Deciphering neural activity in the posterior intralaminar thalamus during competing multisensory pup cues

• Applicant: Mingyu Yang, Ph.D.
• Subject Area: Experimental and Theoretical Network Neuroscience
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 537190041

Offspring-oriented maternal care is often driven by the multimodal sensory signals that infants emit to communicate their physiological needs. However, for mothers with multiple children, the sensory cues from different infants may compete and create conflicting demands. In such situations, mothers must be able to flexibly adjust and switch their behavior to ensure the well-being of each infant. Therefore, it is critical to understand the neural substrates in the maternal brain that underlie the processing of infant-related multisensory competition and how they influence maternal behavioral switches. An example of competing multisensory infant cues received by maternal mice (dams) that occurs naturally in the wild, where they encounter somatosensory cues from pups in need of nursing and crouching over in the nest, as well as auditory cues of distress calls from isolated pups outside the nest that need to be retrieved. Interestingly, pup distress calls were found to reliably induce a rapid maternal behavioral switch from nursing/crouching over in the nest to actively searching for pups outside the nest. This suggests that auditory pup cues may act as a 'winning signal' over somatosensory pup cues, driving the maternal behavioral switch in this scenario. The posterior intralaminar complex of the thalamus (PIL) is a potential neural substrate involved in the processing of these competing multisensory pup cues. PIL receives input from primary sensory regions, such as the inferior colliculus and spinal cord, and responds to both auditory and somatosensory stimuli. Notably, silencing PIL via chemogenetic methods prevents dams from responding to pup distress calls. Moreover, within PIL, a specific subpopulation of neurons expressing calbindin (CB) is known to be particularly activated during maternal behaviors and social interactions. In the proposed project, I aim to investigate the activity of CB neurons in PIL in response to competing multisensory cues from infants and its influence on maternal behavior at the synaptic, circuit, and behavioral levels. To achieve this, I will combine electrophysiology in vitro, viral tracing techniques, fiber photometry, optogenetics in vivo, and behavioral studies using mice. By exploring the neural mechanisms behind maternal responses to competing multisensory infant cues, this research will significantly advance our understanding of how the maternal brain processes and resolves conflicting demands from offspring. The insights gained from this study have the potential to improve parenting strategies and promote the well-being of both mothers and their offspring.

• DFG Programme: WBP Position