Serotonergic influence on the potentiation of D-amphetamine and apomorphine-induced rotational behavior by the α2-adrenoceptor antagonist 2-methoxy idazoxan in hemiparkinsonian rats

Summary. The α₂-adrenoceptor antagonists potentiate both ipsilateral and contralateral rotations induced by amphetamine and apomorphine respectively in hemiparkinsonian rats. The present study investigated the role of serotonergic transmission in this potentiation in unilaterally 6-hydroxydopamine nigral lesioned rats. D-amphetamine (0.5 mg/kg, i.p.) produced ipsilateral rotations, which were decreased by the dopamine receptor antagonist haloperidol (0.2 mg/kg, i.p.) and the α₁-receptor antagonist prazosin (1 mg/kg, i.p.). The selective α₂-antagonist 2-methoxy idazoxan (0.2 mg/kg, i.p.) potentiated the amphetamine-induced ipsilateral rotations, that were attenuated by haloperidol and prazosin. The selective serotonin re-uptake inhibitor citalopram (10 mg/kg, i.p.) and selective serotonin synthesis inhibitor p-chlorophenylalanine (150 mg/kg, i.p., 3 days) decreased and increased the observed potentiation respectively. Apomorphine (0.2 mg/kg, s.c.) produced contralateral rotations, which were decreased by haloperidol but not by prazosin. 2-methoxy idazoxan potentiated these rotations which were attenuated by haloperidol but not by prazosin. Citalopram and p-chlorophenylalanine increased and decreased the observed potentiation respectively. Citalopram and p-chlorophenylalanine had no effect by per se on D-amphetamine and apomorphine-induced rotations. 2-methoxy idazoxan alone increased both ipsilateral and contralateral spontaneous rotations. Taken together, these findings indicate that an increase in noradrenergic tone by 2-methoxy idazoxan potentiates both D-amphetamine-induced ipsilateral and apomorphine induced contralateral rotations. α₁-Antagonism attenuates D-amphetamine induced ipsilateral rotations and its potentiation by 2-methoxy idazoxan but not apomorphine rotations or its potentiation. Increasing and decreasing the serotonergic transmission decreases and increases D-amphetamine potentiation, whereas increases and decreases apomorphine potentiation respectively. The possible mechanisms for these findings are discussed.     

Neuroticism and affective instability: the same or different?

OBJECTIVE: The purpose of this study was to examine the correlates and consequences of two constructs related to affective experience: neuroticism and affective instability. METHOD: One hundred thirty-two patients were assessed at intake for axis I and II symptoms, general personality traits, and specific impairments, including impairments in interpersonal functioning. The data included responses to structured and semistructured interviews, self-reports of interpersonal problems, and reports of interpersonal problems from significant others. Clinical ratings of axis I and II symptoms and of impairment were made by using the LEAD (i.e., longitudinal, expert, all data) consensus approach. Ninety-one of the 132 patients were reassessed at 12-month follow-up. RESULTS: Neuroticism and affective instability manifested varied concurrent relations, with neuroticism being strongly related to an anxious, avoidant style and affective instability related to more externalizing personality styles. Prospectively, neuroticism predicted later symptoms, occupational impairment, and global dysfunction, whereas affective instability predicted romantic impairment. CONCLUSIONS: The findings suggest that neuroticism and affective instability--which are considered core aspects of personality pathology--are related but distinct constructs with unique correlates and different predictive abilities.     

Maternal behavior: activation of the central oxytocin receptor system in parturient rats?

Parturition plays a critical role in the full expression of maternal behavior in postpartum females, yet the precise mechanism remains unclear. Here we examined the role of parturition in the activation of Fos and FosB in the central oxytocin receptor (OTR) system in rats. Although expression of FosB, not Fos, was seen in the piriform cortex (Pir) and caudate putamen of virgin and pregnant females, activation of Fos and FosB with extensive co-localization was found in the medial preoptic area, the bed nucleus of the stria terminalis and Pir of parturient brain. This parturition induced activation of Fos and FosB was identified in the central OTR-expressing cells as well as in oxytocinergic neurons. Our data provide direct evidence, for the first time, that parturition activates Fos and FosB in the central OTR system. We propose that Fos and FosB may have comparable functions on initiating maternal behavior at parturition.     

Grief hallucinations: true or pseudo? Serious or not? An inquiry into psychopathological and clinical features of a common phenomenon

An inquiry into the psychopathology and the clinical significance of grief hallucinations is presented and two cases with severe grief hallucinations are described. Unlike many cases in the literature, the two female patients were young (aged 43 and 45, respectively) and both suffered from the loss of a daughter. The heterogeneous concept of grief hallucinations is described and discussed, focusing particularly on the difficulties of reaching a differentiation between hallucination and pseudohallucination. Basic theses of the article are: (1) Contrary to a widely held view, grief hallucinations can display all the characteristics of 'true' hallucinations. (2) The concept of grief hallucinations probably comprises a heterogeneous group of disturbances of perception and of thought processes. They can be experienced as comforting but can also cause considerable distress. (3) There are essentially two definitions of pseudohallucinations and they contradict each other. The extremely vague concept of pseudohallucinations appears to be of questionable value and should be abandoned.     

Pedunculopontine nucleus and basal ganglia: distant relatives or part of the same family?

The basal ganglia are more highly interconnected with the pedunculopontine tegmental nucleus (PPN) than with any other brain region. Regulation and relay of basal ganglia activity are two key functions of the PPN. The PPN provides an interface for the basal ganglia to influence sleep and waking, and the two structures are similarly implicated in learning, reward and other cognitive functions. Perturbations of basal ganglia activity have consequences for the PPN and vice versa, exemplified by their interdependencies in motor function and Parkinson's disease. Thus, close anatomical and physiological links between the PPN and basal ganglia make it increasingly difficult to consider the two as separate functional entities.     

Impaired processing of relative distances between features and of the eye region in acquired prosopagnosia—Two sides of the same holistic coin?

Acquired prosopagnosia (AP) is characterized by impaired recognition of individual faces following brain damage. The nature of the functional impairment(s) underlying AP remains debated. Recent studies have demonstrated deficient processing of diagnostic information in the region of the eyes (Caldara et al., 2005); other studies suggest that patients fail to judge relative distances between facial features (Barton et al., 2002). We hypothesized that these apparently different observations are related to a common cause. More precisely, we suggest that AP arises due to an impairment of a process that reduces uncertainty about the nature/location of the diagnostic cues for face individualization: the ability to perceive multiple elements of a face as a single global representation (holistic processing). Being impaired at processing individual faces holistically, prosopagnosic patients would tend to perform relatively worse for processing facial areas containing multiple elements (i.e., the eyes), and for elements that are widely spaced apart. Here we tested PS, a single case of AP, at matching unfamiliar faces differing either with respect to local features or inter-feature distances, over the upper and lower areas of the face. A pilot study and Experiment 1 confirmed that PS was extremely poor at using information encompassing the eyes, but was also deficient at perceiving relative distances between features. When uncertainty about the location and nature of the diagnostic cue was removed in Experiment 2, PS' performance remained below normal range, but she improved substantially. Most interestingly, her pattern of performance across the different conditions appeared qualitatively identical to that of normal controls. In line with previous observations of PS and other cases of prosopagnosia, our findings indicate that the reduced reliance on the area of the eyes and on relative distances between features in AP may have a common underlying cause—the disruption of holistic processing of the individual face.     

Atypical scanpaths in schizophrenia: Evidence of a trait- or state-dependent phenomenon?

The development of trait markers of schizophrenia would represent an important advance in understanding the genetic architecture of the disease. To date, no candidate markers have satisfied all of the trait marker criteria, and many are not specific to the schizophrenia spectrum. Abnormalities in visual scanpaths are frequently reported in patients with schizophrenia and are emerging as a novel candidate for a schizophrenia biomarker. Here we review the suitability of scanpath measures as a target for trait marker research in schizophrenia. Papers reporting scanpath patterns in patients with schizophrenia were identified by PubMed and Google Scholar searches and by scanning reference lists in relevant articles. Search terms included "schizophrenia," "psychosis," "scanpath," "scan path," "fixation," "saccade" and "eye movement." Scanpath abnormalities afford impressive sensitivity and specificity and appear largely independent of psychotropic medications. Scanpaths may demonstrate some fluctuation with symptomatology and may be useful in illuminating illness state or subtypes. However, there is evidence that viewing behaviours remain atypical regardless of symptom remission and may be present in unaffected relatives of individuals with schizophrenia. This research is in its early stages, and further investigation regarding patterns of inheritance is required. Our findings support scanpath measures as a favourable topic for further investigation as a trait marker.     

Ependymoma and intraparenchymal calcifying pseudoneoplasm of the neural axis: incidental collision or unique reactive phenomenon?

The so-called “calcifying pseudoneoplasm of the neural axis” is a rare tumefactive lesion presumed to be reactive in nature. To our knowledge, association with a true neoplasm has not been previously reported. We recently encountered the case of a 67-year-old woman who underwent resection of an incidentally discovered cerebellar cystic mass with a distinct, calcified component. Histology demonstrated a partially ossified, lobulated, chondrocalcific lesion surrounded by chronic inflammation, spindle to epithelioid cells, and occasional multinucleated giant cells—all features of calcifying pseudoneoplasm of the neural axis. A low-grade ependymoma associated with marked piloid gliosis was found contiguous to the lesion. The unique combination of an ependymoma with marked reactive gliosis and a calcifying pseudoneoplasm supports the reactive nature of the latter.     

Covert and overt voluntary attention: linked or independent?

Recent evidence indicates that reflexive shifts in spatial attention with eye movements (overt orienting) and without eye movements (covert orienting) can be dissociated [J. Exp. Psychol. Hum. Percept. Perform., in press]. Here, we show that a similar dissociation exists for voluntary shifts in overt and covert attention. Our study is consistent with general theories of attention that assume bottom-up (reflexive) processes and top-down (voluntary) processes converge on a common neural architecture.     

Theory of mind and central coherence in eating disorders: Two sides of the same coin?

The aim of this study was to evaluate central coherence and theory of mind (ToM) and explore the relationships between these domains in patients with eating disorders (ED). ToM and central coherence were assessed in 72 women [24 with anorexia nervosa (AN), 24 with bulimia nervosa (BN) and 24 healthy controls (HC)]. The Reading the Mind in the Eyes (RME) and the Faux Pas Test (FPT) to measure ToM, and the copy strategy of the Rey–Osterrieth Complex Figure Test to assess central coherence were used. It was observed that patients with ED had a decrease in central coherence skills compared with the control group; that patients with anorexia had a poor performance on RME ToM task compared with BN patients and HCs, and also that these measures were related in both clinical groups. The statistically significant correlation between them suggests that the central coherence and ToM measures might involve common cognitive processes. These results provide a better understanding of the nature of the socio-cognitive deficits observed in patients with eating disorders.     

Fever and sickness behavior: Friend or foe?

Fever has been recognized as an important symptom of disease since ancient times. For many years, fever was treated as a putative life-threatening phenomenon. More recently, it has been recognized as an important part of the body’s defense mechanisms; indeed at times it has even been used as a therapeutic agent. The knowledge of the functional role of the central nervous system in the genesis of fever has greatly improved over the last decade. It is clear that the febrile process, which develops in the sick individual, is just one of many brain-controlled sickness symptoms. Not only will the sick individual appear “feverish” but they may also display a range of behavioral changes, such as anorexia, fatigue, loss of interest in usual daily activities, social withdrawal, listlessness or malaise, hyperalgesia, sleep disturbances and cognitive dysfunction, collectively termed “sickness behavior”. In this review we consider the issue of whether fever and sickness behaviors are friend or foe during: a critical illness, the common cold or influenza, in pregnancy and in the newborn. Deciding whether these sickness responses are beneficial or harmful will very much shape our approach to the use of antipyretics during illness.