Projections from the posterolateral olfactory amygdala to the ventral striatum: neural basis for reinforcing properties of chemical stimuli

<p>Abstract</p> <p>Background</p> <p>Vertebrates sense chemical stimuli through the olfactory receptor neurons whose axons project to the main olfactory bulb. The main projections of the olfactory bulb are directed to the olfactory cortex and olfactory amygdala (the anterior and posterolateral cortical amygdalae). The posterolateral cortical amygdaloid nucleus mainly projects to other amygdaloid nuclei; other seemingly minor outputs are directed to the ventral striatum, in particular to the olfactory tubercle and the islands of Calleja.</p> <p>Results</p> <p>Although the olfactory projections have been previously described in the literature, injection of dextran-amines into the rat main olfactory bulb was performed with the aim of delimiting the olfactory tubercle and posterolateral cortical amygdaloid nucleus in our own material. Injection of dextran-amines into the posterolateral cortical amygdaloid nucleus of rats resulted in anterograde labeling in the ventral striatum, in particular in the core of the nucleus accumbens, and in the medial olfactory tubercle including some islands of Calleja and the cell bridges across the ventral pallidum. Injections of Fluoro-Gold into the ventral striatum were performed to allow retrograde confirmation of these projections.</p> <p>Conclusion</p> <p>The present results extend previous descriptions of the posterolateral cortical amygdaloid nucleus efferent projections, which are mainly directed to the core of the nucleus accumbens and the medial olfactory tubercle. Our data indicate that the projection to the core of the nucleus accumbens arises from layer III; the projection to the olfactory tubercle arises from layer II and is much more robust than previously thought. This latter projection is directed to the medial olfactory tubercle including the corresponding islands of Calleja, an area recently described as critical node for the neural circuit of addiction to some stimulant drugs of abuse.</p

Neuronal and glial characterization in the rostrocaudal axis of the human anterior olfactory nucleus: Involvement in Parkinson’s disease

Hyposmia is one of the prodromal symptoms of Parkinson’s disease (PD) and a red flag in clinical diagnosis. Neuropathologically, this sign correlates with α-synuclein involvement in the anterior olfactory nucleus (AON). Neurodegeneration, microgliosis, and astrogliosis in AON are poorly studied, and bulbar AON is the focus of these studies with contradictory results. Additionally, male sex is a risk marker for developing PD, but sexual dimorphism of neural and glial populations in the AON has rarely been considered. The aim of this study was to analyze the density of NeuN, Iba-1, GFAP, and Lewy bodies (LBs), as well as the relationship of these cell type markers with pathology along the rostrocaudal axis of the AON (bulbar, retrobulbar, cortical anterior, and posterior divisions). Cavalieri, optical fractionator, and area fraction fractionator stereological approaches were used for the volume, cell populations and LBs densities, area fraction, and percentage of overlap. Iba-1 and α-syn intensities were measured using ImageJ. In non-PD (NPD) cases, the volume was lower in the AON at the extremes of the rostrocaudal axis than in the intermediate divisions. Cortical anterior AON volume decreased in PD compared with NPD cases. NeuN density decreased rostrocaudally in AON portions in NPD and PD cases. This occurred similarly in Iba-1 but only in PD samples. Iba-1 intensity significantly increased in bulbar AON between PD and NPD. No changes were found in astrocytes. Eight percent of NeuN, 0.1% of Iba-1, and 0.1% of GFAP areas overlapped with LBs area along the AON portions. The data indicate that bulbar AON, which is the most rostral portion in this axis, could play a major role in the pathology. This could be related to the larger area occupied by LBs in these divisions

Anatomical prosection practices in the Occupational Therapy degree. Student anxiety levels and academic effectiveness

CONTEXT. The practice of anatomical dissection and/or prosection on human cadavers is an essential component of human anatomy training programmes. However, this activity can be stressful for inexperienced students when exposed to cadavers for the first time, and it may generate high anxiety levels. The aims of this study are threefold: 1) To analyse the thoughts and feelings of firstyear students of the Occupational Therapy degree about prosection practices; 2) to examine their anxiety levels in relation to these practices; and 3) to evaluate how useful and effective they are as an educational tool for anatomy training. METHODS. This is a before-and-after cross-sectional study of first-year students of the Occupational Therapy degree at the Universidad de Castilla-La Mancha, Spain. These students had not previously participated in prosection practices. An anonymous questionnaire was distributed among the students before and after the practice, in order to examine their feelings and perceptions during the practice. To examine their anxiety levels we used a State-Trait Anxiety Inventory (STAI) questionnaire. To assess their learning outcomes the students had to complete two practical tests of recognition of anatomical structures, one before attending the practice and one immediately after. RESULTS. Basal anxiety levels, measured as trait anxiety (TA), remained stable and did not show significant differences during the practice (p>0.05). Their emotional anxiety, measured as state anxiety (SA), dropped after the practice from 14.7 to 10 points (p<0.05). Before the start of the practice 11 students (19%) showed signs of anxiety, and these remained so at the end of the practical session (p>0.05). As for their academic performance, we observed that the number of students able to pass the test after attending the prosection practice increased notably (by more than 60%). Additionally, 100% of the students recommended that the practice be retained for future courses, giving it an approval rate of 9.1 out of 10. CONCLUSION. Although anatomy is usually an attractive subject for Occupational Therapy students and they value prosection practices positively, they remain a potentially complex and stressful experience. Some students find that their experiences in the dissecting room can upset their emotional balance, however the implementation of coping mechanisms could be a very effective strategy to reduce their anxiety and also to improve their learning outcomes, helping to strengthen their practical 3 knowledge of anatomy as we have observed in this study. The students not only value positively these practices, they also believe that they are an extremely useful tool for both teaching and learning anatomy, and they recommend their routine use as part of the training process

Differential Effects of Parkinson’s Disease on Interneuron Subtypes within the Human Anterior Olfactory Nucleus

Synucleinopathies (including α-synucleinopathies), which include Parkinson’s disease (PD), manifest themsevles early on (stage 1) in the olfactory system; preferentially in the anterior olfactory nucleus (AON). In particular, the non-motor, early manifestations of PD include hyposmia, which is the partial loss of the sense of smell. The neural basis of hyposmia in PD, however, is poorly understood; but the AON appears to be a key structure in the disease’s progression. We analyzed whether α-synuclein was involved in the differential interneuron vulnerability associated with PD in the retrobulbar, cortical anterior and cortical posterior divisions of the AON. First, we determined the expression of the calcium binding interneuron markers, calretinin, calbindin and parvalbumin, as well as non-calcium binding interneuron marker, somatostatin, in neuronal cell bodies alone (cells/mm2) and in neuronal cell bodies and neurites (% of area fraction) of post-mortem tissue from PD cases and age-matched controls (n = 4 for each) by immunofluorescent confocal microscopy. Results indicated that parvalbumin expression was upregulated in neuronal cell bodies throughout the anterior olfactory nucleus of PD cases compared with controls. Furthermore, there was increased calbindin, calretinin and parvalbumin expression in the cell bodies and neurites of neurons in the retrobulbar division and also increased parvalbumin expression in the neurites of neurons in the cortical division; calretinin expression was also increased in neuronal cell bodies and neurites in the cortical posterior division. Second, we analyzed the co-localization of the above markers with α-synuclein, with results indicating that α-synuclein co-localized with the calcium-binding proteins, but only partially with somatostatin. Taken together, these results indicate differential expression levels among different neural markers in the divisions of the AON in PD cases and point to several possibilities, among them: possible neuroprotective mechanisms of calcium-binding proteins against α-synuclein; and the differential involvement of somatostatin in α-synuclein-positive cell bodies and neurites

Neurodegeneration and contralateral α-synuclein induction after intracerebral α-synuclein injections in the anterior olfactory nucleus of a Parkinson’s disease A53T mouse model

Abstract Parkinson’s disease is characterized by a proteinopathy that includes aggregates of α-synuclein. A recent hypothesis proposes a prion-like spreading mechanism for this α-synucleinopathy. Early neuropathological deposits occur, among others, in the anterior olfactory nucleus (AON). This study investigates the anterograde and/or retrograde transmissibility of exogenous α-synuclein inoculated in the right AON of the A53T model of Parkinson’s disease and wild-type mice as well as neuronal and glial involvement. Seven experimental groups were established: wild-type injected with tracers; A53T mice injected with either α-synuclein or saline 2 months beforehand; wild-type injected with either α-synuclein or saline 2 months beforehand; and wild-type injected with either α-synuclein or saline 4 months beforehand. Weight and behavioral changes were analyzed. Immunohistochemistry against α-synuclein, NeuN, Iba-1 and GFAP was performed. Volume and marker distributions in the olfactory bulb (OB), AON and piriform cortex were analyzed using unbiased stereology. The behavioral analyses reveal higher levels of hyperactivity in transgenic as compared to wild-type mice. Tract-tracing experiments show that the main contralateral afferent projections to the dorsal AON come from the AON and secondarily from the OB. In saline-injected transgenic animals, α-synuclein expression in the OB and the AON is higher in the left hemisphere than in the right hemisphere, which could be due to basal interhemispheric differences. α-synuclein injection could provoke a significant increase in the left hemisphere of the transgenic mice’s OB, compared to saline-injected animals. Neuronal loss was observed in saline-injected transgenic mice relative to the saline-injected wild-type group. There were no overall differences in neuron number following injection of α-synuclein into either wild-type or transgenic mice, however some neuron loss was apparent in specific regions of α-synuclein injected wild-types. Microglia labeling appeared to be correlated with surgery-induced inflammation. Astroglial labeling was higher in transgenic animals, which could be due to endogenous α-synucleinopathy. This study suggests α-synucleinopathy induction, via retrograde and contralateral projections, within the olfactory system of transgenic animals

Fratura sacral por fadiga como causa de dor glútea profunda: revisão bibliográfica e apresentação de um caso clínico

El Síndrome de Dolor Glúteo Profundo lo puede causar una fractura de fatiga del sacro. Objetivo: Facilitar el diagnóstico del Síndrome de Dolor Glúteo Profundo exponiendo un caso clínico y revisión bibliográfica de fractura de fatiga del sacro. Metodología: Búsqueda bibliográfica en PubMed sobre fractura de fatiga del sacro en atletas y descripción de un caso clínico de ésta. Resultados: De la bibliografía consultada se desprende que los principales factores predisponentes de una fractura de fatiga del sacro son las cargas desproporcionadas, baja densidad mineral ósea, alteraciones biomecánicas y una superficie de carrera dura. Estas fracturas son más frecuentes en corredores de larga distancia. El diagnóstico de elección es la Resonancia Magnética Nuclear. El tratamiento recomendable sería el reposo de la actividad causante, suplementación con vitamina D y calcio y magnetoterapia. Se describe la clínica, exploraciones complementarias y evolución de un duatleta con fractura de fatiga de sacroDeep Gluteal Pain Syndrome can be caused by a stress fracture of the sacrum. Objective: To facilitate the diagnosis of Deep Gluteal Pain Syndrome exposing a clinical case and bibliographic review of fatigue fracture of the sacrum. Methodology: Bibliographic search in PubMed on fatigue fracture of the sacrum in athletes and description of a clinical case of this. Results: From the consulted bibliography it appears that the main predisposing factors for a stress fracture of the sacrum are disproportionate loads, low bone mineral density, biomechanical abnormalities, and a hard-running surface. These fractures are more common in long-distance runners. The diagnosis of choice is Nuclear Magnetic Resonance. The recommended treatment would be, rest from the causative activity, supplementation with vitamin D and calcium, and magnetotherapy. The symptoms, complementary examinations, and evolution of a duathlete with a fatigue fracture of the sacrum are describedA Síndrome da Dor Glútea Profunda pode ser causada por uma fratura por estresse do sacro. Objetivo: Facilitar o diagnóstico da Síndrome da Dor Glútea Profunda expondo um caso clínico e revisão bibliográfica de fratura por fadiga do sacro. Metodologia: Pesquisa bibliográfica no PubMed sobre fratura por fadiga do sacro em atletas e descrição de um caso clínico desta. Resultados: Da bibliografia consultada verifica-se que os principais fatores predisponentes para uma fratura por estresse do sacro são cargas desproporcionais, baixa densidade mineral óssea, anormalidades biomecânicas e uma superfície de corrida dura. Essas fraturas são mais comuns em corredores de longa distância. O diagnóstico de escolha é a Ressonância Magnética Nuclear. O tratamento recomendado seria no repouso da atividade causadora, suplementação com vitamina D e cálcio e magnetoterapia. São descritos os sintomas, exames complementares e evolução de um atleta com fratura de fadiga do sacr

Elaboración de un instrumento evaluativo de resolución de problemas de enunciado verbal para determinar los tipos de sentencias y tipos de problemas que pueden dominar un niño de cuarto año básico

Tesis (Psicopedagogo, Licenciado en Educación)Objetivo General Diseñar un instrumento de evaluación psicopedagógica en el área de las matemáticas en resolución de problemas de planteamiento verbal para alumnos de cuarto año básico. Objetivos Específicos a. Fundamentar teóricamente la propuesta a través de la investigación de los tipos de problemas de planteamiento verbal y tipos de sentencias de adición y sustracción. b. Construir un instrumento de evaluación psicopedagógica de resolución de problemas en el área de la matemática, para determinar qué tipo de sentencias domina un niño de cuarto año básico. c. Construir un instrumento de evaluación psicopedagógica de resolución de problemas en el área de la matemática, para determinar qué tipos de problemas de planteamiento verbal de adición y sustracción domina un niño de cuarto año básico. d. Realizar un estudio piloto para determinar si el instrumento evaluativo es adecuado en relación al contenido y estructura lingüística para alumnos que cursan cuarto año básico