Cerebral oxygenation saturation in childhood: difference by age and comparison of two cerebral oximetry algorithms.

Few reports are available on the monitoring of regional cerebral oxygen saturation (rSO2) in pediatric patients undergoing non-cardiac surgical procedures. In addition, no study has examined the rSO2 levels in children of a broad age range. In this study, we aimed to assess and compare rSO2 levels in pediatric patients of different age groups undergoing non-cardiac surgery. We used two oximeters, tNIRS-1, which uses time-resolved spectroscopy, and conventional INVOS 5100C. Seventy-eight children-26 infants, 26 toddlers, and 26 schoolchildren-undergoing non-cardiac surgery were included. We investigated the differences in the rSO2 levels among the age groups and the correlation between the models and physiological factors influencing the rSO2 values. rSO2 measured by INVOS 5100C was significantly lower in infants than those in other patients. rSO2 measured by tNIRS-1 was higher in the toddler group than those in the other groups. The rSO2 values of tNIRS-1 and INVOS 5100C were moderately correlated (r = 0.41); however, those of INVOS 5100C were approximately 20% higher, and a ceiling effect was observed. The values in INVOS 5100C and tNIRS-1 were affected by blood pressure and the minimum alveolar concentration of sevoflurane, respectively. In pediatric patients undergoing non-cardiac surgery, rSO2 values differed across the three age groups, and the pattern of these differences varied between the two oximeters employing different algorithms. Further research must be conducted to clarify cerebral oxygenation in children.

Nonlinear age-related differences in probabilistic learning in mice: A 5-armed bandit task study.

This study explores the impact of aging on reinforcement learning in mice, focusing on changes in learning rates and behavioral strategies. A 5-armed bandit task (5-ABT) and a computational Q-learning model were used to evaluate the positive and negative learning rates and the inverse temperature across three age groups (3, 12, and 18 months). Results showed a significant decline in the negative learning rate of 18-month-old mice, which was not observed for the positive learning rate. This suggests that older mice maintain the ability to learn from successful experiences while decreasing the ability to learn from negative outcomes. We also observed a significant age-dependent variation in inverse temperature, reflecting a shift in action selection policy. Middle-aged mice (12 months) exhibited higher inverse temperature, indicating a higher reliance on previous rewarding experiences and reduced exploratory behaviors, when compared to both younger and older mice. This study provides new insights into aging research by demonstrating that there are age-related differences in specific components of reinforcement learning, which exhibit a non-linear pattern.

Trigeminal Sensitization in a Closed Head Model for Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI) is often accompanied by neurological and ocular symptoms that involve trigeminal nerve pathways. Laser-induced shock wave (LISW) was applied to the skull of male rats as a model for mTBI, while behavioral and neural recording methods were used to assess trigeminal function. The LISW caused greater eye wiping behavior to ocular instillation of hypertonic saline (Sham = 4.83 ± 0.65 wipes/5 min, LISW = 12.71 ± 1.89 wipes/5 min, p < 0.01) and a marked reduction in the time spent in bright light consistent with enhanced periocular and intraocular hypersensitivity, respectively (Sham = 16.3 ± 5.6 s, LISW = 115.5 ± 27.3 s, p < 0.01). To address the early neural mechanisms of mTBI, single trigeminal brainstem neurons, identified by activation to corneal or dural mechanical stimulation, were recorded in trigeminal subnucleus interpolaris/caudalis (Vi/Vc) and trigeminal subnucleus caudalis/upper cervical cord (Vc/C1) regions. The LISW caused marked sensitization to hypertonic saline and to exposure to bright light in neurons of both regions (p < 0.05). Laser speckle imaging revealed an increase in meningeal arterial blood flow to bright light after LISW (Sham = 4.7 ± 2.0 s, LISW = 469.0 ± 37.9 s, p < 0.001). Local inhibition of synaptic activity at Vi/Vc, but not at Vc/C1, by microinjection of CoCl2, prevented light-evoked increases in meningeal blood flow in LISW-treated rats. By contrast, topical meningeal application of phenylephrine significantly reduced light-evoked responses of Vi/Vc and Vc/C1 neurons. These data suggested that neurons in both regions became sensitized after LISW and were responsive to changes in meningeal blood flow. Neurons at the Vi/Vc transition and at Vc/C1, however, likely serve different roles in mediating the neurovascular and sensory aspects of mTBI.

BK channel dysfunction disrupts attention-controlled behaviors and altered perseverative responses in murine instrumental learning.

This study examined the effect of knockout of KCNMA1 gene, coding for the BK channel, on cognitive and attentional functions in mice, with an aim to better understand its implications for human neurodevelopmental disorders. The study used the 3-choice serial reaction time task (3-CSRTT) to assess the learning performance, attentional abilities, and repetitive behaviors in mice lacking the KCNMA1 gene (KCNMA1-/-) compared to wild-type (WT) controls. Results showed no significant differences in learning accuracy between the two groups. However, KCNMA1-/- mice were more prone to omitting responses to stimuli. In addition, when the timing of cue presentation was randomized, the KCNMA1-/- showed premature responses. Notably, these mice also demonstrated a marked reduction in perseverative responses, which include repeated nose-poke behaviors following decisions. These findings highlight the involvement of the KCNMA1 gene in managing attention, impulsivity, and potentially moderating repetitive actions.