Social anxiety is reliably characterized by biases toward avoidance and aversive learning. Here, we examined the neurocomputational processes underlying these biases and examined whether these biases persist across different social contexts. A sample of 154 participants (84% female, mean age = 20.42) with subclinical to minimal levels of social anxiety completed a probabilistic selection task in two contexts: performing alone and under social scrutiny. We analyzed frontal midline theta (FM-theta) EEG activity to uncover neurocomputational processes underlying aversive learning in social anxiety. Results showed that participants performed more accurately alone and predominantly preferred a win-stay strategy. Social anxiety led to an increased use of both win-stay and lose-switch strategies (e.g., repeating a choice after receiving positive feedback or switching to a different choice after receiving negative feedback, respectively). In response to negative feedback, FM-theta power predicted post-error slowing, an effect heightened in socially anxious participants. Punishment-based learning was stronger than reward-based learning in all participants, but social anxiety amplified this effect, particularly when participants performed alone. Our findings suggest that social anxiety modulates FM-theta activity in aversive control, promoting reactive avoidance in decision-making. This mechanistic insight links social anxiety to a cascade of orienting, control, and learning biases and positions FM-theta as a potential neural target for interventions aimed at reducing maladaptive avoidance and enhancing adaptive learning in socially anxious individuals.

Human navigation heavily relies on visual information. Although many previous studies have investigated how navigational information is inferred from visual features of scenes, little is understood about the impact of navigational experience on visual scene representation. In this study, we examined how navigational experience influences both the behavioral and neural responses to a visual scene. During training, participants navigated in the virtual reality (VR) environments, which we manipulated navigational experience while holding the visual properties of scenes constant. Half of the environments allowed free navigation (navigable), while the other half featured an "invisible wall" preventing the participants to continue forward even though the scene was visually navigable (nonnavigable). During testing, participants viewed scene images from the VR environment while completing either a behavioral perceptual identification task (Experiment 1) or an fMRI scan (Experiment 2). Behaviorally, we found that participants judged a scene pair to be significantly more visually different if their prior navigational experience varied, even after accounting for visual similarities between the scene pairs. Neurally, multivoxel pattern of the parahippocampal place area distinguished visual scenes based on prior navigational experience alone. These results suggest that the human visual scene cortex represents information about navigability obtained through prior experience, beyond those computable from the visual properties of the scene. Taken together, these results suggest that scene representation is modulated by prior navigational experience to help us construct a functionally meaningful visual environment.

Nonhuman primate studies traditionally use two or three animals. We previously used standard statistics to argue for using either one animal, for an inference about that sample, or five or more animals, for a useful inference about the population. A recently proposed framework argued for testing three animals and accepting the outcome found in the majority as the outcome that is most representative for the population. The proposal tests this framework under various assumptions about the true probability of the representative outcome in the population, that is, its typicality. On this basis, it argues that the framework is valid across a wide range of typicalities. Here, we show (1) that the error rate of the framework depends strongly on the typicality of the representative outcome; (2) that an acceptable error rate requires this typicality to be very high (87% for a single type of outlier), which actually renders empirical testing beyond a single animal obsolete; and (3) that moving from one to three animals decreases error rates mainly for typicality values of 70%-90% and much less for both lower and higher values. Furthermore, we use conjunction analysis to demonstrate that two out of three animals with a given outcome only allow to infer a lower bound to typicality of 9%, which is of limited value. Thus, the use of two or three animals does not allow a useful inference about the population, and if this option is nevertheless chosen, the inferred lower bound of typicality should be reported.

Cortical activity shows the ability to recover from distractions. We analyzed neural activity from the pFC of monkeys performing working memory tasks with mid-memory delay distractions (a cued gaze shift or an irrelevant visual input). After distraction, there were state-space rotational dynamics that returned spiking to population patterns similar to those predisruption. In fact, rotations were fuller when the task was performed correctly versus when errors were made. We found a correspondence between state-space rotations and traveling waves across the surface of pFC. This suggests a role for emergent dynamics like state-space rotations and traveling waves in recovery from distractions.

While the unmasked priming paradigm has effectively revealed a biphasic pattern of morphological decomposition-early morpho-orthographic segmentation followed by later morpho-semantic integration-it remains unsettled which ERP components reliably reflect these distinct stages of morphological processes. To address this, we systematically compared ERP responses across three priming conditions-morphological (e.g., swiftly-swift), orthographic (e.g., surgeon-surge), and semantic (e.g., explode-burst)-focusing on the N250, early N400, late N400, and late negativity (LN). The N250 showed no facilitative effects and instead exhibited increased negativities across all conditions, challenging its reliability as a marker of early morpho-orthographic processing under unmasked priming. In contrast, both the early and late N400 subcomponents provided consistent indices of morpho-orthographic segmentation and morpho-semantic integration, respectively. In the early N400, morphological priming elicited earlier and stronger negativity attenuation than orthographic priming, with minimal semantic influence-reflecting semantically blind morpho-orthographic segmentation. In the late N400, negativity attenuation for morphological priming was further amplified and exceeded that of semantic priming, indicating morpho-semantic integration via shared morphemes. Notably, we also observed a unique biphasic orthographic priming pattern with embedded word targets: a relatively short and weak early N400 attenuation followed by an LN peak, reflecting initial facilitation from embedded word identification and subsequent lateral inhibition between orthographically related but semantically unrelated words. These findings establish the early and late N400 as robust ERP signatures of biphasic morphological processing under unmasked priming and elucidate the temporal dynamics of morphological, orthographic, and semantic processes.

The human voice is a highly socially relevant auditory stimulus, which has been shown to have a special status, both perceptually and neurally. Perceptual studies have revealed adaptation effects in the behavioral categorization of sounds as either human voice or musical instruments. The current study measured evoked responses using EEG to voice and instrument sounds under passive listening to explore the neural underpinnings of both categorization and context effects. In Experiment 1, vowel utterances (/a/, /o/, /u/, and /i/) and instrumental tones (bassoon, horn, saxophone, and viola) were presented with equal probability in a random sequence. The two sound categories were found to produce reliably distinguishable EEG responses at latencies of between 70 and 280 msec. In Experiment 2, an MMN paradigm resulted in mixed evidence for early neural categorization, with an MMN observed for rare instrumental tones embedded in a random sequence of four different vowels, but no significant MMN for a rare vowel embedded in a random sequence of four different instrumental tones. In Experiment 3, ambiguous voice-instrument morphs were used to show that brain responses could be used to predict the context (voice or instrument sound) in which the morphed sounds were presented. The results show that neural correlates of both categorization (voice vs. nonvoice) and context effects can be observed in EEG responses under passive listening conditions.

Humans excel at avoiding distraction in visual environments, successfully filtering out repeated salient distractors that could otherwise capture attention. A recent theoretical perspective posits a mechanism whereby such distractors can be proactively suppressed, reducing their impact on attentional deployment. Electrophysiological evidence for this view comes from the distractor positivity (PD), a neural component associated with distractor handling. The PD has been observed at early latencies (< 200 msec) following distractor appearance, a timing interpreted as reflecting distractor suppression before attentional capture. However, the relationship between this "early PD" and distractor suppression remains fundamentally correlational. This raises critical questions about the extent to which this neural marker exclusively indexes mechanisms of suppression, as opposed to being driven by other factors confounded with distractor presence, such as stimulus salience. We tested the specificity of this early positivity to distractor handling across three experiments employing visual search tasks. Participants were presented with unique color singletons serving as distractors, targets, or task-irrelevant items. The early lateralized positivity was elicited by salient color distractors, but also appeared in response to all other salient singletons, including those that could not be proactively suppressed. Our findings indicate that the early positivity is not unique to suppressed distractors-instead, it likely reflects sensory imbalance between visual hemifields or salience tagging in response to lateralized stimuli. Consequently, we argue that the "early PD" does not provide definitive evidence for proactive distractor suppression, as its association with distractor presence appears to be incidental rather than causal.

Neocortical circuits consist of multiple neuronal cell types, each likely playing distinct roles in flexible behavior. However, studies of decision-making have often overlooked these cell types, limiting our understanding of their specific contributions to local circuit functions. To address this, we simultaneously recorded neuronal activity from the frontal eye field (FEF), lateral PFC, and lateral intraparietal area (LIP) in a macaque monkey performing a visuomotor decision-making task. We used extracellular spike waveforms to reliably identify two functional classes of neurons: broad-spiking (BS) putative pyramidal cells and narrow-spiking (NS) putative interneurons. These cell types exhibited distinct response dynamics and choice-related information encoding across cortical regions. NS neurons in LIP and PFC showed higher choice-related activity and contributed to early encoding of decisions, whereas in FEF, NS neurons demonstrated dynamic encoding patterns, with BS neurons exhibiting significantly more stable encoding. Our findings reveal that choice information is represented differently across cell types and cortical regions, with NS neurons favoring early population coding in PFC and LIP and BS neurons exhibiting more static encoding in FEF. This heterogeneous coding strategy suggests that decision-related dynamics in the frontoparietal network are shaped by interactions between these distinct neuronal populations. The results provide new insights into cortical circuit dynamics and cell-type-specific contributions to decision-making.

How long do the neural and cognitive effects of a brief odor experience last? This study investigated whether short exposures to pleasant and unpleasant odors can induce sustained changes in brain activity and influence memory formation for events occurring several seconds later. Using EEG, we combined univariate ERP analyses with time-resolved multivariate decoding to track neural responses during a 6-sec delay between odor presentation and visual memory encoding. We found that brief odor cues elicited sustained neural activity that persisted well beyond odor offset. Unpleasant odors, in particular, were associated with higher sustained ERP amplitudes compared with pleasant ones. Behaviorally, participants showed greater confidence in recognizing images that had been preceded by unpleasant odors, suggesting that even brief olfactory experiences can modulate memory encoding for temporally distant events. These findings demonstrate that brief olfactory cues have a lasting effect on both neural activity and subsequent memory performance.

The default mode network (DMN) is a collection of interconnected transmodal brain regions that is engaged during internally oriented thought processes. It has been linked with multiple functions, including self-referential judgment, social cognition, episodic memory, and semantic memory. In an effort to identify a unitary overarching purpose of the DMN, Menon [Menon, V. 20 years of the default mode network: A review and synthesis. Neuron, 111, 2469-2487, 2023] proposed that it uses its diverse capacities to create an "ongoing internal narrative" that represents dynamically shifting frames of thought and develops ontogenetically from self-directed overt speech during childhood. My aim was to evaluate this hypothesis. The core of the hypothesis is the notion of an ongoing internal narrative, but this is open to different interpretations. If it is interpreted rather narrowly as referring to a story-like stream of inner speech (IS), then Menon's hypothesis faces at least five challenges. First, regarding its developmental assumptions, research suggests that IS does not originate from self-directed overt speech. Second, there are huge individual differences in the frequency of IS, which implies that if the DMN does mediate an internal narrative, this narrative is not ongoing for everyone; instead, its rate of occurrence varies greatly across the population. Third, rodents and nonhuman primates possess a putative DMN, but they lack language and hence also IS, so the function of their DMN is left unclear. Fourth, IS often has a condensed, note-like form rather than being experienced as a full-fledged narrative. And fifth, so far only a couple neuroscientific studies support DMN engagement during IS. It is also possible, however, to interpret Menon's key notion of an ongoing internal narrative more broadly as involving a coherent sequence of situation models that are strongly influenced by language but not completely dependent on it. This interpretation not only obviates most of the problems just mentioned but also brings Menon's hypothesis more in line with other recent proposals regarding the DMN. Further work is needed, however, to refine and test this version of the hypothesis.