Cholecystokinin-Expressing Interneurons of the Medial Prefrontal Cortex Mediate Working Memory Retrieval.

Distinct components of working memory are coordinated by different classes of inhibitory interneurons in the PFC, but the role of cholecystokinin (CCK)-positive interneurons remains enigmatic. In humans, this major population of interneurons shows histological abnormalities in schizophrenia, an illness in which deficient working memory is a core defining symptom and the best predictor of long-term functional outcome. Yet, CCK interneurons as a molecularly distinct class have proved intractable to examination by typical molecular methods due to widespread expression of CCK in the pyramidal neuron population. Using an intersectional approach in mice of both sexes, we have succeeded in labeling, interrogating, and manipulating CCK interneurons in the mPFC. Here, we describe the anatomical distribution, electrophysiological properties, and postsynaptic connectivity of CCK interneurons, and evaluate their role in cognition. We found that CCK interneurons comprise a larger proportion of the mPFC interneurons compared with parvalbumin interneurons, targeting a wide range of neuronal subtypes with a distinct connectivity pattern. Phase-specific optogenetic inhibition revealed that CCK, but not parvalbumin, interneurons play a critical role in the retrieval of working memory. These findings shine new light on the relationship between cortical CCK interneurons and cognition and offer a new set of tools to investigate interneuron dysfunction and cognitive impairments associated with schizophrenia.SIGNIFICANCE STATEMENT Cholecystokinin-expressing interneurons outnumber other interneuron populations in key brain areas involved in cognition and memory, including the mPFC. However, they have proved intractable to examination as experimental techniques have lacked the necessary selectivity. To the best of our knowledge, the present study is the first to report detailed properties of cortical cholecystokinin interneurons, revealing their anatomical organization, electrophysiological properties, postsynaptic connectivity, and behavioral function in working memory.

Maternal Obesity and Patterns in Postnatal Diet, Physical Activity and Weight among a Highly Deprived Population in the UK: The GLOWING Pilot Trial.

Preconception obesity is associated with adverse pregnancy outcomes and deprivation. The postnatal period provides an opportunity for preconception intervention. There is a lack of published postnatal behaviour and weight data to inform intervention needs. Secondary analysis of the GLOWING study explored postnatal diet, physical activity (PA) and weight among women living with obesity in deprivation. Thirty-nine women completed food frequency and PA questionnaires and provided weight measurement(s) between 3-12 months postnatal. Women's diet and PA fell short of national guidelines, especially for fruit/vegetables (median 1.6-2.0 portions/day) and oily fish (0-4 g/day). PA was predominantly light intensity. Patterns in weight change across time points indicated postnatal weight loss compared with 1st (median -0.8 to -2.3 kg) and 3rd-trimester weights (-9.0 to -11.6 kg). Weight loss was higher among women without excessive gestational weight gain (GWG) (-2.7 to -9.7 kg) than those with excessive GWG (2.3 to -1.8 kg), resulting in postnatal weight measurements lower than their 1st trimester. These pilot data suggest preconception interventions should commence in pregnancy with a focus on GWG, and postnatal women need early support to achieve guideline-recommendations for diet and PA. Further research in a larger population could inform preconception intervention strategies to tackle inequalities in maternal obesity and subsequent pregnancy outcomes.