Michihiko Koeda

Effects of sports participation on psychiatric symptoms and brain activations during sports observation in schizophrenia

Weight gain has been identified as being responsible for increased morbidity and mortality rates of schizophrenia patients. For the management of weight gain, exercise is one of the most acknowledged interventions. At the same time, exercise and sports have been recognized for their positive impact on psychiatric symptoms of schizophrenia. However, the neurobiological basis for this remains poorly understood. We aimed to examine the effect of sports participation on weight gain, psychiatric symptoms and brain activation during sports observation in schizophrenia patients. Thirteen schizophrenia patients who participated in a 3-month program, including sports participation and 10 control schizophrenia patients were studied. In both groups, body mass index (BMI), Positive and Negative Syndrome Scale (PANSS), and brain activation during observation of sports-related actions measured by functional magnetic resonance imaging were accessed before and after a 3-month interval. BMI and general psychopathology scale of PANSS were significantly reduced in the program group but not in the control group after a 3-month interval. Compared with baseline, activation of the body-selective extrastriate body area (EBA) in the posterior temporal-occipital cortex during observation of sports-related actions was increased in the program group. In this group, increase in EBA activation was associated with improvement in the general psychopathology scale of PANSS. Sports participation had a positive effect not only on weight gain but also on psychiatric symptoms in schizophrenia. EBA might mediate these beneficial effects of sports participation. Our findings merit further investigation of neurobiological mechanisms underlying the therapeutic effect of sports for schizophrenia.

Language Processing and Human Voice Perception in Schizophrenia: A Functional Magnetic Resonance Imaging Study

BACKGROUNDnNeuroimaging studies have demonstrated either reduced left-lateralized activation or reversed language dominance in schizophrenia. These findings of left hemispheric dysfunction could be attributed to language processing tasks, which activate mainly left hemispheric function. Recent functional magnetic resonance imaging studies reported right-lateralized temporal activation by human voice perception, but few studies have investigated activation by human voice in schizophrenia. We aimed to clarify the cerebral function of language processing in schizophrenia patients by considering cerebral activation of human voice perception.nnnMETHODSnFourteen right-handed schizophrenia patients and 14 right-handed controls with matched handedness, sex, and education level were scanned by functional magnetic resonance imaging while listening to sentences (SEN), reverse sentences (rSEN), and identifiable non-vocal sounds (SND).nnnRESULTSnUnder the SEN-SND and SEN-rSEN contrasts including language processing, patients showed less activation of the left hemisphere than controls in the language-related fronto-tempo-parietal region, hippocampus, thalamus and cingulate gyrus. Under the rSEN-SND contrast including human voice perception, patients showed less activation than controls in the right-lateralized temporal cortices and bilateral posterior cingulate.nnnCONCLUSIONSnOur results indicate that schizophrenia patients have impairment of broader bilateral cortical-subcortical regions related to both the semantic network in the left hemisphere and the voice-specific network in the right hemisphere.

Cross-cultural differences in the processing of non-verbal affective vocalizations by Japanese and canadian listeners.

The Montreal Affective Voices (MAVs) consist of a database of non-verbal affect bursts portrayed by Canadian actors, and high recognitions accuracies were observed in Canadian listeners. Whether listeners from other cultures would be as accurate is unclear. We tested for cross-cultural differences in perception of the MAVs: Japanese listeners were asked to rate the MAVs on several affective dimensions and ratings were compared to those obtained by Canadian listeners. Significant Groupu2009×u2009Emotion interactions were observed for ratings of Intensity, Valence, and Arousal. Whereas Intensity and Valence ratings did not differ across cultural groups for sad and happy vocalizations, they were significantly less intense and less negative in Japanese listeners for angry, disgusted, and fearful vocalizations. Similarly, pleased vocalizations were rated as less intense and less positive by Japanese listeners. These results demonstrate important cross-cultural differences in affective perception not just of non-verbal vocalizations expressing positive affect (Sauter et al., 2010), but also of vocalizations expressing basic negative emotions.

Cerebral activation associated with speech sound discrimination during the diotic listening task: An fMRI study

Comprehending conversation in a crowd requires appropriate orienting and sustainment of auditory attention to and discrimination of the target speaker. While a multitude of cognitive functions such as voice perception and language processing work in concert to subserve this ability, it is still unclear which cognitive components critically determine successful discrimination of speech sounds under constantly changing auditory conditions. To investigate this, we present a functional magnetic resonance imaging (fMRI) study of changes in cerebral activities associated with varying challenge levels of speech discrimination. Subjects participated in a diotic listening paradigm that presented them with two news stories read simultaneously but independently by a target speaker and a distracting speaker of incongruent or congruent sex. We found that the voice of distracter of congruent rather than incongruent sex made the listening more challenging, resulting in enhanced activities mainly in the left temporal and frontal gyri. Further, the activities at the left inferior, left anterior superior and right superior loci in the temporal gyrus were shown to be significantly correlated with accuracy of the discrimination performance. The present results suggest that the subregions of bilateral temporal gyri play a key role in the successful discrimination of speech under constantly changing auditory conditions as encountered in daily life.

Cerebral responses to vocal attractiveness and auditory hallucinations in schizophrenia: a functional MRI study

Impaired self-monitoring and abnormalities of cognitive bias have been implicated as cognitive mechanisms of hallucination; regions fundamental to these processes including inferior frontal gyrus (IFG) and superior temporal gyrus (STG) are abnormally activated in individuals that hallucinate. A recent study showed activation in IFG-STG to be modulated by auditory attractiveness, but no study has investigated whether these IFG-STG activations are impaired in schizophrenia. We aimed to clarify the cerebral function underlying the perception of auditory attractiveness in schizophrenia patients. Cerebral activation was examined in 18 schizophrenia patients and 18 controls when performing Favorability Judgment Task (FJT) and Gender Differentiation Task (GDT) for pairs of greetings using event-related functional MRI. A full-factorial analysis revealed that the main effect of task was associated with activation of left IFG and STG. The main effect of Group revealed less activation of left STG in schizophrenia compared with controls, whereas significantly greater activation in schizophrenia than in controls was revealed at the left middle frontal gyrus (MFG), right temporo-parietal junction (TPJ), right occipital lobe, and right amygdala (p < 0.05, FDR-corrected). A significant positive correlation was observed at the right TPJ and right MFG between cerebral activation under FJT minus GDT contrast and the score of hallucinatory behavior on the Positive and Negative Symptom Scale. Findings of hypo-activation in the left STG could designate brain dysfunction in accessing vocal attractiveness in schizophrenia, whereas hyper-activation in the right TPJ and MFG may reflect the process of mentalizing other persons behavior by auditory hallucination by abnormality of cognitive bias.

Interaction effect between handedness and CNTNAP2 polymorphism (rs7794745 genotype) on voice-specific frontotemporal activity in healthy individuals: an fMRI study

Recent neuroimaging studies have demonstrated that Contactin-associated protein-like2 (CNTNAP2) polymorphisms affect left-hemispheric function of language processing in healthy individuals, but no study has investigated the influence of these polymorphisms on right-hemispheric function involved in human voice perception. Further, although recent reports suggest that determination of handedness is influenced by genetic effect, the interaction effect between handedness and CNTNAP2 polymorphisms for brain activity in human voice perception and language processing has not been revealed. We aimed to investigate the interaction effect of handedness and CNTNAP2 polymorphisms in respect to brain function for human voice perception and language processing in healthy individuals. Brain function of 108 healthy volunteers (74 right-handed and 34 non-right-handed) was examined while they were passively listening to reverse sentences (rSEN), identifiable non-vocal sounds (SND), and sentences (SEN). Full factorial design analysis was calculated by using three factors: (1) rs7794745 (A/A or A/T), (2) rs2710102 [G/G or A carrier (A/G and A/A)], and (3) voice-specific response (rSEN or SND). The main effect of rs7794745 (A/A or A/T) was significantly revealed at the right middle frontal gyrus (MFG) and bilateral superior temporal gyrus (STG). This result suggests that rs7794745 genotype affects voice-specific brain function. Furthermore, interaction effect was significantly observed among MFG-STG activations by human voice perception, rs7794745 (A/A or A/T), and handedness. These results suggest that CNTNAP2 polymorphisms could be one of the important factors in the neural development related to vocal communication and language processing in both right-handed and non-right-handed healthy individuals.

Hypofunction of left dorsolateral prefrontal cortex in depression during verbal fluency task: A multi-channel near-infrared spectroscopy study

BACKGROUNDnPrevious functional neuroimaging studies of depression have demonstrated frontotemporal dysfunction, including the dorsolateral prefrontal cortex, while patients perform working memory and language comprehension tasks. Recent near-infrared spectroscopy (NIRS) studies have shown frontotemporal hypofunction in depression by verbal fluency task, but the regions of impairment affecting respective depressive symptoms still remain unclear. We investigated frontotemporal function during word production task in depression with multi-channel NIRS. Further, we aimed to clarify whether any depressive symptoms affect frontotemporal dysfunction.nnnMETHODSnOne hundred seventy-seven major depressive patients and 50 healthy control volunteers participated in this study. Their cerebral activations were compared during verbal fluency task.nnnRESULTSnAlthough performance was not significantly different, hypoactivation in the bilateral frontotemporal regions was significantly observed in depressed patients, compared with controls. Left lateral frontotemporal activation was significantly reduced in the group with mandatory symptom, which is depressed mood, or loss of interest or pleasure, compared with the group that still has residual depressive symptoms in spite MDD having been remitted.nnnLIMITATIONnthe MDD group had significantly higher age and education level than the controls. Conclusions Our findings indicate hypofunction of the bilateral frontotemporal regions in depression during verbal fluency task. Further, hypofunction of these regions in the left hemisphere by this task could reflect whether the subjects recovered from depressed mood, or loss of interest or pleasure.

20 Mazindol effect on cerebral response to nonverbal affective vocalisation in healthy individuals: an fmri study

Background/Aims Mazindol is known as one of the anorexiants for morbid obesity. According to previous study, the pharmacological property is similar to amphetamine, and this drug has an augmenting role of dopamine and serotonin by the inhibition of presynapse transporter. However, the neural basis of how mazindol acts on affective processing has been unclear. We investigated the cerebral response to nonverbal affective vocalisation to clarify the effect of mazindol by functional magnetic resonance imaging (fMRI). Methods 20 healthy subjects (11 males, 9 females: mean age: 28.2u2009years, SD=6.4) participated in this study. The study protocol was approved by the ethics committee of Nippon Medical School, and all subjects provided their informed consent. This experiment was performed by randomised controlled trial. Each subject underwent two fMRI experiments, taking either a placebo or 0.5u2009mg of mazindol 2u2009hours before the scan. For each subject, the two experiments were separated by at least 2u2009weeks. Event-related fMRI experiments were performed in this study. The subjects listened to 3 types of emotional sounds: happy, sad, and neutral sounds. Each subject judged whether the emotional valence was positive, negative, or neutral. Data analysis was performed by statistical parametric mapping (SPM8). Results As for fMRI accuracy, two-way repeated ANOVA (3 emotions×2u2009medications (placebo/mazindol)) showed no significant difference both in main effect of emotion (F (2, 76)=1.22, p>0.05), and in main effect of medication (placebo/mazindol: F (1, 38)=2.01, p>0.05). The fMRI experiment according to two-way repeated ANOVA showed significant difference both in main effect of emotion (F (2, 76)=60.7, p<0.001), and in main effect of medication (placebo/mazindol: F (1, 38)=11.82, p<0.001). In cerebral response, two-way repeated ANOVA showed significant difference in main effect of emotion at the bilateral superior temporal gyrus, and left prefrontal gyrus (p<0.001, uncorrected). In main effect of medication, significant activation was observed at the bilateral medial frontal cortex, bilateral putamen, left superior frontal gyrus, and anterior cingulate (p<0.001, uncorrected). Further interaction effect (emotion × medication) was observed at bilateral caudate (p<0.001, uncorrected). Conclusion According to these results, cerebral function in vocal affective processing was changed by the action of madindol, especially in the area associated with dopaminergic neuron including medial frontal cortex and anterior cingulate.

Effect of apolipoprotein E phenotype on the association of plasma amyloid β and amyloid positron emission tomography imaging in Japan

The plasma concentration of beta‐amyloid (Aβ) has been considered another biomarker of Alzheimers disease and was reportedly associated with cortical Aβ accumulation.

A CASE OF ORGANIC AMNESIC DISORDER SYNDROME DIAGNOSED WITH FMRI

Objective Post-concussion syndrome after traffic accident is often clinically associated with prolonged cognitive impairment due to brain lesions, but sometimes a symptom like amnesia may occur without structural abnormality in neuroimaging. The question is whether cognitive impairment may be caused by subtle lesions that cannot be detected with conventional structural MRI or CT. We report a case in which measurement of cognitive function with functional Magnetic Resonance Imaging (fMRI) was useful to assess the organic origin of an amnesic disorder after concussion. Method A 48 year old female suffered from prolonged memory disturbance after concussion. Her brain structural CT and MRI (T1 and T2) appeared normal. Her consciousness level was alert. Insomnia, physical anxiety, and depressive symptom were not observed. In order to investigate cerebral function with regards to memory processing, we carried out an fMRI study to test working memory (WM) for emotional voice stimuli from the Montreal Affective Voices. Furthermore, the neurobehavioral cognitive status was tested with a battery of neuropsychological tests (Cognistat). Results Brain structural CT and MRI were normal, however, the patients cerebral activation was significantly reduced in the bilateral hippocampi and left inferior frontal gyrus compared to 14 healthy control subjects in the WM vs Rest contrast. Furthermore, amnesic deficits were observed in Cognistat. Conclusion These results demonstrate that fMRI along with neuropsychological assessment is a useful tool to unravel organic origin of an amnesic disorder even if structural brain imaging appears normal.