Interoception is a term used to describe the processes by which the brain detects, interprets, and responds adaptively to signals (pain, hunger, fatigue, etc.) coming from various organs in the body. In this episode University of Pennsylvania neuroscientist Nick Betley talks about recent research that has revealed key roles for relatively small numbers of neurons in the hypothalamus in interoception. Using cutting-edge imaging and molecular genetic tools Betley and his colleagues have shown how specific hypothalamic neurons can turn off pain signals and suppress inflammation. These findings have important implications for the development of interventions that alleviate chronic pain Intriguingly, they recently discovered that activation of a group of hypothalamic neurons (SF1 neurons) occurs in response exercise and their activation is required for endurance to increase with training. These findings suggest enhancement of hypothalamic SF1 neuron activity might prevent muscle loss during aging or in certain diseases or physical disabilities.

LINKS
Betley laboratory page:

https://web.sas.upenn.edu/betley-lab/

Exercise-induced activation of ventromedial hypothalamic steroidogenic factor-1 neurons mediates improvements in endurance.

https://www.cell.com/action/showPdf?pii=S0896-6273%2825%2900989-4

Anti-inflammatory effects of hunger are transmitted to the periphery via projection-specific AgRP circuits.

https://www.cell.com/action/showPdf?pii=S2211-1247%2823%2901350-5

A Neural Circuit for the Suppression of Pain by a Competing Need State.

https://www.cell.com/action/showPdf?pii=S0092-8674%2818%2930234-4

Normally activity in the brain's neural networks is tightly regulated by the interplay between neuronal excitation by the neurotransmitter glutamate and inhibition by GABA. An epileptic seizure is a dramatic example of what can happen when an abrupt excitatory imbalance occurs. However, excitatory imbalances also occur during aging and contribute to the dysfunction and degeneration of neurons in Alzheimer's disease. In this episode I talk with University of Washington Associate Professor Melissa Barker-Haliski about how neural network activity is normally regulated, the causes of hyperexcitability in neurological disorders, and the benefits and pitfalls of drugs that suppress neural network excitability.

LINKS

Barker-Haliski lab page:

https://sites.uw.edu/mhaliski/

Review articles:

https://pmc.ncbi.nlm.nih.gov/articles/PMC11390315/pdf/nihms-2013484.pdf

https://pmc.ncbi.nlm.nih.gov/articles/PMC9096090/pdf/fneur-13-833624.pdf

Original research articles:

https://www.sciencedirect.com/science/article/pii/S0014488625004510?via%3Dihub

https://journals.sagepub.com/doi/epub/10.1177/13872877251343321

https://onlinelibrary.wiley.com/doi/epdf/10.1111/epi.18395?saml_referrer

Stanford Professor Liqun Luo's laboratory investigates the mechanisms by which neural circuits in the brain are assembled during development and how this neuroarchitecture enables their functions throughout life. During the past 30 years his work has provided technical advances that enabled the establishment of roles for specific proteins in the formation of synaptic connections between individual neurons. In this episode I talk with Liqun about experiments using these technologies that revealed specific molecular codes on the surface of neurons that mediate either adhesive or repulsive interactions and thereby instruct synaptic partner matching during development neural circuits. Recent research in his laboratory has shown that the three-dimensional complexity of neural circuits in the olfactory system is achieved by serial reduction to one-dimensional projections. Professor Luo is a member of the National Academy of Sciences and author of "Principles of Neurobiology" a textbook widely used for undergraduate and graduate neuroscience courses.

LINKS

Luo lab webpage:

https://luolab.stanford.edu/

Review article on the architectures of neural circuits:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8916593/pdf/nihms-1746805.pdf

Article in Science on dimensionality reduction:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12614222/pdf/nihms-2120734.pdf

Article in Nature on repulsions and synaptic partner matching:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12804089/pdf/41586_2025_Article_9768.pdf

Article in Nature on altering an olfactory circuit by manipulating cell surface molecular codes:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12804075/pdf/41586_2025_Article_9769.pdf