Anxiety disorders, such as phobias and posttraumatic stress disorder, are among the most common mental disorders. Cognitive therapy helps in treating these disorders; however, many cases relapse or resist the therapy, which justifies the search for cognitive enhancers that might augment the efficacy of cognitive therapy. Studies suggest that enhancement of plasticity in certain brain regions such as the prefrontal cortex (PFC) and/or hippocampus might enhance the efficacy of cognitive therapy. We found that elevation of brain magnesium, by a novel magnesium compound [magnesium-L-threonate (MgT)], enhances synaptic plasticity in the hippocampus and learning and memory in rats. Here, we show that MgT treatment enhances retention of the extinction of fear memory, without enhancing, impairing, or erasing the original fear memory. We then explored the molecular basis of the effects of MgT treatment on fear memory and extinction. In intact animals, elevation of brain magnesium increased NMDA receptors (NMDARs) signaling, BDNF expression, density of presynaptic puncta, and synaptic plasticity in the PFC but, interestingly, not in the basolateral amygdala. In vitro, elevation of extracellular magnesium concentration increased synaptic NMDAR current and plasticity in the infralimbic PFC, but not in the lateral amygdala, suggesting a difference in their sensitivity to elevation of brain magnesium. The current study suggests that elevation of brain magnesium might be a novel approach for enhancing synaptic plasticity in a regional-specific manner leading to enhancing the efficacy of extinction without enhancing or impairing fear memory formation.

Mice with cytotoxic lesions of the dorsal hippocampus (DH) underestimated 15 s and 45 s target durations in a bi-peak procedure as evidenced by proportional leftward shifts of the peak functions that emerged during training as a result of decreases in both ‘start’ and ‘stop’ times. In contrast, mice with lesions of the ventral hippocampus (VH) displayed rightward shifts that were immediately present and were largely limited to increases in the ‘stop’ time for the 45 s target duration. Moreover, the effects of the DH lesions were congruent with the scalar property of interval timing in that the 15 s and 45 s functions superimposed when plotted on a relative timescale, whereas the effects of the VH lesions violated the scalar property. Mice with DH lesions also showed enhanced reversal learning in comparison to control and VH lesioned mice. These results are compared with the timing distortions observed in mice lacking δ -opioid receptors (Oprd1 −/− ) which were similar to mice with DH lesions. Taken together, these results suggest a balance between hippocampal–striatal interactions for interval timing and demonstrate possible functional dissociations along the septotemporal axis of the hippocampus in terms of motivation, timed response thresholds and encoding in temporal memory.

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The claustrum has been proposed as a possible neural candidate for the coordination of conscious experience due to its extensive "connectome". Herein we propose that the claustrum contributes to consciousness by supporting the temporal integration of cortical oscillations in response to multisensory input. A close link between conscious awareness and interval timing is suggested by models of consciousness and conjunctive changes in meta-awareness and timing in multiple contexts and conditions. Using the striatal beat-frequency model of interval timing as a framework, we propose that the claustrum integrates varying frequencies of neural oscillations in different sensory cortices into a coherent pattern that binds different and overlapping temporal percepts into a unitary conscious representation. The proposed coordination of the striatum and claustrum allows for time-based dimensions of multisensory integration and decision-making to be incorporated into consciousness.

Bilateral intratympanic sodium arsenate injections (100 mg/ml in isotonic saline) in adult male Long Evans rats produced impairments in allocentric navigation using a 12-arm radial maze procedure as well as a motor test battery designed to evaluate vestibular function. In contrast, no impairments in the accuracy or precision of duration reproduction using 20-s and 80-s peak-interval procedures were observed when both target durations were associated with the same lever response, but distinguished by signal modality (e.g., light or sound). In contrast, an ordinal-reproduction procedure with 800, 3200, and 12,800 ms standards requiring the timing of self-initiated movements during the production phase revealed large impairments in the accuracy and precision of timing for vestibular lesioned rats. These impairments were greater on trials in which self-initiated body movements (e.g., holding down the response lever for a fixed duration) were required without the support of external stimuli signaling the onset and offset of the reproduced duration in contrast to trials in which such external support was provided. The conclusion is that space and time are separable entities and not simply the product of a generalized system, but they can be integrated into a common metric using gravity and self-initiated movement as a reference.

Rationale: Hematopoietic stem cell transplantation (HSCT) is the most effective treatment for the majority of patients who have malignant haemolytic disease. Although the success rate of HSCT has increased, the increasing number of cases suffering from secondary solid malignancies after HSCT has attracted more interest recently. Patient concerns: A 16-year-old female patient from China presented with a crusty and painful lesion on the left buccal mucosa with a history of chronic graft-versus-host disease following allogeneic HSCT for acute myeloid leukaemia. Diagnosis: An incisional biopsy of the lesion showed stratified squamous epithelium mucosa with severe dysplasia (carcinoma in situ). Subsequently, a wide local excision was performed and histological examination revealed early infiltrating squamous epithelial mucosa (carcinoma in situ). Interventions: She was being treated in the oral and maxillofacial surgery clinic with an incisional biopsy of the left buccal mucosa. She also received a wide local excision. Outcomes: Follow-up for 4 years showed no recurrence. Lessons: This case helps raise awareness of the diagnosis of oral symptoms in young patients after HSCT. Due to the increasing application of HSCT, raising awareness in oral and dental physicians may be required to improve long-term clinical outcome of patients who underwent HSCT.

Using rodent models to explore the motivation of helping behaviors has become a new trend in recent years. Empathy, the alleviation of personal distress, and desire for social contact have been considered motivations for rodents to engage in helping behaviors. We used 108 Sprague-Dawley rats as subjects and modified the two-chambered helping behavior experimental setup in Carvalheiro and colleagues' study to explore the main motivations of helping behavior in rodents through three experiments. The findings suggest that (1) the desire for social contact and pursuit of an interesting environment are the primary motivations for helping behavior, regardless of the presence of a dark chamber, and (2) the alleviation of personal distress and prior experience of social contact rather than distress experience contribute to the onset and persistence of helping behavior.