Altered prefrontal lobe oxygenation in bipolar disorder: a study by near-infrared spectroscopy.

BACKGROUND: Previous studies have reported prefrontal cortex (PFC) pathophysiology in bipolar disorder. METHOD: We examined the hemodynamics of the PFC during resting and cognitive tasks in 29 patients with bipolar disorder and 27 healthy controls, matched for age, verbal abilities and education. The cognitive test battery consisted of letter and category fluency (LF and CF), Sets A and B of the Raven's Colored Progressive Matrices (RCPM-A and RCPM-B) and the letter cancellation test (LCT). The tissue oxygenation index (TOI), the ratio of oxygenated hemoglobin (HbO2) concentration to total hemoglobin concentration, was measured in the bilateral PFC by spatially resolved near-infrared spectroscopy. Changes in HbO2 concentration were also measured. RESULTS: The bipolar group showed slight but significant impairment in performance for the non-verbal tasks (RCPM-A, RCPM-B and LCT), with no significant between-group differences for the two verbal tasks (LF and CF). A group x task x hemisphere analysis of variance (ANOVA) on the TOI revealed an abnormal pattern of prefrontal oxygenation across different types of cognitive processing in the bipolar group. Post hoc analyses following a group x task x hemisphere ANOVA on HbO2 concentration revealed that the bipolar group showed a greater increase in HbO2 concentration in the LCT and in RCPM-B, relative to controls. CONCLUSIONS: Both indices of cortical activation (TOI and HbO2 concentration) indicated a discrepancy in the PFC function between verbal versus non-verbal processing, indicating task-specific abnormalities in the hemodynamic control of the PFC in bipolar disorder.

Facial affect recognition in pre-lingually deaf people with schizophrenia.

The present study examined facial affect recognition in pre-lingually deaf individuals with schizophrenia. Affective facial-labeling task and the control task of face feature processing (the Benton facial recognition test) were performed by deaf subjects with schizophrenia using French sign language (FSL), hearing subjects with schizophrenia, and hearing healthy controls. Deaf subjects with schizophrenia performed more poorly than hearing clinical controls with schizophrenia or healthy controls on the affective facial-labeling task. No differences were found on the control task between deaf subjects with schizophrenia and hearing clinical or healthy controls. The results showed that facial affect recognition and face feature processing were differently impaired in pre-lingually deaf individuals with schizophrenia, suggesting that neurocognitive backgrounds of impaired affective facial processing may be distinct from those of general impairment in face processing.

Frontal midline theta rhythm is correlated with cardiac autonomic activities during the performance of an attention demanding meditation procedure.

Frontal midline theta rhythm (Fm theta), recognized as distinct theta activity on EEG in the frontal midline area, reflects mental concentration as well as meditative state or relief from anxiety. Attentional network in anterior frontal lobes including anterior cingulate cortex is suspected to be the generator of this activity, and the regulative function of the frontal neural network over autonomic nervous system (ANS) during cognitive process is suggested. However no studies have examined peripheral autonomic activities during Fm theta induction, and interaction of central and peripheral mechanism associated with Fm theta remains unclear. In the present study, a standard procedure of Zen meditation requiring sustained attention and breath control was employed as the task to provoke Fm theta, and simultaneous EEG and ECG recordings were performed. For the subjects in which Fm theta activities were provoked (six men, six women, 48% of the total subjects), peripheral autonomic activities were evaluated during the appearance of Fm theta as well as during control periods. Successive inter-beat intervals were measured from the ECG, and a recently developed method of analysis by Toichi et al. (J. Auton. Nerv. Syst. 62 (1997) 79-84) based on heart rate variability was used to assess cardiac sympathetic and parasympathetic functions separately. Both sympathetic and parasympathetic indices were increased during the appearance of Fm theta compared with control periods. Theta band activities in the frontal area were correlated negatively with sympathetic activation. The results suggest a close relationship between cardiac autonomic function and activity of medial frontal neural circuitry.

Verbal association for simple common words in high-functioning autism.

We investigated conceptual relationships in semantic memory using an indirect priming technique in high-functioning autistic adolescents and their controls who were matched for age, verbal IQ, performance IQ, and nonverbal reasoning ability. The prime was a single word and the target task was completing a word fragment that was semantically related or unrelated to the prime word. The autistic subjects and controls showed similar semantic priming effects, indicating intact conceptual relationships for simple common words in those with autism. Only in the autistic group was a significant correlation found between performance for the related items and two nonverbal cognitive measures, which suggests a possibility that semantic processing in individuals with autism might be qualitatively different from that in controls.

Dual access to semantics in autism: is pictorial access superior to verbal access?

The main aim of the present study was to compare pictures and words with respect to access to semantic systems in autism using a semantic priming paradigm. A word completion task was conducted using both within-modality (word word, WW) and cross-modality (picture word, PW) conditions on a group of high-functioning adolescents and adults with autism (N = 20) and a control group (N = 20) matched on chronological age, mental age, Verbal IQ and Performance IQ. Both groups showed semantic priming effects in both modality conditions. generating significantly more responses for related prime-target pairs than for unrelated pairs. Although the control group performed similarly on both priming tasks, the autistic group performed significantly better on a PW task than on a WW task. These findings suggest the possible advantage of pictures over words in access to semantics in autism. The theoretical implications are discussed in terms of functional asymmetry between verbal and pictorial semantic operations that may be specific to autism.

Emotional cognition without awareness after unilateral temporal lobectomy in humans.

To investigate the function of the amygdala in human emotional cognition, we investigated the electrodermal activity (EDA) in response to masked (unseen) visual stimuli. Six epileptic subjects were investigated after unilateral temporal lobectomy. Emotionally valenced photographic slides (10 negative, 10 neutral) from the International Affective Picture System were presented to their unilateral visual fields under either subliminal or supraliminal conditions. An interaction between hemispheres and emotional valences was found only under the subliminal conditions; greater EDA responses to negative stimuli compared with neutral ones were observed when stimuli were presented to the intact hemispheres. The findings suggest that nonconscious emotional processing is reflected in EDA in a different manner from conscious emotional processing. Medial temporal structures, including the amygdala, thus appear to play a critical role in the neural substrates for this automatic processing.

The influence of psychotic states on the autonomic nervous system in schizophrenia.

Abnormal autonomic activity in patients with schizophrenia has been reported, but how psychotic states influence the autonomic nervous system (ANS) has remained unclear due to methodological limitations. The influence of psychotic states on ANS activity in patients with schizophrenia was investigated using a recently developed method of analysis based on heart rate variability which assesses cardiac sympathetic and parasympathetic function separately. Cardiac autonomic function (CAF), together with psychotic states, was assessed at the beginning and the end of an 8-week study period in 53 patients with chronic schizophrenia. The CAF in age- and sex-matched control subjects was also examined. There were no significant differences between the patients and the control subjects in the mean R-R interval (RRI) or in the indices of the sympathetic and the parasympathetic function. In the patients who changed in psychotic states, the parasympathetic index was significantly decreased without significant changes in the sympathetic index when their psychotic states were more pronounced, suggesting psychotic states suppressed the parasympathetic function without affecting the sympathetic function. In these patients, the mean RRI was smaller when their psychotic states were more pronounced. Our results demonstrate that psychotic states affect the ANS, suggesting a relationship between cerebral cognitive and peripheral ANS activities, and that this is presumably mediated through the parasympathetic nervous system. These findings are discussed in comparison with previous reports on the CAF in schizophrenia.

What is meant by "misidentification" in delusional misidentification syndromes? Comparison between Capgras' syndromes and "clonal pluralization of a person'.

The semantic structure of Capgras' syndrome (CS) was analyzed within the framework of "the theory of reference" of analytic philosophy to elucidate the concept of misidentification in delusional misidentification syndromes (DMS). The close relationship between the semantic structure of CS and the ordinary use of a proper name, which is not synonymous with the description but has the function of indicating an object rigidly, is shown. CS is redefined from this perspective, and a novel misidentification symptom, which we call "clonal pluralization of a person", is contrasted to CS. Among so-called DMS, there are at least two types of misidentification with different semantic structures.

Interictal change in cardiac autonomic function associated with EEG abnormalities and clinical symptoms: a longitudinal study following acute deterioration in two patients with temporal lobe epilepsy.

The purpose of the present study was to investigate the ictal and interictal changes in cardiac autonomic function (CAF), and the relationship between the interictal change in CAF to the electroencephalogram (EEG) and clinical findings. In two patients with temporal lobe epilepsy (TLE) showing acute deterioration, a quantitative evaluation of their interictal CAF based on heart rate variability and their EEG using spectral analysis was conducted, and the findings compared with repeated clinical evaluations during the recovery period. The ictal heart rate changes and their temporal relationship to ictal discharge were investigated using simultaneous EEG/electrocardiogram (ECG) monitoring in one of the patients. Interictal parasympathetic function was decreased during the period of acute deterioration, but was increased in association with improvements in the EEG and clinical findings. In contrast, the sympathetic function showed no specific changes. The ictal discharges were preceded by a brief bradycardia, with a long delay of up to 40s. The results demonstrated that this decrease in parasympathetic function was closely related to the interictal changes in central nervous system function. On the other hand, the ictal discharges in one of the patients were thought to have caused a transient elevation of parasympathetic function. It is strongly suggested that patients with TLE have interictal as well as ictal changes in CAF that are mediated mainly through the parasympathetic nervous system.

Reduplicative paramnesia in patients with focal brain damage.

Reduplicative paramnesia (RP) has drawn attention as a distinct behavioral syndrome caused by focal brain damage. To elucidate the pathogenesis of RP, we assessed its prevalence among patients with focal brain damage and followed those patients with typical RP. Seventy-seven patients with focal brain damage (47 with left hemispheric, 21 with right hemispheric, and 9 with bilateral damage) were assessed for the presence of RP using a questionnaire intended to elucidate this condition. Two patients showed typical RP for place, and four patients showed atypical RP (three for place and one for person); altogether, these six patients constituted 7.8% of the sample. In three patients, the lesions were situated in the right hemisphere; in two, the lesions were bilateral (right dominant); and in one, the lesions were in the left hemisphere, indicating the relative importance of right hemispheric damage and a possible contributory role of additional left hemispheric damage in RP. The case studies of patients with typical RP suggest the heterogeneity of the underlying cognitive factors in RP.

Dreamy states and psychoses in temporal lobe epilepsy: mediating role of affect.

Among 104 patients with temporal lobe epilepsy treated in our clinic between 1992-1995, thirteen patients with repeated dreamy states were evaluated for affective manifestations of dreamy states and their relationship with psychotic states. The types of dreamy states were classified as déjà vu, jamais vu and reminiscence. The affective experiences during dreamy states were evaluated as positive, negative or neutral. As a result, seven patients had déjà vu and/or reminiscence: seizure manifestations in four of these patients were affectively evaluated as positive (familiar and/or pleasurable), and three as neutral. Six cases had experience of jamais vu: five of them were affectively evaluated as negative (mostly fear), and one as neutral. Psychiatrically, only four patients with jamias vu accompanied by feelings of fear had mental disorders: a chronic paranoid-hallucinatory state in two cases, a chronic paranoid state in one case, and obsessive-compulsive symptoms in one case. Other patients who had positive or neutral affect did not demonstrate psychiatric disturbances. Thus, most patients with jamais vu were accompanied by negative affect of fear, and those patients with jamais vu tended to show more psychotic symptoms than those with reminiscence or déjà vu, which were associated with positive or neutral affects. Based on these results, we discuss the possibility that repeated negative feelings associated with jamais vu are one of the causes for developing epileptic psychoses.

A new method of assessing cardiac autonomic function and its comparison with spectral analysis and coefficient of variation of R-R interval.

A new non-linear method of assessing cardiac autonomic function was examined in a pharmacological experiment in ten healthy volunteers. The R-R interval data obtained under a control condition and in autonomic blockade by atropine and by propranolol were analyzed by each of the new methods employing Lorenz plot, spectral analysis and the coefficient of variation. With our method we derived two measures, the cardiac vagal index and the cardiac sympathetic index, which indicate vagal and sympathetic function separately. These two indices were found to be more reliable than those obtained by the other two methods. We anticipate that the non-invasive assessment of short-term cardiac autonomic function will come to be performed more reliably and conveniently by this method.

Functional psychosis mimicking acute confusional state: longitudinal neuropsychological assessment of an acute and transient psychotic patient.

One patient with acute and transient functional psychosis was assessed repeatedly using a brief neuropsychological assessment during his recovery from the psychotic episode. The psychotic features of the patient were characterized by perplexed behavior, attentional disturbance and emotional turmoil. Characteristic findings, including impairment of attention tests, dysgraphia and constructional disturbances, were seen. Findings improved in accordance with recovery on a behavioral level. We discussed the similarity of neuropsychological and behavioral abnormalities of this patient and those of patients in an acute confusional state.