Manfred Hallschmid (academic)

Manfred Hallschmid is a German academic who is Professor (W3) of Behavioral Neurobiology at the Department of Medical Psychology and Behavioral Neurobiology of the University of Tübingen, Germany. He obtained his PhD in psychology/human biology in 2005 and received awards by the German Society of Psychology, the German Society of Endocrinology, and the German Diabetes Society. Hallschmid’s primary research area is the central nervous regulation of energy fluxes in humans, with a focus on the role of neuropeptidergic messengers for metabolic control, as well as on the relationship between sleep, food intake and cognition.

Research

Hallschmid’s work includes studies on the role of oxytocin in food intake control, on brain effects of insulin, on the role of sleep for metabolic regulation, and on cognitive control as a target of neuromodulation-based interventions to improve eating behavior. His studies were among the first to provide evidence for a critical role of sex differences in central nervous insulin effects in humans, and to show that oxytocin, a hormone predominantly known for its psychosocial effects, regulates eating behavior in humans. Hallschmid’s research ranges from experiments in healthy humans to clinical populations to animal models and highlights the crucial links between metabolism and brain health.

His group showed that after intranasal administration, oxytocin markedly curbs primarily reward-driven (hedonic) calorie intake: in comparison to placebo, oxytocin reduced the consumption of chocolate cookies by 25%. Remarkably, the potential of acutely administered oxytocin to reduce food intake appears to be even more pronounced in males with increased body weight. In related experiments, oxytocin’s acute contribution to glucose homeostasis was studied in healthy, fasted male individuals. Intranasal oxytocin attenuated the peak excursion of plasma glucose and augmented the early increases in insulin and C-peptide concentrations in response to an oral glucose tolerance test while slightly blunting insulin and C-peptide peaks. Oral minimal model analyses revealed that oxytocin, compared with placebo, induced a pronounced increase in β-cell responsivity. These results highlight the role of oxytocin in the acute regulation of glucose metabolism in humans and support the conclusion that the oxytocin system may be a target of antidiabetic treatment. Still, results obtained in individuals with obesity or type 2 diabetes indicate that oxytocin administration is less effective in individuals with chronically impaired insulin sensitivity.

Hallschmid’s studies on the brain impact of insulin revealed that the hormone, when administered via the intranasal route, reduces food intake and, across longer intervention periods, body weight in healthy, normal-weight male individuals. These findings were among the first to confirm in humans the concept that insulin, like leptin, provides the brain with negative feedback on energy stored as body fat and thereby contributes to the regulation of food intake. In a parallel line of work, Hallschmid, together with Christian Benedict, investigated the potential of intranasal insulin to improve memory function in humans, a topic of particular interest in the context of memory impairments like Alzheimer’s disease. Notably, Hallschmid’s findings suggest that the role of brain insulin in food intake control may be more relevant in males than females, underlining the role of sex differences for brain functions and metabolic control. In further experiments, Hallschmid and coworkers investigated brain insulin sensitivity in postmenopausal females and the interplay between estrogen and insulin in food intake control and memory function. These studies open up avenues for future research into sex-specific differences in hormonal influences on cognition. With colleagues at the University of Tübingen, Hallschmid is currently exploring the nuanced complexities of sex and gender differences in brain function.

While Hallschmid’s research also tackles topics like hedonic hunger in obesity and how to normalize hunger in individuals with increased body weight with the help of fMRI neurofeedback, his studies have moreover added significant insights into the role of sleep for the control of eating behavior and peripheral metabolism. Work by Hallschmid and colleagues has, for example, shown that sleep contributes to the formation of metabolic memory because sleep deprivation prevents the adaptation of the counterregulatory response to recurrent hypoglycemia. Together with Jan Born, he demonstrated that slow-wave sleep, which predominantly occurs during the first night-half, renormalizes the strength of synaptic connections in the hypothalamus and, thereby, likely supports homeostatic control processes. On the other hand, pilot experiments indicate that – in healthy men – intensifying sleep slow oscillations does not acutely improve metabolic control. With a view to women’s mental health across the reproductive years, Hallschmid’s group came up with good news for expecting women by showing that, despite popular beliefs about the “baby brain”, sleep-associated memory formation is not impaired during the third trimester of pregnancy.

External links

• https://www.medizin.uni-tuebingen.de/de/das-klinikum/mitarbeiter/profil/1965
• https://orcid.org/0000-0002-0352-1106
• https://scholar.google.com/citations?hl=en&user=TswAdXAAAAAJ
• https://www.researchgate.net/scientific-contributions/Manfred-Hallschmid-38672523