Hironobu Kamimura

Continuous measurement of blood pressure, heart rate and left ventricular performance during and after isometric exercise in head-out water immersion

Experiments were performed to determine the changes in blood pressure (BP), heart rate (HR) and left ventricular function during and after isometric knee extension during thermoneutral (35°C) head-out water immersion (HWI) or in air. Seven healthy male subjects mean age 24 (SD 3) years kept their knees extended (60% maximal voluntary extension) until they reached exhaustion. The mean BP at rest was 80 (SD 10) and 78 (SD 8) mmHg [10.7 (SD 1.33) and 10.4 (SD 1.07) kPa] in air and during HWI, respectively, (NS). They increased progressively (P < 0.01) during contraction and reached maximal values of 148 (SD 22) and 143 (SD 26) mmHg [19.7 (SD 2.93) and 19.1 (SD 3.47) kPa] in air and in HWI, respectively, (NS). The mean HR at rest was 74 (SD 8) and 70 (SD 11) beats·min−1 in air and in HWI, respectively, (NS). They also increased progressively (P < 0.01) and reached 126 (SD 14) and 118 (SD 17) beats·min−1 in air and in HWI, respectively, (NS). The changes in BP and HR during contraction in HWI tended to be smaller than those in air (NS). Left ventricular end diastolic diameters (dd) at rest in HWI were greater than those in air and were maintained at higher values during and after isometric contraction. In contrast, dd decreased during isometric contraction in air (P < 0.01). The change of left ventricular systolic diameters (ds) in HWI was no different to those in air. From these findings, isometric exercise in thermoneutral HWI would seem to be characterized by a greater dd than in air and this could be useful for patients with deconditioning effects such as orthostatic hypotension.

Effect of Odorant Presentation on Changes in Cognitive Interference and Brain Activity during Counting Stroop Task

Cognitive task for longer duration increases subjects psychological loadings because of extracting ordered answer from visual stimuli. The present study investigated how intermittent odorant presentation during cognitive task contributes to cognitive function and statement of psychological loadings. We asked ten male subjects to perform counting stroop task that repeatedly counts the pieces of digits displayed on a monitor. The task consisted three tasks that the digits and the number were consisted (task1), non-consisted (task2), and both the former tasks combined (task3). The duration of each task was four minutes, and thus subjects totally performed the tasks for 12 minutes. Four kinds of odorant stimuli (non-odor, lemon, peppermint (pmint), and skatole (ska)) were used in this study and each odor was presented after beginning of each task for one minute. Behavioral results, rate of content of ƒ¿, ƒÀ, ƒÂ, and ƒÆ waves from EEG, and oxygenated hemoglobin concentration (ƒ¢O2Hb) were measured and compared between each odor condition. Behavioral results, the reaction time and the percentage of questions answered correctly, ƒ¢O2Hb in right hemisphere related to pleasant emotion, and rate of content of ƒ¿ wave were significantly increased when pmint and ska were presented. The findings indicated that intermittent odor presentation induced pleasant emotion and increased cognitive function and state of concentration, regardless of odors.

Effect of Different Flavors on Physiological and Psychological Responses after Soup Intake with Nutritional Equivalence

This research examined the effect of two soups with equivalent nutritional values but with different flavors on measures of palatability and physiological responses (the frontal cortex blood flow and the respiratory cardiovascular system). A significant difference in palatability between the two soups was confirmed through sensory evaluation. In terms of the physiological responses, significant differences between the two soups were observed in the oxygenated hemoglobin at the right side of the frontal cortex, the heart rate, and the respiratory quotient after soup intake. In particular, the intake of the soup with low palatability caused a rise in oxygenated hemoglobin at the right side of the frontal cortex, followed by a sustained rise in the heart rate in the cardiovascular system and a reduction in the respiratory quotient, all of which, we believe, were stress responses.

Intermittent Presentation of Hinoki Odor as the Inhibitory Factor on the Performance and Physiological Responses in Stroop Task

This experiment examines how intermittent presentation of olfactory stimulus affects performance and physiological responses on performing Stroop task. Eight participants performs word-color Stroop task while Hinoki or no odors are presented for 10 sec in every 45 second. Results show Hinoki, compared with no odor, reduce the performances as indicated in longer correct response time and a larger number of error responses. Hinoki activates left forehead cortical activity as measuren in more OxyHb, and sympathetic nervous function shown in decreased plethysmograpy amplitude and increased alpha amylase. These results indicate intermittent presentation activates attentional process, raises arousal level. The differential results of more and less Hinoki favorite groups of participants indicates less favorite participants are diverted their attention to Hinoki and disturbed to performe the task.

The pleasant odor reduces the brain activity and enhances behavioral performance during kanji word-color stroop task: A multi-fiber NIRS study

The purpose of this study was to investigate that the effect of sensed pleasant odor on the increased psychological loading and brain activity due to the confliction and intervention by the difference between meaning of kanji words and word color. During word-color stroop task, brain activity was estimated by oxy-hemoglobin concentration (ΔO2Hb) and psychological loadings, i.e., status of the autonomic activity, was measured by ECG signal and peripheral blood flow. As a result, when the lavender aroma sensed, ΔO2Hb was decreased and mean response time was significantly shortened as compared with non-odor. The results indicate that the pleasant emotion evoked by the pleasant odor and further the calling effect by lavender aroma inhibited the over activity due to stoop task, and thus facilitate precise reading of the logographical kanji word and word color.

The performance and physical responses during an attention shift task with grapefruit and skatole odor presentation

Performance and physiological responses within performing an attention shift task were compared between grapefruit odor, skatole, odorless air presentation. Ten male students participated in this experiment. They performed 15 min digit detection task three times, that required quick attention shift. During the task, 1 min odor was presented three times. Near infrared spectroscopy and EEG were monitored through the experiment, and offered physiological indexes of oxy-Hb, deoxy-Hb and beta wave component. The number of correct responses and reaction time were better in both grapefruit and skatole presentation than in odorless air. Increased oxy-Hb that indicates activated brain function, was observed only in grapefruit presentation at left forehead. Increased beta wave component that reflects relaxation, was found in grapefruit presentation at F4 (left middle forehead), while decreased beta in skatoke presentation. These findings suggest grapefruit acts as an activator, while skatole as a sedative.