RESUMO
Much is known about the neural circuits of conditioned fear and its relevance to understanding anxiety disorders, but less is known about other anxiety-related behaviors such as active avoidance. Using a tone-signaled, platform-mediated avoidance task, we observed that pharmacological inactivation of the prelimbic prefrontal cortex (PL) delayed avoidance. Surprisingly, optogenetic silencing of PL glutamatergic neurons did not delay avoidance. Consistent with this, inhibitory but not excitatory responses of rostral PL neurons were associated with avoidance training. To test the importance of these inhibitory responses, we optogenetically stimulated PL neurons to counteract the tone-elicited reduction in firing rate. Photoactivation of rostral (but not caudal) PL neurons at 4 Hz impaired avoidance. These findings suggest that inhibitory responses of rostral PL neurons signal the avoidability of a potential threat and underscore the importance of designing behavioral optogenetic studies based on neuronal firing responses.
Assuntos
Aprendizagem da Esquiva/fisiologia , Sistema Límbico/fisiologia , Inibição Neural/fisiologia , Córtex Pré-Frontal/fisiologia , Animais , Ansiedade/fisiopatologia , Medo , Locomoção , Masculino , Optogenética , Ratos Sprague-DawleyRESUMO
El sistema nervioso autónomo (SNA) es un componente fundamental del sistema nervioso cuya función es mantener la homeostasis y reaccionar de forma adaptativa a los cambios en el medio externo e interno. Participa en la regulación de la respiración, la circulación, la digestión, el metabolismo y el medio interno, la secreción exocrina y endocrina, las respuestas inmunes, la temperatura corporal y la reproducción. En este trabajo se analizará cómo la organización del SNA se construye en 4 niveles jerárquicos, a partir de un periodo de diferenciación crítico neonatal en el cual el medio ambiente y el vínculo afectivo con la madre juega un rol predominante. A continuación, se discutirá cómo la función del SNA cambia en las tres configuraciones corporales (vigilia, sueño de ondas lentas, sueño de movimientos oculares rápidos, REM) que se suceden durante un ciclo de 24 horas. Por último, se discutirá la aplicación de estos conceptos en la Unidad Neurofisiología del Curso de Fisiología para alumnos de 2º año de la Facultad de Ciencias Médicas, UCA, enfatizando los aspectos instrumentales destinados a aumentar la participación de los alumnos en el proceso de enseñanza
The autonomic nervous system (ANS) is a fundamental component of the nervous system whose function is to maintain homeostasis and react adaptively to changes in the external and internal environment. It participates in the regulation of respiration, circulation, digestion, metabolism and internal environment, exocrine and endocrine secretion, immune response, body temperature and reproduction. In this review article I will analyze how the organization of the ANS is built on 4 hierarchical levels, starting from a period of critical neonatal differentiation in which the environment and the affective bond with the mother plays a predominant role. Next, I will discuss how the ANS function changes in the three body configurations (wakefulness, slow wave sleep, fast eye movement, REM) that occur during a 24 hour cycle. Finally, the application of these concepts to teaching Neurophysiology at the Physiology Course for 2nd year medical students of the Faculty of Medical Sciences, Pontificia Universidad Católica Argentina, emphasizing the instrumental aspects intended to increase the participation of students in the teaching process is discussed.
Assuntos
Humanos , Células Receptoras Sensoriais/fisiologia , Sistema Nervoso Autônomo/fisiologia , Modelos Biopsicossociais , Sistema Límbico/fisiologiaRESUMO
There are reports of patients whose epileptic seizures are prevented by means of olfactory stimulation. Similar findings were described in animal models of epilepsy, such as the electrical kindling of amygdala, where olfactory stimulation with toluene (TOL) suppressed seizures in most rats, even when the stimuli were 20% above the threshold to evoke seizures in already kindled animals. The Wistar Audiogenic Rat (WAR) strain is a model of tonic-clonic seizures induced by acute acoustic stimulation, although it also expresses limbic seizures when repeated acoustic stimulation occurs - a process known as audiogenic kindling (AK). The aim of this study was to evaluate whether or not the olfactory stimulation with TOL would interfere on the behavioral expression of brainstem (acute) and limbic (chronic) seizures in the WAR strain. For this, animals were exposed to TOL or saline (SAL) and subsequently exposed to acoustic stimulation in two conditions that generated: I) acute audiogenic seizures (only one acoustic stimulus, without previous seizure experience before of the odor test) and II) after AK (20 acoustic stimuli [2 daily] before of the protocol test). We observed a decrease in the seizure severity index of animals exposed only to TOL in both conditions, with TOL presented 20s before the acoustic stimulation in both protocols. These findings were confirmed by behavioral sequential analysis (neuroethology), which clearly indicated an exacerbation of clusters of specific behaviors such as exploration and grooming (self-cleaning), as well as significant decrease in the expression of brainstem and limbic seizures in response to TOL. Thus, these data demonstrate that TOL, a strong olfactory stimulus, has anticonvulsant properties, detected by the decrease of acute and AK seizures in WARs.
Assuntos
Estimulação Acústica , Excitação Neurológica/fisiologia , Sistema Límbico/fisiologia , Convulsões , Olfato/efeitos dos fármacos , Tolueno/farmacologia , Tonsila do Cerebelo , Animais , Tronco Encefálico , Modelos Animais de Doenças , Epilepsia Reflexa , Masculino , Ratos , Ratos WistarRESUMO
Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.
Assuntos
Medo/fisiologia , Sistema Límbico/fisiologia , Consolidação da Memória/fisiologia , Córtex Pré-Frontal/fisiologia , Tonsila do Cerebelo/fisiologia , Animais , Condicionamento Psicológico , Extinção Psicológica , Hipocampo/fisiologia , Hormônios/fisiologia , Humanos , Plasticidade Neuronal , Neurotransmissores/fisiologia , Transtornos de Estresse Pós-Traumáticos/terapia , Sinapses/fisiologiaRESUMO
Patients with posttraumatic stress disorder (PTSD) show hypo-active ventromedial prefrontal cortices (vmPFC) that correlate with their impaired ability to discriminate between safe and dangerous contexts and cues. Previously, we found that auditory fear conditioning depresses the excitability of neurons populating the homologous structure in rodents, the infralimbic cortex (IL). However, it is undetermined if IL depression was mediated by the cued or contextual information. The objective of this study was to examine whether contextual information was sufficient to depress IL neuronal excitability. After exposing rats to context-alone, pseudoconditioning, or contextual fear conditioning, we used whole-cell current-clamp recordings to examine the excitability of IL neurons in prefrontal brain slices. We found that contextual fear conditioning reduced IL neuronal firing in response to depolarizing current steps. In addition, neurons from contextual fear conditioned animals showed increased slow afterhyperpolarization potentials (sAHPs). Moreover, the observed changes in IL excitability correlated with contextual fear expression, suggesting that IL depression may contribute to the encoding of contextual fear.
Assuntos
Condicionamento Clássico/fisiologia , Medo/fisiologia , Sistema Límbico/fisiologia , Potenciais de Ação/fisiologia , Animais , Extinção Psicológica/fisiologia , Masculino , Neurônios/fisiologia , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-DawleyRESUMO
El estudio de las emociones, su desarrollo, procesamiento y comprensión, se ha limitado a la funcionalidad de estructuras subcorticales; sin embargo, recientemente se han propiciado investigaciones que reorientan y amplían el campo de estudio del procesamiento emocional hacia vínculos con regiones corticales del cerebro. Pese a lo anterior, no se había planteado claramente la importancia de eliminar el sesgo localizacionista en los procesos emocionales; este artículo realiza un recorrido por los inicios griegos con tendencia científica en el abordaje y estudio de las emociones, y la evolución que estos preconceptos y resultados han tenido a lo largo del último par de siglos donde se ha intensificado la comprensión de la actividad cerebral, así como las limitantes que han logrado trascender a lo largo del último siglo y que presentan perspectivas parciales del funcionamiento y procesamiento emocional en los circuitos biológicos del cerebro. De igual forma, se hace pertinente resaltar la importancia de las emociones en regiones corticales, que intervienen en la actividad cognitiva y motora que allí se suscita, y cómo éstas pueden afectar o favorecer su funcionalidad.
The study of emotions, development, processing and understanding has been limited to the functionality of subcortical structures; however, recently been reoriented led reearch and expand the field of study of emotional processing to links with cortical regions of the brain. Despite this, they had not clearly stated the importance of eliminating the bias localizationist emotional processes; This article takes a journey through the Greek incios with scientific trend in the approach and study of emotions, and the evolution of these preconceptions and results have had over the last couple of centuries where there is increased understanding of brain activity, as well as the limitations that have managed to transcend throughout the last century and have partial perspectives of functioning and emotional processing in biological brain circuits. Similarly, it is pertinent to highlight the importance of emotions in cortical regions involved in cognitive and motor activity that arises there, and how they can affect or favor their functionality.
Assuntos
Humanos , Cérebro , Emoções , Sistema Límbico/fisiologia , NeuropsicologiaRESUMO
OBJECTIVE: this study investigated the association of somatic and cognitive-affective symptoms with sex and age, among patients hospitalized with heart disease. METHOD: this study was a secondary analysis of two previous observational studies totaling 531 patients with heart disease, hospitalized from 2005 to 2011 in two public hospitals in Ribeirão Preto, state of São Paulo, Brazil. Somatic and cognitive-affective symptoms were assessed using the subscales of the Beck Depression Inventory - I (BDI-I). RESULTS: of 531 participants, 62.7% were male, with a mean age 57.3 years (SD= 13.0) for males and 56.2 years (SD= 12.1) for females. Analyses of variance showed an effect of sex (p<0.001 for somatic and p=0.005 for cognitive-affective symptoms), but no effect of age. Women presented with higher mean values than men in both BDI-I subscales: 7.1 (4.5) vs. 5.4 (4.3) for somatic, and 8.3 (7.9) vs. 6.7 (7.2) for cognitive-affective symptoms. There were no differences by age for somatic (p=0.84) or cognitive-affective symptoms (p=0.84). CONCLUSION: women hospitalized with heart disease had more somatic and cognitive-affective symptoms than men. We found no association of somatic and cognitive-affective symptoms with age. Future research for these patients could reveal whether these differences according to sex continue throughout the rehabilitation process. .
OBJETIVO: investigar a associação de sintomas somáticos e cognitivo-afetivos ao sexo e à idade de pacientes hospitalizados com doença cardíaca. MÉTODO: este estudo é resultado de uma análise secundária de dois estudos observacionais anteriores, totalizando 531 pacientes com doença cardíaca, internados de 2005 a 2011, em dois hospitais públicos em Ribeirão Preto, estado de São Paulo, Brasil. Os sintomas somáticos e cognitivo-afetivos foram avaliados utilizando-se as subescalas do Inventário de Depressão de Beck - I (IDB-I). RESULTADOS: dos 531 participantes, 62,7% são do sexo masculino, com média de idade de 57,3 anos (DP= 13,0) para os homens e 56,2 anos (DP = 12,1) para as mulheres. A análise da variância mostrou um efeito relacionado ao sexo do paciente (p<0,001 para sintomas somáticos e p=0,005 para os sintomas cognitivo-afetivos), mas nenhum efeito relacionado à idade. As mulheres apresentaram maiores escores do que os homens em ambas subescalas IDB-I: 7,1 (4,5) e 5,4 (4,3) para os sintomas somáticos, e 8,3 (7,9) e 6,7 (7,2) para os sintomas cognitivo-afetivos, respectivamente. Não houve diferenças referentes à idade para sintomas somáticos (p=0,84) ou sintomas cognitivo-afetivos (p=0,84). CONCLUSÃO: as mulheres internadas com doença cardíaca apresentaram mais sintomas somáticos e cognitivo-afetivos do que os homens. Não houve associação dos sintomas somáticos e cognitivo-afetivos com a idade. Pesquisas futuras desses pacientes poderiam revelar se essas diferenças de acordo com o sexo permanecem durante todo o processo de reabilitação. .
OBJETIVO: este estudio investigó la asociación de síntomas somáticos y cognitivo-afectivos con el sexo y la edad en pacientes hospitalizados con enfermedad cardíaca. MÉTODO: este estudio fue un análisis secundario de dos estudios observacionales anteriores, totalizando 531 pacientes con enfermedad cardíaca, internados de 2005 a 2011, en dos hospitales públicos en Ribeirão Preto, estado de São Paulo, Brasil. Los síntomas somáticos y cognitivo-afectivos fueron evaluados utilizándose las subescalas del Inventario Beck de Depresión - I (IBD-I). RESULTADOS: de los 531 participantes, 62,7% era del sexo masculino, con promedio de edad de 57,3 años (DE= 13,0) para los hombres y 56,2 años (DE = 12,1) para el sexo femenino. El análisis de variancia mostró un efecto del sexo (p<0,001 para síntomas somáticos y p=0,005 para los síntomas cognitivo-afectivos), pero ningún efecto de la edad. Las mujeres presentaron valores medios más altos que los hombres en ambas subescalas IBD-I: 7,1 (4,5) vs. 5.4 (4.3) para los síntomas somáticos, y 8,3 (7,9) vs. 6,7 (7,2) para los síntomas cognitivo-afectivos. No fueron encontradas diferencias por edad para síntomas somáticos (p=0,84) o síntomas cognitivo-afectivos (p=0,84). CONCLUSIÓN: las mujeres internadas con enfermedad cardíaca tenían más síntomas somáticos y cognitivo-afectivos que los hombres. No fue encontrada asociación de los síntomas somáticos y cognitivo-afectivos con la edad. Investigaciones futuras de esos pacientes podrían revelar si esas diferencias por sexo continúan durante todo el proceso de rehabilitación. .
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Comportamento do Adolescente/fisiologia , Desenvolvimento do Adolescente/fisiologia , Sistema Límbico/anatomia & histologia , Vias Neurais/anatomia & histologia , Assunção de Riscos , Análise de Variância , Desenvolvimento do Adolescente/efeitos dos fármacos , Mapeamento Encefálico/métodos , Imagem de Tensor de Difusão/métodos , Função Executiva/fisiologia , Seguimentos , Lobo Frontal/anatomia & histologia , Lobo Frontal/fisiologia , Modelos Lineares , Sistema Límbico/fisiologia , Fatores de Risco , Autorrelato , Transtornos Relacionados ao Uso de Substâncias/epidemiologiaRESUMO
'Hunger is the best spice' is an old and wise saying that acknowledges the fact that almost any food tastes better when we are hungry. The neurobiological underpinnings of this lore include activation of the brain's reward system and the stimulation of this system by the hunger-promoting hormone ghrelin. Ghrelin is produced largely from the stomach and levels are higher preprandially. The ghrelin receptor is expressed in many brain areas important for feeding control, including not only the hypothalamic nuclei involved in energy balance regulation, but also reward-linked areas such as the ventral tegmental area. By targeting the mesoaccumbal dopamine neurones of the ventral tegmental area, ghrelin recruits pathways important for food reward-related behaviours that show overlap with but are also distinct from those important for food intake. We review a variety of studies that support the notion that ghrelin signalling at the level of the mesolimbic system is one of the key molecular substrates that provides a physiological signal connecting gut and reward pathways.
Assuntos
Trato Gastrointestinal/fisiologia , Grelina/metabolismo , Sistema Límbico/fisiologia , Recompensa , Transdução de Sinais , HumanosRESUMO
In rodents, the infralimbic (IL) region of the medial prefrontal cortex plays a key role in the recall of fear extinction. Previously we showed that fear conditioning decreases the intrinsic excitability of IL neurons, and that fear extinction reverses the depressed excitability. In the current study, we examined the time course of the extinction-induced changes in adolescent rats. Immediately after extinction, IL neurons continued to show depressed excitability. However 4 hours after extinction, IL neurons showed an increase in evoked spikes that correlated with a reduced fast afterhyperpolarizing potential. This suggests that acquisition of fear extinction induces an increase in spike firing 4 hours later, during the consolidation of extinction. We also examined IL excitability in a group of rats that showed spontaneous recovery of fear 17 days after extinction (SR group). Similar to neurons after fear conditioning, IL neurons from the SR group showed depressed intrinsic excitability compared to neurons 4 hours after extinction, suggesting that extinction-induced enhancement in intrinsic excitability decreases with time reverting back to a depressed state. These results suggest that plasticity in IL contributes to the spontaneous recovery of fear and preventing this depression of IL excitability could prolong fear extinction.
Assuntos
Potenciais de Ação/fisiologia , Extinção Psicológica/fisiologia , Medo/psicologia , Sistema Límbico/fisiologia , Neurônios/fisiologia , Animais , Masculino , Ratos Sprague-DawleyRESUMO
Overconsumption of palatable energy-dense foods has negative health implications and it is associated with obesity and several eating disorders. Currently, little is known about the neuronal circuitries activated by the acute ingestion of a rewarding stimulus. Here, we used a combination of immunohistochemistry, pharmacology and neuronal tracing analyses to examine the role of the mesolimbic system in general, and the orexin neurons in particular, in a simple experimental test in which naïve mice are allowed to spontaneously eat a pellet of a high fat diet (HFD) for 2 h. We found that acute HFD activates c-Fos expression in several reward-related brain areas, including the ventral tegmental area (VTA), nucleus accumbens, central amygdala and lateral hypothalamic area. We also found that: i- HFD-mediated orosensory stimulation was required for the mesolimbic pathway activation, ii- acute HFD differentially activates dopamine neurons of the paranigral, parabrachial pigmented and interfascicular sub-regions of the VTA, and iii- orexin neurons of the lateral hypothalamic area are responsive to acute HFD. Moreover, orexin signaling blockade, with the orexin 1 receptor antagonist SB-334867, reduces acute HFD consumption and c-Fos induction in the VTA but not in the other mesolimbic nuclei under study. Finally, we found that most orexin neurons responsive to acute HFD innervate the VTA. Our results show that acute HFD consumption recruits the mesolimbic system and that the full manifestation of this eating behavior requires the activation of orexin signaling.
Assuntos
Dieta Hiperlipídica , Gorduras na Dieta/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Sistema Límbico/fisiologia , Vias Neurais/fisiologia , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Área Tegmentar Ventral/fisiologia , Análise de Variância , Animais , Benzoxazóis , Imuno-Histoquímica , Sistema Límbico/metabolismo , Camundongos , Naftiridinas , Vias Neurais/metabolismo , Técnicas de Rastreamento Neuroanatômico , Orexinas , Proteínas Proto-Oncogênicas c-fos/metabolismo , Recompensa , Transdução de Sinais/fisiologia , Ureia/análogos & derivados , Área Tegmentar Ventral/metabolismoRESUMO
It is thought that discrete subregions of the medial prefrontal cortex (mPFC) regulate different aspects of appetitive behavior, however, physiological support for this hypothesis has been lacking. In the present study, we used multichannel single-unit recording to compare the response of neurons in the prelimbic (PL) and infralimbic (IL) subregions of the mPFC, in rats pressing a lever to obtain sucrose pellets on a variable interval schedule of reinforcement (VI-60). Approximately 25% of neurons in both structures exhibited prominent excitatory responses during rewarded, but not unrewarded, lever presses. The time courses of reward responses in PL and IL, however, were markedly different. Most PL neurons exhibited fast and transient responses at the delivery of sucrose pellets, whereas most IL neurons exhibited delayed and prolonged responses associated with the collection of earned sucrose pellets. We further examined the functional significance of reward responses in IL and PL with local pharmacological inactivation. IL inactivation significantly delayed the collection of earned sucrose pellets, whereas PL inactivation produced no discernible effects. These findings support the hypothesis that PL and IL signal distinct aspects of appetitive behavior, and suggest that IL signaling facilitates reward collection.
Assuntos
Comportamento Apetitivo/fisiologia , Condicionamento Operante/fisiologia , Sistema Límbico/fisiologia , Neurônios/fisiologia , Animais , Comportamento Apetitivo/efeitos dos fármacos , Condicionamento Operante/efeitos dos fármacos , Sistema Límbico/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Recompensa , Sacarose/farmacologia , Fatores de TempoRESUMO
The amygdaloid nuclei form an important hub of structures associated with diverse aspects of cognition and emotional behavior. Homologous structures have been determined in tetrapods, but homology of amygdala-like regions in bony fishes is presently unclear. Based on connectivity patterns, genoarchitecture, chemical neuroanatomy, and functional studies, we suggest that the dorsomedial portion of the pallium of Actinopterygii is the homolog of the basolateral/lateral amygdala ("frontotemporal amygdaloid system"), while the supracommissural and postcommissural portions of the subpallium are homologous to the extended central amygdala (central amygdaloid nucleus and bed nucleus of the stria terminalis). Nonetheless, the differentiation between these nuclei is not as clear-cut as in mammals, and there is no clear evidence for the existence of an "olfactory" medial amygdala in Actinopterygii, suggesting that the parcellation of one or two amygdaloid nuclei into many subnuclei occurred with the appearance of a true vomeronasal system.
Assuntos
Tonsila do Cerebelo/fisiologia , Sistema Nervoso Autônomo/fisiologia , Peixes/fisiologia , Sistema Límbico/fisiologia , Tonsila do Cerebelo/anatomia & histologia , Tonsila do Cerebelo/química , Animais , Sistema Nervoso Autônomo/anatomia & histologia , Sistema Nervoso Autônomo/química , Comportamento Animal/fisiologia , Evolução Biológica , Peixes/genética , Sistema Límbico/anatomia & histologia , Sistema Límbico/químicaRESUMO
Deficiencies of nutrients such as amino acids, vitamins, lipids, and trace elements during gestation and early infanthood have strong deleterious effects on the development of the limbic system; these effects may be irreversible, even when adequate supplementation is provided at later developmental stages. Recent advances in the neurochemistry of biometals are increasingly establishing the roles of the trace elements iron, copper, zinc, and selenium in a variety of cell functions and are providing insight into the repercussions of deficiencies and excesses of these elements on the development of the central nervous system, especially the limbic system. The limbic system comprises diverse areas with high metabolic demands and differential storage of iron, copper, zinc, and selenium. This review summarizes available evidence suggesting the involvement of these trace elements in pathological disorders of the limbic system.
Assuntos
Encefalopatias/etiologia , Sistema Límbico/efeitos dos fármacos , Sistema Límbico/crescimento & desenvolvimento , Oligoelementos/sangue , Oligoelementos/deficiência , Encefalopatias/sangue , Cobre/sangue , Cobre/deficiência , Cobre/fisiologia , Humanos , Ferro/sangue , Ferro/fisiologia , Deficiências de Ferro , Sistema Límbico/fisiologia , Fenômenos Fisiológicos da Nutrição/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição/fisiologia , Necessidades Nutricionais , Selênio/sangue , Selênio/deficiência , Selênio/fisiologia , Zinco/sangue , Zinco/deficiência , Zinco/fisiologiaRESUMO
Se cita la etimología de la palabra emoción, la evolución histórica de las diferentes teorías de esta y se profundiza en la Teoría de las emociones de A. Damasio, quien clasifica las emociones como: de fondo, primarias y secundarias, describe el procesamiento emocional, diferencia y define emoción de sentimiento. El planteo es ¿procesan igual las emociones los adultos mayores que los jóvenes?, si fuera así, ¿qué beneficios les traería? Se revisaron trabajos neurobiológicos que muestran un mejor procesamiento de las emociones positivas que de las negativas en la vejez sana a través de estudios con RMCf (Resonancia Magnética de Cerebro funcional). Se cita la Teoría de la selectividad socioemocional. En 1993, L. Carstensen postula que con el envejecimiento se produce un cambio motivacional por el cual las personas jerarquizan las metas, su significado y la optimizacion de su experiencia. Frente a eventos vitales negativos (enfermedades, pérdidas afectivas, etc. las personas mayores siguen manteniendo niveles similares o superiores de bienestar subjetivo es la Paradoja del bienestar en la vejez. Se analizan trabajos sobre emociones y enfermedad de Alzheimer.
The etymology of the word "emotion" is explained as well as its evolution throughout the years. Antonio Damasio's classification of backgrounds, primary and secondary emotions are described along with its differences in moaning with the word "feeling". Two differences in emotional Procedure between older and young adults are mentions. RMCf was shown a better positive emotional processing in old age. From Social Theories, Selectivity, Hierarchical organization of goals, paradox in the elderly, emotional balance, and subjective dimensions and shown. The relationship between these change and life quality during normal and pathological aging as well as Alzheimer's disease is also mentions.
Assuntos
Humanos , Idoso , Fatores Etários , Afeto/fisiologia , Tonsila do Cerebelo/fisiologia , Córtex Pré-Frontal/fisiologia , Emoções/classificação , Doença de Alzheimer/fisiopatologia , Envelhecimento/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Pensamento/fisiologia , Sistema Límbico/fisiologiaRESUMO
Se cita la etimología de la palabra emoción, la evolución histórica de las diferentes teorías de esta y se profundiza en la Teoría de las emociones de A. Damasio, quien clasifica las emociones como: de fondo, primarias y secundarias, describe el procesamiento emocional, diferencia y define emoción de sentimiento. El planteo es ¿procesan igual las emociones los adultos mayores que los jóvenes?, si fuera así, ¿qué beneficios les traería? Se revisaron trabajos neurobiológicos que muestran un mejor procesamiento de las emociones positivas que de las negativas en la vejez sana a través de estudios con RMCf (Resonancia Magnética de Cerebro funcional). Se cita la Teoría de la selectividad socioemocional. En 1993, L. Carstensen postula que con el envejecimiento se produce un cambio motivacional por el cual las personas jerarquizan las metas, su significado y la optimizacion de su experiencia. Frente a eventos vitales negativos (enfermedades, pérdidas afectivas, etc. las personas mayores siguen manteniendo niveles similares o superiores de bienestar subjetivo es la Paradoja del bienestar en la vejez. Se analizan trabajos sobre emociones y enfermedad de Alzheimer.(AU)
The etymology of the word "emotion" is explained as well as its evolution throughout the years. Antonio Damasios classification of backgrounds, primary and secondary emotions are described along with its differences in moaning with the word "feeling". Two differences in emotional Procedure between older and young adults are mentions. RMCf was shown a better positive emotional processing in old age. From Social Theories, Selectivity, Hierarchical organization of goals, paradox in the elderly, emotional balance, and subjective dimensions and shown. The relationship between these change and life quality during normal and pathological aging as well as Alzheimers disease is also mentions.(AU)
Assuntos
Humanos , Idoso , Emoções/classificação , Afeto/fisiologia , Sistema Límbico/fisiologia , Pensamento/fisiologia , Córtex Pré-Frontal/fisiologia , Envelhecimento/fisiologia , Fatores Etários , Reconhecimento Fisiológico de Modelo/fisiologia , Doença de Alzheimer/fisiopatologia , Tonsila do Cerebelo/fisiologiaRESUMO
There is considerable interest in identifying pharmacological compounds that could be used to facilitate fear extinction. Recently, we showed that the modulation of M-type K(+) channels regulates the intrinsic excitability of infralimbic (IL) neurons and fear expression. As muscarinic acetylcholine receptors inhibit M-type K(+) channels, cholinergic inputs to IL may have an important role in controlling IL excitability and, thereby, fear expression and extinction. To test this model, we combined whole-cell patch-clamp electrophysiology and auditory fear conditioning. In prefrontal brain slices, muscarine enhanced the intrinsic excitability of IL neurons by reducing the M-current and the slow afterhyperpolarization, resulting in an increased number of spikes with shorter inter-spike intervals. Next, we examined the role of endogenous activation of muscarinic receptors in fear extinction. Systemic injected scopolamine (Scop) (muscarinic receptor antagonist) before or immediately after extinction training impaired recall of extinction 24-h later, suggesting that muscarinic receptors are critically involved in consolidation of extinction memory. Similarly, infusion of Scop into IL before extinction training also impaired recall of extinction 24-h later. Finally, we demonstrated that systemic injections of the muscarinic agonist, cevimeline (Cev), given before or immediately after extinction training facilitated recall of extinction the following day. Taken together, these findings suggest that cholinergic inputs to IL have a critical role in modulating consolidation of fear extinction and that muscarinic agonists such as Cev might be useful for facilitating extinction memory in patients suffering from anxiety disorders.
Assuntos
Potenciais de Ação/fisiologia , Extinção Psicológica/fisiologia , Medo/fisiologia , Sistema Límbico/fisiologia , Neurônios/fisiologia , Receptores Muscarínicos/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Colinérgicos/farmacologia , Extinção Psicológica/efeitos dos fármacos , Medo/efeitos dos fármacos , Medo/psicologia , Sistema Límbico/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Ratos , Ratos Sprague-DawleyRESUMO
The peptide hormone ghrelin acts in the central nervous system as a potent orexigenic signal. Not only is ghrelin recognized as playing an important role in feeding circuits traditionally thought of as affecting body weight homeostasis, but also an accumulating number of scientific studies have identified ghrelin as being a key regulator of reward-based, hedonic eating behaviors. In the current article, we review ghrelin's orexigenic actions, the evidence linking ghrelin to food reward behavior, potential mechanisms by which ghrelin mediates reward-based eating behavior, and those studies suggesting an obligatory role for ghrelin in the changed eating behaviors induced by stress.
Assuntos
Peso Corporal/fisiologia , Comportamento Alimentar/fisiologia , Grelina/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Recompensa , Estresse Psicológico , Animais , Dopamina/metabolismo , Comportamento Alimentar/psicologia , Humanos , Sistema Límbico/fisiologia , Vias Neurais/fisiologia , RatosRESUMO
Throughout the centuries, scientific observers have endeavoured to extend their knowledge of the interrelationships between the brain and its regulatory control of human emotions and behaviour. Since the time of physicians such as Aristotle and Galen and the more recent observations of clinicians and neuropathologists such as Broca, Papez, and McLean, the field of affective neuroscience has matured to become the province of neuroscientists, neuropsychologists, neurologists, and psychiatrists. It is accepted that the prefrontal cortex, amygdala, anterior cingulate cortex, hippocampus, and insula participate in the majority of emotional processes. New imaging technologies and molecular biology discoveries are expanding further the frontiers of knowledge in this arena. The advancements of knowledge on the interplay between the human brain and emotions came about as the legacy of the pioneers mentioned in this field. The aim of this paper is to describe the historical evolution of the scientific understanding of interconnections between the human brain, behaviour, and emotions.
Assuntos
Emoções/fisiologia , Sistema Límbico/fisiologia , Rede Nervosa/fisiologia , Comportamento/fisiologia , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , História do Século XX , História Antiga , Humanos , Sistema Límbico/anatomia & histologia , Rede Nervosa/anatomia & histologia , Neuroimagem/métodos , Neuropsicologia/história , Neurociências/históriaRESUMO
Mandibular movements occur through the triggering of trigeminal motoneurons. Aberrant movements by orofacial muscles are characteristic of orofacial motor disorders, such as nocturnal bruxism (clenching or grinding of the dentition during sleep). Previous studies have suggested that autonomic changes occur during bruxism episodes. Although it is known that emotional responses increase jaw movement, the brain pathways linking forebrain limbic nuclei and the trigeminal motor nucleus remain unclear. Here we show that neurons in the lateral hypothalamic area, in the central nucleus of the amygdala, and in the parasubthalamic nucleus, project to the trigeminal motor nucleus or to reticular regions around the motor nucleus (Regio h) and in the mesencephalic trigeminal nucleus. We observed orexin co-expression in neurons projecting from the lateral hypothalamic area to the trigeminal motor nucleus. In the central nucleus of the amygdala, neurons projecting to the trigeminal motor nucleus are innervated by corticotrophin-releasing factor immunoreactive fibers. We also observed that the mesencephalic trigeminal nucleus receives dense innervation from orexin and corticotrophin-releasing factor immunoreactive fibers. Therefore, forebrain nuclei related to autonomic control and stress responses might influence the activity of trigeminal motor neurons and consequently play a role in the physiopathology of nocturnal bruxism.
Assuntos
Tronco Encefálico/fisiologia , Mandíbula/fisiologia , Prosencéfalo/fisiologia , Tonsila do Cerebelo/anatomia & histologia , Tonsila do Cerebelo/fisiologia , Animais , Tronco Encefálico/anatomia & histologia , Corantes , Hormônio Liberador da Corticotropina/análise , Imunofluorescência , Região Hipotalâmica Lateral/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/análise , Sistema Límbico/fisiologia , Masculino , Neurônios Motores/citologia , Neurônios Motores/fisiologia , Movimento , Fibras Nervosas/fisiologia , Fibras Nervosas/ultraestrutura , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Neurônios Eferentes/fisiologia , Neurônios Eferentes/ultraestrutura , Neuropeptídeos/análise , Orexinas , Prosencéfalo/anatomia & histologia , Ratos , Ratos Wistar , Formação Reticular/anatomia & histologia , Formação Reticular/fisiologia , Técnicas Estereotáxicas , Núcleo Subtalâmico/anatomia & histologia , Núcleo Subtalâmico/fisiologia , Núcleos do Trigêmeo/anatomia & histologia , Núcleos do Trigêmeo/fisiologiaRESUMO
Extinction of conditioned fear is an active learning process involving inhibition of fear expression. It has been proposed that fear extinction potentiates neurons in the infralimbic (IL) prefrontal cortex, but the cellular mechanisms underlying this potentiation remain unknown. It is also not known whether this potentiation occurs locally in IL neurons as opposed to IL afferents. To determine whether extinction enhances the intrinsic excitability of IL pyramidal neurons in layers II/III and V, we performed whole-cell patch-clamp recordings in slices from naive, conditioned, or conditioned-extinguished rats. We observed that conditioning depressed IL excitability compared with slices from naive animals, as evidenced by a decreased number of spikes evoked by injected current and an increase in the slow afterhyperpolarizing potential (sAHP). Extinction reversed these conditioning-induced effects. Furthermore, IL neurons from extinguished rats showed increased burst spiking compared with naive rats, which was correlated with extinction recall. These changes were specific to IL prefrontal cortex and were not observed in prelimbic prefrontal cortex. Together, these findings suggest that IL intrinsic excitability is reduced to allow for expression of conditioning memory and enhanced for expression of extinction memory through the modulation of Ca(2+)-gated K(+) channels underlying the sAHP. Inappropriate modulation of these intrinsic mechanisms may underlie anxiety disorders, characterized by exaggerated fear and deficient extinction.