pre-Bötzinger Complex Research Articles

Endomorphin-2 (Endo2) and substance P (SubP) co-application attenuates SubP-induced excitation and alters frequency plasticity in neonatal rat in vitro preparations

Substance P (SubP) and endomorphin-2 (Endo2) are co-localized presynaptically in vesicles of neurons adjacent to inspiratory rhythm-generating pre-Botzinger Complex (preBotC) neurons but the effects of co-released SubP and Endo2 on respiratory motor control are not known. To address this question, SubP alone or a combination of SubP and Endo2 (SubP/Endo2) were bath-applied in a sustained (15-min) or intermittent (5-min application, 5-min washout, x3) pattern at 10–100 nM to neonatal rat brainstem-spinal cord preparations. During neuropeptide application, SubP/Endo2 co-applications generally attenuated SubP-induced increases in burst frequency and decreases in burst amplitude. With respect to frequency plasticity (long-lasting increase in burst frequency 60 min post-neuropeptide application), SubP-induced frequency plasticity was increased with sustained SubP/Endo2 co-applications at 20 and 100 nM. Intermittent SubP/Endo2 co-applications tended to decrease the level of frequency plasticity induced by intermittent SubP alone applications. SubP/Endo2 co-applications revealed potentially new functions for neurokinin-1 (NK1R) and mu-opioid (MOR) receptors on respiratory rhythm-generating medullary neurons.

Influence of Microinjection of Kynurenic acid into the Pre-Botzinger Complex on Swallowing in the Cat

Recent evidence supports the involvement of the pre-BÖtzinger complex (pre-BOT) in spatiotemporal features of swallowing and swallowing-breathing coordination in mice. We hypothesized that pharmacological disruption of glutamate neurotransmission in this brainstem region would perturb the swallow motor pattern in anesthetized cats. Electromyograms (EMGs) of upper airway muscles were recorded in anesthetized, spontaneously breathing cats (n=5). Swallowing was induced by injection of 3 cc of water into the oropharynx. Multi-barrel micropipettes were employed to inject artificial cerebrospinal fluid or kynurenic acid (KYN; 50 mM, 44±3 nL per injection) bilaterally into the region of the pre-BOT. Microinjection sites were confirmed histologically by detection of fluorescent beads that were suspended in the microinjectate. Blocking glutamate-related neuronal excitation by bilateral microinjections of the nonspecific glutamate receptor antagonist kynurenic acid had no effect on the number of swallows induced by water injection (control 2.3±0.3; KYN 3.0±0.7; P<0.32). Swallow durations were significantly increased following microinjections of KYN from 691±54 ms to 812±81 ms (p<0.04). KYN significantly reduced the magnitudes of geniohyoid (control 97±3 % of median; Kyn 47±12% of control median, p<0.02), thyrohyoid (control 100±3% of median; KYN 69±8% of control median, p<0.01), and posterior cricoarytenoid (control 103±2% of median; KYN 74±8% of control median, p<0.04) muscle EMGs during swallowing. There was no significant effect of microinjection of KYN on the magnitudes of thyroartytenoid, mylohyoid, or thyropharyngeus electromyograms during swallowing. The results suggest that disruption of glutamate neurotransmission in the preBOT has preferential effects consistent with actions on motor drive to hypoglossal and ventrolateral motoneuron pools that participate in swallowing. Lengthening of swallow duration induced by KYN supports a role for the preBOT in modulating the excitability of the swallow oscillatory circuit. NIH HL163008; NIH HL 131716; HL 155721. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Synchronization degree of a two-compartment neuron based on transcranial magnetic stimulation

Synchronization is a very important phenomenon in the nervous system, which is closely related to the encoding, integration and transmission of information. In this paper, synchronization and transition of a two-compartment respiratory neuron model under transcranial magnetic stimulation (TMS) are studied from the perspective of synchronization degree for the first time. We are established the correlation degree with synchronization, and discussed the firing mode and transition rule of the neurons in the two-compartment compartment pre-Bötzinger complex (PBC) by means of bifurcation theory and Lyapunov index. The results show that the synchronization of neurons has a great influence under TMS, which is embodied in the fact that the somatic will experience a peak firing and a transition from bursting to resting under the magnetic stimulation,which was a phenomenon never before shown in PBC neurons. These results fully reveal the dynamic behavior of PBC nervous system under TMS, and provide theoretical value for further understanding of respiratory rhythm.

TNFR1-mediated neuroinflammation is necessary for respiratory deficits observed in 6-hydroxydopamine mouse model of Parkinsońs Disease

Parkinson's Disease (PD) is characterized by classic motor symptoms related to movement, but PD patients can experience symptoms associated with impaired autonomic function, such as respiratory disturbances. Functional respiratory deficits are known to be associated with brainstem neurodegeneration in the mice model of PD induced by 6-hydroxydopamine (6-OHDA). Understanding the causes of neuronal death is essential for identifying specific targets to prevent degeneration. Many mechanisms can explain why neurons die in PD, and neuroinflammation is one of them. To test the influence of inflammation, mediated by microglia and astrocytes cells, in the respiratory disturbances associated with brainstem neurons death, we submitted wild-type (WT) and TNF receptor 1 (TNFR1) knockout male mice to the 6-OHDA model of PD. Also, male C57BL/6 animals were induced using the same PD model and treated with minocycline (45 mg/kg), a tetracycline antibiotic with anti-inflammatory properties. We show that degeneration of brainstem areas such as the retrotrapezoid nucleus (RTN) and the pre-Botzinger Complex (preBotC) were prevented in both protocols. Notably, respiratory disturbances were no longer observed in the animals where inflammation was suppressed. Thus, the data demonstrate that inflammation is responsible for the breathing impairment in the 6-OHDA-induced PD mouse model.

Dorsal raphe nucleus to pre-Bötzinger complex serotonergic neural circuit is involved in seizure-induced respiratory arrest

SummarySudden unexpected death in epilepsy (SUDEP) is the leading cause of death among patients with epilepsy. However, the underlying mechanism of SUDEP remains elusive. Previous studies showed seizure-induced respiratory arrest (S-IRA) is the main factor in SUDEP, and that enhancement of serotonin (5-HT) function in the dorsal raphe nucleus (DR) can significantly reduce the incidence of S-IRA in the DBA/1 mouse model of SUDEP. The pre-Bötzinger complex (PBC), known for its role in regulating respiratory rhythm, can express the 5-HT2A receptor (5-HT2AR). Here, using the pharmacological and optogenetic methods, respectively, we observed that the serotonergic neural circuit between DR and PBC was involved in S-IRA evoked by either acoustic stimulation or pentylenetetrazole (PTZ) injection in the DBA/1 mice, and found 5-HT2AR located in PBC plays an important role in it. Our findings will further significantly improve our understanding of SUDEP and provide a promising therapeutic target for SUDEP prevention.

Raphe and ventrolateral medulla proteomics in epilepsy and sudden unexpected death in epilepsy.

Brainstem nuclei dysfunction is implicated in sudden unexpected death in epilepsy. In animal models, deficient serotonergic activity is associated with seizure-induced respiratory arrest. In humans, glia are decreased in the ventrolateral medullary pre-Botzinger complex that modulate respiratory rhythm, as well as in the medial medullary raphe that modulate respiration and arousal. Finally, sudden unexpected death in epilepsy cases have decreased midbrain volume. To understand the potential role of brainstem nuclei in sudden unexpected death in epilepsy, we evaluated molecular signalling pathways using localized proteomics in microdissected midbrain dorsal raphe and medial medullary raphe serotonergic nuclei, as well as the ventrolateral medulla in brain tissue from epilepsy patients who died of sudden unexpected death in epilepsy and other causes in diverse epilepsy syndromes and non-epilepsy control cases (n = 15–16 cases per group/region). Compared with the dorsal raphe of non-epilepsy controls, we identified 89 proteins in non-sudden unexpected death in epilepsy and 219 proteins in sudden unexpected death in epilepsy that were differentially expressed. These proteins were associated with inhibition of EIF2 signalling (P-value of overlap = 1.29 × 10−8, z = −2.00) in non-sudden unexpected death in epilepsy. In sudden unexpected death in epilepsy, there were 10 activated pathways (top pathway: gluconeogenesis I, P-value of overlap = 3.02 × 10−6, z = 2.24) and 1 inhibited pathway (fatty acid beta-oxidation, P-value of overlap = 2.69 × 10−4, z = −2.00). Comparing sudden unexpected death in epilepsy and non-sudden unexpected death in epilepsy, 10 proteins were differentially expressed, but there were no associated signalling pathways. In both medullary regions, few proteins showed significant differences in pairwise comparisons. We identified altered proteins in the raphe and ventrolateral medulla of epilepsy patients, including some differentially expressed in sudden unexpected death in epilepsy cases. Altered signalling pathways in the dorsal raphe of sudden unexpected death in epilepsy indicate a shift in cellular energy production and activation of G-protein signalling, inflammatory response, stress response and neuronal migration/outgrowth. Future studies should assess the brain proteome in relation to additional clinical variables (e.g. recent tonic–clonic seizures) and in more of the reciprocally connected cortical and subcortical regions to better understand the pathophysiology of epilepsy and sudden unexpected death in epilepsy.

Systemic 8-OH-DPAT challenge causes hyperventilation largely via activating pre-botzinger complex 5-HT1A receptors

Systemic 8-OH-DPAT (a 5-HT1A receptor agonist) challenge evokes hyperventilation independent of peripheral 5-HT1A receptors. Though the pre-Botzinger Complex (PBC) is critical in generating respiratory rhythm and activation of local 5-HT1A receptors induces tachypnea via disinhibition of local GABAA neurons, its role in the respiratory response to systemic 8-OH-DPAT challenge is still unclear. In anesthetized rats, 8-OH-DPAT (100 μg/kg, iv) was injected twice to confirm the reproducibility of the evoked responses. The same challenges were performed after bilateral microinjections of (S)-WAY-100135 (a 5-HT1A receptor antagonist) or gabazine (a GABAA receptor antagonist) into the PBC. Our results showed that: 1) 8-OH-DPAT caused reproducible hyperventilation associated with hypotension and bradycardia; 2) microinjections of (S)-WAY-100135 into the PBC attenuated the hyperventilation by ˜60 % without effect on the evoked hypotension and bradycardia; and 3) the same hyperventilatory attenuation was also observed after microinjections of gabazine into the PBC. Our data suggest that PBC 5-HT1A receptors play a key role in the respiratory response to systemic 8-OH-DPAT challenge likely via disinhibiting local GABAergic neurons.

Opioids and obstructive sleep apnea.

Freire C, Sennes LU, Polotsky VY. Opioids and obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):647-652.

Dynamics Analysis of Firing Patterns in Pre-Bötzinger Complex Neurons Model.

Pre-Bötzinger complex (PBC) neurons located in mammalian brain are the necessary conditions to produce respiratory rhythm, which has been widely verified experimentally and numerically. At present, one of the two different types of bursting mechanisms found in PBC mainly depends on the calcium-activated of non-specific cation current (ICaN). In order to study the influence of ICaN and stimulus current Iexc in PBC inspiratory neurons, a single compartment model was simplified, and firing patterns of the model was discussed by using stability theory, bifurcation analysis, fast, and slow decomposition technology combined with numerical simulation. Under the stimulation of different somatic applied currents, the firing behavior of neurons are studied and exhibit multiple mix bursting patterns, which is helpful to further understand the mechanism of respiratory rhythms of PBC neurons.

Last Word on Viewpoint: Nondyspnogenic acute hypoxemic respiratory failure in COVID-19 pneumonia-Breathing pattern in patients with SARS-CoV-2.

Last Word on Viewpoint: Nondyspnogenic acute hypoxemic respiratory failure in COVID-19 pneumonia-Breathing pattern in patients with SARS-CoV-2.

Correlation Analysis of Synchronization Type and Degree in Respiratory Neural Network.

Pre-Bötzinger complex (PBC) is a necessary condition for the generation of respiratory rhythm. Due to the existence of synaptic gaps, delay plays a key role in the synchronous operation of coupled neurons. In this study, the relationship between synchronization and correlation degree is established for the first time by using ISI bifurcation and correlation coefficient, and the relationship between synchronization and correlation degree is discussed under the conditions of no delay, symmetric delay, and asymmetric delay. The results show that the phase synchronization of two coupling PBCs is closely related to the weak correlation, that is, the weak phase synchronization may occur under the condition of incomplete synchronization. Moreover, the time delay and coupling strength are controlled in the modified PBC network model, which not only reveals the law of PBC firing transition but also reveals the complex synchronization behavior in the coupled chaotic neurons. Especially, when the two coupled neurons are nonidentical, the complete synchronization will disappear. These results fully reveal the dynamic behavior of the PBC neural system, which is helpful to explore the signal transmission and coding of PBC neurons and provide theoretical value for further understanding respiratory rhythm.

Multi-time scale dynamics of mixed depolarization block bursting

Two-coupled excitatory neurons model containing both calcium-activated non-specific cationic and persistent sodium current in the pre-Botzinger complex (pre-BotC) is studied. A new type of mixed burst similar to a depolarization block bursting (DB-bursting) is observed in the model of pre-BotC neurons. The multi-time scale dynamics, one- and two-parameter bifurcation analysis, are used to study the types of mixed burst and their transition mechanisms. The results show that the periodic fluctuation of calcium concentration has a great influence on the generation of mixed bursting. The change of time scale caused by fluctuation of calcium concentration and the relative position of bifurcation curves have great influence on patterns of bursting.

The effect of the leak conductance parameter on the dynamics of a mathematical model of pre-Botzinger complex pacemaker neurons: period-doubling bifurcation and chaotic activity

The effect of the leak conductance parameter on the dynamics of a mathematical model of pre-Botzinger complex pacemaker neurons: period-doubling bifurcation and chaotic activity

Dynamical analysis of dendritic mixed bursting within the pre-Bötzinger complex

A special class of neurons within the brainstem pre-Botzinger complex (pre-BotC) may perform diversified electrical actions, which are closely related to the generation of mammalian respiratory rhythm. Researches on electrical activities of those neurons are of highly interest and have been conducted both experimentally and computationally. One interesting firing activity observed experimentally is the so-called mixed bursting (MB), which exhibits more than one type of short bursts within a periodic cycle and is believed to be generated by the joint action of persistent sodium current and intracellular calcium oscillations. In this paper, based on Park and Rubin’s model for single pre-BotC neuron, we numerically find that MB can also be driven by the sole action of intracellular calcium oscillations originating from the dendrite. We call such MB the dendritic mixed bursting (DMB). We show several special DMBs one after another and interpret their dynamical mechanisms via fast–slow decomposition and bifurcation analysis. In addition, we show how calcium-activated nonspecific cationic conductance ( $$g_{\text{ CAN }}$$ ) affects certain DMB activities. This work may provide significant insights for comprehending compound kinetics scenarios within the pre-BotC.

Chronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre-Bötzinger complex of rats.

Mitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Bötzinger complex (pre-BötC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BötC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BötC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BötC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BötC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.

Oxidative stress in the medullary respiratory neurons contributes to respiratory dysfunction in the 6-OHDA model of Parkinson's disease.

Parkinson's disease (PD) is associated with respiratory dysfunction. In the 6-OHDA rat model of PD this is seen as a reduction in respiratory frequency and minute ventilation during normoxia and hypercapnia stimulus. Respiratory dysfunction is caused by neuronal death of medullary respiratory nuclei in the 6-OHDA model of PD. Oxidative stress can be considered a strong candidate for neurodegeneration via miR-34c downregulation and pro-apoptotic signalling in respiratory neurons, preceding the functional impairment observed in the 6-OHDA model of PD. Parkinson's disease (PD) is a neurodegenerative disease caused by dopaminergic neuron death in the substantia nigra (SN). New evidence has revealed that this neurodegeneration is the result of complex interactions between genetic abnormalities, environmental toxins, mitochondrial dysfunction and disruption of the blood-brain barrier (BBB) in the SN. In addition to classic symptoms, PD patients also exhibit respiratory failure. Here, we investigated whether oxidative stress was associated with neurodegeneration in a respiratory group (RG) of 6-OHDA-treated rats, which act as a model of PD. We analysed how oxidative stress affected apoptotic signalling in the RG 30days after 6-OHDA treatment, shortly before commencement of breathing impairment (40days). After 30days, a dihydroethidium assay showed increased oxidative stress in the RG, anti-apoptotic signalling, as shown by an increase in p-Akt and BcL-2 and a decrease in Bax in the caudal aspect of the nucleus of the solitary tract (cNTS), and a decrease in p-p38 and Bax levels in the retrotrapezoid nucleus (RTN); pro-apoptotic signalling was indicated by a decrease in p-Akt and BcL-2 and an increase in Bax in the rostral ventral respiratory group (rVRG) and pre-Botzinger complex (preBotC). miR-34c, a known oxidative stress protector, was downregulated in 6-OHDA animals in the RC. After 40days of 6-OHDA, the NTS, rVRG, preBotC and RTN exhibited reduced NeuN immunoreactivity, no BBB disruption and an increase in thiobarbituric acid reactivity. We conclude that in the 6-OHDA model of PD, oxidative stress contributes to neurodegeneration in medullary respiratory neurons.

Microglia Activation and IL‐1β Expression in Select Ventilatory Control Regions Following Exposure to Chronic Sustained Hypoxia

Ventilatory acclimatization to hypoxia (VAH) is defined as the time‐dependent increase in ventilation which occurs with chronic sustained hypoxia (CSH) of several hours to months. Previous research has shown that astrocytes and microglia undergo a morphology shift, indicating a possible change in activity, upon exposure to hypoxic conditions and may contribute to VAH. Understanding when and how the different cell types in respiratory control regions are activated is pertinent to understanding ventilatory control during hypoxic conditions. The first part of this study aimed to optimize the Sholl analysis method to detect morphological changes in microglia. Two different microglia antibodies, Iba‐1 and CD11b[Ox42], were compared using Sholl analysis to determine which antibody best represents the branching pattern of the individual microglia. Analysis indicated that neither antibody was statistically different from the other in terms of microglia branching (p>0.05), so CD11b[Ox42] was chosen to simplify the immunohistochemistry protocol. The second part of this study assessed the morphology shift of microglia in the nucleus tractus solitarius (NTS) and Pre‐Bötzinger Complex (PBC) following CSH exposure. Based on previous research, we hypothesized that microglia in the NTS and PBC would be activated following CSH exposure, as assessed via a morphology shift to a more amoeboid state indicated by less microglia branch crossings of the Sholl brackets. To address this hypothesis, rats were exposed to either normoxic, 60‐minutes of CSH, or 12‐hours of CSH. Microglia morphology was assessed in perfused brainstem tissue via immunohistochemistry, confocal imaging, and image analysis. In the NTS, microglia branching analysis revealed a trend towards a more amoeboid morphology at the 60‐minute CSH time point, but only one of the Sholl analysis brackets, 21–30μM, was statistically significant from normoxic conditions (p<0.05). In the PBC, microglia branching analysis also revealed a trend towards a more amoeboid morphology at the 60‐minute CSH time point with statistically significant (p<0.05) branch patterns at the 11–20μM, 21–30μM, and 31–40 μM Sholl brackets. A morphology shift of microglia to a more amoeboid state could indicate their localized response to neurotransmitters or cytokines. In a follow‐up study we investigated the expression of IL‐1β in the NTS region using immunofluorescent labeling. Rat brainstem tissue from normoxic conditions, 15‐minute CSH, and 60‐minute CSH was labeled with antibodies against IL‐1β, GFAP, and Cd11b[Ox42]. IL‐1β positive cells were counted in the NTS region. This preliminary set of cell counts (n=2) suggests that there is an increase in IL‐1β positive cells with CHS exposure (normoxic 17 ± 2 IL‐1β positive cells, 15‐minute CSH 31.5 ± 0.5 IL‐1β positive cells, 60‐minute CSH 29.5 ± 9.5 IL‐1β positive cells). Taken together these data provide a great starting point in assessing the activation profiles of glial cells and cytokine activity in select respiratory control regions in the brainstem.Support or Funding InformationCentenary College Student‐Faculty Summer Research Award 2018 and 2019 (JRF and JAS); NIH R01HL081823 (FLP)

Complex bursting dynamics in an embryonic respiratory neuron model.

Pre-Bötzinger complex (pre-BötC) network activity within the mammalian brainstem controls the inspiratory phase of the respiratory rhythm. While bursting in pre-BötC neurons during the postnatal period has been extensively studied, less is known regarding inspiratory pacemaker neuron behavior at embryonic stages. Recent data in mouse embryo brainstem slices have revealed the existence of a variety of bursting activity patterns depending on distinct combinations of burst-generating INaP and ICAN conductances. In this work, we consider a model of an isolated embryonic pre-BötC neuron featuring two distinct bursting mechanisms. We use methods of dynamical systems theory, such as phase plane analysis, fast-slow decomposition, and bifurcation analysis, to uncover mechanisms underlying several different types of intrinsic bursting dynamics observed experimentally including several forms of plateau bursts, bursts involving depolarization block, and various combinations of these patterns. Our analysis also yields predictions about how changes in the balance of the two bursting mechanisms contribute to alterations in an inspiratory pacemaker neuron activity during prenatal development.

Whole-Brain Monosynaptic Inputs to Hypoglossal Motor Neurons in Mice

Hypoglossal motor neurons (HMNs) innervate tongue muscles and play key roles in a variety of physiological functions, including swallowing, mastication, suckling, vocalization, and respiration. Dysfunction of HMNs is associated with several diseases, such as obstructive sleep apnea (OSA) and sudden infant death syndrome. OSA is a serious breathing disorder associated with the activity of HMNs during different sleep–wake states. Identifying the neural mechanisms by which the state-dependent activities of HMNs are controlled may be helpful in providing a theoretical basis for effective therapy for OSA. However, the presynaptic partners governing the activity of HMNs remain to be elucidated. In the present study, we used a cell-type-specific retrograde tracing system based on a modified rabies virus along with a Cre/loxP gene-expression strategy to map the whole-brain monosynaptic inputs to HMNs in mice. We identified 53 nuclei targeting HMNs from six brain regions: the amygdala, hypothalamus, midbrain, pons, medulla, and cerebellum. We discovered that GABAergic neurons in the central amygdaloid nucleus, as well as calretinin neurons in the parasubthalamic nucleus, sent monosynaptic projections to HMNs. In addition, HMNs received direct inputs from several regions associated with respiration, such as the pre-Botzinger complex, parabrachial nucleus, nucleus of the solitary tract, and hypothalamus. Some regions engaged in sleep–wake regulation (the parafacial zone, parabrachial nucleus, ventral medulla, sublaterodorsal tegmental nucleus, dorsal raphe nucleus, periaqueductal gray, and hypothalamus) also provided primary inputs to HMNs. These results contribute to further elucidating the neural circuits underlying disorders caused by the dysfunction of HMNs.

Development of the brainstem respiratory circuit.

The respiratory circuit is comprised of over a dozen functionally and anatomically segregated brainstem nuclei that work together to control respiratory rhythms. These respiratory rhythms emerge prenatally but only acquire vital importance at birth, which is the first time the respiratory circuit faces the sole responsibility for O2 /CO2 homeostasis. Hence, the respiratory circuit has little room for trial-and-error-dependent fine tuning and relies on a detailed genetic blueprint for development. This blueprint is provided by transcription factors that have specific spatiotemporal expression patterns along the rostral-caudal or dorsal-ventral axis of the developing brainstem, in proliferating precursor cells and postmitotic neurons. Studying these transcription factors in mice has provided key insights into the functional segregation of respiratory control and the vital importance of specific respiratory nuclei. Many studies converge on just two respiratory nuclei that each have rhythmogenic properties during the prenatal period: the preBötzinger complex (preBötC) and retrotrapezoid nucleus/parafacial nucleus (RTN/pF). Here, we discuss the transcriptional regulation that guides the development of these nuclei. We also summarize evidence showing that normal preBötC development is necessary for neonatal survival, and that neither the preBötC nor the RTN/pF alone is sufficient to sustain normal postnatal respiratory rhythms. Last, we highlight several studies that use intersectional genetics to assess the necessity of transcription factors only in subregions of their expression domain. These studies independently demonstrate that lack of RTN/pF neurons weakens the respiratory circuit, yet these neurons are not necessary for neonatal survival because developmentally related populations can compensate for abnormal RTN/pF function at birth. This article is categorized under: Nervous System Development > Vertebrates: Regional Development.