Recording and Quantifying C. elegans Behavior

Studies of C. elegans behavior have been crucial in identifying genetic pathways that control nervous system development and function, as well as basic principles of neural circuit function. Modern analysis of C. elegans behavior commonly relies on video recordings of animals, followed by automated image analysis and behavior quantification. Here, we describe two methods for recording and quantifying C. elegans behavior: a single-worm tracking approach that provides high-resolution behavioral data for individual animals and a multi-worm tracking approach that allows for quantification of the behavior of many animals in parallel. These approaches should be useful to a wide range of researchers studying the nervous system and behavior of C. elegans.

Heart rate variability in neonatal seizures: Investigation and implications for management

Many factors acting during the neonatal period can affect neurological development of the infant. Neonatal seizures (NS) that frequently occur in the immature brain may influence autonomic maturation and lead to detectable cardiovascular signs. These autonomic manifestations can also have significant diagnostic and prognostic value. The analysis of Heart Rate Variability (HRV) represents the most used and feasible method to evaluate cardiac autonomic regulation. This narrative review summarizes studies investigating HRV dynamics in newborns with seizures, with the aim of highlighting the potential utility of HRV measures for seizure detection and management. While HRV analysis in critically ill newborns is influenced by many potential confounders, we suggest that it can enhance the ability to better diagnose seizures in the clinical setting. We present potential applications of the analysis of HRV, which could have a useful future role, beyond the research setting.

Preterm infants' orally directed behaviors and behavioral state responses to the integrated H-HOPE intervention

Preterm infants are challenged by immature infant behavioral organization which may negatively influence their ability to oral feed. The purpose of this study was to determine whether the integrated H-HOPE (Hospital to Home: Optimizing the Infant's Environment) intervention would improve infant behavioral organization by increasing the frequency of orally directed behaviors and the proportion of time spent in an alert behavioral state when offered prior to oral feeding. Mother-infant dyads (n=198) were randomly assigned to the H-HOPE intervention or the Attention Control groups. Infants were born at 29-34 weeks gestation and were clinically stable. Mothers had at least two social environmental risk factors such as minority status or less than high school education. H-HOPE is an integrated intervention that included (1) twice-daily infant directed stimulation using the ATVV intervention (auditory, tactile, visual, and vestibular stimuli) and (2) maternal participatory guidance sessions by a nurse-community advocate team. Orally directed behaviors and behavioral states were assessed weekly prior to feeding during hospitalization when infants were able to feed orally. There were no differences between the groups at baseline (Day 0, prior to the initiation of the integrated H-HOPE intervention). We observed a pattern of increased frequency of orally directed behaviors in the H-HOPE intervention group when compared to the Attention Control group, however, the proportion of time spent in an alert behavioral state remained stable in both groups over the course of the study. On Day 7, the H-HOPE intervention group exhibited a significantly higher mean frequency of orally directed behaviors than the Attention Control group (12.6 vs. 7.1 pre-intervention, 51.8 vs. 33.2 during intervention, 4.3 vs. 3.2 immediately after intervention, and 8.9 vs. 5.3 immediately prior to feeding). On Day 7, the H-HOPE intervention group exhibited a significantly higher proportion of time spent in an alert behavioral state only during intervention (0.26 vs. 0.11) and immediately after intervention (0.28 vs. 0.06). These findings are suggestive that the integrated H-HOPE intervention facilitated infant behavioral organization for clinically stable infants born between 29 and 34 weeks gestation. The orally directed behaviors appear to be an important indicator of the infant's preparation for feeding, and when used in conjunction with assessment of behavioral states, are especially valuable to the clinician. Use of this combined assessment approach in practice would strengthen clinician assessment for initiation of (beginning the first oral feeding) and daily preparation for oral feeding in preterm infants.

Behavioral states may be associated with distinct spatial patterns in electrocorticogram

To determine if behavioral states are associated with unique spatial electrocorticographic (ECoG) patterns, we obtained recordings with a microgrid electrode array applied to the cortical surface of a human subject. The array was constructed with the intent of extracting maximal spatial information by optimizing interelectrode distances. A 34-year-old patient with intractable epilepsy underwent intracranial ECoG monitoring after standard methods failed to reveal localization of seizures. During the 8-day period of invasive recording, in addition to standard clinical electrodes a square 1 × 1 cm microgrid array with 64 electrodes (1.25 mm separation) was placed on the right inferior temporal gyrus. Careful review of video recordings identified four extended naturalistic behaviors: reading, conversing on the telephone, looking at photographs, and face-to-face interactions. ECoG activity recorded with the microgrid that corresponded to these behaviors was collected and ECoG spatial patterns were analyzed. During periods of ECoG selected for analysis, no electrographic seizures or epileptiform patterns were present. Moments of maximal spatial variance are shown to cluster by behavior. Comparisons between conditions using a permutation test reveal significantly different spatial patterns for each behavior. We conclude that ECoG recordings obtained on the cortical surface with optimal high spatial frequency resolution reveal distinct local spatial patterns that reflect different behavioral states, and we predict that similar patterns will be found in many if not most cortical areas on which a microgrid is placed.