If a neuron is being recorded while a trained animal performs a 2x2 stimulus-response association task, how can we decide whether it is related more to the encoding and analysis of the sensory stimulus, to the preparation and execution of the motor response, or to the animal's decision that associates the two? The difficulty arises because, within a single task, stimulus and response are intrinsically confounded per task instruction; it is only through proper analysis of errors in performance (behavioral noise) and variance in recorded neural activity (neuronal noise) that one can identify the sensorimotor significance of such activity. A quantitative technique is proposed here, based on the framework of signal detection theory, to determine the sensorimotor "locus" of a neural process when recorded simultaneously with the animal's performance on a trial-by-trial basis. The premise is that a pure sensory process should be influenced only by the nature of the sensory stimulus regardless of the nature of the behavioral response, and vice versa for a pure motor process. From the recorded neural activity, we calculate the prediction or discriminability (by an ideal operator) for the stimulus categories and for the response categories. These discriminability values are then compared with each other to infer whether the neural process is more related to stimulus or to response. An index is derived that quantitatively specifies the processing locus of a given neural process along the sensorimotor continuum, with pure sensory and pure motor processes at the two extremes. In between lies the locus of decision-related processes whose activities allow equal (but not chance) prediction for stimulus and response categories. The technique is applied to single-unit activities recorded in monkey primary motor cortex (MI) while the monkey performed a simple go/nogo task involving visual stimulus and hand/wrist movement. We find that sensorimotor indices of MI neurons are widely distributed, with a preponderance of motor-related units (that better predict go/nogo response than go/nogo stimulus) but also sensory-related ones (with predictabilities reversed). Copyright 1997 Academic Press
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http://dx.doi.org/10.1006/jmps.1997.1168 | DOI Listing |
Hear Res
January 2025
Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom.
The cortical tracking of the acoustic envelope is a phenomenon where the brain's electrical activity, as recorded by electroencephalography (EEG) signals, fluctuates in accordance with changes in stimulus intensity (the acoustic envelope of the stimulus). Understanding speech in a noisy background is a key challenge for people with hearing impairments. Speech stimuli are therefore more ecologically valid than clicks, tone pips, or speech tokens (e.
View Article and Find Full Text PDFPLoS Comput Biol
January 2025
Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
Sensory neurons continually adapt their response characteristics according to recent stimulus history. However, it is unclear how such a reactive process can benefit the organism. Here, we test the hypothesis that adaptation actually acts proactively in the sense that it optimally adjusts sensory encoding for future stimuli.
View Article and Find Full Text PDFCogn Neurodyn
December 2025
Department of Psychology, Graduate School of Humanities, Kobe University, 1-1 Rokkodai- cho, Nada, Kobe, 657-8501 Japan.
Unlabelled: The integration of auditory and visual stimuli is essential for effective language processing and social perception. The present study aimed to elucidate the mechanisms underlying audio-visual (A-V) integration by investigating the temporal dynamics of multisensory regions in the human brain. Specifically, we evaluated inter-trial coherence (ITC), a neural index indicative of phase resetting, through scalp electroencephalography (EEG) while participants performed a temporal-order judgment task that involved auditory (beep, A) and visual (flash, V) stimuli.
View Article and Find Full Text PDFJ Cogn
January 2025
Dipartimento di Psicologia, Universitàdi Bologna and Centro studi e ricerche in Neuroscienze Cognitive, Universitàdi Bologna, Cesena, Italy.
Decisional confidence refers to the subjective evaluation of the accuracy of a decision based on sensory information. While these judgments are typically grounded in the strength of evidence leading to a decision, they are also subjected to influence from top-down factors such as prior expectations. Previous research has highlighted the impact of prior information on decision parameters such as reaction times and decision criteria placement.
View Article and Find Full Text PDFNurs Crit Care
January 2025
Departament d'Infermeria, Universitat Rovira i Virgili, Campus Catalunya, Tarragona, Spain.
Background: The process of discharging the critical patient to the ward (discharge from critical care to the general ward-DCCW) is often described as an experience involving uncertainty which may affect the patient's quality of life and ability to cope. Coping with uncertainty is an individual response not related to the course of the illness that is dependent on external and internal resources and the ability to utilize them. Mishel's theory of uncertainty identifies aspects of care that can shape the experience of uncertainty associated with the illness.
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