Katsuki Nakamura

Vocal identification of speaker and emotion activates differerent brain regions

REGIONAL cerebral blood flow was measured in six healthy volunteers by positron emission tomography during identification of speaker and emotion from spoken words. The speaker identification task activated several audio-visual multimodal areas, particularly the temporal poles in both hemispheres, which may be involved in connecting vocal attributes with the visual representations of speakers. The emotion identification task activated regions in the cerebellum and the frontal lobe, suggesting a functional relationship between those regions involved in emotion. The results suggest that different anatomical structures contribute to the vocal identification of speaker and emotion.

Recognition of emotion from facial, prosodic and written verbal stimuli in Parkinson's disease.

Although the basal ganglia are thought to be important in recognizing emotion, there is contradictory evidence as to whether patients with Parkinsons disease (PD) have deficits in recognizing facial expressions. In addition, few studies have examined their ability to recognize emotion from non-visual stimuli, such as voices. We examined the ability of PD patients and age-matched controls to recognize emotion in three different modalities: facial, prosodic, and written verbal stimuli. Compared to controls, PD patients showed deficits in recognizing fear and disgust in facial expressions. These impairments were not seen in their recognition of prosodic or written verbal stimuli. This modality-specific deficit suggests that the neural substrates for recognizing emotion from different modalities are not fully identical.

The primate temporal pole: its putative role in object recognition and memory

In this article, we consider both the ventral temporopolar cortex and the perirhinal cortex (areas 35 and 36) as the anterior ventromedial temporal (aVMT) cortex, and discuss its role based on recent data in monkeys and human subjects. In monkeys, the aVMT cortex receives its primary input from area TE, and only minor input from other cortical areas. Laminar patterns of connections suggest that the aVMT cortex is a hierarchically higher-order area than area TE. Lesions of this cortex produce deficits in the learning and performance of visual memory tasks. Neurons in the aVMT cortex respond selectively to complex stimuli and changes in activity related to visual memory tasks. In humans, damage of this cortex induces deficits in the recognition of familiar objects and faces. The aVMT cortex is activated during recognition of familiar faces. In addition, the aVMT cortex is one of the most vulnerable areas in Alzheimers disease. All these data indicate that the aVMT cortex is a higher-order visual cortical area that is related to object recognition and memory. The anterior area TE has been implicated in both functions. We propose here that these areas and the anterior entorhinal cortex are designated as the temporal pole, a brain region which is specialized for both object recognition and memory.

Neuroanatomical correlates of the assessment of facial attractiveness.

FRONTAL cortical damage can lead to changes in affective aspects of personality. However, the difficulty of dissociating such abnormalities from cognitive disorders has overshadowed most previous findings. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) while normal subjects were assessing facial attractiveness. Two left frontal regions showed a significant increase in rCBF while assessing facial attractiveness. The increased rCBF in the left anterior frontal cortex correlated with the overall percentage of assessments of a face as unattractive, while that in the left fronto-temporal junction correlated with the percentage of assessments of a face as attractive. These findings provide direct evidence that the left frontal regions are engaged in the assessment of facial attractiveness.

Oscillatory neuronal activity related to visual short-term memory in monkey temporal pole

The activity of single neurons was recorded extracellularly from the temporal pole of monkeys while they were performing a visual short-term memory task. Neurons in the ventral part of the temporal pole showed sustained firing during the memorization delay period of the task when the monkey was remembering particular visual stimuli. The presence and absence of the firing were correlated with the correct and incorrect performance of the task, respectively. The sustained firing showed oscillation. The data suggest that visual information was stored as sustained firing among certain group of neurons producing oscillations.

The use of nasal skin temperature measurements in studying emotion in macaque monkeys.

Using an infrared thermographic system, we have demonstrated, as previously reported, that temperatures in the nasal region of macaque monkeys decrease during negative emotional states, such as when facing a threatening person. In this study, we explored the usefulness of measuring nasal skin temperatures in studies of monkey emotions as manifested by conspecific emotional behaviors and expressions. We measured nasal skin temperatures of rhesus monkeys (Macaca mulatta) in response to video clips, all showing monkeys: a raging individual (Experiment 1), three distinct emotional expressions (Experiment 2), and only faces or voices representing a threat (Experiment 3). We found that nasal skin temperatures significantly decreased in response to a threatening stimulus, even when the stimulus was a 2D image with digitized sound, similar to those used in many psychological or neurophysiological studies on animal emotion. Moreover, species-specific aggressive threats invariably elicited a decrease in nasal skin temperatures and skin conductance responses; however, screams or coos did not elicit this response. Simultaneous perception of both facial expressions and vocalizations induced a more prominent decrease in nasal skin temperatures than did the perception of facial expressions or vocalizations alone. Taken together, these data suggest that decreased nasal skin temperatures should be added to the list of indicators of emotional states in animals.

The marmoset monkey: a multi-purpose preclinical and translational model of human biology and disease.

The development of biologic molecules (monoclonal antibodies, cytokines, soluble receptors) as specific therapeutics for human disease creates a need for animal models in which safety and efficacy can be tested. Models in lower animal species are precluded when the reagents fail to recognize their targets, which is often the case in rats and mice. In this Feature article we will highlight the common marmoset, a small-bodied nonhuman primate (NHP), as a useful model in biomedical and preclinical translational research.

Phased processing of facial emotion: an ERP study.

We examined the temporal characteristics of facial-emotion processing. The stimuli were several morphed images containing seven facial emotions (neutral, anger, happiness, disgust, sadness, surprise, and fear) and ten-graded intensity levels to parametrically control these aspects of facial emotions. Brain activity was recorded with electroencephalography as the subjects detected the facial emotion and assessed its intensity. We found that the temporal profile of detection was quite different from the assessment of intensity. A positive component 100 ms after stimulus onset (P100) was significantly correlated with the correct detection of facial emotion, whereas a negative component 170 ms after stimulus onset (N170) was significantly correlated with the assessment of intensity level. The source of both the P100 and N170 signals was consistently localized to the right occipito-parietal region. We propose phased processing of facial emotion, in which rapid detection of any facial emotion occurs within 100 ms and detailed processing, including the assessment of the intensity, occurs shortly afterwards.

Oxytocin changes primate paternal tolerance to offspring in food transfer

Oxytocin facilitates social recognition in rats and mice, onset of maternal behavior in virgin mice and formation of pair bonds without copulation in prairie voles. However, the relationship between this peptide and paternal behavior in primates remains largely unknown. We investigated whether oxytocin affects paternal behavior in common marmosets. In these primates, fathers as well as mothers take care of their infants, and transferring food to the infants is one of their more obvious caretaking behaviors. We tested whether oxytocin and an oxytocin receptor antagonist affect the transfer of food to offspirng by fathers. After intracerebroventricular infusion of the vehicle, oxytocin, or the oxytocin receptor antagonist, the fathers’ behavior, including picking up food, transferring food to the offspring, and refusing to transfer food to the offspring, was analyzed. Compared with the vehicle, oxytocin reduced the frequency of refusal. This was not caused by reduction of appetite. Although the oxytocin receptor antagonist did not change the frequency of refusal behavior of the fathers statistically significant manner, these observations suggest that the tolerance of the adult male marmoset toward its offspring as shown by the transfer of food is increased by oxytocin administered into the central nervous system.

Different time course between scene processing and face processing: a MEG study.

Using magnetoencephalography (MEG), the neural response to scenes was recorded and compared with that to faces. The prominent MEG signals in response to scenes appeared 200-300 ms after the stimulus presentation while those in response to faces appeared between 150 and 200 ms. Source locations of the signals were estimated in the right parahippocampal and parieto-occipital regions with a latency of 300 ms for the scene response, whereas those were estimated in the lingual or fusiform gyri bilaterally with a latency of 160 ms for the face response. These data suggest that both the temporal and parietal regions process scenes, while the occipito-temporal regions process faces, and that scene processing takes a longer time than face processing.