Acute effect of callosotomy on cortical temporal coupling in humans: intraoperative electrocorticographic recording.

OBJECTIVE: To investigate the acute role of the corpus callosum in inter- and intrahemispheric temporal coupling. METHODS: Intraoperative electrocorticography (ECoG) makes it possible to investigate the acute role of the corpus callosum in cortical temporal coupling, or synchrony, without additional surgical intervention, thus avoiding the confounding effects of scalp recordings and the long-term reorganization of functional connectivity. ECoGs were recorded in three patients during callosotomies. Bilateral electrode grids were placed over the frontal cortex. ECoGs were recorded immediately before and after performing the anterior two-thirds callosal transection, were digitalized at a sampling rate of 512Hz, inspected for artifacts, and later analyzed offline. Cross-correlation between inter- and intrahemispheric electrode pairs were obtained for 1Hz bins and special broad bands obtained by principal component analysis for each patient pre- and post-callosotomy. RESULTS: A statistically significant change was observed in intrahemispheric temporal coupling between electrode pairs that exceeded the confidence limit of correlation. CONCLUSIONS: Present results show that interrupting the influence of the corpus callosum has an acute effect on intrahemispheric activity by decreasing temporal coupling between cortical areas. SIGNIFICANCE: Intrahemispheric temporal coupling does not depend exclusively on ipsilateral cortico-cortical pathways or on subcortical influences, but also on callosal pathways.

Gender differences in EEG coherent activity before and after training navigation skills in virtual environments.

Gender differences in electroencephalographic activity (EEG) changes during navigation task performance after training were assessed in young adults. Female and male subjects were matched on initial navigation performance. EEG recordings were obtained while subjects navigated in an immersive virtual environment without visual cues, before and after a navigational skills training (9 sessions). In spite of task performance was similar in both groups, females showed higher theta band coherent activity between frontal and parietal and frontal and central regions than males before training. Correlation in theta band between fronto-central, fronto-parietal, and centro-parietal regions was enhanced in the left hemisphere for females but in the right hemisphere for males after training. Females also demonstrated a decreased in correlation in theta band over the right hemisphere between centro-parietal regions, whereas males demonstrated a similar effect over the left hemisphere. Navigation training seems to promote fronto-central-parietal synchronization in both genders but in different hemisphere. These results are interpreted as reflecting verbal-analytical working memory functions in females and global-spatial working memory mode in males.

Increased lipid peroxidation and neuron specific enolase in treatment refractory schizophrenics.

It is well-known that increased lipid peroxidation and failure of antioxidant mechanisms leads to neuronal damage in schizophrenic patients. However, this neurodegenerative mechanism has not been studied in treatment refractory schizophrenics (TRS). Therefore, the main purpose of this study was to determine neuronal damage in TRS in comparison to non-refractory schizophrenics (NRS) by means of quantitative analysis of lipid peroxidation and neuron specific enolase (NSE) related to the psychopathology severity. Two groups of paranoid schizophrenics, TRS and NRS, and a group of healthy controls (CO) were assembled (n=13). Lipid peroxidation was analyzed through spectrophotometry for quantification of malonaldehyde (MDA) and 4-hydroxynonenal (4-HNE) serum concentrations. As well, serum NSE was quantified by radioimmunoassay (ELSA). Psychopathology was evaluated using the brief psychiatric rating scale (BPRS) and the positive and negative symptoms scale (PANSS). TRS showed significant higher concentrations of lipoperoxides by-products and NSE, than NRS and CO. Clinical scores also revealed a more severe pathology in TRS, than in NRS. Raised lipoperoxidation correlated with higher delusions and emotional withdrawal symptoms, and increased NSE correlated with a lower flow of the conversation and lack of spontaneity. All these results together suggest that TRS patients suffer a greater lipid peroxidation and neuronal damage than NRS, apparently related to worsening of some of the psychiatric symptoms.

Within-subject reliability and inter-session stability of EEG power and coherent activity in women evaluated monthly over nine months.

OBJECTIVE: Quantitative EEG parameters during resting conditions are used as baseline in research on cognition and in serial-EEG recordings. Despite its increasing use in cognitive research and the numerous evidences of the existence of sex differences in EEG, EEG stability has been mainly investigated in men. Particularly, studies on stability of coherent activity are scarce. The aim of this study was to investigate within-subject reliability and inter-session stability of resting EEG over a nine-month period in women. METHODS: Within-subject reliability and inter-session stability were analyzed for absolute power and inter- and intrahemispheric coherent activity at central and posterior regions, once a month, in resting conditions, with eyes open and closed. RESULTS: Within-subject reliability was very high (r>0.89) for all subjects and EEG parameters. Inter-session stability was higher with eyes closed and for interhemispheric coherent activity, and poorer with eyes open especially in the alpha band. CONCLUSIONS: Present results indicate high reliability of the pattern of power and coherent activity of each individual woman during rest, and group stability of EEG activity with eyes closed at least over a nine-month period. SIGNIFICANCE: These results provide information on EEG stability in women over a long period.

Role of corpus callosum in interhemispheric coherent activity during sleep.

OBJECTIVE: To investigate to what extent the increase in interhemispheric coherent activity observed from wakefulness to sleep depends on the integrity of the corpus callosum (CC). METHODS: Interhemispheric coherent activity was analyzed in two epileptic patients selected for callosotomy because of multifocal refractory epilepsy, before and 4 months after callosotomy. One patient underwent complete callosotomy and another was subjected to callosotomy of the anterior 2/3, which offered the possibility of comparing the role of the CC in the coherent activity increase from wakefulness to sleep, between anterior regions with interrupted CC communication (in the two patients) and posterior regions with intact communication (in one of them). Results were compared with a group of normal subjects. RESULTS: Both patients showed increased coherent activity from wakefulness to sleep after surgery. CONCLUSIONS: Results demonstrate that interhemispheric coherent activity, despite an attenuation after surgery, is higher during SWS than during wakefulness after sectioning the CC; however, they have to be taken with caution because they come from two patients only. SIGNIFICANCE: Present results show that the increase in coherent activity during sleep does not depend exclusively on callosal integrity but also on state-dependent influences from sleep-promoting mechanisms, probably spread throughout the thalamo-cortical network.

[Differential effect of left and right temporal lobectomy on emotional recognition and experience in patients with epilepsy]. / Efecto diferencial de la lobectomía temporal izquierda y derecha sobre el reconocimiento y la experiencia emocional en pacientes con epilepsia.

INTRODUCTION: Temporal lobe and amygdala are structures that participate in emotional processing. The purpose of this study was to determine the differential effect of left (LTL) and right (RTL) temporal lobectomy on emotional recognition and experience as well as mood in treatment resistant epileptics who were evaluated pre and post-surgically. PATIENTS AND METHODS: Five temporal lobe epileptic patients participated in the study (two from the right and three from the left hemisphere) who were evaluated before and after three months of the surgery. Emotional and prosodic recognition were evaluated, inside and outside of a social context, with and without time limit. Besides, subjective emotional experience while seeing movie fragments was evaluated as well as positive and negative emotional states, anxiety and depression. RESULTS: After the surgery, patients with RTL had lower number of correct responses in fear facial and prosodic recognition, while patients with LTL did not show deterioration or they even improved. There were not differences as a function of the intervened hemisphere neither in the intensity of emotions perceived in the scenes, nor in the emotional experience, however, both groups experienced a decrease of negative emotions and anxiety. CONCLUSIONS: The results suggest that RTL had a greater effect on emotional recognition outside of a context and with limited time than LTL, while in the emotional experience there were not differences between groups. Lobectomy induced an improvement on affective states.

Efecto diferencial de la lobectomía temporal izquierda y derecha sobre el reconocimiento y la experiencia emocional en pacientes con epilepsia / Differential effect of left and right temporal lobectomy on emotional recognition and experience in patients with epilepsy

Introducción. El lóbulo temporal y la amígdala son estructuras que participan en el procesamiento emocional. La finalidad del presente estudio fue determinar el efecto diferencial de la lobectomía temporal izquierda (LTI) y derecha (LTD) en el reconocimiento y la experiencia emocional, así como en los estados afectivos en pacientes epilépticos refractarios al tratamiento evaluados pre y posquirúrgicamente. Pacientes y métodos. Participaron cinco pacientes con epilepsia del lóbulo temporal (dos del hemisferio derecho y tres del izquierdo) a los que se evaluó antes y después de tres meses de la cirugía. Se estudió el reconocimiento emocional facial y prosódico dentro y fuera de un contexto social, con y sin tiempo límite. Además, se valoró la experiencia emocional subjetiva ante fragmentos de películas y los estados emocionales positivos y negativos, la ansiedad y la depresión. Resultados. Posquirúrgicamente, los pacientes con LTD tuvieron menos aciertos en el reconocimiento de la expresión de miedo con tiempo límite y de la prosodia, mientras que los pacientes con LTI no mostraron deterioro o incluso mejoraron. No hubo diferencias en función del hemisferio intervenido ni en la intensidad con que percibieron las emociones en las escenas, ni en la experiencia emocional, aunque ambos grupos experimentaron una disminución de las emociones negativas y la ansiedad. Conclusiones. Los resultados sugieren que la LTD tuvo un mayor efecto sobre el reconocimiento emocional fuera de un contexto y con tiempo límite que la LTI, mientras que en la experiencia emocional no se observaron diferencias entre grupos. La lobectomía indujo una mejoría en los estados afectivos (AU)

Introduction. Temporal lobe and amygdala are structures that participate in emotional processing. The purpose of this study was to determine the differential effect of left (LTL) and right (RTL) temporal lobectomy on emotional recognition and experience as well as mood in treatment resistant epileptics who were evaluated pre and post-surgically. Patients and methods. Five temporal lobe epileptic patients participated in the study (two from the right and three from the left hemisphere) who were evaluated before and after three months of the surgery. Emotional and prosodic recognition were evaluated, inside and outside of a social context, with and without time limit. Besides, subjective emotional experience while seeing movie fragments was evaluated as well as positive and negative emotional states, anxiety and depression. Results. After the surgery, patients with RTL had lower number of correct responses in fear facial and prosodic recognition, while patients with LTL did not show deterioration or they even improved. There were not differences as a function of the intervened hemisphere neither inthe intensity of emotions perceived in the scenes, nor in the emotional experience, however, both groups experienced a decrease of negative emotions and anxiety. Conclusions. The results suggest that RTL had a greater effect on emotional recognition outside of a context and with limited time than LTL, while in the emotional experience there were not differences between groups. Lobectomy induced an improvement on affective states (AU)

[Olanzapine effects on emotional recognition in treatment refractory schizophrenics]. / Efectos de la olanzapina sobre el reconocimiento emocional en pacientes esquizofrénicos refractarios al tratamiento.

INTRODUCTION: The main purpose of this study was to determine if olanzapine (OLZ) can improve the ability to recognize emotional expressions, in the facial, prosodic and contextual modalities in treatment refractory schizophrenics (TRS) and, if this could be related to its effects on depressive symptoms. METHOD: 14 TRS participated in the study. The Calgary Depression Scale and tasks for recognition of facial, prosodic and contextual emotions were applied prior to and 8 weeks after consuming OLZ. The results were compared to a control group (CO). RESULTS: TRS obtained lower scores than the CO on the recognition of facial and prosodic emotions. They also showed less empathy to the happiness film and they expressed incongruous answers on the contextual emotions. The TRS increased the number of correct responses for the prosodic recognition of happiness and they showed a reduction in their depressive symptomatology after OLZ treatment. CONCLUSIONS: OLZ caused a decrease of the depressive symptoms and improved the interpretation of positive prosodic affective stimuli, an aspect that may facilitate the social adaptation of TRS.

Efectos de la olanzapina sobre el reconocimiento emocional en pacientes esquizofrénicos refractarios al tratamiento / Olanzapine effects on emotional recognition in treatment refractory schizophrenics

Introducción. El objetivo principal del presente trabajo fue determinar si la olanzapina (OLZ) puede mejorar la capacidad para reconocer expresiones emocionales en las modalidades facial, prosódica y contextual de pacientes esquizofrénicos refractarios (ERT) y si ello pudiera tener relación con su efecto sobre síntomas depresivos. Método. Participaron 14 ERT a quienes se les aplicaron antes y después de 8 semanas de consumir OLZ la Escala de Calgary de Depresión y las tareas de reconocimiento de emociones faciales, prosódicas y contextuales. Los resultados fueron comparados con un grupo control (CO).Resultados. Los ERT obtuvieron menores puntajes que los CO ante el reconocimiento de emociones faciales y prosódicas; asimismo mostraron menor empatía ante la película de alegría y expresaron respuestas incongruentes ante las emociones contextuales. Los ERT incrementaron el número de aciertos para el reconocimiento prosódico de alegría y disminuyeron su sintomatología depresiva después del tratamiento con OLZ. Conclusiones. La OLZ causó una disminución de los síntomas depresivos y mejoró la interpretación de estímulos afectivos prosódicos positivos, condición que podría facilitar la adaptación social en los ERT (AU)