Structural connectivity between the hippocampus and cortical/subcortical area relates to cognitive impairment in schizophrenia but not in mood disorders

Cognitive impairment in schizophrenia and other psychiatric disorders is a challenge to be overcome in order to maintain patients' quality of life and social function. The neurological pathogenesis of cognitive impairment requires further elucidation. In general, the hippocampus interacts between the cortical and subcortical areas for information processing and consolidation and has an important role in memory. We examined the relationship between structural connectivity of the hippocampus and cortical/subcortical areas and cognitive impairment in schizophrenia, major depressive disorder and bipolar disorder. Subjects comprised 21 healthy controls, 19 patients with schizophrenia, 20 patients with bipolar disorder and 18 patients with major depressive disorder. Diffusion-weighted tensor images data were processed using ProbtrackX2 to calculate the structural connectivity between the hippocampus and cortical/subcortical areas. Cognitive function was assessed using the Brief Assessment of Cognition in schizophrenia composite score. Hippocampal structural connectivity index was significantly correlated with composite score in the schizophrenia group but not in the healthy control, major depressive disorder or bipolar disorder groups. There were no statistically significant differences in hippocampal structural connectivity index between the four groups. Structural connectivity between the hippocampus and cortical/subcortical areas is suggested to be a pathophysiological mechanism of comprehensive cognitive impairment in schizophrenia.     

Effect of a total smoking ban in a maximum security psychiatric hospital

An archival study was performed in a maximum security forensic hospital to evaluate the effects of a total ban on smoking and all tobacco products. One hundred and forty patients were characterized as nonsmokers or light, moderate or heavy smokers. Patient records for the four weeks prior to the ban were compared with their records for the four weeks subsequent to the ban. Numbers of sick calls, total disruptive behaviors and verbal aggression declined markedly and significantly following the ban in those patients previously classified as moderate or heavy smokers. Weight increased significantly, but almost equally regardless of previous smoking status. Patients, and eventually staff, tolerated the smoking ban without significant negative effects. Patients relied very little on treatment modalities to alleviate nicotine withdrawal. Pre-ban apprehension by staff and patients dissipated with time after the smoking ban started.     

Instruction in reliability and magnitude of evaluation parameters at each phase of a sit-to-stand movement

The sit-to-stand movement strategy of each subject is different depending on whether the subjects perform voluntary movements or have concrete instructions (i.e., stand quickly), which is strongly reflected in the performance of each sit-to-stand movement phase. Thirty young-adult male subjects participated in this study (M age=20.7 yr; SD=2.6). Subjects performed the two movements from a chair height adjusted to the subject's lower thigh length. In the self-administered (SA) condition, subjects voluntarily stood up from the chair without instruction, and in the assigned-ordered (AO) condition subjects stood up from the chair as fast as possible. Vertical floor reaction force and electromyograms of the rectus femoris and tibialis anterior muscles were measured, and 15 parameters were selected. The parameters in the phase between the peak value of the floor reaction force and completion of the movement was highly reliable regardless of instruction. However, other parameters had different reliabilities between the instruction conditions. In particular, the parameters in the phase between starting the movement and the peak value of the floor reaction force under the assigned-order were higher than those of the self-administered condition. Moreover, the sit-to-stand movement was conducted faster in the assigned-order condition during the phase between starting the movement and buttocks-syneresis, and the peak value of the floor reaction force and completion of the movement. From the above, in the assigned-order condition "as fast as possible," the anteflexion bending movement and extension of knee and trunk joints were faster, and anteflexion movement was repeated more similarly under a concrete instruction such as moving as fast as possible.     

Mushroom bodies of the honeybee brain show cell population-specific plasticity in expression of amine-receptor genes

Dopamine and octopamine released in the mushroom bodies of the insect brain play a critical role in the formation of aversive and appetitive memories, respectively. As recent evidence suggests a complex relationship between the effects of these two amines on the output of mushroom body circuits, we compared the expression of dopamine- and octopamine-receptor genes in three major subpopulations of mushroom body intrinsic neurons (Kenyon cells). Using the brain of the honeybee, Apis mellifera, we found that expression of amine-receptor genes differs markedly across Kenyon cell subpopulations. We found, in addition, that levels of expression of these genes change dramatically during the lifetime of the bee and that shifts in expression are cell population-specific. Differential expression of amine-receptor genes in mushroom body neurons and the plasticity that exists at this level are features largely ignored in current models of mushroom body function. However, our results are consistent with the growing body of evidence that short- and long-term olfactory memories form in different regions of the mushroom bodies of the brain and that there is functional compartmentalization of the modulatory inputs to this multifunctional brain center.     

Different step-over movement strategies for disturbance stimulations

This study examined differences in performance when 10 healthy adult participants took steps under three different disturbance stimulations (with opened and closed eyes and with the use of light), with and without an obstacle present. In the voluntary condition, participants recognized the obstacle beforehand and stepped over it quickly; in the light condition, participants recognized the obstacle beforehand and quickly stepped over it after light stimulation; in the closed eyes condition, participants did not recognize the obstacle beforehand, but after opening their eyes when hearing a sound, they quickly stepped over the obstacle. The swing time of the gait was significantly longer in obstacle conditions for all stimulations. The swing time was significantly longer under the closed eyes condition than the light and voluntary conditions. The clearances were significantly higher in order of the closed eyes, light, and voluntary conditions in the presence of an obstacle.     

Proposal for a new body sway evaluation method

This study is aimed at examining body sway factors for 1107 healthy people aged 16 to 69 years and to propose a practical body sway evaluation method. The center of foot pressure measurement was carried out twice for 1 min. with a 1-min. rest. 30 parameters with high reliability selected from 6 domains (distance, distribution of amplitude, area, velocity, power spectrum, and body sway vector) were summarized objectively into 4 body sway factors (unit time sway, front-back sway, left-right sway, and high frequency band power). Factor scores were calculated by the estimate equation and the total standard scores of parameters with high factor loadings. Considering this result, a total standard score for each factor was classified into 4 percentile categories based on percentile rank. Using this classification criteria, body sway scores for each individual were classified into any of the above 4 domains for each factor. It was confirmed that young adults mainly belong to percentile Categories A and B and the elderly mainly belong to percentile Categories C and D. It was found that a great effect on body sway occurred when an individual's conscious condition changed (contracting a cold or after exercise). In conclusion, the body sway of healthy people can be explained by these 4 sway factors. An evaluation of the body sway pattern using the 4 sway factors may enable us to concretely understand individuals' disorders and abnormal states in addition to changes in body sway that occur with aging.     

Implicit phonetic symbolism in voicing of consonants and visual lightness using Garner's speeded classification task

The present study examines implicit phonetic symbolism which posits that arbitrary linguistic sound is related to certain aspects of characteristics of other modalities, such as color, touch, or emotion. In consonant discrimination and lightness discrimination using Garner's speeded classification paradigm, spoken sounds (voiced/voiceless consonants) and lightness of visual stimuli (black/white squares) were systematically varied to assess cross-modal interactions. Congruent audio-visual pairs (voiced consonants and black, and between voiceless consonants and white) facilitated consonant discrimination. In lightness discrimination, no congruent facilitation or congruence effect was observed. These results indicated that cross-modal interactions in implicit phonetic symbolism can be found in correlations between linguistic spoken sounds and visual lightness.     

Selection of useful parameters to evaluate center-of-foot pressure movement

This study aimed to objectively summarize the parameters for evaluating the center-of-foot pressure and to select useful parameters with high reliability and validity with 220 healthy university students. In addition, 50 healthy university students were selected to examine cross validity. The measurement of center-of-foot pressure was carried out 3 times with a 1-min. rest and the mean of Trials 2 and 3 was used for the analysis. The data sampling frequency was 20 Hz. 34 parameters were selected from 6 domains: distance, distribution, area, velocity, spectrum, and vector. As a result of factor analysis the following four factors were interpreted: unit time sway, front-back sway, left-right sway and high frequency band sway. Their intraclass correlation coefficients were very high (ICC=.89-.95). Five parameters representing each factor were selected using stepwise selection by regression analysis. There were no significant differences between the mean factor scores estimated by the above five parameters in the original and in cross-validity groups, and relationships between factors in both groups were very high. The center-of-foot pressure may be predicted and systematically evaluated by the above four factors. Five parameters selected from each factor are considered to be useful ones with high validity and practicability.     

The effects of local prevalence and explicit expectations on search termination times

In visual search tasks, the relative proportions of target-present and -absent trials have important effects on behavior. Miss error rates rise as target prevalence decreases (Wolfe, Horowitz, & Kenner, Nature 435, 439-440, 2005). At the same time, search termination times on target-absent trials become shorter (Wolfe & Van Wert, Current Biology 20, 121-124, 2010). These effects must depend on some implicit or explicit knowledge of the current prevalence. What is the nature of that knowledge? In Experiment 1, we conducted visual search tasks at three levels of prevalence (6%, 50%, and 94%) and analyzed performance as a function of "local prevalence," the prevalence over the last n trials. The results replicated the usual effects of overall prevalence but revealed only weak or absent effects of local prevalence. In Experiment 2, the overall prevalence in a block of trials was 20%, 50%, or 80%. However, a 100%-valid cue informed observers of the prevalence on the next trial. These explicit cues had a modest effect on target-absent RTs, but explicit expectation could not explain the full prevalence effect. We conclude that observers predict prevalence on the basis of an assessment of a relatively long prior history. Each trial contributes a small amount to that assessment, and this can be modulated but not overruled by explicit instruction.