The cerebellum: from structure to control

edited by C.I. De Zeeuw, P. Strata and J. Voogd, Elsevier, 1998. ￡125.00 (xii+610 pages) ISBN 0 444 82313.     

Perception of emotional tears with body postures,visual scenes,and written scenarios

Emotional tears tend to increase perceived sadness in facial expressions. However, it is unclear whether tears would still be seen as an indicator of sadness when a tearful face is observed in an emotional context (e.g., a touching moment during a wedding ceremony). We examine the influence of context on the sadness enhancement effect of tears in three studies. In Study 1, participants evaluated tearful or tearless expressions presented without body postures, with emotionally neutral postures, or with emotionally congruent postures (i.e., postures indicating the same emotion as the face). The results show that the presence of tears increases the perceived sadness of faces regardless of context. Similar results are found in Studies 2 and 3, which used visual scenes and written scenarios as contexts, respectively. Our findings demonstrate that tears on faces reliably indicate sadness, even in the presence of contextual information that suggests non-sadness emotions.     

Effects of type of cognitive demand on bilateral advantage in interhemispheric processing

The relationship between cognitive task demand and effect of bilateral advantage (BLA) was examined. In Experiment 1, the task demand based upon visual stimulus complexity was manipulated. One-digit and two-digit numbers were presented in the left, right or both visual fields tachistoscopically and subjects were requested to identify the numbers. The results showed no BLA, although a right visual field advantage was demonstrated. In Experiment 2, cognitive demand in terms of memory was manipulated. Subjects were asked to recall one-digit numbers that were presented successively once, three and five times in the left, right or the both visual fields. The results did not show any sign of BLA in the recall of numbers. In Experiment 3, a greater memory load task was given than that in Experiment 2, where two-digit numbers were presented successively (once, three and five times). Subjects were asked to recall the numbers. The results showed a significant BLA in the recall of numbers, i.e., the correct numbers in the correct temporal positions. These results strongly suggest that a benefit of redundant bilateral visual fields presentation is shown only in a highly cognitively demanding task, especially when it involves phonological memory loads.     

Dopamine D1 receptors regulate protein synthesis-dependent long-term recognition memory via extracellular signal-regulated kinase 1/2 in the prefrontal cortex

Several lines of evidence suggest that extracellular signal-regulated kinase1/2 (ERK1/2) and dopaminergic system is involved in learning and memory. However, it remains to be determined if the dopaminergic system and ERK1/2 pathway contribute to cognitive function in the prefrontal cortex (PFC). The amount of phosphorylated ERK1/2 was increased in the PFC immediately after exposure to novel objects in the training session of the novel object recognition test. An inhibitor of ERK kinase impaired long-term recognition memory 24 h after the training although short-term memory tested 1 h after the training was not affected by the treatment. The dopamine D1 receptor agonist increased ERK1/2 phosphorylation in the PFC in vivo as well as in cortical neurons in vitro. Microinjection of the dopamine D1 receptor antagonist into the PFC impaired long-term recognition memory whereas the D2 receptor antagonist had no effect. Immunohistochemistry revealed that exposure to novel objects resulted in an increase in c-Fos expression in the PFC. Microinjection of the protein synthesis inhibitor anisomycin into the PFC impaired the long-term recognition memory. These results suggest that the activation of ERK1/2 following the stimulation of dopamine D1 receptors is necessary for the protein synthesis-dependent long-term retention of recognition memory in the PFC.     

A randomized controlled trial on the long-term effects of a 1-month behavioral weight control program assisted by computer tailored advice

OBJECTIVES: To examine the long-term effects of a new behavioral weight control program (Kenkou-tatsujin, KT program). The program consisted of twice-interactive letter communications including computer-tailored personal advice on treatment needs and behavioral modification. DESIGN: A randomized controlled trial comparing Group KM: KT program with 6-month weight and targeted behavior's self-monitoring, Group K: KT program only, Group BM: an untailored self-help booklet with 7-month self-monitoring of weight and walking, and Group B: the self-help booklet only. PARTICIPANTS: Two hundreds and five overweight Japanese females were recruited via a local newspaper. MEASUREMENTS: Weight loss (body weight, BMI, reduction quotient, etc.) and behavioral changes (daily eating, exercise and sleeping habits). FINDINGS: A significant weight loss was observed in all groups. At 1 month, Groups KM and K were superior, but at 7 months, the mean weight loss was significantly more in Group KM than the other 3 groups. At 7 months, 8 dietary habits and 4 physical activities were improved in all subjects. Habitual improvement was related to the weight loss in Groups KM and K at 1 month.     

Multiple Cues in Social Perception: The Time Course of Processing Race and Facial Expression

The purpose of the present study was to examine the time course of race and expression processing to determine how these cues influence early perceptual as well as explicit categorization judgments. Despite their importance in social perception, little research has examined how social category information and emotional expression are processed over time. Moreover, although models of face processing suggest that the two cues should be processed independently, this has rarely been directly examined. Event-related brain potentials were recorded as participants made race and emotion categorization judgments of Black and White men posing either happy, angry, or neutral expressions. Our findings support that processing of race and emotion cues occur independently and in parallel, relatively early in processing.     

Velocity-dependent EMG activity of masseter and sternocleidomastoideus muscles during a ballistic arm thrusting movement

Two experiments were conducted to investigate the functional relationship between the general somatic motor function and the oral motor function. In Experiment 1, we analyzed the relationship between the amount of masseter muscle (MSS) activity and the velocity of a ballistic, 'karate-do' arm thrusting movement (ThrMov). ThrMov velocity was measured from video images taken with a high-speed CCD camera at a frequency of 500Hz. EMGs of MSS and sternocleidomastoideus (SCM) muscles as well as other related muscles were recorded simultaneously with video images in 6 varsity 'karate-do' athletes. Pearson's correlation coefficients were calculated between EMG amplitude and movement velocity. EMG activity of MSS as well as the other muscles increased as a function of ThrMov velocity in all participants, as evidenced by highly significant (p<.01) correlation coefficients, ranging from .64 to .87 (mean: .75). MSS EMG activity attained during ThrMovs performed at maximum velocity ranged between 14.6% and 113.8% of this muscle's MVC (45.7+/-39.3% MVC, mean+/-SD). SCM was also strongly active and closely associated with MSS. Besides changes in amount of EMG activity, it was further found that R-MSS EMG onset progressively shifted to the earlier phase of the ThrMov as ThrMov velocity increased. EMG onset time of R-MSS as well as R- and L-SCMs was negatively correlated with ThrMov velocity; when performed at maximum velocity MSS activation preceded the start of ThrMov by more than 100ms, whereas MSS was recruited last at approximately 150ms after the start of ThrMov when performed at moderate speed ( approximately 50% of maximum). In Experiment 2, the effects of head movement relative to the trunk on R-MSS and SCMs EMG activity were tested in both gazing and sidelong glancing conditions. A much smaller head rotation relative to the trunk was necessary during the ThrMov in the sidelong glancing condition compared to the gazing condition. R-MSS EMG activity was affected significantly by the difference between these conditions and decreased by 5.2% MVC in the sidelong glancing condition compared to the gazing condition. In association with the change in requirement for head movement between those conditions, EMG balance between the bilateral SCMs changed substantially. Finally, marked muscle activity during ThrMov was found in the MSS that was not directly involved in performing this movement, indicating a form of 'remote facilitation'.     

Online/offline self-disclosure to offline friends and relational outcomes in a diary study: The moderating role of self-esteem and relational closeness

Previous work suggests that the experiences of online and offline self-disclosure are heterogeneous among individuals. Yet little work has been done to identify the moderating role of individual characteristics and pre-existing relationship characteristics on the diverse relational outcomes. The present study using a 7-day diary design examined whether individuals' self-esteem level and relational closeness would moderate the relationships between online and offline self-disclosure to offline friends and two relational outcomes, that is, relationship satisfaction and trust in friendships. The analyses on 686 diary responses from 98 participants revealed that offline self-disclosure generally predicted greater relationship satisfaction and trust in friendships, whereas the role of online self-disclosure was not statistically significant. More importantly, self-esteem moderated the pattern associated with offline self-disclosure but not that with online self-disclosure. Specifically, offline self-disclosure predicted greater benefits to people with lower self-esteem relative to people with higher self-esteem. Moreover, pre-existing relational closeness moderated the relationship between offline self-disclosure and trust in friendships such that casual friendships benefited more from offline self-disclosure than close friendships did. The present study highlights the importance of personal characteristics and relationship characteristics in understanding the heterogeneous relational influence of different communication modes.     

Cortical shape adaptation transforms a circle into a hexagon: a novel afterimage illusion

After viewing a colored figure on a uniform gray background, an observer will see a negative afterimage after the colored figure disappears. This study shows that the shapes of afterimages vary systematically according to the shape of the adaptation stimuli, a phenomenon that could be caused only by cortical shape adaptation. In the experiments reported here, participants typically saw a hexagonal afterimage after viewing a circle and sometimes saw a circular afterimage after viewing a hexagon. When observers were adapted to rotating circles or hexagons, which produced the same circular retinal painting, they reliably reported that afterimages of circles appeared as hexagons, and vice versa. Furthermore, the fact that this effect also arose through interocular transfer confirms that a cortical process with binocular inputs must have contributed to it. This novel finding reveals that afterimage formation is determined mainly by a cortical process, not by retinal bleaching, and that rival mechanisms detect corners and curves of shapes in cortical processing.     

Ab initio pseudopotential studies on an Al Σ = 9 grain boundary: Effects of Na and Ca impurities

The electronic properties of an Al = 9 tilt grain boundary with segregated Na and Ca impurity atoms have been calculated by a first-principles pseudopotential method. The results show that the boundary expands and the charge density decreases significantly over the whole boundary by the segregation of Na and Ca, and there are no stronger bonds than those associated with metallic bonding in the boundary even with the impurities. It is concluded that the embrittlement promotion mechanism by Na or Ca segregation in the Al boundaries is one kind of 'decohesion model'.