Visual-Stimulus-Recognition Guidance for a boy with Visual-Perception Difficulties

Results from two experiments employing a location-cueing paradigm demonstrated that the features of a visual stimulus do not appear to be used for stimulus identification at a time prior to the localization of the stimulus by an attentional system. However, the experiments also revealed that a stimulus is processed (at least to some extent) prior to the arrival of attention at the stimulus. The results support the hypothesis that a visual stimulus must be located by an attentional system before results of initial processing of the stimulus can be used in identification. Implications for the design of visual display systems in which it is important for the user to identify stimuli both quickly and accurately are discussed.

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Neurophysiological correlates of visual stimulus recognition in man

International Journal of Psychophysiology ◽

10.1016/0167-8760(84)90025-4 ◽

1984 ◽

Vol 1 (4) ◽

pp. 317-324 ◽

Cited By ~ 8

Author(s):

N.P. Bechtereva ◽

Yu.D. Kropotov

Keyword(s):

Visual Stimulus ◽

Stimulus Recognition

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Stimulus dependence of theta rhythmic activity in primate V1 and its potential relevance for visual perception

10.1101/2021.11.30.470367 ◽

2021 ◽

Author(s):

Prasakti Tenri Fanyiwi ◽

Beshoy Agayby ◽

Ricardo Kienitz ◽

Marcus Haag ◽

Michael C. Schmid

Keyword(s):

Visual Perception ◽

Visual Stimulus ◽

Neural Activity ◽

Temporal Dynamics ◽

Reaction Times ◽

Rhythmic Activity ◽

Peak Frequency ◽

Theta Oscillations ◽

Theta Power ◽

Fixational Eye Movements

AbstractA growing body of psychophysical research reports theta (3-8 Hz) rhythmic fluctuations in visual perception that are often attributed to an attentional sampling mechanism arising from theta rhythmic neural activity in mid- to high-level cortical association areas. However, it remains unclear to what extent such neuronal theta oscillations might already emerge at early sensory cortex like the primary visual cortex (V1), e.g. from the stimulus filter properties of neurons. To address this question, we recorded multi-unit neural activity from V1 of two macaque monkeys viewing a static visual stimulus with variable sizes, orientations and contrasts. We found that among the visually responsive electrode sites, more than 50 % showed a spectral peak at theta frequencies. Theta power varied with varying basic stimulus properties. Within each of these stimulus property domains (e.g. size), there was usually a single stimulus value that induced the strongest theta activity. In addition to these variations in theta power, the peak frequency of theta oscillations increased with increasing stimulus size and also changed depending on the stimulus position in the visual field. Further analysis confirmed that this neural theta rhythm was indeed stimulus-induced and did not arise from small fixational eye movements (microsaccades). When the monkeys performed a detection task of a target embedded in a theta-generating visual stimulus, reaction times also tended to fluctuate at the same theta frequency as the one observed in the neural activity. The present study shows that a highly stimulus-dependent neuronal theta oscillation can be elicited in V1 that appears to influence the temporal dynamics of visual perception.

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Detection performance for short visual stimuli depends on the duration of co-occuring auditory stimuli

Seeing and Perceiving ◽

10.1163/187847612x646479 ◽

2012 ◽

Vol 25 (0) ◽

pp. 24

Author(s):

Roberto Cecere ◽

Benjamin De Haas ◽

Harriett Cullen ◽

Jon Driver ◽

Vincenzo Romei

Keyword(s):

Visual Perception ◽

Auditory Stimulus ◽

Visual Stimulus ◽

Visual Detection ◽

Visual Stimuli ◽

Detection Performance ◽

Detection Sensitivity ◽

Auditory Stimuli ◽

Sound Duration ◽

Perceived Duration

There is converging evidence that the duration of an auditory event can affect the perceived duration of a co-occurring visual event. When a brief visual stimulus is accompanied by a longer auditory stimulus, the perceived visual duration stretches. If this reflects a genuine sustain of visual stimulus perception, it should result in enhanced perception of non-temporal visual stimulus qualities. To test this hypothesis, in a temporal two-alternative forced choice task, 28 participants were asked to indicate whether a short (∼24 ms), peri-threshold, visual stimulus was presented in the first or in the second of two consecutive displays. Each display was accompanied by a sound of equal or longer duration (36, 48, 60, 72, 84, 96, 190 ms) than the visual stimulus. As a control condition, visual stimuli of different durations (matching auditory stimulus durations) were presented alone. We predicted that visual detection can improve as a function of sound duration. Moreover, if the expected cross-modal effect reflects sustained visual perception it should positively correlate with the improvement observed for genuinely longer visual stimuli. Results showed that detection sensitivity (d′) for the 24 ms visual stimulus was significantly enhanced when paired with longer auditory stimuli ranging from 60 to 96 ms duration. The visual detection performance dropped to baseline levels with 190 ms sounds. Crucially, the enhancement for auditory durations 60–96 ms significantly correlates with the d′ enhancement for visual stimuli lasting 60–96 ms in the control condition. We conclude that the duration of co-occurring auditory stimuli not only influences the perceived duration of visual stimuli but reflects a genuine sustain in visual perception.

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Primary visual cortex is necessary for blindsight-like behavior in neurologically healthy individuals: Review of transcranial magnetic stimulation studies

10.31234/osf.io/gs9ur ◽

2021 ◽

Author(s):

Henry Railo ◽

Mikko Hurme

Keyword(s):

Visual Cortex ◽

Transcranial Magnetic Stimulation ◽

Visual Perception ◽

Primary Visual Cortex ◽

Visual Stimulus ◽

Magnetic Stimulation ◽

Neural Mechanisms ◽

Partial Recovery ◽

Visually Guided ◽

Healthy Individuals

The visual pathways that bypass the primary visual cortex (V1) are often assumed to support visually guided behavior in humans in the absence of conscious vision. This conclusion is largely based on findings on patients: V1 lesions cause blindness but sometimes leave some visually guided behaviors intact—this is known as blindsight. With the aim of examining how well the findings on blindsight patients generalize to neurologically healthy individuals, we review studies which have tried to uncover transcranial magnetic stimulation (TMS) induced blindsight. In general, these studies have failed to demonstrate a completely unconscious blindsight-like capacity in neurologically healthy individuals. A possible exception to this is TMS-induced blindsight of stimulus presence or location. Because blindsight in patients is often associated with some form of introspective access to the visual stimulus, and may be associated with neural reorganization, we suggest that rather than revealing a dissociation between neural mechanisms of behavior and conscious seeing, blindsight may reflect preservation or partial recovery of conscious visual perception after the lesion.

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