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This study uses EEG in humans to isolate and track an evolving, domain-general decision signal, which varies with accumulated evidence, but is independent of overt actions. In theoretical accounts of perceptual decision-making, a decision variable integrates noisy sensory evidence and determines action through a boundary-crossing criterion. Signals bearing these very properties have been characterized in single neurons in monkeys, but have yet to be directly identified in humans. Using a gradual target detection task, we isolated a freely evolving decision variable signal in human subjects that exhibited every aspect of the dynamics observed in its single-neuron counterparts. This signal could be continuously tracked in parallel with fully dissociable sensory encoding and motor preparation signals, and could be systematically perturbed mid-flight during decision formation. Furthermore, we found that the signal was completely domain general: it exhibited the same decision-predictive dynamics regardless of sensory modality and stimulus features and tracked cumulative evidence even in the absence of overt action. These findings provide a uniquely clear view on the neural determinants of simple perceptual decisions in humans.

This study aims to evaluate the effect of a structured family auditory stimulation on preventing ICU delirium among patients with unplanned admissions. A three-arm parallel, single-blinded, randomized controlled trial was designed. Patients were randomly assigned to one of three groups: structured family auditory stimulation (Group A), unstructured family auditory stimulation (Group B), and usual care (Group C). The primary outcome was delirium incidence, and secondary outcomes included delirium severity, delirium duration, delirium-free days, delirium subtypes, time to first delirium, the family anxiety and depression levels. A total of 213 patients were randomly assigned to three groups. There were no significant differences in demographic or clinical characteristics among the three groups. For the primary outcome, fewer patients developed delirium in Group A than in Group B and Group C (22.5 % vs. 26.8 % vs. 49.3 %, P = 0.001). For secondary outcomes, Group A had lower delirium severity scores than the other groups did (3.1 ± 0.4 vs. 4.0 ± 0.3 vs. 5.1 ± 0.3, P < 0.001). Patients in Group A had shorter delirium durations (2.0 vs. 3.0 vs.4.0 days, P < 0.001) and longer delirium-free days (3.0 vs. 2.0 vs. 1.0 days, P < 0.001) than those in Group B and Group C. The time to first delirium was 3.0, 2.0, and 2.0 days, respectively (P < 0.001). The SAS scores of the families in the three groups were 47.1 ± 5.7, 48.9 ± 5.5, and 56.5 ± 7.5 (P < 0.001) and the SDS scores were 38.2 ± 5.8, 38.3 ± 5.7, and 42.7 ± 7.2 (P < 0.001). The results revealed that structured family auditory stimulation could reduce delirium incidence, decrease its severity, shorten the duration of delirium, increase delirium-free days, and prolong the time to first delirium among ICU patients with unplanned admission. Additionally, it could alleviate families’ anxiety and depression levels. Structured family auditory stimulation prevents ICU delirium by maintaining the patients’ cognitive function and promoting early recovery, showing significant clinical potential in ICU delirium.

The brain activity of multiple subjects has been shown to synchronize during salient moments of natural stimuli, suggesting that correlation of neural responses indexes a brain state operationally termed ‘engagement’. While past electroencephalography (EEG) studies have considered both auditory and visual stimuli, the extent to which these results generalize to music—a temporally structured stimulus for which the brain has evolved specialized circuitry—is less understood. Here we investigated neural correlation during natural music listening by recording EEG responses from N=48 adult listeners as they heard real-world musical works, some of which were temporally disrupted through shuffling of short-term segments (measures), reversal, or randomization of phase spectra. We measured correlation between multiple neural responses (inter-subject correlation) and between neural responses and stimulus envelope fluctuations (stimulus-response correlation) in the time and frequency domains. Stimuli retaining basic musical features, such as rhythm and melody, elicited significantly higher behavioral ratings and neural correlation than did phase-scrambled controls. However, while unedited songs were self-reported as most pleasant, time-domain correlations were highest during measure-shuffled versions. Frequency-domain measures of correlation (coherence) peaked at frequencies related to the musical beat, although the magnitudes of these spectral peaks did not explain the observed temporal correlations. Our findings show that natural music evokes significant inter-subject and stimulus-response correlations, and suggest that the neural correlates of musical ‘engagement’ may be distinct from those of enjoyment. [Display omitted] •We recorded EEG from 48 adults as they heard intact and scrambled natural music.•Inter-subject and stimulus-response EEG correlation and coherence were computed.•Neural correlation was significant for all stimuli retaining musical features.•Time-domain correlation was highest for music shuffled in short time segments.•Coherence peaks implicated frequencies related to metrical pulse.

Children with dyslexia often exhibit increased variability in sensory and cognitive aspects of hearing relative to typically developing peers. Assistive listening devices (classroom FM systems) may reduce auditory processing variability by enhancing acoustic clarity and attention. We assessed the impact of classroom FM system use for 1 year on auditory neurophysiology and reading skills in children with dyslexia. FM system use reduced the variability of subcortical responses to sound, and this improvement was linked to concomitant increases in reading and phonological awareness. Moreover, response consistency before FM system use predicted gains in phonological awareness. A matched control group of children with dyslexia attending the same schools who did not use the FM system did not show these effects. Assistive listening devices can improve the neural representation of speech and impact reading-related skills by enhancing acoustic clarity and attention, reducing variability in auditory processing.

This study provides causal evidence demonstrating that consuming a high flavanol diet improves dentate gyrus function and dentate gyrus–dependent cognitive functions in aged humans. The dentate gyrus (DG) is a region in the hippocampal formation whose function declines in association with human aging and is therefore considered to be a possible source of age-related memory decline. Causal evidence is needed, however, to show that DG-associated memory decline in otherwise healthy elders can be improved by interventions that enhance DG function. We addressed this issue by first using a high-resolution variant of functional magnetic resonance imaging (fMRI) to map the precise site of age-related DG dysfunction and to develop a cognitive task whose function localized to this anatomical site. Then, in a controlled randomized trial, we applied these tools to study healthy 50–69-year-old subjects who consumed either a high or low cocoa flavanol–containing diet for 3 months. A high-flavanol intervention was found to enhance DG function, as measured by fMRI and by cognitive testing. Our findings establish that DG dysfunction is a driver of age-related cognitive decline and suggest non-pharmacological means for its amelioration.

Background Early and continuous exposure to painful stimuli in premature infants leads to short-and long-term complications. Listening to white noise is an accessible and inexpensive non-invasive method that can be used as a safe nursing intervention in hospitals. This study aimed to assess white noise’s effect on premature Infants’ physiological parameters during peripheral intravenous catheter insertion. Methods The present experimental study was conducted on 40 premature Infants. From 5 min before Indwelling catheters to 10 min after, white noise was played through headphones to infants at a controlled volume in the test group. Using a monitor, physiological parameters were recorded from 10 min before to 30 min after the Indwelling catheter. Statistical analysis was done through the SPSS version 27 software program. Results Regarding respiratory rate, there was no statistically significant difference between the two groups in the first, second, and sixth stages ( p  < 0.05). However, in the third, fourth, and fifth stages, RR in the control group was significantly higher than the test group ( p  ≤ 0.05). In terms of mean arterial blood pressure, there was no statistically significant difference between the two groups in any of the stages ( p  < 0.05). In terms of heart rate, there was no statistically significant difference between the two groups in the first, second, and sixth stages ( p  < 0.05). However, in the third, fourth, and fifth stages, HR in the control group was significantly higher than the test group ( p  ≤ 0.05). Regarding oxygen saturation percentage, there was no statistically significant difference between the two groups in the first, second, third, and sixth stages ( p  < 0.05). In contrast, in the fourth and fifth stages, the oxygen saturation percentage in the test group was significantly higher than in the control group ( p  < 0.05). Conclusions Although in both groups the painful procedure led to an increase in physiological variables (respiratory rate, heart rate, mean arterial blood pressure) and a decrease in blood oxygen saturation, in the test group these variables approached their initial state more quickly within half an hour after exposure to white noise. This confirms that the effect of white noise on the improvement of physiological variables is gradual. Clinical trial number Not applicable.

Δ-9-tetrahydrocannabinol (Δ-9-THC) and Cannabidiol (CBD), the two main ingredients of the Cannabis sativa plant have distinct symptomatic and behavioral effects. We used functional magnetic resonance imaging (fMRI) in healthy volunteers to examine whether Δ-9-THC and CBD had opposite effects on regional brain function. We then assessed whether pretreatment with CBD can prevent the acute psychotic symptoms induced by Δ-9-THC. Fifteen healthy men with minimal earlier exposure to cannabis were scanned while performing a verbal memory task, a response inhibition task, a sensory processing task, and when viewing fearful faces. Subjects were scanned on three occasions, each preceded by oral administration of Δ-9-THC, CBD, or placebo. BOLD responses were measured using fMRI. In a second experiment, six healthy volunteers were administered Δ-9-THC intravenously on two occasions, after placebo or CBD pretreatment to examine whether CBD could block the psychotic symptoms induced by Δ-9-THC. Δ-9-THC and CBD had opposite effects on activation relative to placebo in the striatum during verbal recall, in the hippocampus during the response inhibition task, in the amygdala when subjects viewed fearful faces, in the superior temporal cortex when subjects listened to speech, and in the occipital cortex during visual processing. In the second experiment, pretreatment with CBD prevented the acute induction of psychotic symptoms by Δ-9-tetrahydrocannabinol. Δ-9-THC and CBD can have opposite effects on regional brain function, which may underlie their different symptomatic and behavioral effects, and CBD's ability to block the psychotogenic effects of Δ-9-THC.

In this study, we sought to examine the effect of experimentally induced somatic pain on memory. Subjects heard a series of words and made categorization decisions in two different conditions. One condition included painful shocks administered just after presentation of some of the words; the other condition involved no shocks. For the condition that included painful stimulations, every other word was followed by a shock, and subjects were informed to expect this pattern. Word lists were repeated three times within each condition in randomized order, with different category judgments but consistent pain-word pairings. After a brief delay, recognition memory was assessed. Non-pain words from the pain condition were less strongly encoded than non-pain words from the completely pain-free condition. Recognition of pain-paired words was not significantly different than either subgroup of non-pain words. An important accompanying finding is that response times to repeated experimental items were slower for non-pain words from the pain condition, compared to non-pain words from the completely pain-free condition. This demonstrates that the effect of pain on memory may generalize to non-pain items experienced in the same experimental context.

We report on in vitro wound-healing and cell-growth studies under the influence of radio-frequency (rf) cell stimuli. These stimuli are supplied either by piezoactive surface acoustic waves (SAWs) or by microelectrode-generated electric fields, both at frequencies around 100 MHz. Employing live-cell imaging, we studied the time- and power-dependent healing of artificial wounds on a piezoelectric chip for different cell lines. If the cell stimulation is mediated by piezomechanical SAWs, we observe a pronounced, significant maximum of the cell-growth rate at a specific SAW amplitude, resulting in an increase of the wound-healing speed of up to 135 ± 85% as compared to an internal reference. In contrast, cells being stimulated only by electrical fields of the same magnitude as the ones exposed to SAWs exhibit no significant effect. In this study, we investigate this effect for different wavelengths, amplitude modulation of the applied electrical rf signal, and different wave modes. Furthermore, to obtain insight into the biological response to the stimulus, we also determined both the cell-proliferation rate and the cellular stress levels. While the proliferation rate is significantly increased for a wide power range, cell stress remains low and within the normal range. Our findings demonstrate that SAW-based vibrational cell stimulation bears the potential for an alternative method to conventional ultrasound treatment, overcoming some of its limitations.

Slow-wave sleep (SWS) is important for overall health since it affects many physiological processes including cardio-metabolic function. Sleep and autonomic nervous system (ANS) activity are closely coupled at anatomical and physiological levels. Sleep-related changes in autonomic function are likely the main pathway through which SWS affects many systems within the body. There are characteristic changes in ANS activity across sleep stages. Notably, in non-rapid eye-movement sleep, the progression into SWS is characterized by increased parasympathetic activity, an important measure of cardiovascular health. Experimental manipulations that enhance slow-wave activity (SWA, 0.5–4 Hz) can improve sleep-mediated memory and immune function. However, effects of SWA enhancement on autonomic regulation have not been investigated. Here, we employed an adaptive algorithm to deliver 50 ms sounds phase-locked to slow-waves, with regular pauses in stimulation (~5 s ON/~5 s OFF), in healthy young adults. We sought to determine whether acoustic enhancement of SWA altered parasympathetic activity during SWS assessed with heart rate variability (HRV), and evening-to-morning changes in HRV, plasma cortisol, and blood pressure. Stimulation, compared with a sham condition, increased SWA during ON versus OFF intervals. This ON/OFF SWA enhancement was associated with a reduction in evening-to-morning change of cortisol levels and indices of sympathetic activity. Furthermore, the enhancement of SWA in ON intervals during sleep cycles 2–3 was accompanied by an increase in parasympathetic activity (high-frequency, HRV). Together these findings suggest that acoustic enhancement of SWA has a positive effect on autonomic function in sleep. Approaches to strengthen brain–heart interaction during sleep could have important implications for cardiovascular health.