Most statistical inferences in neuroscience and psychology are based on frequentist statistics, which rely on sampling distributions: the long-run outcomes of multiple experiments, given a certain model. Yet, sampling distributions are poorly understood and rarely explicitly considered when making inferences. In this tutorial and commentary, I demonstrate how to use simulations to illustrate sampling distributions to answer simple practical questions: for instance, if we could run thousands of experiments, what would the outcome look like? What do these simulations tell us about the results from a single experiment? Such simulations can be run a priori, given expected results, or a posteriori, using existing datasets. Both approaches can help make explicit the data generating process and the sources of variability; they also reveal the large uncertainty in our experimental estimation and lead to the sobering realization that, in most situations, we should not make a big deal out of results from a single ex...

Experimental design is a core competency of scientific training with profound implications for research rigor and reproducibility. Yet, trainees often receive minimal guidance to structure their thinking around experimental design. Metacognition—reflecting on one's own thinking—offers a powerful tool to strengthen reasoning in this process. Here, we present the AiMS framework, which adapts the classic plan–monitor–evaluate cycle of metacognition to the context of experimental design. This framework emphasizes three iterative stages—Awareness, Analysis, and Adaptation—that scaffold reflection on an experimental system defined by its Models, Methods, and Measurements and evaluated through Specificity, Sensitivity, and Stability. We illustrate application of the AiMS framework through an interactive neuroanatomy case study and provide a structured worksheet to guide readers in applying it to their own experiments. We also highlight how the framework can assist researchers in organizing their ideas for researc...

Perception is shaped by both the physical properties of stimuli and their contextual presentation, often leading to systematic biases such as the central tendency effect, where perceptual judgments shift toward the average of the stimulus set. This study explored the central tendency bias in vibrotactile perception, an area that has received limited attention while also replicating its well-documented occurrence in color perception to validate previous findings. Using a within-subject design, participants (5 males, 15 females) completed color and vibrotactile discrimination tasks, each consisting of three blocks, which comprised systematically shifted stimulus sets. In an established virtual reality color task, stimuli ranged from yellow–green to blue–green, while in the vibrotactile task, stimuli varied in vibration intensity around a baseline distribution. As predicted, the point of subjective equality shifted toward the mean of the stimulus sets in both tasks, confirming the presence of a central tenden...

The parabrachial (PB) nucleus participates in taste processing and integration with other senses. PB neurons that express the Calca gene support sensory-integrative responses, albeit only limited data have addressed their influence on taste. Here we investigated how chemogenetic dampening of PB- Calca neurons affected mouse orosensory preferences for diverse taste stimuli in brief-access fluid exposure tests, which capture oral sensory/tongue control of licking behavior. Intracranial delivery of Cre-dependent viruses in female and male Calca Cre/+ mice induced expression of the inhibitory designer receptor hM4Di:mCherry (hM4Di mice) or fluorophore mCherry alone (mCherry control mice) in PB- Calca neurons. Several weeks later, hM4Di and mCherry mice entered brief-access tests where they could lick solutions during discrete, seconds-long trials. Stimuli included concentration series of the behaviorally avoided bitter taste stimuli quinine and cycloheximide, the appetitive sugar sucrose, and mildly cool water...

Social interactions are fundamental to human cognition, with the right temporoparietal junction (rTPJ) playing a key role in integrating motor coordination and social inference. While transcranial random noise stimulation (tRNS) is a promising technique for modulating cortical excitability in real time, its effect on dynamic social processes remains largely unexplored. This study applied high-definition tRNS (HD-tRNS) over the rTPJ during an interactive task to modulate motor coordination and social inference. Eighty neurotypical adults (49 female) were equally distributed across two experiments: Experiment 1, a block design with randomized active and sham stimulation blocks; or Experiment 2, a trial-by-trial design with intermixed stimulation protocols. Participants performed a coordination task with a covert virtual partner programmed to behave cooperatively or competitively. Kinematic data and self-reported attributions of humanness and cooperativeness were analyzed. The results showed that HD-tRNS over...

Despite various histological, electrophysiological, and imaging studies, the topographic organization of saccade-related activity in the posterior parietal cortex (PPC) has been notoriously difficult to characterize. In part, this is because areas of interest in PPC are often embedded deep in sulci in macaques and humans. Understanding the extent of topographic organization in PPC can provide insights into the computation contributions of PPC. The lissencephalic cortex of the common marmoset offers a unique opportunity to investigate fine-scale topographic organization in PPC. Recordings were obtained from the PPC of two male marmosets performing a visually guided center-out saccade task with 8 or 36 peripheral targets using multichannel electrode arrays with 100 μm spacing. By plotting the pattern of saccade direction tuning preferences across all penetrations and cortical depths, we uncovered topographic organizational features within the PPC. Like other primates, multiunits in marmoset PPC tend to prefe...

Recent investigations have revealed that selective attention to lateralized speech increases ipsilateral tonic electromyographic activity in the vestigial human auriculomotor system. However, it has yet to be determined whether this modulation depends upon predictive cues that are inherent in continuous speech or whether it is a general concomitant of selective attention to sounds in the auditory periphery. The present study addressed this question by replacing speech with randomized, unpredictable sequences of brief tonal stimuli in a dichotic listening task that necessitated a sustained anticipatory focus of attention. Participants (8 female, 23 male) were presented with sequences of brief tone bursts in one ear and frequency-modulated “chirps” in the other ear and were instructed to focus on sounds in one ear and report attenuated deviant stimuli in that ear. Posterior auricular muscle (PAM) activity was recorded behind both ears, and non-rectified stimulus-locked responses were assessed to ensure the r...

Previous studies emphasize the importance of prestimulus neural oscillations in shaping endogenous brain states that substantially impact perceptual outcomes. However, what features in such oscillations drive perception remains unknown. Furthermore, research has shown that non-oscillatory activity is also important for cognitive processing. However, their interaction prior to perceiving a multisensory stimulus remains unexplored. In this human EEG study ( n  = 18, 10 males and 8 females), we investigated the role of prestimulus periodic power and aperiodic activity in modulating perception of the widely studied McGurk illusion on a trial-by-trial basis. Using logistic mixed-effects models, we reveal that the illusion perception is associated with reduced prestimulus alpha (8–12 Hz) and beta (15–30 Hz) power over frontal and occipital regions; increased theta (4–7 Hz) power in parietal, central, and occipital regions; and increased gamma (31–45 Hz) power across the scalp. Furthermore, lower aperiodic offset...

Loss-of-function (LOF) Frazzled/DCC mutants disrupt synaptogenesis in the Giant Fiber (GF) System of Drosophila . We observed weaker physiology in LOF male and female specimens, characterized by longer latencies and reduced response frequencies between the GFs and the motor neurons. These physiological phenotypes are linked to a loss of gap junctions in the GFs, specifically the loss of the shaking-B(neural+16) isoform of innexin in the presynaptic terminal. We present evidence of Frazzled's role in gap junction regulation by utilizing the UAS-GAL4 system in Drosophila to rescue mutant phenotypes. Expression of various UAS-Frazzled constructs in a Frazzled LOF background was used to dissect the role of different parts of the Frazzled receptor in the assembly of electrical synapses. Expressing Frazzled’s intracellular domain in Frazzled LOF mutants rescued axon pathfinding and synaptogenesis. This is supported by the complementary result that Frazzled fails to rescue synaptic function when the transcription...

Novel stimuli can be stressful for individuals with autism spectrum disorders (ASD), though repeated exposure can reduce this effect. In Cntnap2-/- and Shank3B+/− mouse models of ASD, novel background odors impaired behavioral target odor recognition but that deficit improved with training. To investigate the neural basis of this improvement, we used wide-field calcium imaging to measure olfactory bulb responses in Cntnap2−/− and Shank3B+/− mice and WT mice of either sex. Training with background odors enhanced both behavioral performance and neural discriminability of odor mixtures in both Cntnap2−/− and Shank3B+/− as well as WT mice. Naive Cntnap2−/− and Shank3B+/− mice showed greater trial-to-trial neural variability than WT mice, but training stabilized neural responses. Critically, training produced a widespread reduction in olfactory bulb responses to background odors in ASD models, but not in WT mice. Thus, despite similar behavioral improvements as WT mice, Cntnap2−/− and Shank3B+/− mice relied on ...