Hierarchical Error Evaluation: The Role of Medial-Frontal Cortex in Postural Control

Motor error evaluation appears to be a hierarchically organized process subserved by 2 distinct systems: a higher level system within medial-frontal cortex responsible for movement outcome evaluation (high-level error evaluation) and a lower level posterior system(s) responsible for the mediation of within-movement errors (low-level error evaluation). While a growing body of evidence suggests that a reinforcement learning system within medial-frontal cortex plays a crucial role in the evaluation of high-level errors made during discrete reaching movements and continuous motor tracking, the role of this system in postural control is currently unclear. Participants learned a postural control task via a feedback-driven trial-and-error shaping process. In line with previous findings, electroencephalographic recordings revealed that feedback about movement outcomes elicited a feedback error–related negativity: a component of the human event-related brain potential associated with high-level outcome evaluation within medial-frontal cortex. Thus, the data provide evidence that a high-level error-evaluation system within medial-frontal cortex plays a key role in learning to control our body posture.     

Lone‐Actor Terrorists’ Emotions and Cognition: An Evaluation Beyond Stereotypes

Lone‐actor terrorists are very often presented as emotionally and/or cognitively impaired—yet is it really the case? The present article provides the first rigorous assessment of the hypotheses according to which a high level of negative emotions, especially anger, and a lack of cognitive flexibility and complexity play a role in lone‐actor terrorists’ violent actions. Using a sample of lone‐actor terrorists’ writings, we use the LIWC (a fully automated language use analysis software) to compare terrorists’ cognition and emotion with those of other control groups, most notably nonviolent radical activists. Results strongly support the first hypothesis but clearly refute the second one, suggesting that lone‐actor terrorists are in fact characterized by a specific combination of high‐anger and high‐cognitive complexity. These method and results lay the groundwork for a more systematic and nuanced analysis of the psychology of terrorists, which is currently in a deadlock.     

Directional learning,but no spatial mapping by rats performing a navigational task in an inverted orientation

Previous studies have identified neurons throughout the rat limbic system that fire as a function of the animal’s head direction (HD). This HD signal is particularly robust when rats locomote in the horizontal and vertical planes, but is severely attenuated when locomoting upside-down (Calton & Taube, 2005). Given the hypothesis that the HD signal represents an animal’s sense of directional heading, we evaluated whether rats could accurately navigate in an inverted (upside-down) orientation. The task required the animals to find an escape hole while locomoting inverted on a circular platform suspended from the ceiling. In Experiment 1, Long-Evans rats were trained to navigate to the escape hole by locomoting from either one or four start points. Interestingly, no animals from the 4-start point group reached criterion, even after 29 days of training. Animals in the 1-start point group reached criterion after about six training sessions. In Experiment 2, probe tests revealed that animals navigating from either 1- or 2-start points utilized distal visual landmarks for accurate orientation. However, subsequent probe tests revealed that their performance was markedly attenuated when navigating to the escape hole from a novel start point. This absence of flexibility while navigating upside-down was confirmed in Experiment 3 where we show that the rats do not learn to reach a place, but instead learn separate trajectories to the target hole(s). Based on these results we argue that inverted navigation primarily involves a simple directional strategy based on visual landmarks.     

Can a Connection to Culture Reduce Mental Illness Symptoms and Risk for Future Violence?

Recent policy initiatives and service provider strategic frameworks from the state of Victoria have highlighted intentions to invest in culturally safe practices for justice-involved Indigenous individuals. However, the culturally themed frameworks and protocols presented by health and justice organisations appear to be largely underpinned by theoretical and/or anecdotal evidence. This commentary summarises findings from the first Australian program of research to investigate the influence of cultural identity and cultural engagement on mental health symptoms and violence for Indigenous people in custody. Implications for correctional policy and forensic clinical practice are discussed in this article.     

A limited role for the hippocampus in the modulation of novel-object preference by contextual cues

Recent evidence suggests that rats require an intact hippocampus in order to recognize familiar objects when they encounter them again in a different context. The two experiments reported here further examined how changes in context affect rats' performance on the novel-object preference (NOP) test of object-recognition memory, and how those effects interact with the effects of HPC damage. Rats with HPC lesions and control rats received NOP testing in either the same context in which they had previously encountered sample objects, or in a different but equally familiar context. In Experiment 1, the two contexts had very few overlapping cues within or outside the apparatus; thus, the differences between them were global. Consistent with previous results, control rats showed a novel-object preference in both the unchanged and (globally) changed contexts, whereas rats with HPC lesions displayed a preference only in the unchanged context. In Experiment 2, the context shift included only local features proximal to the test objects. The main results were the reverse of Experiment 1--rats with HPC lesions displayed a novel-object preference in both the unchanged and (locally) changed contexts, whereas control rats displayed a preference only in the unchanged context. The findings are consistent with the view that HPC damage does not cause a general inability to recognize objects, nor an inability to encode or store a representation of the context in which the objects are encountered. They suggest instead that HPC damage impairs the ability to remember specific locations of familiar objects within a particular context.     

Sex differences in the expression of depression in adolescents

The purpose of the present study is to examine the patterns of depressive response of adolescents on The Beck Depression Inventory (BDI). Subjects, who were registered at the Western Québec Regional School Board (Grades 7–12), completed the BDI in the context of intact classes. Out of 1015 subjects, 249 (152 females, 97 males) met the cut-off score of 15 and above on the BDI, and were retained for the study. Sixty-three percent were francophone and 37 percent were anglophone. Ages ranged from 12 to 17 years. Results did not reveal any difference in the BDI scores as a function of either sex, age, or language. However, a significant discriminant function was obtained from subjects' responses that correctly differentiates depressed males from depressed females in 67.8% of the cases. These differential patterns of depressive responding are compared with those observed in depressed college students and adult psychiatric patients, and discussed in light of the literature on adolescent depression.This is an extended version of a poster paper presented at the 48th annual meeting of the Canadian Psychological Association, Vancouver, June 1987.     

Object recognition memory and the rodent hippocampus

In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR task. Rats received 12 5-min exposures to two identical objects and then received either bilateral lesions of the hippocampus or sham surgery 1 d, 4 wk, or 8 wk after the final exposure. On a retention test 2 wk after surgery, the 1-d and 4-wk hippocampal lesion groups exhibited impaired object recognition memory. In contrast, the 8-wk hippocampal lesion group performed similarly to controls, and both groups exhibited a preference for the novel object. These same rats were then given four postoperative tests using unique object pairs and a 3-h delay between the exposure phase and the test phase. Hippocampal lesions produced moderate and reliable memory impairment. The results suggest that the hippocampus is important for object recognition memory.Recognition memory refers to the ability to judge a previously encountered item as familiar and depends on the integrity of the medial temporal lobe (Squire et al. 2007). Tasks that assess recognition memory (and object recognition memory in particular) have become increasingly useful tools for basic and preclinical research investigating the neural basis of memory (Winters et al. 2008). Perhaps the best known of these tasks is the novel object recognition task (NOR) (also known as the visual paired-comparison task in studies with humans and monkeys).Studies of the NOR task in humans with hippocampal damage (McKee and Squire 1993; Pascalis et al. 2004) and in monkeys with selective damage to the hippocampus (Pascalis and Bachevalier 1999; Zola et al. 2000; Nemanic et al. 2004) have resulted in clear and consistent findings. Damage limited to the hippocampus is sufficient to produce impaired recognition memory (Squire et al. 2007, Box 1). In rats and mice, the NOR task has become particularly popular and is currently a benchmark task for assessing recognition memory. Yet despite its widespread use in rodents, the findings are rather mixed. For example, in the rat, although there is agreement that the perirhinal cortex is critically important for normal NOR performance, there is less agreement about the hippocampus (for review, see Winters et al. 2008). Although some of the discrepancies between studies may be attributed to differences in lesion size and in the length of the retention delay (Broadbent et al. 2004), these factors cannot account for all the findings (Squire et al. 2007).Whereas most studies have investigated the effects of hippocampal lesions on postoperative NOR performance, there is also interest in the effects of hippocampal lesions on memory for previously encountered objects. For a number of tasks, hippocampal lesions produce temporally graded retrograde amnesia, such that memory acquired recently is impaired and memory acquired more remotely is spared (for review, see Squire et al. 2004; Frankland and Bontempi 2005). In the case of the single study of retrograde memory that has involved the NOR task, recognition memory was impaired when a 5-wk interval intervened between training and hippocampal surgery (Gaskin et al. 2003). It remains possible that memory might be spared if a longer delay was imposed between training and surgery.The aim of the present study was to assess both the anterograde and retrograde effects of hippocampal lesions on recognition memory using the NOR task. To thoroughly assess the effects of hippocampal lesions we used (1) large groups of animals, (2) multiple tests of NOR memory, (3) a scoring method that allowed object preference to be determined on a second-by-second basis during the recognition tests, and (4) a novel training protocol that permitted the evaluation of recognition memory even after a retention interval as long as 10 wk.     

Conditional reasoning with causal premises: Evidence for a retrieval model

This study examined the hypothesis that a key process in conditional reasoning with concrete premises involves on-line retrieval of information about potential alternate antecedents. Participants were asked to solve reasoning problems with causal conditional premises (If cause P then effect Q). These premises were inserted into short contexts. The availability of potential alternatives was varied from one context to another by adding statements that explicitly invalidated one or more of these alternatives (i.e., other causes that lead to the effect (Q). The invalidated alternatives differed in the degree of their semantic association to the consequent term (Q). The results show that the effect of invalidating one or more potential alternatives on the two uncertain logical forms, AC and DA, was largely determined by their relative associative strength. These results strongly support a model for conditional reasoning with causal premises that supposes that a key element in responding to the uncertain logical forms is on-line retrieval of at least one potential alternative antecedent.     

Family Dynamics in Digital Homes: The Role Played by Parental Mediation in Young Children’s Digital Practices Around 14 European Countries

In contemporary society, digital media are fully integrated in our daily lives, indispensable for our routines, always connected and at-hand. Our research thus explores the parental mediation of portable digital devices in families with young children, addressing the following questions: (a) which are the most common parental mediation styles adopted towards young children; and (b) which individual features of the parents or contextual factors influence the parental mediation style adopted. Our methodology is exploratory and qualitative, considering as empirical corpus 14 national reports from the European-scale study “Young Children (0–8) and Digital Technologies” for a comparative thematic analysis. The authoritative style was the most common parental mediation style related to technology use. In general, there are transversal rules to all parental mediation styles (except laissez-faire style), such as withdraw or give devices to children according to their behavior, control (inappropriate) content and control the time of use. Also, parental perceptions and attitudes about the technologies played a heavier weight on the parental mediation style adopted, and consequently influenced the relationship of the children with digital media. Some implications for future studies, preventive actions, and family therapy are discussed.