Navigation, finding food sources, and avoiding danger critically depend on the identification and spatial localization of airborne chemicals. When monitoring the olfactory environment, rodents spontaneously engage in active olfactory sampling behavior, also referred to as exploratory sniffing [1]. Exploratory sniffing is characterized by stereotypical high-frequency respiration, which is also reliably evoked by novel odorant stimuli [2, 3]. To study novelty-induced exploratory sniffing, we developed a novel, non-contact method for measuring respiration by infrared (IR) thermography in a behavioral paradigm in which novel and familiar stimuli are presented to head-restrained mice. We validated the method by simultaneously performing nasal pressure measurements, a commonly used invasive approach [2, 4], and confirmed highly reliable detection of inhalation onsets. We further discovered that mice actively orient their nostrils toward novel, previously unexperienced, smells. In line with the remarkable speed of olfactory processing reported previously [3, 5, 6], we find that mice initiate their response already within the first sniff after odor onset. Moreover, transecting the anterior commissure (AC) disrupted orienting, indicating that the orienting response requires interhemispheric transfer of information. This suggests that mice compare odorant information obtained from the two bilaterally symmetric nostrils to locate the source of the novel odorant. We further demonstrate that asymmetric activation of the anterior olfactory nucleus (AON) is both necessary and sufficient for eliciting orienting responses. These findings support the view that the AON plays an important role in the internostril difference comparison underlying rapid odor source localization.

The new algorithm facilitates the application of IR thermography for measuring respiration in biomedical research and in clinical settings.

The aim of this study is to detect preeclampsia-related cardiac dysfunction within 24-48 hours of delivery in newborns born from preeclamptic mothers. Forty newborns from mildly preeclamptic mothers formed the study group and the control group was formed by 40 healthy newborns. Cardiac function for the groups were evaluated using conventional echocardiography and myocardial performance index (MPI) within the first 24-48 hours of their lifetime and the results of both groups were compared. A significant difference between the groups was observed especially in the PW Doppler MPI measurements (the left ventricle MPI 0.37 ± 0.09 and 0.26 ± 0.11, p < .001; the right ventricle MPI 0.29 ± 0.08 and 0.26 ± 0.07, p < .035) for the control group and the study group. Elongation in the left and right ventricle MPI was detected to be more significant in terms of comparing systolic and diastolic functions to determine preeclampsia-related cardiac injury in newborns from preeclamptic mothers within the first 24-48 hours of their lifetime. Impact statement Today, the methods which may detect cardiac injury earlier than conventional echocardiographic methods are used for evaluating cardiac functions. Among them, myocardial performance index (MPI) measurement with PW Doppler is the most common ones. While studies are available in the literature evaluating foetal cardiac functions with MPI in foetuses of preeclamptic women, studies evaluating cardiac functions with MPI index within the first 24-48 hours in postnatal period are not available. This is the first study to detect cardiac injury by measuring cardiac functions of the newborns of preeclamptic babies using conventional echocardiography (EF, SF, mitral and tricuspid E/A) and myocardial performance index within the first 24-48 hours of life and compare these values with those of a control group composed of healthy newborns with similar demographic characteristics. According to the results of the study, elongation in right and left ventricle MPI was detected to be more significant compared to systolic and diastolic functions for determining preeclampsia-related cardiac injury in newborns of preeclamptic mothers within 24-48 hours of delivery. Ventricle functions of the newborns of preeclamptic mothers should also be evaluated with MPI measurement besides conventional echocardiographic measurements.