The Organization of Extrinsic Neurons and Their Implications in the Functional Roles of the Mushroom Bodies in Drosophila melanogaster Meigen

Although the importance of the Drosophila mushroom body in olfactory learning and memory has been stressed, virtually nothing is known about the brain regions to which it is connected. Using Golgi and GAL4–UAS techniques, we performed the first systematic attempt to reveal the anatomy of its extrinsic neurons. A novel presynaptic reporter construct, UAS-neuronal synaptobrevin–green fluorescent protein (n-syb–GFP), was used to reveal the direction of information in the GAL4-labeled neurons. Our results showed that the main target of the output neurons from the mushroom body lobes is the anterior part of the inferior medial, superior medial, and superior lateral protocerebrum. The lobes also receive afferents from these neuropils. The lack of major output projections directly to the deutocerebrum’s premotor pathways discourages the view that the role of the mushroom body may be that of an immediate modifier of behavior. Our data, as well as a critical evaluation of the literature, suggest that the mushroom body may not by itself be a “center” for learning and memory, but that it can equally be considered as a preprocessor of olfactory signals en route to “higher” protocerebral regions.     

Apparent body tilt and postural aftereffect

Apparent orientation of the body tilted laterally in the frontal plane was studied with the methods of absolute judgments in four experiments. In Experiment 1, 17 subjects, who maintained the normal adaptation of body to gravity, estimated their body tilts under the condition of seeing the gravitational vertical and under the condition of eliminating it. The results showed that (1) there was not a significant difference between the two conditions and (2) the small tilts of less than 45° were exactly estimated, whereas the large tilts of 45°–108° were overestimated. In Experiment 2,10 subjects estimated their body tilts under three velocities of a rotating chair on which each subject was placed. Although both body tilt and chair velocity were found to influence tilt estimation, the effect of body tilt was overwhelmingly greater than that of chair velocity. In Experiment 3, 11 subjects adapted their bodies to a 72° left tilt for 10 min and then estimated various body tilts around the adapting tilt. The estimations obtained under the 72° adaptation were lower than those obtained under the 0° adaptation, and this reduction was greater for the test tilt that was farther away from the adapting tilt. In Experiment 4, 11 subjects adjusted their own body tilts to designated angles. The results confirmed the outcomes of absolute estimation in Experiments 1-3. From these findings and past literature, the judgments of body tilt were considered to be subserved by a single sensory process that was based on the cutaneous and muscular proprioceptors, rather than the vestibular and joint proprioceptors.     

Evaluation of third-party reciprocity by squirrel monkeys (<Emphasis Type="Italic">Saimiri sciureus</Emphasis>) and the question of mechanisms

Social evaluation during third-party interactions emerges early in human ontogeny, and it has been shown in adult capuchin monkeys who witness violations of reciprocity in object exchanges: Monkeys were less inclined to accept food from humans who refused to reciprocate with another human. A recent study reporting similar evidence in marmoset monkeys raised the possibility that such evaluations might be based on species’ inherent cooperativeness. We tested a species not renowned for cooperativeness—squirrel monkeys—using the procedure used with marmosets and found a similar result. This finding rules out any crucial role for cooperative tendencies in monkeys’ responses to unfair exchanges. We then tested squirrel monkeys using procedures more similar to those used in the original study with capuchins. Squirrel monkeys again accepted food less frequently from non-reciprocators, but unlike capuchins, they also strongly preferred reciprocators. We conclude that neither squirrel monkeys nor marmoset monkeys engaged in emotional bookkeeping of the type that probably underlies social evaluation in capuchin monkeys; instead, they employed one or more simple behavioral rules. Further comparative studies are required to clarify the mechanisms underlying social evaluation processes across species.     

Avoidance behavior associated with depressive symptoms in patients with implantable cardioverter defibrillators

Objective: Many patients with implantable cardioverter defibrillators experience depressive symptoms. In addition, avoidance behavior is a common problem among patients with implantable cardioverter defibrillators. We examined the association between avoidance behaviors and depressive symptoms in patients with implantable cardioverter defibrillators. Method: We conducted a single-center, cross-sectional study with self-completed questionnaires between May 2010 and March 2011. We measured avoidance behaviors (avoidance of places, avoidance of objects, and avoidance of situations) and depressive symptoms (using the Beck Depression Inventory, Version II) in 119 participants. An avoidance behaviors instrument was developed for this study and we confirmed its internal consistency reliability. Results: Ninety-two (77.3%) patients were aged older than 50 years, and 86 (72.3%) were men. Fifty-one (42.9%) patients reported “avoidance of places”, 34 (28.6%) reported “avoidance of objects”, and 63 (52.9%) reported “avoidance of activity”. Avoidance behavior was associated with increased odds for the presence of depressive symptoms (OR 1.31; 95% CI 1.06–1.62). Conclusions: This was the first study to identify the relationship between avoidance behavior and depressive symptoms among patients with implantable cardioverter defibrillators; however, there are a few methodological limitations.     

Automatic auditory disambiguation of visual awareness

Multisensory integration can play a critical role in producing unified and reliable perceptual experience. When sensory information in one modality is degraded or ambiguous, information from other senses can crossmodally resolve perceptual ambiguities. Prior research suggests that auditory information can disambiguate the contents of visual awareness by facilitating perception of intermodally consistent stimuli. However, it is unclear whether these effects are truly due to crossmodal facilitation or are mediated by voluntary selective attention to audiovisually congruent stimuli. Here, we demonstrate that sounds can bias competition in binocular rivalry toward audiovisually congruent percepts, even when participants have no recognition of the congruency. When speech sounds were presented in synchrony with speech-like deformations of rivalling ellipses, ellipses with crossmodally congruent deformations were perceptually dominant over those with incongruent deformations. This effect was observed in participants who could not identify the crossmodal congruency in an open-ended interview (Experiment 1) or detect it in a simple 2AFC task (Experiment 2), suggesting that the effect was not due to voluntary selective attention or response bias. These results suggest that sound can automatically disambiguate the contents of visual awareness by facilitating perception of audiovisually congruent stimuli.     

Mental Health Inventory for Infants: Scale Development and Japanese Infants’ Characteristics

Early detection and treatment promote positive outcomes in mental health problems among infants. This study developed a simple and reliable screening inventory for infants’ mental health. Participants were 579 primary caregivers who had Japanese infants aged 2–6 years. Participants evaluated their children using the Mental Health Inventory for Infants (MHII; developed in this study), which contains 24 items. Exploratory factorial analysis identified the MHII factor structure; confirmatory factorial analysis examined its factorial validity. Internal consistency and criterion-related validity were also examined. Irritability (8 items), somatic symptoms (6 items), and signs of insecurity (4 items) were identified as factors in the MHII; each of these factors measures a critical aspect of infants’ mental health. The MHII’s internal consistency and scale homogeneity were acceptable; its criterion-related validity was supported. In this study, male infants exhibited greater irritability and less insecurity than females. The present results support the MHII’s reliability and validity; additionally, they indicate that caregivers may use the MHII to quickly screen for three critical aspects of infants’ mental health. We expect that the MHII will be used for early detection of mental health difficulties in infants to facilitate treatment.     

Do bantams (Gallus gallus domesticus) amodally complete partly occluded lines? An analysis of line classification performance

Humans perceive a line touching an edge of a large rectangle longer than the reality. Kanizsa (1979) has suggested that this illusion occurs because we perceive that the line is partly "hidden" behind the rectangle and automatically completes it. We tested whether bantams (Gallus gallus domesticus) would experience this perceptual phenomenon using a line classification task on the touch monitor, which was used in our previous study with rhesus monkeys and pigeons (Fujita, 2001). We trained three bantams to classify six lengths of black target lines into two categories, "short" or "long," ignoring a gray rectangle (Experiment 1) or a gray area (i.e., a left or a right half of the monitor was filled with gray; Experiment 2) located at the same distance (8 pixels) from the target line. In the test, the gap between the line and the gray rectangle (or area) sometimes changed (0, 4, or 8 pixels; we labeled these stimuli as G0, G4, and G8 respectively). Both of the two successfully trained bantams showed an illusion for G0, but the direction of illusion was reversed; that is, they judged the line in G0 to be "shorter" than that in G4 and G8. Further analyses proved that neither the gaps between the target line and the gray rectangle nor the total widths of the stimuli could account for the bantams' responses. These results suggest that bantams do not complete the "occluded" portion even when identification of its shape is not required.     

Is lesion of Exner's area linked to progressive agraphia in amyotrophic lateral sclerosis with dementia? An autopsy case report

Agraphia, as a neuropsychological symptom of ALS, especially ALS with dementia (ALS-D), has recently attracted more attention. However, the brain lesion responsible has not been identified. Here we present an autopsy case of ALS-D of a patient with obvious agraphia, without aphasia, that also presented cerebrospinal degeneration with TDP-43-pathology compatible with ALS-D. Of the pre-motor frontal lobe cortices, degeneration and immuno-histochemical pathology were most obvious in the caudal area of the left middle frontal gyrus, or Exner's area. Assuring this area plays a pivotal role in the kanji and kana formation used in writing the Japanese language, this case of ALS-D showed both agraphia and Exner's area stressed pathological lesions. It may thus be the first case to indicate an intimate relationship between the neuropsychological symptoms and an associated lesion for ALS-D.     

Tufted capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>) show understanding of human attentional states when requesting food held by a human

Researchers have investigated to what extent non-human primates understand others’ attentional states, as this ability is considered an important prerequisite for theory of mind. However, previous studies using food requesting tasks have failed to show that non-human primates attribute perception to others as a function of their attentional states. One possible reason is that food requesting tasks may require subjects not only to take into account an experimenter’s attentional state but also to direct it toward the food. The present study tested tufted capuchin monkeys’ (Cebus apella) understanding of others’ attentional states in a food requesting task. In the first situation, monkeys were required only to attract an experimenter’s attention. In the second situation, the monkeys were required to both attract the experimenter’s attention and direct it toward food on a table. The results revealed that capuchin monkeys showed evidence of understanding the experimenter’s attentional variations only in the former condition. This suggests that previous tasks, requiring referential gestures, lacking in most non-human primates, failed to reveal sensitivity to human attentional states because the subjects might not have understood the requesting situation. In conclusion, capuchin monkeys can understand variations in others’ attentional states, although this ability appears limited compared to what is seen in humans.     

Sex differences in audiovisual discrimination learning by Bengalese finches (Lonchura striata var. domestica)

Both visual and auditory information are important for songbirds, especially in developmental and sexual contexts. To investigate bimodal cognition in songbirds, the authors conducted audiovisual discrimination training in Bengalese finches. The authors used two types of stimulus: an "artificial stimulus," which is a combination of simple figures and sound, and a "biological stimulus," consisting of video images of singing males along with their songs. The authors found that while both sexes predominantly used visual cues in the discrimination tasks, males tended to be more dependent on auditory information for the biological stimulus. Female responses were always dependent on the visual stimulus for both stimulus types. Only males changed their discrimination strategy according to stimulus type. Although males used both visual and auditory cues for the biological stimulus, they responded to the artificial stimulus depending only on visual information, as the females did. These findings suggest a sex difference in innate auditory sensitivity.