Seeing feels immediate; we open our eyes and the world seems to appear as a continuous stream. But some visual illusions show that events occurring later can change how we perceive what happened earlier, suggesting that the brain may collect and combine information for a short time before producing the experience that reaches awareness.

This effect is known as “postdiction.” Here’s an example: Two colored dots appear briefly in different places, but people see only a single moving dot that changes color along the way. This means that the second dot must influence how the first is perceived, a typical example of postdiction.

The frontal cortex (FC) has been implicated in many of the cognitive and executive control functions required for goal-directed behavior (Komura et al., 2001; Bruni et al., 2015; Duan et al., 2021; Friedman and Robbins, 2021), including decision-making (Coley et al., 2021; Liu et al., 2021), response inhibition (Schiller et al., 2014; Li et al., 2020), working memory (O’Reilly and Frank, 2006; Miller et al., 2018; Wilhelm et al., 2023), attentional control (Zikopoulos and Barbas, 2007; Gregorlou et al., 2014), and adaptive modulation of sensory filters (Banerjee et al., 2020). In the auditory system, cortical neurons can rapidly adapt their receptive field tuning and spectrotemporal selectivity reflecting changing stimulus context and task conditions (Fritz et al., 2003, 2005, 2007; David et al., 2012; Yin et al., 2014; Elgueda et al., 2019). This task-related receptive field plasticity may be shaped by changing functional connectivity between FC and auditory cortex (Fritz et al., 2010; Sheikhattar et al., 2018; Yin et al., 2020). This adaptive capacity is critical since context can transform the behavioral meaning of incoming stimuli and even cause the same sound to mean two opposite things in different circumstances.

In this study, we explored the role of the FC in this adaptive decision-making process by employing the same sounds to signify diametrically opposite meanings depending on task context and reward valence. In one behavioral paradigm, upon hearing a Target sound, animals initiated licking to obtain a water reward (positive reward; P-paradigm). In the other paradigm, animals learned to stop licking for water when presented with the same Target stimulus in order to avoid a mild shock (negative reward; N-paradigm). In an earlier study (David et al., 2012), we found that such different task reward structures and stimulus-action contingencies induced two strikingly distinct forms of receptive field plasticity in primary auditory cortex (A1). In light of the strong top-down projections from the FC to auditory cortex (AC) influencing dynamic sensory filters (Caras and Sanes, 2017; Bimbard et al., 2018; Schneider et al., 2018; Winkowski et al., 2018; Mittelstadt and Kanold, 2023; Macedo-Lima et al., 2024), we wondered whether the differential receptive plasticity was driven by distinct FC representations of the two opposite behavioral paradigms.

Therefore, we trained two groups of ferrets on two opposite auditory categorical Go-NoGo paradigms, requiring each group to discriminate noncompact sound categories (Yin et al., 2016, 2020). Task stimuli varied along two acoustic feature dimensions: spectral frequency (TN-task) or temporal modulation rate (amplitude-modulated white noise, AM-task). As indicated above, in the P-paradigm group, ferrets learned to lick for water reward when Target stimuli were presented and refrained from licking to Reference stimuli. In contrast, the group that learned the N-paradigm performed the opposite behavior and refrained from licking for water when Target stimuli were presented but could lick freely to Reference sounds (Fig. 1 A).

Are some interventions designed to induce gratitude more effectively than others? In which countries and cultures do they work best to improve mood, strengthen bonds between people and promote social reciprocity? A study aimed at answering these questions—conducted in 34 countries with more than 10,000 participants—had its results published in PNAS. In Brazil, the project received the help of researchers and 598 volunteers who responded to intervention prompts via an online tool.

“One of our main overall findings is that all the proposed interventions worked,” says Paulo Sérgio Boggio, a psychologist, professor at Mackenzie Presbyterian University and coordinator of the National Institute of Science and Technology in Social and Affective Neuroscience (INCT-Sani). Boggio and his former graduate student, Beatriz Bezerra de Souza, are the two Brazilian co-authors of the article.

Thirty-six researchers are listed as authors of the paper, including experimental psychologist Michael McCullough, a professor at the University of California, San Diego. The study was coordinated by Nicholas Coles, a researcher at the University of Florida.

What if everything you think you know about reality is only the surface? His followers believe Dr. Jacobo Grinberg may have unlocked a hidden world beneath our everyday experience, one where consciousness reshapes reality itself.

On December 8, 1994, this brilliant neuroscientist vanished without a trace, disappearing into thin air while investigating mysteries most scientists dared not touch.

Dr. Jacobo Grinberg was no ordinary scientist. He was a bold explorer of the mind, a pioneer in consciousness, on a quest to unlock new chapters of reality. But was Dr. Grinberg’s disappearance the end of his story, or the beginning of something far stranger?