Simultaneous single-unit recording from the basal amygdala and dorsal hippocampus

Animals seeking survival needs must be able to assess different locations
of threats in their habitat. However, the neural integration of spatial
and risk information essential for guiding goal-directed behavior remains
poorly understood. Thus, we investigated simultaneous activities of
fear-responsive basal amygdala (BA) and place-responsive dorsal
hippocampus (dHPC) neurons as rats left the safe nest to search for food
in an exposed space and encountered a simulated ‘predator.’ In this
realistic situation, BA cells increased their firing rates and dHPC place
cells decreased their spatial stability near the threat. Importantly, only
those dHPC cells synchronized with the predator-responsive BA cells
remapped significantly as a function of escalating risk location.
Moreover, optogenetic stimulation of BA neurons was sufficient to cause
spatial avoidance behavior and disrupt place fields. These results suggest
a dynamic interaction of BA’s fear signaling cells and dHPC’s spatial
coding cells as animals traverse safe-danger areas of their environment.

为满足生存需求，动物必须能够评估其栖息地内不同位置存在的威胁。然而，指导目标导向行为所必需的空间信息与风险信息的神经整合机制，目前仍未得到充分阐释。为此，我们在大鼠离开安全巢穴前往开阔空间觅食并遭遇模拟“捕食者”的实验情境中，同步记录了恐惧响应性基底杏仁核（basal amygdala, BA）与位置响应性背侧海马体（dorsal hippocampus, dHPC）神经元的活动。在该贴近自然的实验场景中，BA神经元的放电频率显著升高，而dHPC位置细胞在威胁附近区域的空间稳定性出现下降。尤为关键的是，仅与捕食者响应性BA神经元实现同步的dHPC细胞，会随风险位置的升级发生显著的重映射现象。此外，对BA神经元施加光遗传刺激，足以诱发空间回避行为并破坏dHPC的位置野。上述结果表明，当动物在环境的安全区域与危险区域间穿梭时，BA的恐惧信号神经元与dHPC的空间编码神经元之间存在动态交互作用。