Cell-type-specific hypothalamic pathways to brainstem drive context-dependent strategies in response to stressors.

Adaptive behavioral responses to stressors are critical for survival. However, which brain areas orchestrate switching the appropriate stress responses to distinct contexts is an open question. This study aimed to identify the cell-type-specific brain circuitry governing the selection of distinct behavioral strategies in response to stressors. Through novel mouse behavior paradigms, we observed distinct stressor-evoked behaviors in two psycho-spatially distinct contexts characterized by stressors inside or outside the safe zone. The identification of brain regions activated in both conditions revealed the involvement of the dorsomedial hypothalamus (DMH). Further investigation using optogenetics, chemogenetics, and photometry revealed that glutamatergic projections from the DMH to periaqueductal gray (PAG) mediated responses to inside stressors, while GABAergic projections, particularly from tachykinin1-expressing neurons, played a crucial role in coping with outside stressors. These findings elucidate the role of cell-type-specific circuitry from the DMH to the PAG in shaping behavioral strategies in response to stressors. These findings have the potential to advance our understanding of fundamental neurobiological processes and inform the development of novel approaches for managing context-dependent and anxiety-associated pathological conditions such as agoraphobia and claustrophobia.

Involvement of superior colliculus in complex figure detection of mice.

Object detection is an essential function of the visual system. Although the visual cortex plays an important role in object detection, the superior colliculus can support detection when the visual cortex is ablated or silenced. Moreover, it has been shown that superficial layers of mouse SC (sSC) encode visual features of complex objects, and that this code is not inherited from the primary visual cortex. This suggests that mouse sSC may provide a significant contribution to complex object vision. Here, we use optogenetics to show that mouse sSC is involved in figure detection based on differences in figure contrast, orientation, and phase. Additionally, our neural recordings show that in mouse sSC, image elements that belong to a figure elicit stronger activity than those same elements when they are part of the background. The discriminability of this neural code is higher for correct trials than for incorrect trials. Our results provide new insight into the behavioral relevance of the visual processing that takes place in sSC.