The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, ...there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment.
Abstract Recent neuroimaging evidence suggests that the retrieval of a prior episode reactivates sensory-processing brain regions that were active when the episode was encoded. However, with regard ...to reactivation of the medial temporal lobe (MTL), the results remain controversial. In the present study, we used positron emission tomography (PET) to identify the brain regions associated with the encoding and retrieval of motion information. Specifically, we assessed whether overlapping activity was found in both the MTL structures and motion-related cortical regions during the encoding and retrieval of motion information attached to meaningless shapes. During the study, subjects were asked to encode moving (rotating to the right or left) and static meaningless shapes. At subsequent testing, subjects were presented with only static shapes, which had been presented with or without motion during encoding, and were engaged in retrieval tasks of shapes and motion. Overlapping activity was found in the right middle temporal gyrus (V5/MT+) and the left MTL (hippocampus) during the encoding and retrieval of shapes with motion compared with those without motion. These results support the view that the retrieval of specific event information is associated with reactivation of both the MTL and the regions involved during the encoding of that information.
...to identify the neural activity specifically associated with the retrieval of occupations of family members, we performed conjunction analysis of Occupation vs. ...to identify the neural activity ...specifically associated with the retrieval of family relationships, we performed conjunction analysis of Relation vs.
The results indicate that the memory traces for specific event information are stored in the cortices engaged in on-line processing of that information and in the MTL structures binding these ...constituents with each other and with event-specific contextual information. ...the present findings support the view that the retrieval of specific event information is associated with reactivation of both the MTL structures and the regions involved during encoding of the information.
The dynamics of virus interference in
Cucumber mosaic virus (CMV) infection in cowpea were investigated by tissue-blotting and in situ hybridization. Using co-inoculation assays, we discovered that ...spatial competition between CMV-LE (subgroup I) and CMV-m2 (subgroup II) occurred in the inoculated leaves. Interestingly, competitive interactions between the two viruses also could be observed in the non-inoculated upper leaf tissues of the plants. Furthermore, the pattern of exclusive distribution was observed between challenge and protecting viruses in the serially inoculated leaves. Taken together, it is suggested that the dynamics of competitive interactions between the two subgroups could be characterized by exclusive infection and multiplication of the individual viruses in cowpea plants.
Investigating disturbance properties of reaction wheels (RWs), a key component in attitude control system of spacecraft, is important for health monitoring of RWs, exploration of new RWs, designing ...attitude control systems, and so on. In this paper, we first present a recently developed disturbance detector and experiment results for practical RWs. The new detector enables detecting low-frequency disturbances, which was difficult for previous detectors. Next, we will describe dynamics simulation results. In this simulation, we investigate the effects of imperfections such as misalignment, sizing error, and mass imbalances.
Application of green tea extract (GTE) to food preservation was investigated. Viable counts of cucumber pickled overnight at 10degC with seasoning solution containing acetic acid, NaCl, and/or GTE ...were determined during cold storage at 10degC. Viable counts did not increase above the initial values for 7 days of treatment with seasoning solution containing 0.1% acetic acid, 2% NaCl, and 0.05% GTE. Use of these seasoning components alone or in combination showed no bacteriostatic effects on the pickled cucumber. Viable counts of Escherichia coli O157 : H7 did not increase when the cucumber was artificially contaminated with this bacterium and then pickled overnight with the seasoning solution containing 0.1% acetic acid. These results indicated that the addition of GTE to seasoning solution containing both acetic acid and NaCl prolongs the shelf life of overnight pickled cucumber.
PDF
