Body Dysmorphic Disorder (BDD) is a mental disorder where the patient is preoccupied with a misperceived deficit in their appearance. It is a common disorder (~2% prevalence worldwide), leaving the patients significantly disabled and distressed. Comorbid disorders such as social phobia, depression, and anxiety disorders appear frequently. Previous neuroimaging studies have found heterogeneous abnormalities in brain regions involved in visual and emotional processing when comparing BDD patients to healthy controls. Some of these areas are involved in limbic structures. The emotional limbic system (involved in emotion recognition, reward, social behaviour, and decision-making) and the memory hippocampal limbic system (involved in episodic memory, information about objects, faces, and spatial locations) have been stated as two separate neural systems. The aim of this systematic review was to analyse the neural correlates of BDD focusing on structural changes in limbic structures, and further investigate whether the emotional limbic circuit exclusively is affected or solely higher influenced than the rest of the limbic structures. Abnormalities in information processing due to aberrant WM connectivity was found, as well as that volumetric alterations in GM and WM tracts correlate with clinical symptomatology. The relationship between visual and emotional processing system abnormalities and BDD severity suggests an involvement of the emotional limbic system in BDD.

Relatively little is known about the existence and traits of a possible nucleus accumbens (Acc) region in non-mammals. The current project investigated a likely candidate for such a structure in pigeons, the medioventral (mvMSt) and mediodorsal (mdMSt) parts of avian medial striatum (MSt). The methods employed were threefold: 1) tract-tracing to determine anatomical connections of the MSt; 2) lesion studies to assess MSt's role in a cognitive task (reversal learning); and 3) measuring an immediate-early gene induced protein, ZENK, in striatal regions during courtship behavior in male pigeons. The MSt was found to have many forebrain (amygdala, hippocampus, dorsal thalamus) and midbrain (ventral tegmental area, substantia nigra) connections similar to those of Acc. In addition, differences in connection patterns between mvMSt and mdMSt indicated that mvMSt was comparable to the shell of Acc, while the mdMSt showed characteristics of Acc core. Effects of MSt lesions on pattern discrimination and reversal learning were assessed. Both lesion subjects and controls performed similarly on original discrimination. Furthermore, there were no significant differences in MSt lesioned birds compared to controls. However, there was a tendency for the two groups to make different types of errors. Error patterns indicated that sham-lesioned birds had deficits due to key preference, whereas lesioned birds had fixation on previous reward contingencies (perseverative errors). The performance of the lesioned birds was consistent with Acc lesion effects on reversal learning in mammals. The expression of ZENK in the mvMSt, mdMSt, lateral MSt, and lateral striatum of male birds exposed to either an empty cage or a live female pigeon was quantified. Higher ZENK expression was found in the live pigeon condition for all the striatal structures. However, the degree of difference between live and empty was much higher in the mvMSt and mdMSt than in the other areas. Therefore, mvMSt and mdMSt appear to play a role in anticipatory sexual behaviors, as has been shown in Acc. The anatomical and functional data from the current study indicate that avian mMSt has numerous similarities with mammalian Acc. These findings will contribute to understanding the evolution of mammalian Acc and identifying the functional significance of avian MSt.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 105-133). Available also in a digital version from Dissertation Abstracts.

Excitatory glutamatergic inputs from limbic regions such as the hippocampus and the basolateral amygdala (BLA), and dopaminergic inputs from the ventral tegmental area converge in the nucleus accumbens (NAc). It has been proposed that interactions between these glutamatergic and dopaminergic pathways play an important role in adaptive behaviors. The present thesis employed a multidisciplinary approach to study these interactions, with a specific emphasis on the importance of mesoaccumbens dopamine (DA) transmission, in order to obtain a better understanding of the neural mechanisms by which the NAc transforms signals from the temporal lobes into behavior. The experiments of Chapter 2 utilized extracellular single-unit recordings of individual NAc neurons in combination with electrochemical measures of DA efflux in the NAc. Recordings from NAc neurons which received input from the hippocampus but not the BLA revealed that increased efflux of mesoaccumbens DA, evoked by tetanic stimulation of the fimbria, potentiated hippocampal-evoked neural activity in these cells. These effects were mediated by both DA and NMDA receptors. Similar recordings from neurons which received converging input from both the hippocampus and the BLA revealed tetanic stimulation of the fimbria again potentiated hippocampal evoked spiking activity, while concurrently suppressing BLA-evoked spiking activity in the same neurons. The suppression of BLA-evoked spiking activity was activity-dependent, and was mediated by both D, and adenosine A, receptors. Chapter 3 showed that random foraging on a radial-arm maze, which is dependent on a neural circuit linking the hippocampus to the NAc, was correlated with an increase in mesoaccumbens DA extracellular levels, as measured with microdialysis. In Chapter 4, pharmacological blockade of DA or NMDA receptors in the NAc, or selective disruption of dopaminergic modulation of ventral subicular inputs to the NAc (using an asymmetrical infusion procedure) significantly disrupted random foraging. These effects were mediated by the Dl receptor. In Chapter 5, the present data are integrated with previous research to formulate a model of ventral striatal function. It is proposed that the NAc mediates behavior through distinct patterns of activity and inactivity driven by excitatory limbic input projecting to different groups of neural ensembles. Mesoaccumbens DA transmission plays an essential role in regulating the synchrony ensemble activity, augmenting activity in one ensemble while suppressing activity in another. It is argued that the modulatory effects of DA appears to be essential when an organism must switch from one form of adaptive behavior to another in response to a constantly changing environment.

Thesis (M.A.)--University of Delaware, 2008. / Principal faculty advisor: Jeffrey B. Rosen, Dept. of Psychology. Includes bibliographical references.

Thesis (Ph. D. in Molecular Physiology and Biophysics)--Vanderbilt University, Aug. 2009. / Title from title screen. Includes bibliographical references.

Excitatory glutamatergic inputs from limbic regions such as the hippocampus and the basolateral amygdala (BLA), and dopaminergic inputs from the ventral tegmental area converge in the nucleus accumbens (NAc). It has been proposed that interactions between these glutamatergic and dopaminergic pathways play an important role in adaptive behaviors. The present thesis employed a multidisciplinary approach to study these interactions, with a specific emphasis on the importance of mesoaccumbens dopamine (DA) transmission, in order to obtain a better understanding of the neural mechanisms by which the NAc transforms signals from the temporal lobes into behavior. The experiments of Chapter 2 utilized extracellular single-unit recordings of individual NAc neurons in combination with electrochemical measures of DA efflux in the NAc. Recordings from NAc neurons which received input from the hippocampus but not the BLA revealed that increased efflux of mesoaccumbens DA, evoked by tetanic stimulation of the fimbria, potentiated hippocampal-evoked neural activity in these cells. These effects were mediated by both DA and NMDA receptors. Similar recordings from neurons which received converging input from both the hippocampus and the BLA revealed tetanic stimulation of the fimbria again potentiated hippocampal evoked spiking activity, while concurrently suppressing BLA-evoked spiking activity in the same neurons. The suppression of BLA-evoked spiking activity was activity-dependent, and was mediated by both D, and adenosine A, receptors. Chapter 3 showed that random foraging on a radial-arm maze, which is dependent on a neural circuit linking the hippocampus to the NAc, was correlated with an increase in mesoaccumbens DA extracellular levels, as measured with microdialysis. In Chapter 4, pharmacological blockade of DA or NMDA receptors in the NAc, or selective disruption of dopaminergic modulation of ventral subicular inputs to the NAc (using an asymmetrical infusion procedure) significantly disrupted random foraging. These effects were mediated by the Dl receptor. In Chapter 5, the present data are integrated with previous research to formulate a model of ventral striatal function. It is proposed that the NAc mediates behavior through distinct patterns of activity and inactivity driven by excitatory limbic input projecting to different groups of neural ensembles. Mesoaccumbens DA transmission plays an essential role in regulating the synchrony ensemble activity, augmenting activity in one ensemble while suppressing activity in another. It is argued that the modulatory effects of DA appears to be essential when an organism must switch from one form of adaptive behavior to another in response to a constantly changing environment. / Arts, Faculty of / Psychology, Department of / Graduate

Decades of research have shown long-term effects of early caregiving adversity on stress physiology and limbic brain regions, two key biological systems that are implicated in risk for internalizing disorders. Although stress physiology and limbic brain structure undergo significant maturational change during childhood and adolescence, and reciprocally influence each other, the effects of early caregiving adversity on these developmental processes is not well understood. In the current study, we used an accelerated longitudinal design to assess the development of stress physiology, amygdala, and hippocampal volume following early institutional care. Previously Institutionalized (PI; N = 93) and comparison (COMP; N = 161) youth (ages 4-20 years old) completed 1-3 waves of data collection, each spaced approximately 2 years apart, for diurnal cortisol (N = 239, providing a total of 380 diurnal datasets), structural MRI (N = 156, providing a total of 306 scans) and parent-reported internalizing symptoms (N = 133, providing a total of 227 time points). We observed a developmental shift in morning cortisol in the PI group, with blunted levels in childhood and heightened levels in late adolescence. PI history was associated with reduced hippocampal volume and reduced growth of the amygdala, resulting in smaller volumes by adolescence. Results also suggested feed-forward brain-to-hormone mechanisms, such that both amygdala and hippocampal volumes were prospectively associated with morning cortisol levels two years later. Finally, amygdala and hippocampal volumes were independently associated with internalizing scores across the entire sample. These results indicate that adversity-related physiological and neural phenotypes are not stationary during development but instead exhibit dynamic and interdependent changes from early childhood to early adulthood.

No description available.

Pesquisas sobre o transtorno obsessivo-compulsivo (TOC) que reunem pacientes em subgrupos homogêneos a partir de dimensões de sintomas, e as que investigam sua validade utilizando métodos genéticos, de neuroimagem e de resposta terapêutica, têm produzido resultados de valor heurístico. Em particular, a dimensão de colecionismo mostrou ser a mais distinta quanto às características neurobiológicas e a mais associada à pior resposta aos tratamentos farmacológicos e psicoterápicos. Paralelamente, novos métodos de tratamento neurocirúrgico para os casos mais refratários e graves tem sido testados no TOC, atingindo mais eficácia e segurança. Entretanto, não há registro na literatura de uma investigação sistemática da relação entre a presença de dimensões de sintomas antes das cirurgias e o resultado clínico. O objetivo deste estudo foi investigar se dimensões de sintomas, em particular o colecionismo, poderiam influenciar a resposta terapêutica às neurocirurgias límbicas para o tratamento do TOC. Informações de 77 pacientes submetidos à cirurgias ablativas para o tratamento de TOC em três centros de pesquisa das cidades de São Paulo (Brasil, n=17), Boston (EUA, n=37) e Estocolmo (Suécia, n=23) foram analisadas utilizando a Dimensional Yale-Brown Obsessive-Compulsive Scale (DYBOCS; São xvi Paulo) ou a Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (YBOCS-SC; Boston e Estocolmo) para a estratificação em dimensões de sintomas, e os escores YBOCS para avaliações de resultado clinico. Após os procedimentos, houve uma diminuição média de 34,2% nos escores YBOCS (IC 95% de 27,2% a 41,3%), com um tempo de seguimento médio de 34,8 meses, sem diferença significativa entre os centros de pesquisa ou em relação ao tipo de cirurgia (capsulotomia, São Paulo e Estocolmo; cingulotomia, Boston). Pacientes com dimensão de colecionismo apresentaram pior resposta ao tratamento (redução média dos escores YBOCS de 22,70% [DP = 32,23] para pacientes com colecionismo versus 41,60% [DP = 25,99] para pacientes sem colecionismo, p=0,006). Pacientes com dimensão de pensamentos proibidos também revelaram pior resposta ao tratamento (redução média dos escores YBOCS de 30,10% [DP = 29,61] para pacientes com pensamentos proibidos versus 51,33% [DP = 32,74] para pacientes sem pensamentos proibidos, p=0,033), mas este efeito dependeu da co-ocorrência das dimensões de pensamentos proibidos e colecionismo. Ao se utilizar um modelo de análise de variância (ANOVA), apenas a influência negativa do colecionismo se manteve: a redução média dos escores YBOCS em todos os pacientes foi de 13 pontos, mas em pacientes com colecionismo essa redução foi de 7 pontos (p=0,002). Concluindo, a presença da dimensão de colecionismo no momento pré-operatório associou-se à redução da melhora clínica decorrente da intervenção neurocirúrgica / Research on obsessive-compulsive disorder (OCD) using symptom dymension strategies to identify more homogeneous patient subgroups, coupled with genetic, neuroimaging, and treatment outcome studies, has produced results of heuristic value. In particular, the hoarding dimension has more distinct neurobiological characteristics and has been associated with worse response to pharmachological and psychoterapeutic treatments. At the same time, the most severe and treatment refractory cases of OCD have been treated with novel neurosurgical techniques, with better efficacy and safety profiles. However, the association between symptom dimensions prior to surgery and the treatment outcome after the limbic procedure has not been sistematically investigated in the literature so far. The objective of this study was to investigate if symptom dymensions, in particular hoarding, could influence treatment outcome of limbic neurosurgeries for OCD. Information on 77 patients that underwent limbic ablative procedures for OCD from three research centers at Sao Paulo (Brazil, n=17), Boston (USA, n=37), and Stockholm (Sweden, n=23) were collected and analyzed. Symptom stratification was obtained using the Dimensional Yale-Brown Obsessive-Compulsive Scale (DYBOCS; Sao Paulo) or the Yale-Brown xix Obsessive-Compulsive Scale Symptom Checklist (YBOCS-SC; Boston and Stockholm) and treatment outcome was defined using YBOCS scores. Mean YBOCS scores reduced 34.2% after surgery (CI 95% = 27.2% to 41.3%) with a mean follow-up of 34.8 months. There was no significant difference among centers or in relation to the method of surgical intervention (capsulotomy, Sao Paulo and Stockholm; cingulotomy, Boston). Patients with hoarding symptoms had worse response to treatment (mean YBOCS reduction of 22.70% [SD = 32.23] for hoarding patients vs. 41.60% [SD = 25.99] for patients without hoarding symptoms, p=0,006). Patients with forbidden thoughts symptoms apparently also had worse response to treatment (mean YBOCS reduction of 30.10% [SD = 29.61] for patients with forbidden thoughts vs. 51.33% [SD = 32.74] for patients without this symptom dymension, p=0,033), but this effect proved dependent on the co-occurence of forbidden thoughts with hoarding dymensions. Indeed, using an analisys of variance model (ANOVA) only the negative influence of the hoarding dymension remained: patients without hoarding had a mean YBOCS redution of 13 points, while in patients with hoarding symptoms the mean reduction was of 7 points (p=0.002). In conclusion, the pre-operative presence of the hoarding dymension was associated with worst clinical outcome after the neurosurgical procedures