Age-dependent effects of nicotine on locomotor activity and conditioned place preference in rats

Rationale Most adult smokers start smoking during their adolescence. This adolescent initiation may be due to multiple factors, but little evidence is available regarding whether their brains are differentially sensitive to the addictive effects of nicotine during adolescence.Objective To test the hypothesis that adolescents are more sensitive than adults to nicotines rewarding actions.Methods An unbiased, counterbalanced, place-conditioning procedure was used to examine drug-induced reward and locomotor activity. Early adolescent (postnatal day 28), late adolescent (P38) and adult (P90) rats received either saline or nicotine (0.125, 0.25 or 0.5 mg/kg, s.c.) and were tested for place conditioning.Results During early adolescence, a single nicotine injection (0.5 mg/kg) induced significant conditioned place preference (CPP). In contrast, during late adolescence or adulthood, nicotine did not induce CPP after either one or four conditioning trials. Initial locomotor responses to acute nicotine administration during the first conditioning trial also differed with age, with no effect at P28, but substantial inhibitory responses at all doses studied (0.125–0.5 mg/kg) at later ages. Although not differing in their initial locomotor response to nicotine, there was a significantly greater tolerance/sensitization during the second and subsequent drug exposures in late adolescents than in adults.Conclusions These findings provide evidence that adolescent brain is differentially sensitive to both the acute and repeated effects of nicotine relative to adult brain. Furthermore, there are significant differences in nicotine sensitivity between early and late phases of adolescence.     

Congenital eye anomalies

Any part of the eye and its surrounding tissues may be affected by congenital malformation. Anomalies may occur in isolation, in combination, or as part of a systemic malformation syndrome. Early identification is essential to remove potential obstructions to visual development and to identify potential underlying multisystem disease. Recognition of congenital eye anomalies can also improve parental understanding and genetic counseling.     

A large planum sphenoidale meningioma with sinonasal extension in a child. Case report and review of the literature

Anterior cranial base meningiomas are rare tumors in children. Due to the extensive involvement of orbit, paranasal sinuses, midface, and anterior skull base, a multidisciplinary approach is warranted. We present a case of a child with a large planum sphenoidale meningioma extending into subfrontal region, ethmoid and maxillary sinuses inferiorly, and orbits laterally. The patient, a 4-year-old girl, presented with long-standing nasal stuffiness and swelling of the midface. An extended frontobasal approach through a bifrontal craniotomy was used to resect the intracranial portion of this mass. The tumor had eroded through nasal septum, medial orbital walls, and left maxilla, structures which were not readily accessible from a cranial approach alone. A modified Weber-Ferguson incision was used for a transfacial approach to resect the residual mass below the skull base. The advantages of combining the bifrontal craniotomy with a transfacial split provided the added exposure to maximize the extent of resection.     

Neural foundations for understanding social and mechanical concepts

Motivated by neuropsychological investigations of category-specific impairments, many functional brain imaging studies have found distinct patterns of neural activity associated with different object categories. However, the extent to which these category-related activation patterns reflect differences in conceptual representation remains controversial. To investigate this issue, functional magnetic resonance imaging (fMRI) was used to record changes in neural activity while subjects interpreted animated vignettes composed of simple geometric shapes in motion. Vignettes interpreted as conveying social interactions elicited a distinct and distributed pattern of neural activity, relative to vignettes interpreted as mechanical actions. This neural system included regions in posterior temporal cortex associated with identifying human faces and other biological objects. In contrast, vignettes interpreted as conveying mechanical actions resulted in activity in posterior temporal lobe sites associated with identifying manipulable objects such as tools. Moreover, social, but not mechanical, interpretations elicited activity in regions implicated in the perception and modulation of emotion (right amygdala and ventromedial prefrontal cortex). Perceiving and understanding social and mechanical concepts depends, in part, on activity in distinct neural networks. Within the social domain, the network includes regions involved in processing and storing information about the form and motion of biological objects, and in perceiving, expressing, and regulating affective responses.     

Multiple visual memory phenomena in a memory search task

This paper reports evidence of the existence of multiple and distinct visual memory processes in a memory search task in which a divided field stimulus presentation was used at study (Experiments 1-3) and either a foveal (Experiments 1 and 2) or a lateralized (Experiment 3) stimulus presentation was used at test. These memory processes can be distinguished on the basis of (1) whether or not they are hemispherically organized; and (2) the locus of their underlying brain activity, as evidenced by the scalp distribution of the event-related brain potentials and by the localization of the event-related optical signal that accompany them. These memory effects are discussed in the context of visual form memory.     

The KickStrip: a novel testing device for periodic limb movement disorder

STUDY OBJECTIVES: In light of the ongoing debate over the clinical significance of periodic limb movement disorder (PLMD) and its monitoring in overnight sleep studies, we introduce a novel, portable, low-cost device for PLMD testing. The KickStrip is a disposable device, which includes a movement sensor, a central processing unit with real-time software, and a display. In the present study, the KickStrip final score (Kscore) is validated against the traditional periodic limb movement index (PLMI) based on overnight recordings in the sleep laboratory. DEISGN: Patients underwent full polysomnographic recordings concomitantly with the use of the KickStrip for a single night. SETTING: Sleep Disorders Unit at Loewenstein Rehabilitation Hospital and Sleep Medicine Center at Rambam Medical Center, Israel. PATIENTS: Eighty-two patients referred for overnight sleep recordings due to sleep disturbance of any kind. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The Kscores were collected and the PLMI computed for each leg separately. Pearson correlations between Kscores and PLMI ranged between r = 0.83 to r = 0.88 (p < 0.001). Sensitivity and specificity values of the Kscores for increasing PLMD thresholds showed sensitivity ranging from 50% to 100% and specificity ranging from 83% to 100%. Receiver operating characteristic curves showed area-under-the-curve values ranging from 82% to 92%. Bland-Altman plot showed high agreement between the methods. CONCLUSIONS: Comparisons between the Kscores and the traditional PLMI show increased accuracy with severity level and excellent agreement. The KickStrip is a valuable tool for PLMD testing for both clinical and research purposes.