Event:

Continuous attractor neural networks, which maintain population activity in a small number of possible states, are believed to support various cognitive functions, from working memory to spatial representations. One example of such networks is the head-direction (HD) circuit, a crucial signal for navigation. During sleep, HD neurons remain coordinated, coding for a "virtual" direction. This observation supports the idea that the HD network is driven by attractor dynamics, yet the origin and function of this coherent population activity during sleep remain unknown. Here, I will present evidence that the thalamus is crucial for the generation of this virtual signal during sleep. This observation confirms that the thalamus is not a mere relay of sensory signals but instead actively shapes representations. Furthermore, I will present evidence that this virtual signal during sleep actively participates in the replay of recently formed activity patterns in the hippocampus– a crucial phenomenon for memory formation. In summary, the thalamus plays a key role in conveying a coherent directional signal and actively contributes to memory processes in the hippocampus and associated structures during sleep.