Discrimination of Spatiotemporal Patterns: The Role of Sustained and Transient Mechanisms

The role of sustained and transient mechanisms in pattern and flicker perception has been examined in two discrimination experiments. In the first, observers were required to analyze the temporal or spatial properties of a stimulus that highly stimulated either sustained or transient mechanisms. The results were only partially consistent with a model identifying sustained mechanisms with pattern perception and transient mechanisms with flicker perception. In the second experiment a subthreshold summation paradigm was used to explore interactions among those mechanisms that encode the temporal and spatial properties of a stimulus. The effect of a subthreshold temporal-frequency change on discrimination performance could not be explained by models in which temporal-frequency and spatial-frequency changes are evaluated separately and then combined.

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The Emotional Glue of the Senses: Affective Certainty and Congruency in the Rubber Hand Illusion

10.1101/401422 ◽

2018 ◽

Author(s):

Maria Laura Filippetti ◽

Louise P. Kirsch ◽

Laura Crucianelli ◽

Aikaterini Fotopoulou

Keyword(s):

Multisensory Integration ◽

Sensory Stimulation ◽

Rubber Hand Illusion ◽

Body Ownership ◽

Top Down ◽

Rubber Hand ◽

Spatial Properties ◽

Affective Quality ◽

Temporal And Spatial

AbstractOur sense of body ownership relies on integrating different sensations according to their temporal and spatial congruency. Nevertheless, there is ongoing controversy about the role of affective congruency during multisensory integration, i.e. whether the stimuli to be perceived by the different sensory channels are congruent or incongruent in terms of their affective quality. In the present study, we applied a widely used multisensory integration paradigm, the Rubber Hand Illusion, to investigate the role of affective, top-down aspects of sensory congruency between visual and tactile modalities in the sense of body ownership. In Experiment 1 (N = 36), we touched participants with either soft or rough fabrics in their unseen hand, while they watched a rubber hand been touched synchronously with the same fabric or with a ‘hidden’ fabric of ‘uncertain roughness’. In Experiment 2 (N = 50), we used the same paradigm as in Experiment 1, but replaced the ‘uncertainty’ condition with an ‘incongruent’ one, in which participants saw the rubber hand being touched with a fabric of incongruent roughness and hence opposite valence. We found that certainty (Experiment 1) and congruency (Experiment 2) between the felt and vicariously perceived tactile affectivity led to higher subjective embodiment compared to uncertainty and incongruency, respectively, irrespective of any valence effect. Our results suggest that congruency in the affective top-down aspects of sensory stimulation is important to the multisensory integration process leading to embodiment, over and above temporal and spatial properties.

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Role of the color-opponent and broad-band channels in vision

Visual Neuroscience ◽

10.1017/s0952523800000420 ◽

1990 ◽

Vol 5 (04) ◽

pp. 321-346 ◽

Cited By ~ 239

Author(s):

Peter H. Schiller ◽

Nikos K. Logothetis ◽

Eliot R. Charles

Keyword(s):

Spatial Frequency ◽

Temporal Frequency ◽

Broad Band ◽

High Spatial Frequency ◽

Brightness Perception ◽

Rods And Cones ◽

Form Vision ◽

Temporal Domain ◽

Frequency Domains

AbstractThe functions of the primate color-opponent and broad-band channels were assessed by examining the visual capacities of rhesus monkeys following selective lesions of parvocellular and magnocellular lateral geniculate nucleus, which respectively relay these two channels to the cortex. Parvocellular lesions impaired color vision, high spatial-frequency form vision, and fine stereopsis. Magnocellular lesions impaired high temporal- frequency flicker and motion perception but produced no deficits in stereopsis. Low spatial-frequency form vision, stereopsis, and brightness perception were unaffected by either lesion. Much as the rods and cones of the retina can be thought of as extending the range of vision in the intensity domain, we propose that the color-opponent channel extends visual capacities in the wavelength and spatial-frequency domains whereas the broad-band channel extends them in the temporal domain.

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Effect of repetitive visual stimuli on behaviour and plasma corticosterone of European starlings

Animal Biology ◽

10.1163/1570756054472827 ◽

2005 ◽

Vol 55 (3) ◽

pp. 245-258 ◽

Cited By ~ 3

Author(s):

◽

Keyword(s):

Spatial Frequency ◽

High Frequency ◽

Temporal Frequency ◽

Low Frequency ◽

High Spatial Frequency ◽

Plasma Corticosterone ◽

European Starlings ◽

Fluorescent Lamps ◽

Spatial Frequencies ◽

Temporal And Spatial

AbstractFlickering light can cause adverse effects in some humans, as can rhythmic spatial patterns of particular frequencies. We investigated whether birds react to the temporal frequency of standard 100 Hz fluorescent lamps and the spatial frequency of the visual surround in the manner predicted by the human literature, by examining their effects on the preferences, behaviour and plasma corticosterone of European starlings (Sturnus vulgaris). We predicted that high frequency lighting (> 30 kHz) and a relatively low spatial frequency on the walls of their cages (0.1 cycle cm−1) would be less aversive than low frequency lighting (100 Hz) and a relatively high spatial frequency (2.5 cycle cm−1). Birds had strong preferences for both temporal and spatial frequencies. These preferences did not always fit with predictions, although there was evidence that 100 Hz was more stressful than 30 kHz lighting, as birds were less active and basal corticosterone levels were higher under 100 Hz lighting. Our chosen spatial frequencies had no overall significant effect on corticosterone levels. Although there are clearly effects of, and interactions between, the frequency of the light and the visual surround on the behaviour and physiology of birds, the pattern of results is not straightforward.

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Temporal and Spatial Response to Second-Order Stimuli in Cat Area 18

Journal of Neurophysiology ◽

10.1152/jn.1998.80.6.2811 ◽

1998 ◽

Vol 80 (6) ◽

pp. 2811-2823 ◽

Cited By ~ 55

Author(s):

Isabelle Mareschal ◽

Curtis L. Baker

Keyword(s):

Spatial Frequency ◽

Frequency Tuning ◽

Temporal Frequency ◽

Second Order ◽

Area 18 ◽

Temporal Properties ◽

Spatial Response ◽

Frequency Components ◽

Parallel Streams ◽

Temporal And Spatial

Mareschal, Isabelle and Curtis L. Baker, Jr. Temporal and spatial response to second-order stimuli in cat area 18. J. Neurophysiol. 80: 2811–2823, 1998. Approximately one-half of the neurons in cat area 18 respond to contrast envelope stimuli, consisting of a sinewave carrier whose contrast is modulated by a drifting sinewave envelope of lower spatial frequency. These stimuli should fail to elicit a response from a conventional linear neuron because they are designed to contain no spatial frequency components within the cell's luminance-defined frequency passband. We measured neurons' responses to envelope stimuli by varying both the drift rate and spatial frequency of the contrast modulation. These data were then compared with the same neurons' spatial and temporal properties obtained with luminance-defined sinewave gratings. Most neurons' responses to the envelope stimuli were spatially and temporally bandpass, with bandwidths comparable with those measured with luminance gratings. The temporal responses of these neurons (temporal frequency tuning and latency) were systematically slower when tested with envelope stimuli than with luminance gratings. The simplest kind of model that can accommodate these results is one having separate, parallel streams of bandpass processing for luminance and envelope stimuli.

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Temporal allele frequency change and estimation of effective size in populations with overlapping generations.

Genetics ◽

10.1093/genetics/139.2.1077 ◽

1995 ◽

Vol 139 (2) ◽

pp. 1077-1090 ◽

Cited By ~ 8

Author(s):

P E Jorde ◽

N Ryman

Keyword(s):

Population Size ◽

Effective Population Size ◽

Allele Frequency ◽

Overlapping Generations ◽

Temporal Frequency ◽

Effective Size ◽

Frequency Change ◽

Effective Population ◽

Frequency Shifts ◽

Frequency Changes

Abstract In this paper we study the process of allele frequency change in finite populations with overlapping generations with the purpose of evaluating the possibility of estimating the effective size from observations of temporal frequency shifts of selectively neutral alleles. Focusing on allele frequency changes between successive cohorts (individuals born in particular years), we show that such changes are not determined by the effective population size alone, as they are when generations are discrete. Rather, in populations with overlapping generations, the amount of temporal allele frequency change is dependent on the age-specific survival and birth rates. Taking this phenomenon into account, we present an estimator for effective size that can be applied to populations with overlapping generations.

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Supplemental Material for The Role of Spatial Frequency in Expert Object Recognition

Journal of Experimental Psychology Human Perception & Performance ◽

10.1037/xhp0000139.supp ◽

2015 ◽

Keyword(s):

Object Recognition ◽

Spatial Frequency

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Giscience in the Mountain Geography

Tribhuvan University Journal ◽

10.3126/tuj.v27i1-2.26390 ◽

2010 ◽

Vol 27 (1-2) ◽

pp. 81-90

Author(s):

Krishna Poudel

Keyword(s):

Spatial Data ◽

Environmental Data ◽

Temporal Data ◽

Observation Systems ◽

Research Findings ◽

Temporal And Spatial ◽

Temporal And Spatial Characteristics ◽

Mountain Geography ◽

Different Sources

Mountains have distinct geography and are dynamic in nature compared to the plains. 'Verticality' and 'variation' are two fundamental specificities of the mountain geography. They possess distinct temporal and spatial characteristics in a unique socio-cultural setting. There is an ever increasing need for spatial and temporal data for planning and management activities; and Geo Information (GI) Science (including Geographic Information and Earth Observation Systems). This is being recognized more and more as a common platform for integrating spatial data with social, economic and environmental data and information from different sources. This paper investigates the applicability and challenges of GISscience in the context of mountain geography with ample evidences and observations from the mountain specific publications, empirical research findings and reports. The contextual explanation of mountain geography, mountain specific problems, scientific concerns about the mountain geography, advances in GIScience, the role of GIScience for sustainable development, challenges on application of GIScience in the contexts of mountains are the points of discussion. Finally, conclusion has been made with some specific action oriented recommendations.

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EEG Correlates of Old/New Discrimination Performance Involving Abstract Figures and Non-Words

Brain Sciences ◽

10.3390/brainsci11060719 ◽

2021 ◽

Vol 11 (6) ◽

pp. 719

Author(s):

Monika Toth ◽

Anke Sambeth ◽

Arjan Blokland

Keyword(s):

Recognition Memory ◽

Current Knowledge ◽

Discrimination Performance ◽

Correct Identification ◽

Memory Strength ◽

Verbal Stimuli ◽

Brain Responses ◽

Three Phase ◽

New Item

The processing of pre-experimentally unfamiliar stimuli such as abstract figures and non-words is poorly understood. Here, we considered the role of memory strength in the discrimination process of such stimuli using a three-phase old/new recognition memory paradigm. Memory strength was manipulated as a function of the levels of processing (deep vs. shallow) and repetition. Behavioral results were matched to brain responses using EEG. We found that correct identification of the new abstract figures and non-words was superior to old item recognition when they were merely studied without repetition, but not when they were semantically processed or drawn. EEG results indicated that successful new item identification was marked by a combination of the absence of familiarity (N400) and recollection (P600) for the studied figures. For both the abstract figures and the non-words, the parietal P600 was found to differentiate between the old and new items (late old/new effects). The present study extends current knowledge on the processing of pre-experimentally unfamiliar figurative and verbal stimuli by showing that their discrimination depends on experimentally induced memory strength and that the underlying brain processes differ. Nevertheless, the P600, similar to pre-experimentally familiar figures and words, likely reflects improved recognition memory of meaningless pictorial and verbal items.

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