Early behavioral and developmental interventions in ADNP-syndrome: A case report of SWI/SNF-related neurodevelopmental syndrome.

BACKGROUND: Autism spectrum disorder (ASD) affects approximately one in 59 children. Variants in the activity-dependent neuroprotector homeobox ADNP (OMIM #611386) gene may be one of the most common single-gene causes of syndromic ASD. Most patients diagnosed with ADNP syndrome have ASD as a comorbidity, and all patients have mild-to-severe intellectual disability. METHODS/CASE REPORT: We present a case report of a patient diagnosed with ADNP syndrome at 2.5 years of age. The patient has many of the key features of the syndrome, including ASD, global developmental delay, behavioral problems, congenital heart defect, early tooth eruption, and vision problems. The patient's initial presentation included congenital diaphragmatic hernia (CDH), which has not been previously reported in this condition. RESULTS: The patient exhibited frequent behavioral outbursts and was initiated on antipsychotic medication with near-complete resolution of symptoms allowing her to engage more fully in early intervention therapies leading to progress in language acquisition. CONCLUSION: This short report provides guidance for antipsychotic medication dosing to improve early intervention outcomes. This is the first report of CDH in this syndrome.

Axenfeld-Rieger Anomaly and Neuropsychiatric Problems-More than Meets the Eye.

OBJECTIVE: The main purpose of this article is to demonstrate the co-occurrence of Axenfeld-Rieger anomaly and neuropsychiatric problems as clinical signs of genetically determined cerebral small vessel disease in two patients. CASE STUDY: We report on two adolescent individuals with ocular anterior segment dysgenesis (Axenfeld-Rieger anomaly) presenting with neuropsychiatric symptoms. Both patients underwent cerebral magnetic resonance imaging showing white matter T2-hyperintensities involving different brain regions, suspective of cerebral small vessel disease. Genetic analysis revealed pathogenic mutations in the FOXC1 gene (patient 1) and the COL4A1 gene (patient 2), respectively. CONCLUSION: We report on the co-occurrence of ocular anterior segment dysgenesis (Axenfeld-Rieger anomaly) and neuropsychiatric symptoms as clinical signs of genetically determined cerebral small vessel disease in two patients. In both patients, the cerebral lesions involved the frontotemporal regions, brain regions that control social behavior as well as executive and cognitive function, highlighting the fact that neuropsychiatric symptoms may be early clinical presentations of cerebral small vessel disease. We further provide a review of monogenic causes of pediatric cerebral small vessel disease, emphasizing the links to childhood-onset neuropsychiatric disease.

The effect of age of first exposure to competitive fighting on cognitive and other neuropsychiatric symptoms and brain volume.

It has long been established that fighting sports such as boxing and mixed martial arts can lead to head injury. Prior work from this group on the Professional Fighters Brain Health Study found that exposure to repetitive head impacts is associated with lower brain volumes and decreased processing speed in fighters. Current and previously licensed professional fighters were recruited, divided into active and retired cohorts, and matched with a control group that had no prior experience in sports with likely head trauma. This study examined the relationship between age of first exposure (AFE) to fighting sports and brain structure (MRI regional volume), cognitive performance (CNS Vital Signs, iComet C3), and clinical neuropsychiatric symptoms (PHQ-9, Barratt Impulsiveness Scale). Brain MRI data showed significant correlations between earlier AFE and smaller bilateral hippocampal and posterior corpus callosum volumes for both retired and active fighters. Earlier AFE in active fighters was correlated with decreased processing speed and decreased psychomotor speed. Retired fighters showed a correlation between earlier AFE and higher measures of depression and impulsivity. Overall, the results help to inform clinicians, governing bodies, parents, and athletes of the risks associated with beginning to compete in fighting sports at a young age.

Cerebrovascular Disease Is a Risk for Getting Lost Behavior in Prodromal Dementia.

Cerebrovascular disease (CVD) contributes to spatial navigation deficits; however, the everyday outcomes of this association remain unexplored. We investigated whether CVD was a risk for getting lost behavior (GLB) in elderly with mild cognitive impairment (MCI) and mild Alzheimer disease (AD). Getting lost behavior was assessed using a semistructured clinical interview and was associated with white matter lesions (WMLs) in patients with MCI. Specifically, right occipital WMLs increased the odds of GLB by 12 times (P = .03) and right temporal WMLs increased the odds of GLB by 4 times (P = .01), regardless of age, gender, global cognitive impairment, and occipital or medial temporal gray matter atrophy. Hypertension increased the risk of GLB in MCI by contributing to the burden of WMLs. White matter lesions were not associated with GLB in mild AD. Our findings suggest that interventions aimed at reducing GLB in prodromal dementia may involve preventing WMLs by optimizing hypertension control.

The relationship between brain atrophy and cognitive-behavioural symptoms in retired Canadian football players with multiple concussions.

Multiple concussions, particularly in contact sports, have been associated with cognitive deficits, psychiatric impairment and neurodegenerative diseases like chronic traumatic encephalopathy. We used volumetric and deformation-based morphometric analyses to test the hypothesis that repeated concussions may be associated with smaller regional brain volumes, poorer cognitive performance and behavioural symptoms among former professional football players compared to healthy controls. This study included fifty-three retired Canadian Football League players, 25 age- and education-matched healthy controls, and controls from the Cambridge Centre for Aging and Neuroscience database for validation. Volumetric analyses revealed greater hippocampal atrophy than expected for age in former athletes with multiple concussions than controls and smaller left hippocampal volume was associated with poorer verbal memory performance in the former athletes. Deformation-based morphometry confirmed smaller bilateral hippocampal volume that was associated with poorer verbal memory performance in athletes. Repeated concussions may lead to greater regional atrophy than expected for age.

Neuropsychiatric Disturbances in Alzheimer's Disease: What Have We Learned from Neuropathological Studies?

Neuropsychiatric symptoms (NPS) are an integral part of the dementia syndrome and were therefore recently included in the core diagnostic criteria of dementia. The near universal prevalence of NPS in Alzheimer's disease (AD), combined with their disabling effects on patients and caregivers, is contrasted by the fact that few effective and safe treatments exist, which is in part to be attributed to our incomplete understanding of the neurobiology of NPS. In this review, we describe the pathological alterations typical for AD, including spreading and evolution of burden, effect on the molecular and cellular integrity, functional consequences and atrophy of NPS-relevant brain regions and circuits in correlation with specific NPS assessments. It is thereby clearly established that NPS are fundamental expressions of the underlying neurodegenerative brain disease and not simply reflect the patients' secondary response to their illness. Neuropathological studies, moreover, include a majority of end-stage patient samples, which may not correctly represent the pathophysiological environment responsible for particular NPS that may already be present in an early stage, or even prior to AD diagnosis. The burdensome nature and high prevalence of NPS, in combination with the absence of effective and safe pharmacotherapies, provide a strong incentive to continue neuropathological and neurochemical, as well as imaging and other relevant approaches to further improve our apprehension of the neurobiology of NPS.

Identification of environmental sounds and melodies in syndromes of anterior temporal lobe degeneration.

Recognition of nonverbal sounds in semantic dementia and other syndromes of anterior temporal lobe degeneration may determine clinical symptoms and help to define phenotypic profiles. However, nonverbal auditory semantic function has not been widely studied in these syndromes. Here we investigated semantic processing in two key nonverbal auditory domains - environmental sounds and melodies - in patients with semantic dementia (SD group; n=9) and in patients with anterior temporal lobe atrophy presenting with behavioural decline (TL group; n=7, including four cases with MAPT mutations) in relation to healthy older controls (n=20). We assessed auditory semantic performance in each domain using novel, uniform within-modality neuropsychological procedures that determined sound identification based on semantic classification of sound pairs. Both the SD and TL groups showed comparable overall impairments of environmental sound and melody identification; individual patients generally showed superior identification of environmental sounds than melodies, however relative sparing of melody over environmental sound identification also occurred in both groups. Our findings suggest that nonverbal auditory semantic impairment is a common feature of neurodegenerative syndromes with anterior temporal lobe atrophy. However, the profile of auditory domain involvement varies substantially between individuals.

White matter structure in youth with behavioral and emotional dysregulation disorders: a probabilistic tractographic study.

IMPORTANCE: Psychiatric disorders in youth characterized by behavioral and emotional dysregulation are often comorbid and difficult to distinguish. An alternative approach to conceptualizing these disorders is to move toward a diagnostic system based on underlying pathophysiologic processes that may cut across conventionally defined diagnoses. Neuroimaging techniques have potentials for the identification of these processes. OBJECTIVE: To determine whether diffusion imaging, a neuroimaging technique examining white matter (WM) structure, can identify neural correlates of emotional dysregulation in a sample of youth with different psychiatric disorders characterized by behavioral and emotional dysregulation. DESIGN, SETTING, AND PARTICIPANTS: Using global probabilistic tractography, we examined relationships between WM structure in key tracts in emotional regulation circuitry (ie, cingulum, uncinate fasciculus, and forceps minor) and (1) broader diagnostic categories of behavioral and emotional dysregulation disorders (DDs) and (2) symptom dimensions cutting across conventional diagnoses in 120 youth with behavioral and/or emotional DDs, a referred sample of the Longitudinal Assessment of Manic Symptoms (LAM) study. Thirty age- and sex-matched typically developing youth (control participants) were included. Multivariate multiple regression models were used. The study was conducted from July 1, 2010, to February 28, 2014. MAIN OUTCOMES AND MEASURES: Fractional anisotropy as well as axial and radial diffusivity were estimated and imported into a well-established statistical package. We hypothesized that (1) youth with emotional DDs and those with both behavioral and emotional DDs would show significantly lower fractional anisotropy compared with youth with behavioral DDs in these WM tracts and (2) that there would be significant inverse relationships between dimensional measures of affective symptom severity and fractional anisotropy in these tracts across all participants. RESULTS: Multivariate multiple regression analyses revealed decreased fractional anisotropy and decreased axial diffusivity within the uncinate fasciculus in youth with emotional DDs vs those with behavioral DDs, those with both DDs, and the controls (F6,160 = 2.4; P = .032; all pairwise comparisons, P < .002). In the same model, greater severity of manic symptoms was positively associated with higher fractional anisotropy across all affected youth (F3,85 = 2.8; P = .044). CONCLUSIONS AND RELEVANCE: These findings suggest that abnormal uncinate fasciculus and cingulum WM structure may underlie emotional, but not behavioral, dysregulation in pediatric psychiatric disorders and that a different neural mechanism may exist for comorbid emotional and behavioral DDs.

The P7C3 class of neuroprotective compounds exerts antidepressant efficacy in mice by increasing hippocampal neurogenesis.

Augmenting hippocampal neurogenesis represents a potential new strategy for treating depression. Here we test this possibility by comparing hippocampal neurogenesis in depression-prone ghrelin receptor (Ghsr)-null mice to that in wild-type littermates and by determining the antidepressant efficacy of the P7C3 class of neuroprotective compounds. Exposure of Ghsr-null mice to chronic social defeat stress (CSDS) elicits more severe depressive-like behavior than in CSDS-exposed wild-type littermates, and exposure of Ghsr-null mice to 60% caloric restriction fails to elicit antidepressant-like behavior. CSDS resulted in more severely reduced cell proliferation and survival in the ventral dentate gyrus (DG) subgranular zone of Ghsr-null mice than in that of wild-type littermates. Also, caloric restriction increased apoptosis of DG subgranular zone cells in Ghsr-null mice, although it had the opposite effect in wild-type littermates. Systemic treatment with P7C3 during CSDS increased survival of proliferating DG cells, which ultimately developed into mature (NeuN+) neurons. Notably, P7C3 exerted a potent antidepressant-like effect in Ghsr-null mice exposed to either CSDS or caloric restriction, while the more highly active analog P7C3-A20 also exerted an antidepressant-like effect in wild-type littermates. Focal ablation of hippocampal stem cells with radiation eliminated this antidepressant effect, further attributing the P7C3 class antidepressant effect to its neuroprotective properties and resultant augmentation of hippocampal neurogenesis. Finally, P7C3-A20 demonstrated greater proneurogenic efficacy than a wide spectrum of currently marketed antidepressant drugs. Taken together, our data confirm the role of aberrant hippocampal neurogenesis in the etiology of depression and suggest that the neuroprotective P7C3-compounds represent a novel strategy for treating patients with this disease.

Effect of GDNF on depressive-like behavior, spatial learning and key genes of the brain dopamine system in genetically predisposed to behavioral disorders mouse strains.

The effect of glial cell line-derived neurotrophic factor (GDNF) on behavior and brain dopamine system in predisposed to depressive-like behavior ASC (Antidepressant Sensitive Cataleptics) mice in comparison with the parental "nondepressive" CBA mice was studied. In 7days after administration (800ng, i.c.v.) GDNF decreased escape latency time and the path traveled to reach hidden platform in Morris water maze in ASC mice. GDNF enhanced depressive-like behavioral traits in both "nondepressive" CBA and "depressive" ASC mice. In CBA mice, GDNF decreased functional response to agonists of D1 (chloro-APB hydrobromide) and D2 (sumanirole maleate) receptors in tail suspension test, reduced D2 receptor gene expression in the substantia nigra and increased monoamine oxydase A (MAO A) gene expression in the striatum. GDNF increased D1 and D2 receptor genes expression in the nucleus accumbens of ASC mice but failed to alter expression of catechol-O-methyltransferase, dopamine transporter, MAO B and tyrosine hydroxylase genes in both investigated mouse strains. Thus, GDNF produced long-term genotype-dependent effect on behavior and the brain dopamine system. GDNF pretreatment (1) reduced D1 and D2 receptors functional responses and D2 receptor gene expression in s. nigra of CBA mice; (2) increased D1 and D2 receptor genes expression in n. accumbens of ASC mice and (3) improved spatial learning in ASC mice. GDNF enhanced depressive-like behavior both in CBA and ASC mice. The data suggest that genetically defined variance in the cross-talk between GDNF and brain dopamine system contributes to the variability of GDNF-induced responses and might be responsible for controversial GDNF effects.

Neuronal targets for reducing mutant huntingtin expression to ameliorate disease in a mouse model of Huntington's disease.

Huntington's disease (HD) is a fatal dominantly inherited neurodegenerative disorder caused by a CAG repeat expansion leading to an elongated polyglutamine stretch in huntingtin. Mutant huntingtin (mHTT) is ubiquitously expressed in all cells but elicits selective cortical and striatal neurodegeneration in HD. The mechanistic basis for such selective neuronal vulnerability remains unclear. A necessary step toward resolving this enigma is to define the cell types in which mHTT expression is causally linked to the disease pathogenesis. Using a conditional transgenic mouse model of HD, in which the mice express full-length human mHTT from a bacterial artificial chromosome transgene (BACHD), we genetically reduced mHTT expression in neuronal populations in the striatum, cortex or both. We show that reduction of cortical mHTT expression in BACHD mice partially improves motor and psychiatric-like behavioral deficits but does not improve neurodegeneration, whereas reduction of mHTT expression in both neuronal populations consistently ameliorates all behavioral deficits and selective brain atrophy in this HD model. Furthermore, whereas reduction of mHTT expression in cortical or striatal neurons partially ameliorates corticostriatal synaptic deficits, further restoration of striatal synaptic function can be achieved by reduction of mHTT expression in both neuronal cell types. Our study demonstrates distinct but interacting roles of cortical and striatal mHTT in HD pathogenesis and suggests that optimal HD therapeutics may require targeting mHTT in both cortical and striatal neurons.

Brief report. Adult patient presenting an interstitial (9) (q21.32q31.1) direct duplication resulting from the malsegregation of a paternal balanced insertional translocation.

BACKGROUND: The partial trisomy 9q syndrome is a well-defined chromosomal disorder with over 40 reported cases in the literature. However, 9q duplications derived from an insertional translocation have rarely been reported. METHODS: Cytogenetic and molecular analyses using G-banding, fluorescence in situ hybridization, and single nucleotide polymorphism array were performed in a 25-year-old male patient with intellectual disability, behavioral abnormalities, speech delay, postnatal growth retardation, distinctive facial features, and pyloric stenosis. RESULTS: G-banding analysis showed an extra chromosome segment of unknown origin inserted into band 4q25. A 16,747,601 bp duplication of 9q21.32q31.1 inserted into band 4q25 and a balanced (4;9) insertional translocation were identified by single nucleotide polymorphism array and fluorescence in situ hybridization analysis respectively in the patient and his healthy father. A literature review was performed to refine genotype-phenotype correlation of the partial trisomy 9q syndrome. CONCLUSION: This is the first report on the molecular characterization of a partial trisomy 9q syndrome derived from an insertional translocation between nonhomologous chromosomes. Our findings provide important information for genetic counseling and prenatal diagnosis of future pregnancies in this family.

Emotional and behavioral symptoms in neurodegenerative disease: a model for studying the neural bases of psychopathology.

Disruptions in emotional, cognitive, and social behavior are common in neurodegenerative disease and in many forms of psychopathology. Because neurodegenerative diseases have patterns of brain atrophy that are much clearer than those of psychiatric disorders, they may provide a window into the neural bases of common emotional and behavioral symptoms. We discuss five common symptoms that occur in both neurodegenerative disease and psychopathology (i.e., anxiety, dysphoric mood, apathy, disinhibition, and euphoric mood) and their associated neural circuitry. We focus on two neurodegenerative diseases (i.e., Alzheimer's disease and frontotemporal dementia) that are common and well characterized in terms of emotion, cognition, and social behavior and in patterns of associated atrophy. Neurodegenerative diseases provide a powerful model system for studying the neural correlates of psychopathological symptoms; this is supported by evidence indicating convergence with psychiatric syndromes (e.g., symptoms of disinhibition associated with dysfunction in orbitofrontal cortex in both frontotemporal dementia and bipolar disorder). We conclude that neurodegenerative diseases can play an important role in future approaches to the assessment, prevention, and treatment of mental illness.

Pathophysiology of Parkinson's disease behavior--a view from the network.

Advancements in neuroscience have uncovered an amazing complexity of connectivity between nuclei sites and circuits within the brain. Moreover, clinical and neuropathological study has revealed diffuse involvement of the nervous system in Parkinson's disease associated with early and/or significant clinical symptoms. Behavior manifestations in Parkinson's disease include cognitive decline and unwanted positive behaviors such as hallucinations and impulse-control disorders. The pathophysiology of Parkinson's disease can be conceptualized at multiple levels that include: (1) Molecular pathogenesis, (2) Cellular/Tissue abnormalities, (3) Neurochemical changes, (4) Site and circuit dysfunction, and (5) Network dysfunction. Currently, there is only a vague correlation with genetic abnormalities that manifest worse Parkinson's disease behavior problems, but abnormalities in misfolded proteins such as α-synuclein and Aß peptide that are increased in cortical and subcortical areas do correlate with worse behavior signs and symptoms. Both Lewy-type synucleinopathy and Alzheimer's disease pathologies, along with loss of synaptic integrity, seem to correlate with Parkinson's disease cognitive decline. Neurochemical changes of dopamine, acetylcholine, and other monoamines are associated. The frontostriate circuit is most commonly implicated in Parkinson's disease behavior. However, there is now beginning to be evidence that diffuse global network dysfunction is possibly the unifying pathophysiology from all of these level abnormalities.

Correlations of behavioral deficits with brain pathology assessed through longitudinal MRI and histopathology in the R6/1 mouse model of Huntington's disease.

Huntington's disease (HD) is caused by the expansion of a CAG repeat in the huntingtin (HTT) gene. The R6 mouse models of HD express a mutant version of exon 1 HTT and typically develop motor and cognitive impairments, a widespread huntingtin (HTT) aggregate pathology and brain atrophy. Unlike the more commonly used R6/2 mouse line, R6/1 mice have fewer CAG repeats and, subsequently, a less rapid pathological decline. Compared to the R6/2 line, fewer descriptions of the progressive pathologies exhibited by R6/1 mice exist. The association between the molecular and cellular neuropathology with brain atrophy, and with the development of behavioral phenotypes remains poorly understood in many models of HD. In attempt to link these factors in the R6/1 mouse line, we have performed detailed assessments of behavior and of regional brain abnormalities determined through longitudinal, in vivo magnetic resonance imaging (MRI), as well as an end-stage, ex vivo MRI study and histological assessment. We found progressive decline in both motor and non-motor related behavioral tasks in R6/1 mice, first evident at 11 weeks of age. Regional brain volumes were generally unaffected at 9 weeks, but by 17 weeks there was significant grey matter atrophy. This age-related brain volume loss was validated using a more precise, semi-automated Tensor Based morphometry assessment. As well as these clear progressive phenotypes, mutant HTT (mHTT) protein, the hallmark of HD molecular pathology, was widely distributed throughout the R6/1 brain and was accompanied by neuronal loss. Despite these seemingly concomitant, robust pathological phenotypes, there appeared to be little correlation between the three main outcome measures: behavioral performance, MRI-detected brain atrophy and histopathology. In conclusion, R6/1 mice exhibit many features of HD, but the underlying mechanisms driving these clear behavioral disturbances and the brain volume loss, still remain unclear.

Psychiatric presentation of sporadic Creutzfeldt-Jakob disease: a challenge to current diagnostic criteria.

Pathological diagnosis remains the gold standard for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), but being able to differentiate between CJD and non-prion diseases clinically is important because many of the non-prion, rapidly progressive dementias are treatable. Diagnostic criteria need both high sensitivity and specificity while remaining applicable to clinical practice. Despite extensive updates to the clinical criteria for sCJD, there remains a heavy emphasis on neurological signs. We describe a psychiatric presentation of sCJD that did not fulfill the diagnostic criteria until very late in a prolonged disease course and required biopsy for diagnosis.

Loss of predominant Shank3 isoforms results in hippocampus-dependent impairments in behavior and synaptic transmission.

The Shank3 gene encodes a scaffolding protein that anchors multiple elements of the postsynaptic density at the synapse. Previous attempts to delete the Shank3 gene have not resulted in a complete loss of the predominant naturally occurring Shank3 isoforms. We have now characterized a homozygous Shank3 mutation in mice that deletes exon 21, including the Homer binding domain. In the homozygous state, deletion of exon 21 results in loss of the major naturally occurring Shank3 protein bands detected by C-terminal and N-terminal antibodies, allowing us to more definitively examine the role of Shank3 in synaptic function and behavior. This loss of Shank3 leads to an increased localization of mGluR5 to both synaptosome and postsynaptic density-enriched fractions in the hippocampus. These mice exhibit a decrease in NMDA/AMPA excitatory postsynaptic current ratio in area CA1 of the hippocampus, reduced long-term potentiation in area CA1, and deficits in hippocampus-dependent spatial learning and memory. In addition, these mice also exhibit motor-coordination deficits, hypersensitivity to heat, novelty avoidance, altered locomotor response to novelty, and minimal social abnormalities. These data suggest that Shank3 isoforms are required for normal synaptic transmission/plasticity in the hippocampus, as well as hippocampus-dependent spatial learning and memory.

El circuito cerebral de la recompensa en los trastornos afectivos / Brain Reward Circuitry in Affective Disorders

Los síntomas conductuales de la depresión son numerosos y variados, cubriendo los dominios emocionales, motivacionales, cognitivos y fisiológicos. Estudios recientes en modelos animales de depresión y en pacientes depresivos utilizando técnicas neuropsicológicas combinadas con imagenología funcional muestran que grandes subgrupos de estos pacientes presentan deficiencias en el procesamiento de las recompensas a los estímulos emocionales positivos, que son nucleares en depresión. La proteína Rac 1, un regulador crítico de la actina del citoesqueleto, se reduce en el NAcc tanto en depresión como en modelos animales de adicción, lo que lleva al crecimiento de espinas dendríticas inmaduras en las MSNs del NAcc y esto es consecuencia de modificaciones epigenéticas selectivas en esta región, del gen que codifica Rac 1, tanto en modelos de estrés en roedores como en humanos depresivos (estudios post-mortem). El gran desarrollo de algunos de los modelos experimentales de depresión que cuentan con evidencias moleculares, sistémicas y conductuales no se han traducido en nuevos medicamentos pero al avanzar en la comprensión patofisiológica del trastorno y sus correlatos neuroimagenológicos, permitirán, junto a las modernas técnicas de investigación, buscar marcadores biológicos de los endofenotipos diferentes que se combinan para generar un trastorno que posee múltiples subtipos que los agrupan en clusters diferentes(AU)

The behavioral symptoms of depression are numerous and varied, and encompass the emotional, motivational and physiologic domains. Recent studies in animal models of depression and depressive patients, which used neuropsychological techniques combined with functional imaging, show that large subgroups of these patients display deficiencies in the processing of rewards to positive emotional stimuli, which are nuclear in depression. Rac 1 protein, a critical regulator of cytoskeleton actin, is reduced in the NAcc, both in depression as well as in animal models of addiction, which leads to the growth of immature dendritic spines in the MSNs of the NAcc, and this is the result of selective epigenetic alterations in this region, of the gene that codifies Rac1, both in models of stress in rodents as well as in depressive human beings (post-mortem studies). The great development of some of the experimental models of depression that provide molecular, systemic and behavioral evidences have not translated into new medications, but the progressive pathophysiological understanding of the disorder and its neuroimaging correlates will enable, together with the modern investigations techniques, to search for biological markers of the different endophenotypes that combine to generate a disorder which has multiple subtypes that gather in different clusters (AU)

El circuito cerebral de la recompensa en los trastornos afectivos / Brain Reward Circuitry in Affective Disorders

Los síntomas conductuales de la depresión son numerosos y variados, cubriendo los dominios emocionales, motivacionales, cognitivos y fisiológicos. Estudios recientes en modelos animales de depresión y en pacientes depresivos utilizando técnicas neuropsicológicas combinadas con imagenología funcional muestran que grandes subgrupos de estos pacientes presentan deficiencias en el procesamiento de las recompensas a los estímulos emocionales positivos, que son nucleares en depresión. La proteína Rac 1, un regulador crítico de la actina del citoesqueleto, se reduce en el NAcc tanto en depresión como en modelos animales de adicción, lo que lleva al crecimiento de espinas dendríticas inmaduras en las MSNs del NAcc y esto es consecuencia de modificaciones epigenéticas selectivas en esta región, del gen que codifica Rac 1, tanto en modelos de estrés en roedores como en humanos depresivos (estudios post-mortem). El gran desarrollo de algunos de los modelos experimentales de depresión que cuentan con evidencias moleculares, sistémicas y conductuales no se han traducido en nuevos medicamentos pero al avanzar en la comprensión patofisiológica del trastorno y sus correlatos neuroimagenológicos, permitirán, junto a las modernas técnicas de investigación, buscar marcadores biológicos de los endofenotipos diferentes que se combinan para generar un trastorno que posee múltiples subtipos que los agrupan en clusters diferentes

The behavioral symptoms of depression are numerous and varied, and encompass the emotional, motivational and physiologic domains. Recent studies in animal models of depression and depressive patients, which used neuropsychological techniques combined with functional imaging, show that large subgroups of these patients display deficiencies in the processing of rewards to positive emotional stimuli, which are nuclear in depression. Rac 1 protein, a critical regulator of cytoskeleton actin, is reduced in the NAcc, both in depression as well as in animal models of addiction, which leads to the growth of immature dendritic spines in the MSNs of the NAcc, and this is the result of selective epigenetic alterations in this region, of the gene that codifies Rac1, both in models of stress in rodents as well as in depressive human beings (post-mortem studies). The great development of some of the experimental models of depression that provide molecular, systemic and behavioral evidences have not translated into new medications, but the progressive pathophysiological understanding of the disorder and its neuroimaging correlates will enable, together with the modern investigations techniques, to search for biological markers of the different endophenotypes that combine to generate a disorder which has multiple subtypes that gather in different clusters