Recording neuronal activity from behaving animals is a powerful technique to understand how neuronal circuitry works in the living organisms. This technique has been developed originally using primates, but is also applicable to rodents, especially transgenic animals. Prof Nambu will talk about their recent studies using this technique, motor functions of the basal ganglia and pathophysiology of movement disorders.

Prof. Kakigi will talk about recent studies on human brain functions using EEG, MEG, fMRI and near-infrared spectroscopy (NIRS), mainly focusing on the following issues.
By recording brain responses to visual, auditory, somatosensory or pain stimuli, the organization of sensory processing in the human brain is being investigated. In particular, our interest is focused on the underlying mechanisms of two-point discrimination, pain perception, visual motion perception, face perception, inhibition processing using Go-NoGo paradigm. Moreover, we recently focused on the development of brain function in infants and children using EEG and NIRS.

Human behaviors in social contexts are complex. They are motivated not only by materialistic rewards but also by abstract social rewards such as good reputation which may be one of the driving forces for altruism unique to human. Despite an increasing focus on the neural basis of human decision-making in neuroscience, relatively little attention has been paid to decision-making in social settings. Moreover, although human social decision-making have been explored in a social psychology context, few neural explanations for the observed findings have been considered.
To bridge this gap and improve models of human social decision-making, we first investigated whether acquiring a good reputation activates the same reward circuitry as monetary rewards. Subjects participated in functional magnetic resonance imaging (fMRI) experiments involving monetary and social rewards. The acquisition of one's good reputation robustly activated reward-related brain areas, notably the striatum, and these overlapped with the areas activated by monetary rewards. This finding indicates that the experienced utilities of both social and monetary rewards are represented in the striatum. Second, to investigate how reputation influence the altruistic behavior such as donation, we investigated the activation of the striatum when individuals freely decided whether to donate to real charities or take the money for themselves in the presence or absence of observers. Underlying idea was that, when choosing an action in social situations, in order to evaluate each action, the brain must convert different types of reward (such as money or reputation) into a common scale. Behavioral evidence showed that the mere presence of observers increased donation rates, and neuroimaging results revealed that activation in the ventral striatum before the same choice ("donate" or "not donate") was significantly modulated by the presence of observers. Particularly high striatal activations were observed when a high social reward was expected (donation in public) and when there was the potential for monetary gain without social cost (no donation in the absence of observers). These findings highlight the importance of the striatum in representing both social and monetary rewards as "decision utility" and add to the understanding of how the brain makes a choice using a "common neural currency" in social situations.

Most proteins exert their physiological functions as a part of a multiprotein complex. The identification of molecular constituents of protein complexes is a critical step in clarifying the molecular mechanisms for various physiological phenomena, including synaptic transmission. Although numerous protein interactions have been identified by yeast two-hybrid screening and pull-down methods, these interactions often include nonphysiological interactions. Here, Prof. Fukata will introduce the several specific purification methods of in vivo protein complexes, such as the advanced tandem affinity purification system. Combined with mass spectrometry, Prof. Fukata and his colleagues have identified various in vivo protein complexes (or protein networks) including ligand-receptor complex.

Focal uncaging of glutamate by laser scanning photostimulation is one of the powerful methods available for the analysis of functional circuits, particularly in neocortex, due to its complicated cellular organization. Here, Prof. Yoshimura will introduce how to map synaptic connectivity in neocortical slice preparations using this method and talk about our recent studies on fine-scale specificity of connections in rat visual cortex.

One of the questions to be answered in the post-genomic era, at a time when most proteins constituting living organisms have been identified, is what particular protein species and amount of each species is expressed in a particular cell type and in their subcellular domains. For subcellular localization that requires nano-scale resolution, pre- and post-embedding immunogold labeling has been widely used. Although these techniques have provided precise details of molecular localization in different subcellular domains, reliable quantification of immunoreactivity has often been hampered by low sensitivity and limited accessibility of antibodies to target molecules buried in tissues. SDS-digested freeze-fracture replica labeling (SDS-FRL) is a new method, by which molecules on the plasma membrane can be directly approached by antibodies and visualized in a two-dimensional manner with high sensitivity and high resolution.