and effects, for both our own actions and when watching others' actions. Using an interval estimation paradigm to elicit intentional binding in self-made and observed actions, we measured the EEG responses indicative of anticipatory processes before an action and the ERPs in response to the sensory consequence. We replicated our previous findings that we form a sense of implicit agency over our own and others' actions. Crucially, EEG results showed that tones caused by either self-made or observed actions both resulted in suppression of the N1 component of the sensory ERP, with no difference in suppression between consequences caused by observed actions compared with self-made actions. Furthermore, this N1 suppression was greatest for tones caused by observed goal-directed actions rather than non-action or non-goal-related visual events. This suggests that top–down processes act upon the neural responses to sensory events caused by goal-directed actions in the same way for events caused by the self or those made by other agents.

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