The molecular mechanisms underlying the spatial mapping of the brain in Nature

How the brain forms these spatial maps is a shockingly complex process involving a complex molecular interaction of genes, proteins, and neural circuits to shape behavior

Now, through a multilablabel collaboration at the Blavatnik Institute at Harvard Medical School at Harvard Medical School, scientists have made significant progress

"This study spans different levels of understanding, establishing a fairly direct link between molecules and the function of behavioral and memory circuits," said

If these findings are translated into humans, they will provide vital new information

Memory-mapped

Located deep in the temporal lobe of the brain, the hippocampus plays an important role

"My lab has been studying spatial navigation for years, including how location cells form environmental maps and form spatial memories," Harvey says, but "the molecular mechanisms behind these processes are difficult to study

To study the molecular cascades involved in this mapping process, Harvey and first author Noah Pettit, a neurobiology researcher in Harvey's lab, and co-senior author Michael Greenberg, Nathan Marsh Pusey Professor of Neurobiology at HMS, and Lynn Yap, a graduate of harvard's Doctor of Neuroscience Program, completed the study

Greenberg's lab studies the Fos gene, which encodes a transcription factor protein

The researchers wondered if Fos was involved in the process

The team found that within a few hours of the mouse completing the navigation task, neurons with high Fos expression were more likely than mice with low Fos expression to form an accurate position field— cluster of position cells, which signal spatial position

When the researchers knocked out Fos in a subset of neurons in the hippocampus, they observed that the cells' spatial mapping of the environment was less accurate

"Fos seems to be important for maintaining the stability and accuracy of location cells, and over time it represents a spatial map in the brain," Greenberg said

For example, Greenberg hopes to delve deeper into the specific molecules and cells

While the study was conducted in mice, the researchers note that much of the system is preserved across species, including humans

"In terms of the work we've done, Harvey and I are almost as far apart as any lab in the department, but we came together to study how molecules interact with neural circuits

Noah L.