Characterization of escalated aggression by GABAB receptor activation in the dorsal raphe nucleus
s Neuroscience Research 71S (2011) e108 e415 e283 posterior cingulate activity was significantly higher during proximity to the unfamiliar other than during isolation. The posterior cingulate activity during proximity to the unfamiliar other was marginally correlated with offensive social response during the direct encounter. The present findings suggest that the disparate domains of MCS may be involved in impression and expression of social response in marmosets as similar to human studies, a part of which may be under serotonergic regulation. Research fund: KAKENHI (19591388) doi:10.1016/j.neures.2011.07.1234 P3 p10 Characterization of escalated aggression by GABAB receptor activation in the dorsal raphe nucleus Aki Takahashi 1 Klaus A. Miczek 2, Tsuyoshi Koide 1 1 Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG) Mishima, Japan 2 Tufts University, Medford, MA, USA Violence and escalated forms of aggressive behavior are major issues in public health; violence kills more than 1.6 million people every year worldwide. The serotonin (5 HT) system in the brain has been implicated in the neurobiological mechanisms of escalated aggression. The 5 HT neurons in the mammalian forebrain originate mainly from a midbrain structure, the dorsal raphe nucleus (DRN) Previously, we have shown that pharmacological activation of GABAB receptors in the DRN increased 5 HT release in the medial prefrontal cortex, and also increased aggressive behavior in male mice. In this study, we characterized this escalated aggression in more detail in order to learn whether this aggressive behavior can be affected by (1) previous fighting experiences, (2) the location of the aggressive confrontation, or (3) time of day. Detailed behavioral analysis showed that the intra DRN administration of GABAB receptor agonist baclofen enhanced aggressive behaviors even in animals without fighting experience, and also in unfamiliar surroundings where aggressive behavior is usually inhibited. This escalated aggression induced by baclofen may be characterized as "abnormal" aggression because the animals attacked vulnerable body targets of intruders that are typically not the targets of attack. However, these resident males did not attack females. Thus, intra DRN baclofen specifically escalates inter male aggression in a species atypical manner. We also found that intra DRN baclofen preferentially escalated aggression during the dark period of day (20:0024:00) but not during the light period (12:00 15:30) This may be due to distinct modulation of DRN 5 HT neurons by GABAB receptors at different times of day. To understand the neural pathway involved in the DRN GABAB heightened aggression, we are currently examining cFos expression in several forebrain areas. Research fund: KAKENHI (23683021) doi:10.1016/j.neures.2011.07.1235 P3 p11 Different temporal pattern of information processing about facial emotion conveyed by single neurons between the monkey amygdala and ventrolateral prefrontal cortex Koji Kuraoka Katsuki Nakamura Sec. of Cog. Neurosci. Primate Res. Inst. Kyoto Univ. Inuyama, Japan Face can convey a variety of social information. The recognition of facial emotion and/or identity has been well studied. In the monkey brain, face responsive neurons have been recorded from several areas, such as the inferior temporal cortex (IT) the superior temporal sulcus (STS) the amygdala, and the ventrolateral prefrontal cortex (VLPFC) Among these areas, the amygdala and VLPFC are implicated in the related to social and emotional behavior. However, the details of the processing of facial emotion or identity and the functional differences between these two areas remain unclear. Thus, in this study, we recorded the activity of single neurons from the amygdala and VLPFC while presenting several video clips of three types of facial emotion recorded from three model monkeys. We calculated the amount of information about facial emotion and identity conveyed by neuronal populations in the amygdala and VLPFC. 76 out of 187 (41% neurons in the amygdala and 53 of 102 (52% neurons in the VLPFC responded to the video stimuli. The amount of information about identity conveyed by the VLPFC neurons as well as the amygdala neurons became high immediately after the stimulus presentation. By contrast, the amount of information about facial emotion conveyed by the amygdala neurons sharply increased just after the stimulus presentation whereas that conveyed by the VLPFC neurons increased gradually after stimulus presentation. These results indicate that the monkey VLPFC processes information about facial emotion slower than the amygdala. The amygdala probably uses the emotional information to generate acute emotional behavior while the VLPFC probably uses the information to plan more complex and social behavior. The different temporal pattern of emotional information processing may reflect these functional differences. Research fund: KAKENHI (21120009) doi:10.1016/j.neures.2011.07.1236 P3 p12 RA pacemaker like spontaneous firing modulated song productions in zebra finch Ayako Ajima 1 Raimu Imai 2, Chihiro Mori 2, Kazuhiro Wada 2, Neal A. Hessler 1 1 Lab. for Vocal Behavior Mechanisms, BSI, RIKEN 2 Div. Integrated Life Science, Faculty of Advanced Life Science, Hokkaido Univ Birdsong, like human speech, requires precise control of vocal and respiratory muscles. In a key nucleus of muscle control, the robust nucleus of arcopallium (RA) neurons display a tonic, pacemaker like activity at rest, while activity becomes highly phasic with prolonged silent periods during singing. The aim of this study was to elucidate the function of RA pacemakerlike spontaneous firing on adult song production. We first used brain slices containing RA nucleus to examine electrophysiological properties and found that tonic activity of RA neurons was independent from synaptic inputs. RA neuron contained Ih potassium current, and its pharmacological block reduced the frequency of tonic firing. To examine the effect of tonic activity on singing in vivo, we injected Ih current blocker though implanted cannulae and observed song production and behavior. Block of the Ih current reduced the frequency of singing, but did not alter song structure. We conclude that the frequency of tonic activity of RA neurons is a regulator controlling song production. Neuromodulatory system such as catecholamines may affect the tonic activity, which could control the behavioral state, and level of motivation. To clarify the influences of catecholamines on RA neuron activity and/or singing, we currently measure dopamine/noradrenaline levels in RA by in vivo voltammetry method. doi:10.1016/j.neures.2011.07.1237 P3 p13 Relationship between task performance and prefrontal cortex activity during working memory tasks: An optical topography study Ryuta Aoki 1,2 Hiroki Sato 3, Takusige Katura 3, Ryoichi Matsuda 1, Hideaki Koizumi 3 1 Grad. Sch. of Arts and Sci. Univ. of Tokyo, Tokyo 2 JSPS Res. Fellow 3 Hitachi, Ltd. Central Res. Lab. Saitama Introduction: Prefrontal cortex (PFC) activity during cognitive tasks is known to reflect individual differences in task performance. However, whether better task performance (higher accuracy and faster response speed) is related to greater or lesser PFC activity remains unclear. We investigated the relationship between task performance and PFC activity during spatial and verbal working memory (WM) tasks by using optical topography (OT) a non invasive neuroimaging technique based on near infrared spectroscopy (NIRS) Measurements: Ninety healthy adults (45 women; mean age 33.5 years) performed spatial and verbal WM tasks that had an identical delayed response paradigm. PFC activity was measured using a 52 channel OT system. Analysis: Increases in the oxy hemoglobin (oxy Hb) signal over the baseline values during the WM tasks were used as an index of PFC activation. The magnitude of PFC activation for each channel, task condition, and participant was expressed using z values (converted from t statistics) taking inter trial variability into consideration. Correlations between PFC activity (increases in the oxy Hb signal) and individual performance measures (accuracy and reaction time) were separately assessed for each task condition. Results: We observed significant PFC activation during the WM tasks, especially in the dorsolateral PFC (DLPFC) on both hemispheres. For both WM tasks, PFC activity was positively correlated with accuracy of performance and negatively correlated with reaction time. In particular, the right DLPFC activity during the spatial WM task showed a significant negative correlation with accuracy. Conclusion: We showed that PFC activity during the WM tasks, which was measured using OT, is associated with increased task performance. Our results suggest that OT signals recorded from the PFC reflect higher levels of concentration on ongoing tasks or readiness for upcoming tasks, which leads to better task performance. doi:10.1016/j.neures.2011.07.1238
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