Substantia Nigra Dopamine Neuronal Responses to Habenular Stimulation and Foot Shock Are Altered by Lesions of the Rostromedial Tegmental Nucleus.

Dopamine (DA) neurons of the substantia nigra (SN) and ventral tegmental area generally respond to aversive stimuli or the absence of expected rewards with transient inhibition of firing rates, which can be recapitulated with activation of the lateral habenula (LHb) and eliminated by lesioning the intermediating rostromedial tegmental nucleus (RMTg). However, a minority of DA neurons respond to aversive stimuli, such as foot shock, with a transient increase in firing rate, an outcome that rarely occurs with LHb stimulation. The degree to which individual neurons respond to these two stimulation modalities with the same response phenotype and the role of the RMTg is not known. Here, we record responses from single SN DA neurons to alternating activation of the LHb and foot shock in male rats. Lesions of the RMTg resulted in a shift away from inhibition to no response during both foot shock and LHb stimulation. Furthermore, lesions unmasked an excitatory response during LHb stimulation. The response correspondence within the same neuron between the two activation sources was no different from chance in sham controls, suggesting that external inputs rather than intrinsic DA neuronal properties are more important to response outcome. These findings contribute to a literature that shows a complex neurocircuitry underlies the regulation of DA activity and, by extension, behaviors related to learning, anhedonia, and cognition.

Perspectives of Home-Based Child Care Providers in New Mexico on Barriers and Facilitators to Participating in the Child and Adult Care Food Program, 2021-2022.

This study examined New Mexico home-based child care provider perspectives (n = 75) on barriers to and facilitators of Child and Adult Care Food Program (CACFP) participation. Two thirds of the sample were Spanish speakers. Providers reported that CACFP reimbursement does not cover actual food costs and the time-and-effort costs of obtaining qualifying foods and completing required documentation. They noted that additional reimbursed meals are needed for children in care for extended hours and that linguistically competent CACFP sponsor staff facilitated their participation. (Am J Public Health. 2023;113(S3):S215-S219. https://doi.org/10.2105/AJPH.2023.307402).

Quantitative and qualitative sex difference in habenula-induced inhibition of midbrain dopamine neurons in the rat.

Introduction: Clinically relevant sex differences have been noted in a number of affective, behavioral, cognitive, and neurological health disorders. Midbrain dopamine neurons are implicated in several of these same disorders and consequently are under investigation for their potential role in the manifestation of these sex differences. The lateral habenula exerts significant inhibitory control over dopamine neuronal firing, yet little is known about sex differences in this particular neurocircuit. Methods: We performed in vivo, single unit, extracellular recordings of dopamine neurons in female and male anesthetized rats in response to single pulse stimulation of the lateral habenula. In addition, we assessed baseline firing properties of lateral habenula neurons and, by immunochemical means, assessed the distribution of estrogen receptor alpha cells in the lateral habenula. Results: Habenula-induced inhibition of dopamine neuronal firing is reduced in female rats relative to male rats. In addition, male rats had a higher prevalence of rebound excitation. Furthermore, the firing pattern of lateral habenula neurons was less variable in female rats, and female rats had a higher density of estrogen receptor alpha positive cells in the lateral habenula. Discussion: We found that the dopamine neuronal response to habenular stimulation is both qualitatively and quantitatively different in female and male rats. These novel findings together with reports in the contemporary literature lead us to posit that the sex difference in dopamine inhibition seen here relate to differential firing properties of lateral habenula neurons resulting from the presence of sex hormones. Further work is needed to test this hypothesis, which may have implications for understanding the etiology of several mental health disorders including depression, schizophrenia, and addiction.

New Mexico Sponsors Identify Time and Money as Factors Affecting Home-Based Provider Child and Adult Care Food Program Engagement.

OBJECTIVE: Describe Child and Adult Care Food Program (CACFP) sponsor perspectives on barriers and facilitators to home-based provider CACFP eligibility, enrollment, and participation and ways to improve provider support. METHODS: Semistructured interviews were conducted with 11 New Mexico CACFP sponsor staff representing 9 out of 13 agencies (69% response rate) from August to September, 2020. Interviews were analyzed using thematic analysis with an essentialist/realist epistemological approach. RESULTS: Sponsor-perceived barriers to provider CACFP: eligibility (costs, background checks, fear/stigma, and delays in becoming state-approved providers); enrollment (lack of translated/low-literacy materials and cumulative systems requirements); and participation (challenges maintaining qualifying menus and documentation and accessing qualifying food, inadequate reimbursements, and unannounced visits). Sponsors suggested systems changes to improve provider support (eg, more assistance with becoming state-approved and for start-up costs and accessible, progressive nutrition training opportunities). CONCLUSIONS AND IMPLICATIONS: Sponsors noted CACFP barriers for home-based providers and identified corresponding systems changes that could be tested.

Characterization of the cognitive impairments induced by prenatal exposure to stress in the rat.

We have previously shown that male rats exposed to gestational stress exhibit phenotypes resembling what is observed in schizophrenia, including hypersensitivity to amphetamine, blunted sensory gating, disrupted social behavior, impaired stress axis regulation, and aberrant prefrontal expression of genes involved in synaptic plasticity. Maternal psychological stress during pregnancy has been associated with adverse cognitive outcomes among children, as well as an increased risk for developing schizophrenia, which is characterized by significant cognitive deficits. We sought to characterize the long-term cognitive outcome of prenatal stress using a preclinical paradigm, which is readily amenable to the development of novel therapeutic strategies. Rats exposed to repeated variable prenatal stress during the third week of gestation were evaluated using a battery of cognitive tests, including the novel object recognition task, cued and contextual fear conditioning, the Morris water maze, and iterative versions of a paradigm in which working and reference memory for both objects and spatial locations can be assessed (the "Can Test"). Prenatally stressed males were impaired relative to controls on each of these tasks, confirming the face validity of this preclinical paradigm and extending the cognitive implications of prenatal stress exposure beyond the hippocampus. Interestingly, in experiments where both sexes were included, the performance of females was found to be less affected by prenatal stress compared to that of males. This could be related to the finding that women are less vulnerable than men to schizophrenia, and merits further investigation.