Brain substrates for automatic retrieval of value memory in the primate basal ganglia

Our behavior is often carried out automatically. Automatic behavior can be guided by past experiences, such as learned values associated with objects. Passive-viewing and free-viewing tasks with no immediate outcomes provide a testable condition in which monkeys and humans automatically retrieve value memories and perform habitual searching. Interestingly, in these tasks, caudal regions of the basal ganglia structures are involved in automatic retrieval of learned object values and habitual gaze. In contrast, rostral regions do not participate in these activities but instead monitor the changes in outcomes. These findings indicate that automatic behaviors based on the value memories are processed selectively by the caudal regions of the primate basal ganglia system. Understanding the distinct roles of the caudal basal ganglia may provide insight into finding selective causes of behavioral disorders in basal ganglia disease.

Capacity for movement is an organisational principle in object representations

The ability to perceive moving objects is crucial for survival and threat identification. The association between the ability to move and being alive is learned early in childhood, yet not all moving objects are alive. Natural, non-agentive movement (e.g., clouds, fire) causes confusion in children and adults under time pressure. Recent neuroimaging evidence has shown that the visual system processes objects on a spectrum according to their ability to engage in self-propelled, goal-directed movement. Most prior work has used only moving stimuli that are also animate, so it is difficult to disentangle the effect of movement from aliveness or animacy in representational categorisation. In the current study, we investigated the relationship between movement and aliveness using both behavioural and neural measures. We examined electroencephalographic (EEG) data recorded while participants viewed static images of moving or non-moving objects that were either natural or artificial. Participants classified the images according to aliveness, or according to capacity for movement. Behavioural classification showed two key categorisation biases: moving natural things were often mistaken to be alive, and often classified as not moving. Movement explained significant variance in the neural data, during both a classification task and passive viewing. These results show that capacity for movement is an important dimension in the structure of human visual object representations.

Neural dynamics of retrieval suppression in abolishing item-specific cortical pattern of unwanted emotional memories

When reminded of an unpleasant experience, people often try to exclude the unwanted memory from awareness in an effort to forget it, a process known as retrieval suppression. Yet, how fast can individual memories be targeted and controlled, and the neural dynamics in modulating cortical traces of individual memories, remain elusive. Here, using multivariate decoding analyses on time-domain and time-frequency-domain EEGs, we found that retrieval suppression of aversive memories was distinct from retrieval and passive viewing, when given a reminder. Specifically, early elevation of mid-frontal theta power during the first 500 ms distinguished retrieval suppression from passive viewing, suggesting that suppression recruited early active control processes. On an item-level, we could discern activities relating to individual memories during active retrieval-initially, based on perceptual responses to reminders (0-500 ms) and later, via the reinstatement and maintenance of the target aversive scenes (500-3000 ms). Critically, suppressing retrieval significantly weakened (during 420-600 ms) and eventually abolished these item-specific cortical patterns till cue disappeared (1200-3000 ms), suggesting the successful exclusion of the unwelcome memory from awareness. Suppression of item-specific cortical patterns bore behavioral consequences in predicting subsequent episodic forgetting. These findings provide unique insight into the neural dynamics underlying the control of unwelcome memories: upon perceiving an unwelcome reminder, people rapidly deploy inhibitory control to truncate retrieval within 500 ms, which likely terminate the reminder-to-memory conversion at around 500 ms that would ordinarily arise through hippocampal pattern completion. We concluded that both rapid and sustained control are critical in abolishing cortical patterns of individual memories, limiting unwelcome awareness, and precipitating later forgetting.

Biased Maintenance of Attention on Sad Faces in Clinically Depressed Youth: An Eye-Tracking Study

The role of negative attention biases (AB), central to cognitive models of adult depression, is yet unclear in youth depression. We investigated negative AB in depressed compared to healthy youth and tested whether AB are more pronounced in depressed than at-risk youth. Negative AB was assessed for sad and angry faces with an eye-tracking paradigm [Passive Viewing Task (PVT)] and a behavioural task [Visual Search Task (VST)], comparing three groups of 9–14-year-olds: youth with major depression (MD; n = 32), youth with depressed parents (high-risk; HR; n = 49) and youth with healthy parents (low-risk; LR; n = 42). The PVT revealed MD participants to maintain attention longer on sad faces compared to HR, but not LR participants. This AB correlated positively with depressive symptoms. The VST revealed no group differences. Our results provide preliminary evidence for a negative AB in maintenance of attention on disorder-specific emotional information in depressed compared to at-risk youth.

Functional Dynamics of Deafferented Early Visual Cortex in Glaucoma

In advanced retinitis pigmentosa with retinal lesions, the lesion projection zone (LPZ) in the early visual cortex can be driven during visual tasks, while it remains unresponsive during passive viewing. We tested whether this finding translates to advanced glaucoma, a major cause of acquired blindness. During visual stimulation, 3T fMRI scans were acquired for participants with advanced glaucoma (n = 4; age range: 51–72) and compared to two reference groups, i.e., advanced retinitis pigmentosa (n = 3; age range: 46–78) and age-matched healthy controls with simulated defects (n = 7). The participants viewed grating patterns drifting in 8 directions (12 s) alternating with uniform gray (12 s), either during passive viewing (PV), i.e., central fixation, or during a one-back task (OBT), i.e., reports of succeeding identical motion directions. As another reference, a fixation-dot task condition was included. Only in glaucoma and retinitis pigmentosa but not in controls, fMRI-responses in the lesion projection zone (LPZ) of V1 shifted from negative for PV to positive for OBT (p = 0.024 and p = 0.012, respectively). In glaucoma, these effects also reached significance in V3 (p = 0.006), while in V2 there was a non-significant trend (p = 0.069). The general absence of positive responses in the LPZ during PV underscores the lack of early visual cortex bottom-up plasticity for acquired visual field defects in humans. Trends in our exploratory analysis suggesting the task-dependent LPZ responses to be inversely related to visual field loss, indicate the benefit of patient stratification strategies in future studies with greater sample sizes. We conclude that top-down mechanisms associated with task-elicited demands rather than visual cortex remapping appear to shape LPZ responses not only in retinitis pigmentosa, but also in glaucoma. These insights are of critical importance for the development of schemes for treatment and rehabilitation in glaucoma and beyond.

Emotion regulation of social exclusion: a cross-cultural study

Social exclusion is harmful to basic human needs. Emotion regulation represents a potential coping strategy. As culture can influence how people react and regulate their emotions, this study examined whether emotional reaction and regulation in response to social exclusion differ between individualistic and collectivistic cultures. A total of 80 college students, half White (n = 40, recruited in Manchester, UK) and half East Asian (n = 40, recruited in Shenzhen, China) viewed social exclusion pictures expressed by same-race or other-race characters. Both groups of participants viewed these pictures under no-reappraisal (passive viewing) and reappraisal (reinterpretation) conditions. Participants rated their vicarious negative emotional experience after each picture presentation. Results showed that both White and East Asian participants expressed greater negative emotion and showed stronger emotion regulation effects when facing own-race social exclusion, i.e., the “own-race bias”. In addition, White participants were more capable of regulating the negative emotions elicited by social exclusion compared to East Asian participants. Findings highlight the importance of considering the role of culture in emotional reaction to and emotion regulation of social exclusion, which may help the development of appropriate interventions across diverse populations.

Pupillary Responses to Faces Are Modulated by Familiarity and Rewarding Context

Observing familiar (known, recognisable) and socially relevant (personally important) faces elicits activation in the brain’s reward circuit. Although smiling faces are often used as social rewards in research, it is firstly unclear whether familiarity and social relevance modulate the processing of faces differently, and secondly whether this processing depends on the feedback context, i.e., if it is different when smiles are delivered depending on performance or in the absence of any action (passive viewing). In this preregistered study, we compared pupillary responses to smiling faces differing in subjective familiarity and social relevance. They were displayed in a passive viewing task and in an active task (a speeded visual short-term memory task). The pupils were affected only in the active task and only by subjective familiarity. Contrary to expectations, smaller dilations were observed in response to more familiar faces. Behavioural ratings supported the superior rewarding context of the active task, with higher reward ratings for the game than the passive task. This study offers two major insights. Firstly, familiarity plays a role in the processing of social rewards, as known and unknown faces influence the autonomic responses differently. Secondly, the feedback context is crucial in reward research as positive stimuli are rewarding when they are dependent on performance.

The Processing of Visual Signals in Major Depressive Disorder

The balanced processing of the internal mental world and the external world is a crucial aspect of everyday well-being. An extensive control of the internal emotional and cognitive world that often results in an internal expression of distress is a common feature of internalizing disorders. However, how depression affects the processing of the external world is still an open question. We, therefore, tested the processing of visual signals in major depressive disorder (MDD). To this end, we recorded the electroencephalogram of 38 MDD patients and 38 controls, while they performed a response-choice task with informative feedback and a passive viewing task. MDD patients differed significantly from controls in the early information processing of visual stimuli. The vertex positive potential (VPP) evoked by feedback in the response-choice task and pictures in the passive viewing task were smaller in MDD patients than in controls. This outcome suggests that depression might subtract attentional resources from external signal processing, with potential consequences in various cognitive domains.

The selective contribution of the right cerebellar lobule VI to reading

Extensive studies have reported significant cerebellar activation during reading tasks. However, it is still unclear which regions in the cerebellum are specifically involved in reading and what this involvement entails. With functional magnetic resonance imaging, we compared Chinese-English bilingual children’s cerebellar neural activity between reading and non-reading conditions and between Chinese characters and English words in a passive viewing paradigm. We observed that the posterior part of the right lobule VI showed greater activation in the reading compared to non-reading tasks. Reading specificity index was significantly in this region. Functional decoding via Neurosynth further showed that this region was responsible for phonological processing and connected with the cerebral reading areas. These results suggest that the posterior part of the right lobule VI might be a reading-selective region in the cerebellum. However, we did not observe any significantly separable activation patterns in the cerebellum between Chinese characters and English words, indicating that the region preferentially responding to reading may not be able to differentiate scripts in a passive viewing condition. In general, these findings deepen our understanding of how the cerebellum contributes to reading.