Coding of space and time in the entorhinal cortex – Michael Hasselmo

TL;DR

Neurons in the brain encode both time and space, with some cells coding for specific intervals of time and others coding for specific locations in space.

Transcript

the four-stroke is by Michael Hassan Oh comes to us from Boston University I discovered he actually doesn't have a PhD which disturbed me but when I found out that he has a D feel from Oxford so that's good news and so he is of course very well known for his really interesting work on especially in your neuromodulators and computational work on und... Read More

Key Insights

• 👾 Neurons in the brain can encode both time and space.
• ❓ Environmental boundaries and neuromodulators can influence the firing patterns of these neurons.
• 👾 There is a continuum of coding characteristics among different types of neurons, suggesting a complex interplay between time and space.
• 👾 The coding of time and space is important for episodic memory and navigation.

Questions & Answers

Q: How do environmental boundaries affect the coding of space by neurons?

Environmental boundaries can influence the firing patterns of grid cells and boundary cells, causing compression or stretching of the spatial coding. This suggests that the brain uses visual features on boundaries to generate an allocentric representation of space.

Q: Are time cells influenced by neuromodulators?

While it hasn't been extensively studied, there is evidence to suggest that neuromodulators can modulate the firing patterns of time cells. Cholinergic modulation, for example, can rescale the coding of time by altering the slope of the firing rate response.

Q: Do neurons in the hippocampus and entorhinal cortex play a role in timing behavior?

Timing behavior is a general brain-wide phenomenon, and the hippocampus and entorhinal cortex are not the sole regions involved. However, these regions are important for timing in the context of episodic memory.

Q: Can head direction and movement direction be used interchangeably in grid cell coding?

No, head direction and movement direction are not the same. Grid cells require inputs from both head direction cells and movement direction signals to generate an allocentric representation of space. Lesions of head direction cells disrupt the spatial coding of grid cells.

Summary & Key Takeaways

• Neurons in the brain can code for both time and space, with some cells coding for specific time intervals and others coding for specific spatial locations.

• The coding of time and space is influenced by factors such as environmental boundaries and neuromodulators, which can affect the firing patterns of these neurons.

• Grid cells and boundary cells are two types of neurons that are involved in the spatial coding, while time cells are involved in the temporal coding of memory.