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Author (up) Adachi, R.; Osada, H.; Shingai, R. file  url
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  Title Phase-dependent preference of thermosensation and chemosensation during simultaneous presentation assay in Caenorhabditis elegans Type Journal Article
  Year 2008 Publication BMC Neuroscience Abbreviated Journal BMC Neurosci  
  Volume 9 Issue Pages 106  
  Keywords Animals; Caenorhabditis elegans; Chemotactic Factors; Chemotaxis--physiology; Choice Behavior; Cold Temperature; Pentanols; Psychomotor Performance--physiology; Sensation; Sensory Receptor Cells--physiology; Sodium Chloride; Thermosensing--physiology  
  Abstract BACKGROUND: Multi-sensory integration is necessary for organisms to discriminate different environmental stimuli and thus determine behavior. Caenorhabditis elegans has 12 pairs of amphid sensory neurons, which are involved in generating behaviors such as thermotaxis toward cultivation temperature, and chemotaxis toward chemical stimuli. This arrangement of known sensory neurons and measurable behavioral output makes C. elegans suitable for addressing questions of multi-sensory integration in the nervous system. Previous studies have suggested that C. elegans can process different chemoattractants simultaneously. However, little is known about how these organisms can integrate information from stimuli of different modality, such as thermal and chemical stimuli. RESULTS: We studied the behavior of a population of C. elegans during simultaneous presentation of thermal and chemical stimuli. First, we examined thermotaxis within the radial temperature gradient produced by a feedback-controlled thermoregulator. Separately, we examined chemotaxis toward sodium chloride or isoamyl alcohol. Then, assays for simultaneous presentations of 15 degrees C (colder temperature than 20 degrees C room temperature) and chemoattractant were performed with 15 degrees C-cultivated wild-type worms. Unlike the sum of behavioral indices for each separate behavior, simultaneous presentation resulted in a biased migration to cold regions in the first 10 min of the assay, and sodium chloride-regions in the last 40 min. However, when sodium chloride was replaced with isoamyl alcohol in the simultaneous presentation, the behavioral index was very similar to the sum of separate single presentation indices. We then recorded tracks of single worms and analyzed their behavior. For behavior toward sodium chloride, frequencies of forward and backward movements in simultaneous presentation were significantly different from those in single presentation. Also, migration toward 15 degrees C in simultaneous presentation was faster than that in 15 degrees C-single presentation. CONCLUSION: We conclude that worms preferred temperature to chemoattractant at first, but preferred the chemoattractant sodium chloride thereafter. This preference was not seen for isoamyl alcohol presentation. We attribute this phase-dependent preference to the result of integration of thermosensory and chemosensory signals received by distinct sensory neurons.  
  Call Number Serial 262  
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Author (up) Cunnington, R.; Windischberger, C.; Robinson, S.; Moser, E. file  url
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  Title The selection of intended actions and the observation of others' actions: a time-resolved fMRI study Type Journal Article
  Year 2006 Publication NeuroImage Abbreviated Journal Neuroimage  
  Volume 29 Issue 4 Pages 1294-1302  
  Keywords Adult; Arousal--physiology; Attention--physiology; Brain Mapping; Contingent Negative Variation--physiology; Female; Gestures; Gyrus Cinguli--physiology; Humans; Image Interpretation, Computer-Assisted; Imagination--physiology; Imitative Behavior--physiology; Intention; Magnetic Resonance Imaging; Male; Motor Cortex--physiology; Nerve Net--physiology; Parietal Lobe--physiology; Prefrontal Cortex--physiology; Psychomotor Performance--physiology; Set (Psychology); Visual Cortex--physiology; Visual Pathways--physiology  
  Abstract Whenever we plan, imagine, or observe an action, the motor systems that would be involved in preparing and executing that action are similarly engaged. The way in which such common motor activation is formed, however, is likely to differ depending on whether it arises from our own intentional selection of action or from the observation of another's action. In this study, we use time-resolved event-related functional MRI to tease apart neural processes specifically related to the processing of observed actions, the selection of our own intended actions, the preparation for movement, and motor response execution. Participants observed a finger gesture movement or a cue indicating they should select their own finger gesture to perform, followed by a 5-s delay period; participants then performed the observed or self-selected action. During the preparation and readiness for action, prior to initiation, we found activation in a common network of higher motor areas, including dorsal and ventral premotor areas and the pre-supplementary motor area (pre-SMA); the more caudal SMA showed greater activation during movement execution. Importantly, the route to this common motor activation differed depending on whether participants freely selected the actions to perform or whether they observed the actions performed by another person. Observation of action specifically involved activation of inferior and superior parietal regions, reflecting involvement of the dorsal visual pathway in visuomotor processing required for planning the action. In contrast, the selection of action specifically involved the dorsal lateral prefrontal and anterior cingulate cortex, reflecting the role of these prefrontal areas in attentional selection and guiding the selection of responses.  
  Call Number Serial 69  
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