scholarly journals Decision-level adaptation in motion perception

2015 ◽  
Vol 2 (12) ◽  
pp. 150418 ◽  
Author(s):  
George Mather ◽  
Rebecca J. Sharman
Keyword(s):  
Sensory Neurons ◽  
Prolonged Exposure ◽  
Visual Stimuli ◽  
Relative Activity ◽  
Sensory Level ◽  
Decision Factors ◽  
Decision Level ◽  
Implied Motion ◽  
Level Of Processing ◽  
Stimulus Direction

Prolonged exposure to visual stimuli causes a bias in observers' responses to subsequent stimuli. Such adaptation-induced biases are usually explained in terms of changes in the relative activity of sensory neurons in the visual system which respond selectively to the properties of visual stimuli. However, the bias could also be due to a shift in the observer's criterion for selecting one response rather than the alternative; adaptation at the decision level of processing rather than the sensory level. We investigated whether adaptation to implied motion is best attributed to sensory-level or decision-level bias. Three experiments sought to isolate decision factors by changing the nature of the participants' task while keeping the sensory stimulus unchanged. Results showed that adaptation-induced bias in reported stimulus direction only occurred when the participants' task involved a directional judgement, and disappeared when adaptation was measured using a non-directional task (reporting where motion was present in the display, regardless of its direction). We conclude that adaptation to implied motion is due to decision-level bias, and that a propensity towards such biases may be widespread in sensory decision-making.

Age-Related Decline in Emotional Prosody Discrimination

2014 ◽  
Vol 61 (3) ◽  
pp. 215-223 ◽  
Author(s):  
Rachel L. C. Mitchell ◽  
Rachel A. Kingston
Keyword(s):  
Older Adults ◽  
Auditory Perception ◽  
Duration Discrimination ◽  
Pitch Perception ◽  
Sensory Level ◽  
Emotional Prosody ◽  
Processing Stage ◽  
Acoustic Characteristics ◽  
Age Related ◽  
Level Of Processing

It is now accepted that older adults have difficulty recognizing prosodic emotion cues, but it is not clear at what processing stage this ability breaks down. We manipulated the acoustic characteristics of tones in pitch, amplitude, and duration discrimination tasks to assess whether impaired basic auditory perception coexisted with our previously demonstrated age-related prosodic emotion perception impairment. It was found that pitch perception was particularly impaired in older adults, and that it displayed the strongest correlation with prosodic emotion discrimination. We conclude that an important cause of age-related impairment in prosodic emotion comprehension exists at the fundamental sensory level of processing.

scholarly journals Visual Adaptation to Goal-directed Hand Actions

2009 ◽  
Vol 21 (9) ◽  
pp. 1805-1819 ◽  
Author(s):  
Nick E. Barraclough ◽  
Rebecca H. Keith ◽  
Dengke Xiao ◽  
Mike W. Oram ◽  
David I. Perrett
Keyword(s):  
Prolonged Exposure ◽  
Visual Stimuli ◽  
Visual Adaptation ◽  
Action Perception ◽  
Cell Responses ◽  
Action Processing ◽  
Opposite Action ◽  
Single Cell Responses ◽  
Adaptation Action ◽  
Processing Mechanisms

Prolonged exposure to visual stimuli, or adaptation, often results in an adaptation “aftereffect” which can profoundly distort our perception of subsequent visual stimuli. This technique has been commonly used to investigate mechanisms underlying our perception of simple visual stimuli, and more recently, of static faces. We tested whether humans would adapt to movies of hands grasping and placing different weight objects. After adapting to hands grasping light or heavy objects, subsequently perceived objects appeared relatively heavier, or lighter, respectively. The aftereffects increased logarithmically with adaptation action repetition and decayed logarithmically with time. Adaptation aftereffects also indicated that perception of actions relies predominantly on view-dependent mechanisms. Adapting to one action significantly influenced the perception of the opposite action. These aftereffects can only be explained by adaptation of mechanisms that take into account the presence/absence of the object in the hand. We tested if evidence on action processing mechanisms obtained using visual adaptation techniques confirms underlying neural processing. We recorded monkey superior temporal sulcus (STS) single-cell responses to hand actions. Cells sensitive to grasping or placing typically responded well to the opposite action; cells also responded during different phases of the actions. Cell responses were sensitive to the view of the action and were dependent upon the presence of the object in the scene. We show here that action processing mechanisms established using visual adaptation parallel the neural mechanisms revealed during recording from monkey STS. Visual adaptation techniques can thus be usefully employed to investigate brain mechanisms underlying action perception.

Neuronal plasticity regulated by the insulin-like signaling pathway underlies salt chemotaxis learning in Caenorhabditis elegans

2011 ◽  
Vol 106 (1) ◽  
pp. 301-308 ◽  
Author(s):  
Shigekazu Oda ◽  
Masahiro Tomioka ◽  
Yuichi Iino
Keyword(s):  
Caenorhabditis Elegans ◽  
Signaling Pathway ◽  
Sensory Neurons ◽  
Neuronal Plasticity ◽  
Behavioral Plasticity ◽  
Prolonged Exposure ◽  
Imaging Techniques ◽  
Synaptic Release ◽  
Starvation Conditions

Quantification of neuronal plasticity in a living animal is essential for understanding learning and memory. Caenorhabditis elegans shows a chemotactic behavior toward NaCl. However, it learns to avoid NaCl after prolonged exposure to NaCl under starvation conditions, which is called salt chemotaxis learning. Insulin-like signaling is important for this behavioral plasticity and functions in one of the salt-sensing sensory neurons, ASE right (ASER). However, how neurons including ASER show neuronal plasticity is unknown. To determine the neuronal plasticity related to salt chemotaxis learning, we measured Ca2+ response and synaptic release of individual neurons by using in vivo imaging techniques. We found that response of ASER increased whereas its synaptic release decreased after prolonged exposure to NaCl without food. These changes in the opposite directions were abolished in insulin-like signaling mutants, suggesting that insulin-like signaling regulates these plasticities in ASER. The response of one of the downstream interneurons, AIB, decreased profoundly after NaCl conditioning. This alteration in AIB response was independent of the insulin-like signaling pathway. Our results suggest that information on NaCl is modulated at the level of both sensory neurons and interneurons in salt chemotaxis learning.

Neural Correlates of High-Level Adaptation-Related Aftereffects

2010 ◽  
Vol 103 (3) ◽  
pp. 1410-1417 ◽  
Author(s):  
Csaba Cziraki ◽  
Mark W. Greenlee ◽  
Gyula Kovács
Keyword(s):  
Prolonged Exposure ◽  
Activity Patterns ◽  
Body Part ◽  
Neural Correlates ◽  
Relative Activity ◽  
The Body ◽  
Perceptual Bias ◽  
Face Area ◽  
Extrastriate Body Area ◽  
High Level

Prolonged exposure to complex stimuli, such as faces, biases perceptual decisions toward nonadapted, dissimilar stimuli, leading to contrastive aftereffects. Here we tested the neural correlates of this perceptual bias using a functional magnetic resonance imaging adaptation (fMRIa) paradigm. Adaptation to a face or hand stimulus led to aftereffects by biasing the categorization of subsequent ambiguous face/hand composite stimuli away from the adaptor category. The simultaneously observed fMRIa in the face-sensitive fusiform face area (FFA) and in the body-part–sensitive extrastriate body area (EBA) depended on the behavioral response of the subjects: adaptation to the preferred stimulus of the given area led to larger signal reduction during trials when it biased perception than during trials when it was less effective. Activity in two frontal areas correlated positively with the activity patterns in FFA and EBA. Based on our novel adaptation paradigm, the results suggest that the adaptation-induced aftereffects are mediated by the relative activity of category-sensitive areas of the human brain as demonstrated by fMRI.

Can a Word Sound Like a Shape Before You Have Seen It? Sound-Shape Mapping Prior to Conscious Awareness

2017 ◽  
Vol 28 (3) ◽  
pp. 263-275 ◽  
Author(s):  
Shao-Min Hung ◽  
Suzy J. Styles ◽  
Po-Jang Hsieh
Keyword(s):  
Visual Stimuli ◽  
Visual Features ◽  
Conscious Awareness ◽  
Word Form ◽  
Continuous Flash Suppression ◽  
Auditory Word ◽  
Word Forms ◽  
Shape Mapping ◽  
Different Cultures ◽  
Level Of Processing

Nonarbitrary mappings between sound and shape (i.e., the bouba-kiki effect) have been shown across different cultures and early in development; however, the level of processing at which this effect arises remains unclear. Here we show that the mapping occurs prior to conscious awareness of the visual stimuli. Under continuous flash suppression, congruent stimuli (e.g., “kiki” inside an angular shape) broke through to conscious awareness faster than incongruent stimuli. This was true even when we trained people to pair unfamiliar letters with auditory word forms, a result showing that the effect was driven by the phonology, not the visual features, of the letters. Furthermore, visibility thresholds of the shapes decreased when they were preceded by a congruent auditory word form in a masking paradigm. Taken together, our results suggest that sound-shape mapping can occur automatically prior to conscious awareness of visual shapes, and that sensory congruence facilitates conscious awareness of a stimulus being present.

scholarly journals Quickly fading afterimages: hierarchical adaptations in human perception

2019 ◽  
Author(s):  
Madeline E. Klinger ◽  
Christian A. Kell ◽  
Danko Nikolić
Keyword(s):  
Prolonged Exposure ◽  
Visual Stimuli ◽  
Human Perception ◽  
Visual Content ◽  
Blank Screen ◽  
Adaptive Mechanisms ◽  
Fast Removal

AbstractAfterimages result from a prolonged exposure to still visual stimuli. They are best detectable when viewed against uniform backgrounds and can persist for multiple seconds. Consequently, the dynamics of afterimages appears to be slow by their very nature. To the contrary, we report here that about 50% of an afterimage intensity can be erased rapidly—within less than a second. The prerequisite is that subjects view a rich visual content to erase the afterimage; fast erasure of afterimages does not occur if subjects view a blank screen. Moreover, we find evidence that fast removal of afterimages is a skill learned with practice as our subjects were always more effective in cleaning up afterimages in later parts of the experiment. These results can be explained by a tri-level hierarchy of adaptive mechanisms, as has been proposed by the theory of practopoiesis.

scholarly journals Pengaruh Pemaparan Medan Magnet Pada Media Mandels Yang Dimodifikasi Terhadap Pertumbuhan Dan Aktivitas Enzim Selulase Bacillus Sp.

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Wayan Hernawati ◽  
Sumardi Sumardi ◽  
Rochman Agustrina ◽  
Herman Yulianto
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Culture Medium ◽  
Structural Changes ◽  
Prolonged Exposure ◽  
Relative Activity ◽  
Bacillus Sp ◽  
Relative Growth ◽  
Cellulase Enzyme ◽  
Bacterium Bacillus

Enzymes can undergo structural changes due to various environmental factor such as pH,temperature, electricity and magnetic fields. The purpose of this study was to investigate theeffect of magnetic field strength and duration of exposure to the modified of media Mandelsused as a culture medium of Bacillus sp. on the growth and activity of cellulase enzyme fromthe bacterium Bacillus sp. Factorial study group were prepared using the method of fullrandomized design (RKLT). The first factor is the strong magnetic field consists of 4 levels ofmagnetic field strength treatment: 0 mT; 0,1 mT; 0,2 mT; 0.3 mT. The second faktor is theprolonged exposure consisting of 4 levels prolonged exposure treatments 0, 10, 20, 30minutes. each unit treatment was repeated 3 times. The results showed that exposure tomagnetic fields on modified of media Mandels causes a decrease in the relative activity ofthe enzyme cellulase and relative growth of Bacillus sp.Keywords: cellulase enzyme, magnetic field, Mandels modification, Bacillus sp.

scholarly journals Stability and individual variability of social attachment in imprinting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bastien S. Lemaire ◽  
Daniele Rucco ◽  
Mathilde Josserand ◽  
Giorgio Vallortigara ◽  
Elisabetta Versace
Keyword(s):  
Social Behaviour ◽  
Prolonged Exposure ◽  
Visual Stimuli ◽  
Bird Species ◽  
Individual Variability ◽  
Social Attachment ◽  
Precocial Bird ◽  
Filial Imprinting ◽  
Past Experiences ◽  
Over Time

AbstractFilial imprinting has become a model for understanding memory, learning and social behaviour in neonate animals. This mechanism allows the youngs of precocial bird species to learn the characteristics of conspicuous visual stimuli and display affiliative response to them. Although longer exposures to an object produce stronger preferences for it afterwards, this relation is not linear. Sometimes, chicks even prefer to approach novel rather than familiar objects. To date, little is known about how filial preferences develop across time. This study aimed to investigate filial preferences for familiar and novel imprinting objects over time. After hatching, chicks were individually placed in an arena where stimuli were displayed on two opposite screens. Using an automated setup, the duration of exposure and the type of stimuli were manipulated while the time spent at the imprinting stimulus was monitored across 6 days. We showed that prolonged exposure (3 days vs 1 day) to a stimulus produced robust filial imprinting preferences. Interestingly, with a shorter exposure (1 day), animals re-evaluated their filial preferences in functions of their spontaneous preferences and past experiences. Our study suggests that predispositions influence learning when the imprinting memories are not fully consolidated, driving animal preferences toward more predisposed stimuli.

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