Prefrontal cortex and behavioral disorders: Theoretical framework and neuropsychological evaluation

Los trastornos del córtex prefrontal (CPF) permiten explicar la sintomatología de importantes cuadros neurológicos y psiquiátricos, tales como las secuelas de traumatismos encéfalo-craneanos y las esquizofrenias. Sin embargo, y a pesar de la gran importancia de sus funciones, su estudio se ha visto dificultado por razones teóricas, experimentales y clínicas. Recientemente han surgido dos nuevos modelos que intentan explicar los mecanismos a la base del funcionamiento del CPF. Presentamos una revisión de las principales manifestaciones clínicas ante su disfunción, los modelos explicativos postulados tradicionalmente, además de las dos propuestas recientes de Koechlin y Mesulam, para finalizar con una revisión de los instrumentos más utilizados en el ámbito clínico para la evaluación de las funciones propias de esta región, denominadas funciones ejecutivas y de autorregulación del comportamiento Dysfunction of prefrontal cortex explains the symptoms of many neurological and psychiatric disorders, such as the consequences of cerebral trauma and schizophrenia. Although the importance of frontal lobe functions in complex cognition has long been recognized, systematic research efforts to specify the nature, organization and roles of these functions have been difficult for theoretical, experimental and clinical reasons. Recently, two new theoretical frameworks have been proposed to explain the role of prefrontal cortex. In this paper, we present a revision of the main clinical manifestations secondary to prefrontal dysfunction, the frameworks proposed by Mesulam and Koechlin to explain the role of prefrontal cortex in behavior and the principal instruments available to evaluate executive and strategic self-regulation function

Psychosis-related matricide associated with a lesion of the ventromedial prefrontal cortex

Matricide, the killing of a mother by her biological child, is a rare event. We report a case of matricide associated with a woman who sustained a right ventromedial prefrontal lesion during surgery for nasal polyposis that was performed when she was 40 years old. After her surgery, she developed psychotic symptoms associated with the emergence of antisocial behavior. She committed matricide 22 years later. Neuropsychological evaluation showed decreased frontal-executive deficits, and magnetic resonance imaging revealed a lesion in the right gyrus rectus area of the ventromedial prefrontal region. This case suggests that a secondary psychotic syndrome associated with a lesion in the frontal neural network, which is disturbed in psychopathy, could facilitate homicidal behavior. Furthermore, this case has legal implications for the prosecution of murder associated with a brain lesion

Executive Functioning in Schizophrenia

The executive function (EF) is a set of abilities, which allows us to invoke voluntary control of our behavioral responses. These functions enable human beings to develop and carry out plans, make up analogies, obey social rules, solve problems, adapt to unexpected circumstances, do many tasks simultaneously, and locate episodes in time and place. EF includes divided attention and sustained attention, working memory (WM), set-shifting, flexibility, planning, and the regulation of goal directed behavior and can be defined as a brain function underlying the human faculty to act or think not only in reaction to external events but also in relation with internal goals and states. EF is mostly associated with dorsolateral prefrontal cortex (PFC). Besides EF, PFC is involved in self-regulation of behavior, i.e., the ability to regulate behavior according to internal goals and constraints, particularly in less structured situations. Self-regulation of behavior is subtended by ventral medial/orbital PFC. Impairment of EF is one of the most commonly observed deficits in schizophrenia through the various disease stages. Impairment in tasks measuring conceptualization, planning, cognitive flexibility, verbal fluency, ability to solve complex problems, and WM occur in schizophrenia. Disorders detected by executive tests are consistent with evidence from functional neuroimaging, which have shown PFC dysfunction in patients while performing these kinds of tasks. Schizophrenics also exhibit deficit in odor identifying, decision-making, and self-regulation of behavior suggesting dysfunction of the orbital PFC. However, impairment in executive tests is explained by dysfunction of prefronto-striato-thalamic, prefronto-parietal, and prefronto-temporal neural networks mainly. Disorders in EFs may be considered central facts with respect to schizophrenia and it has been suggested that negative symptoms may be explained by that executive dysfunction

Trastornos Neurocognitivos en la Esquizofrenia

La esquizofrenia (EQZ) es una enfermedad mental de alta prevalencia (1%). Es una de las enfermedades mentales más invalidantes dado que se inicia en etapas precoces del ciclo vita (la adolescencia) y que se asocia a un deterioro cognitivo y social importante. Tiene un carácter crónico y no existe hasta ahora un tratamiento que logre la remisión absoluta de la enfermedad. La literatura reciente ha procurado caracterizar la prevalencia, el grado y la naturaleza de las anormalidades neuropsicológicas en esta enfermedad. No obstante, no esta claro los procesos cognitivos disfuncionales a la base de las diferentes anormalidades neuropsicológicas. Por lo que, ha sido difícil determinar las bases neurobiológicas de los trastornos observados. Los paradigmas neurocognitivos están siendo utilizados en forma creciente para estudiar la EQZ. Tales paradigmas utilizan tests experimentales y clínicos para caracterizar mejor las anormalidades cognitivas en esta enfermedad. Este acercamiento di?ere de las investigaciones psicológicas previas,por el uso de pruebas neurocognitivas validadas en poblaciones con lesiones cerebrales o por estudios con neuroimágenes funcionales en controles sanos. El estudio de los rendimientos de los pacientes con EQZ en las pruebas neurocognitivas ha permitido identi?car dé?cit cognitivos centrales que podrían explicar una proporción signi?cativa de la morbilidad social y vocacional en esta enfermedad. El objetivo de esta revisión es describir estos estudios, los cuales han contribuido a hacer inferencias de sistemas neurales disfuncionales en la EQZ

Neurocognitive models of schizophrenia: The prefrontal cortex role Modelos neurocognitivos en la esquizofrenia: Rol del córtex prefrontal

Introduction: Neurocognitive models gave place to an important improvement in our understanding of several mental disorders such as schizophrenia. In this context, Prefrontal cortex (PFC) dysfunction is an essential variable for its symptomatology account. It has been observed that abnormal level of PFC activation, as well as connectivity dysfunctions with other cerebral structures, play a central role in the delimitation of the disease. Materials and Methods: Through a theoretical, empirical, and clinical review, five neurocognitive approach of schizophrenia will be described. Conclusion: Although schizophrenia etiology is probably multiple, neural interconnectivity disorders and specially those related to PFC, explain a broad range of its symptoms. © 2006 Sociedad de Neurología, Psiquiatría y Neurocirugía

Training in Neuropsychiatry:a National need?

Carta al EditorProyecto PIA CONICYT, CIE-05

The association of schizophrenia with chronic non transmissible diseases

The life expectancy of patients with schizophrenia (SCH) is 11 to 20 years less than the general population. There is an association between SCH and various diseases and chronic conditions, highlighting the cardio-metabolic diseases. This association has been attributed to the use of antipsychotics, however, evidence has also shown intrinsic susceptibility of schizophrenic patients the development of chronic conditions. This review aims to update knowledge about chronic conditions such as cardiometabolic risk and sleep, bone and kidney disorders related to SCH. These patients have a high prevalence of risk behaviors, including smoking and poor diet. They have a worse metabolic profile than the general population and a greater likelihood of developing metabolic syndrome, diabetes and cardiovascular disease. SCH has also been associated with other chronic diseases such as osteoporosis and chronic kidney disease. The high prevalence of these comorbidities in schizophrenic population is not explained solely by the antipsychotic treatment, therefore intrinsic mechanisms associated to SCH are postulated to be associated with these conditions. This new information requires a change in the multidisciplinary medical approach for the study and management of schizophrenic patients

Satisfaction and the Use of Social Media in Geographically Distant Relationships

Geographically distant relationships have mainly been studied in the context of satisfaction. This study takes geographically distant relationship satisfaction a step further by analyzing the influence social media has on a romantic partner’s satisfaction in the relationship. Respondents (N=95) in a geographically distant relationship reported their level of satisfaction with social media use in their relationship. Qualitative findings reported that romantic partners did not find the use of social media to be a significant contributor in maintaining relational satisfaction. However, it was found that social media helps provide multiple communication outlets in the relationship. Qualitative findings show that there are common themes reported from participants. This study provides a foundation for further research in the field of social media use in geographically distant relationships. Keywords: Social Media, Satisfaction; Geographically Distant Relationships; Social Exchange Theory; Face-to-Face Interactio