Relationship between choice of timing process and temporal information memory in rats

The effect of the interruption of the timing stimulus (gap) in rats was examined by using the durationdiscrimination task. Rats trained to discriminate the duration of light stimulus (2 or 8s), then breaks of stimulus(0.5, 1, 2, 4, 8s) were inserted. They may restart the entire timing process called “reset" or they may “stop"timing for the duration of the gap. The reset had selected by the expansion of the gap duration. The selection rateof the stop increased in the processing at the gap after having trained the temporal information maintenancetask. These results suggested that the choice of timing processes, reset or stop, depend on the memory of thetemporal information

Event-related potentials of the rat during a passive auditory oddball task

The purpose of this experiment was to examine event-related potentials (ERPs) recoreded from the rat's hippocampus and cerebellum during a passive auditory oddball task. It has beeen predicted that mismatch negativity like (MMN-like) and P3-like components are elicited by the infrequent stimuli in the hippocampus. Further it was questioned that whether MMN-like and P3-like components can be observed at the cerebellum. ERPs recorded from those regions consisted of P1,N1,P2,N2,and P3-like components. P3-like component was obscurely elicited by infrequent stimuli at the hippocampus and the cerebellum. In both regions, a significant difference in N2 amplitude between infrequent and frequent stimuli was observed. N2 component of the rat may correspond with MMN of the human. No significant differences of these components amplitude between infrequent and frequent stimuli were found for other components. N1 latency at the cerebellum was significantly shorter than those in the hippocampus. Correlation analysis revealed that the maximal correlation coefficient between the cerebellum and the hippocampus was obtained at -20.0ms (max : -56,min : -7). This finding suggests that information processing in the cerebellum may be carried out earlier than that in the hippocampus

The Effect of Negative and Positive Emotionality on Associative Memory: An fMRI Study

In general, emotion is known to enhance memory processes. However, the effect of emotion on associative memory and the underling neural mechanisms remains largely unexplored. In this study, we explored brain activation during an associative memory task that involved the encoding and retrieval of word and face pairs. The word and face pairs consisted of either negative or positive words with neutral faces. Significant hippocampal activation was observed during both encoding and retrieval, regardless of whether the word was negative or positive. Negative and positive emotionality differentially affected the hemodynamic responses to encoding and retrieval in the amygdala, with increased responses during encoding negative word and face pairs. Furthermore, activation of the amygdala during encoding of negative word and neutral face pairs was inversely correlated with subsequent memory retrieval. These findings suggest that activation of the amygdala induced by negative emotion during encoding may disrupt associative memory performance

Investigation of Whether Value of Travel Time Increases as Travel Time Increases: Case Study of Modal Choice of Interurban Travelers in Japan

This paper analyzes the variation in the value of travel time savings (VTTS) over travel time by applying the method of empirical discrete choice analysis with nonlinear utility functions. First, it formulates the time allocation model and derives VTTS from the model. The theoretical consideration shows that it is impossible to identify the conditions determining the monotonic change in VTTS over travel time. The paper then examines the variation in VTTS over travel time by using empirical data on choices of interurban travel modes in Japan. The empirical analysis assumes constant marginal utility with respect to income for the first case using the model with a nonlinear utility function and assumes nonconstant marginal utility for the second case using the model with a nonlinear utility function. The first case analysis shows that VTTS decreases as travel time increases. The second case shows that variations in the estimated VTTS over travel time appear to be neutral in the case of rail and airplane users, whereas the estimated VTTS appears to decrease as travel time increases in the case of automobile users. If it is acknowledged that VTTS decreases as travel time increases, the marginal benefit arising from the marginal travel time savings would increase as travel time declines, which implies that society will require additional travel time savings as travel time decreases

The association of motivation with mind wandering in trait and state levels.

Mind wandering (MW) is a phenomenon in which attention drifts away from task-related thoughts toward task-unrelated thoughts. Recent studies have demonstrated that MW occurs during tasks in which participants are unmotivated. However, motivation ranges on a continuum from trait to state. We examined the association between trait-state motivation and trait-state MW. Participants (176 undergraduate students 18-24 years old; 68 male) completed three questionnaires for our trait level investigation. State level indices were measured using the experience sampling method with 104 students completing a sustained attention to response task. Through correlation analyses, we demonstrated an association between motivation and MW within the same dimension (trait and state, respectively) but found no association across dimensions in which the correlation coefficient was nearly zero. We show the significant association between motivation and MW whose novelty is especially evident in the trait level. Although the relationship between motivation and MW is substantial, trait-state dimensionality would be important for them. The state MW is a phasic phenomenon driven by a range of factors, one being state motivation. The causality and confounding factors remain to be further studied

Subjective memory complaints are associated with altered resting-state functional connectivity but not structural atrophy

Research indicates that a subtle cognitive decline, accompanied by pathological changes, occurs in individuals with subjective memory complaints (SMC). However, there is less evidence regarding the measurement of resting-state functional connectivity to detect subtle brain network alterations in neurodegenerative illnesses before cognitive change manifestation. We investigated the correlation between SMC and cognitive performance and explored functional and structural brain changes underlying SMC severity, using behavioral and brain imaging data-driven approaches. We observed that SMC was associated with depression but not with cognitive test scores, implying that SMC represent the “worried-well”; however, this model explains only 15% of the target variance. Using a conservative threshold, we observed connectivity related to SMC severity in the lingual gyrus, cuneus, anterior insula, and superior parietal lobule. Post-hoc analysis indicated that occipital and parietal functional connectivity increased with SMC severity. In contrast, volumetric alterations were not associated with SMC, even after applying a liberal threshold. Our findings suggest that altered resting-state functional connectivity in regions associated with SMC might reflect early compensatory changes that occur before cognitive and structural abnormalities develop. Keywords: Aging, Subjective memory complaints, Resting-state fMRI, Voxel-based morphometry, Depressio

Neural correlates of associative memory: The effects of negative emotion

We explored brain activation associated with negative emotionality, during an associative memory task that involved the encoding and retrieval of word pairs. Participants were instructed to memorize word pairs and subsequently retrieve them. The word pairs consisted of either emotional or neutral words. Significant hippocampal activation was observed during both encoding and retrieval of the neutral word pairs, and was correlated with correct response rates during retrieval. However, the negative word pairs activated the left middle temporal gyrus during both encoding and retrieval. These results suggest that hippocampal activation is involved in both the encoding and retrieval of word pairs. However, negative emotionality does not necessarily enhance hippocampal activity and memory performance

Apathy and Executive Function in Healthy Elderly—Resting State fMRI Study

Apathy is a quantitative reduction in goal-directed behaviors, having three subtypes. Despite executive deterioration in healthy aging, researchers have not investigated the “cognitive-deficit” subtype of apathy in healthy populations, which would result from executive dysfunction. We hypothesized that a relationship between apathy and executive function (EF) would be found in healthy older adults, accompanied with neural deterioration with functional dysconnectivity between the striatum and frontal region as suggested by previous studies. A total of 100 healthy adults in a health examination system database were analyzed. The present study indicates that apathy is substantially associated with executive deterioration, which can be partially ascribed to decreased functional connectivity between the frontal and ventral striatum. Despite some limitations, our findings may contribute to research on healthy psychological aging