Infant rats can acquire,but not retain contextual associations in object-in-context and contextual fear conditioning paradigms

Context learning in postnatal day (PD) 16–18 rats has been taken by Revillo, Cotella, Paglini, and Arias (2015, Physiology & Behavior, 148 , 6–21) to challenge the view that the ontogeny of contextual learning is related to the development of the hippocampal system (Rudy, 1993, Behavioral Neuroscience, 107 (5), 887–891; Schiffino, Murawski, Rosen, & Stanton, 2011 Neurobiology of Learning and Memory, 95 (2), 190–198). Whether context learning is “incidental” or “reinforcement-driven” may determine the ontogeny and neural systems involved (Rudy, 2009, Learning & Memory (Cold Spring Harbor, N.Y.), 16 , 573–585). However, we have shown differential ontogeny of two different forms of incidental context learning, the context pre-exposure facilitation effect (CPFE; Jablonski, Schiffino, & Stanton, 2012, Developmental Psychobiology, 54 (7), 714–722), which emerges between PD 17 and 21; and object-in-context recognition (OiC, Ramsaran, Westbrook, & Stanton, 2016, Developmental Psychobiology, 58 (7), 883–895; Ramsaran, Sanders, & Stanton, 2016, Behavioural Brain Research, 298 , 37–47), which is present on PD17. We investigated whether this task-dissociation reflects an encoding or a retention deficit, by varying the sample-to-testing intervals for both tasks. Experiment 1A found that PD17 rats were able to perform the OiC task after short (5 min) but not long (24 hr) sample-to-test intervals. Experiments 1B and 1C found that PD17 rats trained on the CPFE are able to acquire and express context-shock associations after short but not long retention intervals. These findings suggest that pre-weanling rats encode contexts but show poor consolidation or retrieval after longer retention intervals.     

Emotion depends on context,culture and their interaction: evidence from effective connectivity

Situated models of emotion hypothesize that emotions are optimized for the context at hand, but most neuroimaging approaches ignore context. For the first time, we applied Granger causality (GC) analysis to determine how an emotion is affected by a person’s cultural background and situation. Electroencephalographic recordings were obtained from mainland Chinese (CHN) and US participants as they viewed and rated fearful and neutral images displaying either social or non-social contexts. Independent component analysis and GC analysis were applied to determine the epoch of peak effect for each condition and to identify sources and sinks among brain regions of interest. We found that source–sink couplings differed across culture, situation and culture × situation. Mainland CHN participants alone showed preference for an early-onset source–sink pairing with the supramarginal gyrus as a causal source, suggesting that, relative to US participants, CHN participants more strongly prioritized a scene’s social aspects in their response to fearful scenes. Our findings suggest that the neural representation of fear indeed varies according to both culture and situation and their interaction in ways that are consistent with norms instilled by cultural background.     

Hippocampal state transitions at the boundaries between trial epochs

The hippocampus encodes distinct contexts with unique patterns of activity. Representational shifts with changes in context, referred to as remapping, have been extensively studied. However, less is known about transitions between representations. In this study, we leverage a large dataset of neuronal recordings taken while rats performed an olfactory memory task with a predictable temporal structure involving trials and intertrial intervals (ITIs), separated by salient boundaries at the trial start and trial end. We found that trial epochs were associated with stable hippocampal representations despite moment‐to‐moment variability in stimuli and behavior. Representations of trial and ITI epochs were far more distinct than spatial factors would predict and the transitions between the two were abrupt. The boundary was associated with a large spike in multiunit activity, with many individual cells specifically active at the start or end of each trial. Both epochs and boundaries were encoded by hippocampal populations, and these representations carried information on orthogonal axes readily identified using principal component analysis. We suggest that the hippocampus orthogonalizes representations of the trial and ITI epochs and the activity spike at trial boundaries might serve to drive hippocampal activity from one stable state to the other.     

基于薄板样条和形状内容的医学图像非刚性配准方法研究

目的 针对医学图像非刚性点配准的现状,给出一种基于点特征的非刚性配准方法.方法 利用一种新的相似度测量方法--形状内容来解决两幅图像中点的对应关系,并利用点对应关系来估计非刚性映射函数.结果 利用薄板样条实现了医学图像的快速准确非刚性配准.结论 实验结果表明,上述方法获得了很好的配准效果.     

Hippocampal‐striatal functional connectivity supports processing of temporal expectations from associative memory

The hippocampus and dorsal striatum are both associated with temporal processing, but they are thought to play distinct roles. The hippocampus has been reported to contribute to storing temporal structure of events in memory, whereas the striatum contributes to temporal motor preparation and reward anticipation. Here, we asked whether the striatum cooperates with the hippocampus in processing the temporal context of memorized visual associations. In our task, participants were trained to implicitly form temporal expectations for one of two possible time intervals associated to specific cue‐target associations, and subsequently were scanned using ultra‐high‐field 7T functional magnetic resonance imaging. During scanning, learned temporal expectations could be violated when the pairs were presented at either the associated or not‐associated time intervals. When temporal expectations were met during testing trials, activity in left and right hippocampal subfields and right putamen decreased, compared to when temporal expectations were not met. Further, psycho‐physiological interactions showed that functional connectivity between left hippocampal subfields and caudate decreased when temporal expectations were not met. Our results indicate that the hippocampus and striatum cooperate to process implicit temporal expectation from mnemonic associations. Our findings provide further support for a hippocampal‐striatal network in temporal associative processing.     

Behavioral and brain oscillatory correlates of affective processing in subclinical depression

Named among the most dangerous diseases of the modern era, depression is characterized primarily by distortions in the affective sphere. Despite extensive investigations of underlying the neural background, mechanisms of the distortion still remain unknown. The current study analyzed brain oscillatory dynamics in different frequencies during resting state and presentation of affective stimuli in nonclinical individuals with high Beck Depression Inventory–II (BDI–II) scores (HB) versus controls. Both behavioral and electrocortical “markers” of clinical depression were apparent at subclinical level. A resting-state electroencephalogram (EEG) of HB revealed increased power in low frequencies, predominantly in the frontal cortical areas, that is in accordance with a “spatio-temporal dysfunction” model of depression. Related to that, transition from an eyes-closed to eyes-open condition was associated with diminished alpha blockade in HB, suggesting difficulties with the relocation of attention focus from inner processes toward environmental stimuli. Subsequently, independently of a sign of emotion, five out of six discrete emotions were evaluated as less valenced and four out of six as less intense by HB than by controls, corroborating the view of emotion context insensitivity (ECI) associated with depression. Underlying brain oscillatory dynamics revealed that depression was associated with deficits in the early, implicit, processing stages of emotional stimuli. Later processing stages were characterized by prominent power surges in low and alpha frequencies, presumably indicating emotion upregulation processes and increased engagement of cognitive mechanisms in affective tasks. The study provides brain oscillatory-based mechanisms of emotion processing distortions associated with depression.     

Local narratives of sexual and other violence against children and young people in Zanzibar

Understandings of violence, and especially sexual violence against children, must be situated within the local context. The 2009 Violence against Children Survey in Zanzibar indicated that 6% of girls and 9% of boys reported having experienced sexual violence before the age of 18 years. This paper reports on an in-depth qualitative study conducted in Zanzibar to provide further insights to these findings by examining the circumstances for sexual and other violence against children in Zanzibar. Twenty-four in-depth interviews with young people and 18 focus-group discussions with young people and adults were conducted in rural and urban Zanzibar. A further 8 interviews were conducted with parents and key stakeholders in government and NGO offices that provide services for children. The findings revealed that religious and cultural practices, which form the foundation of Swahili culture in Zanzibar, provide a moral frame for childhood development, but structural factors make children vulnerable to sexual violence. Both boys and girls are vulnerable to sexual violence in the home, neighbourhood, at school and, in particular, at madrasa or Qur’anic schools. As religion and culture are strong influences on childhood, preventing sexual violence at madrasa schools would strengthen the positive aspects of religious teachings for ensuring a safe childhood.     

Young children’s emergent science competencies in everyday family contexts: a case study

To address the lack of research in early science learning and young children’s informal science experiences, this exploratory case study investigated a 7-year-old girl’s (Abigail) emergent science competencies and how they are related to her science experiences in everyday family contexts. Data sources included observations, interviews, parent journals, and the child’s digital journals that were collected over six months. Open-ended coding and constant comparison were used to analyse data. Findings revealed that Abigail’s emergent science competencies were naïve but playful and included a developing, but sophisticated, understanding of the nature of science; family learning included both spontaneous and purposeful learning that contributed to her naïve theories and islands of expertise; and her mother’s scaffolding played an important role in her emergent science competencies. The study suggests ways to connect formal science learning with informal science engagement to further young children’s science competencies.     

Context-dependency of cue-elicited urge to smoke

AIMS: Earlier studies have suggested that the cue-induced urge to smoke depends on the expectation of the availability of smoking. The present study investigated whether a 'room context' change could undo the learned discrimination between two stimuli, respectively, predicting smoking availability or smoking unavailability. DESIGN: A 2 (smoking cue) x 2 (availability context cue) x 6 (trial) x 2 (room context change) within-subjects design was used. Participants were repeatedly presented with a context cue predicting smoking availability (blue serving tray) and a context cue predicting unavailability (yellow serving tray) in one room and tested for an effect of context change in a different room. SETTING: Two distinct rooms located in different department buildings of Maastricht University. PARTICIPANTS: Seventeen daily smokers who had smoked at least five cigarettes a day for at least 2 years. MEASUREMENTS: Self-reported urge to smoke using a visual analogue scale (VAS). FINDINGS AND CONCLUSIONS: Results replicated the finding that a context cue that predicted smoking elicited greater urges to smoke than a context cue that predicted no smoking, irrespective of the presence of smoking cues. In addition, this study showed that this differential effect on the urge to smoke was generalized to a context other than the context in which learning took place. These findings are discussed in relation to the significance of a context change regarding the predictive value of smoking availability.