The Perky Effect Revisited: Blocking of Visual Signals by Imagery

1969 ◽  
Vol 28 (3) ◽  
pp. 791-797 ◽  
Author(s):  
Sydney Joelson Segal ◽  
Pearl-Ellen Gordon
Keyword(s):  
Discrimination Task ◽  
Visual Signals ◽  
Simple Discrimination ◽  
Mental Images ◽  
Simple Discrimination Task ◽  
External Stimuli

Perky's 1910 observation that mental images were indistinguishable from external stimuli is considered as two issues: (1) description of images which apparently resemble the unidentified stimulus, has been given, but not satisfactorily measured; (2) poorer detection of ambiguous signals while experiencing images, has been consistently demonstrated. While distraction may play some role, the critical finding was with sensitivity ( d′), which was highest in a simple discrimination task, intermediate when Ss were told both to describe imagery and detect the signals, and poorest when they lacked information that signals might be present during imaging and relied on retrospective judgments (Perky replication). In the intermediate task, alerting Ss to the signals by having them project the slides themselves, did not alter sensitivity or bias (Lx).

scholarly journals RNA induced enhancement of a simple discrimination task

1968 ◽  
Vol 12 (7) ◽  
pp. 295-296 ◽  
Author(s):  
Robert G. Gibby ◽  
David G. Crough ◽  
Samuel J. Twios
Keyword(s):  
Discrimination Task ◽  
Simple Discrimination ◽  
Simple Discrimination Task

scholarly journals Narrow Versus Wide Tuning Curves: What's Best for a Population Code?

1999 ◽  
Vol 11 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Alexandre Pouget ◽  
Sophie Deneve ◽  
Jean-Christophe Ducom ◽  
Peter E. Latham
Keyword(s):  
Discrimination Task ◽  
Tuning Curve ◽  
Technical Analysis ◽  
Common Belief ◽  
Simple Discrimination ◽  
Population Code ◽  
Tuning Curves ◽  
Simple Discrimination Task ◽  
Better Than

Neurophysiologists are often faced with the problem of evaluating the quality of a code for a sensory or motor variable, either to relate it to the performance of the animal in a simple discrimination task or to compare the codes at various stages along the neuronal pathway. One common belief that has emerged from such studies is that sharpening of tuning curves improves the quality of the code, although only to a certain point; sharpening beyond that is believed to be harmful. We show that this belief relies on either problematic technical analysis or improper assumptions about the noise. We conclude that one cannot tell, in the general case, whether narrow tuning curves are better than wide ones; the answer depends critically on the covariance of the noise. The same conclusion applies to other manipulations of the tuning curve profiles such as gain increase.

scholarly journals Postprint: "Temporal matching between interoception and exteroception: electrophysiological responses in a heartbeat discrimination task"

2018 ◽  
Author(s):  
Hirokata Fukushima
Keyword(s):  
Discrimination Task ◽  
Predictive Coding ◽  
Event Related Potential ◽  
Neural Responses ◽  
Cardiac Phase ◽  
Behavioral Measures ◽  
Electrophysiological Responses ◽  
Interoceptive Sensitivity ◽  
External Stimuli ◽  
Healthy Participants

Recent studies on interoception emphasize the importance of multisensory integration between interoception and exteroception. One of the methods frequently applied for assessing interoceptive sensitivity is the heartbeat discrimination task, where individuals judge whether the timing of external stimuli (e.g., tones) are synchronized to their own heartbeat. Despite its extensive use in research, the neural dynamics underlying the temporal matching between interoceptive and exteroceptive stimuli in this task have remained unclear. The present study used electroencephalography (EEG) to examine the neural responses of healthy participants who performed a heartbeat discrimination task. We analyzed the differences between EEG responses to tones, which were likely to be perceived as “heartbeat-synchronous” (200 ms delayed from the R-wave) or “heartbeat-asynchronous” (0 ms delayed). Possible associations of these neural differentiations with task performance were also investigated. Compared with the responses to heartbeat-asynchronous tones, heartbeat-synchronous tones caused a relative decrease in early gamma-band EEG response and an increase in later P2 event-related potential (ERP) amplitude. Condition differences in the EEG/ERP measures were not significantly correlated with the behavioral measures. The mechanisms underlying the observed neural responses and the possibility of electrophysiological measurement of interoceptive sensitivity are discussed in terms of two perspectives: the predictive coding framework and the cardiac-phase-dependent baroreceptor function.

Substantia Nigra Output to Prefrontal Cortex Via Thalamus in Monkeys. II. Activity of Thalamic Relay Neurons in Delayed Conditional Go/No-Go Discrimination Task

2009 ◽  
Vol 102 (5) ◽  
pp. 2946-2954 ◽  
Author(s):  
Ikuo Tanibuchi ◽  
Hiroyuki Kitano ◽  
Kohnosuke Jinnai
Keyword(s):  
Substantia Nigra ◽  
Discrimination Task ◽  
Present Report ◽  
Delay Period ◽  
Visual Signals ◽  
Inhibitory Input ◽  
Related Activity ◽  
Thalamic Relay ◽  
Thalamic Relay Neurons ◽  
Relay Neurons

The present report investigated the involvement of primate nigro-thalamo-cortical projections in discrimination of visual signals with behavioral meaning. We tested the extracellular unit activity of mediodorsal (MD) and ventral anterior (VA) thalamic neurons monosynaptically receiving inhibitory input from the substantia nigra pars reticulata (SNr) and projecting to the frontal cortex in Japanese monkeys performing a delayed conditional go/no-go discrimination task. In the task two colored stimuli (S1, S2) intervened by delay period required the monkeys lifting a lever (go) or not (no-go); the same and different colored pairs of S1 and S2 meant go and no-go signals, respectively. Prominent task-relevant responses were sustained activity with color preference to S1 during delay period and S2-related activity with different firing rates between go and no-go trials. In particular, a high proportion of such go/no-go differential S2-related activity was found in thalamic relay neurons, receiving input from the caudolateral SNr and projecting to the prefrontal area (PSv) ventral to the principal sulcus, in the rostrolateral MD. The findings suggest that the caudolateral SNr–rostrolateral MD–PSv pathways may be possible conduits of signals coding the behavioral meaning of the visual stimuli and thus may be responsible for generating similar neuronal activity in the PSv.

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