Volume 55, February 2024, 101329Author links open overlay panel

Animals face behavioral problems that can be conceptualized in terms of a gradient of spatial and temporal proximity. I propose that solving close-proximity behavioral problems involves integrating disparate types of information in complex and flexible ways. In this framework, the midbrain periaqueductal gray (PAG) is understood as a key region involved in close-proximity motivated cognition. Anatomically, the PAG has access to signals across the neuroaxis via extensive connectivity with the cortex, subcortex, and brainstem. However, the flow of signals is not unidirectional, as the PAG projects to the cortex directly, and further ascending signal flow is attained via the midline thalamus. Overall, the anatomical organization of the PAG allows it to be a critical hub engaged in cognition ‘here and now.’

Section snippetsFrom cognition to motivated cognition

A hallmark of cognition is that it deals with control, goals, and decision-making. Another suggested property is that cognition frees animals from the ‘here and now’ as it involves capacities that can be future-oriented, including planning and selecting relevant sensory information that inform nonimmediate actions. For example, based on the availability of food and other information, chimpanzees may decide to forage in new patches (see [1]). In the process of foraging, the animals may actively

Periaqueductal gray and close-proximity processing

Before the 1980s, the PAG was considered a primitive brainstem reticular structure without differentiation. By the 1990s, the heterogeneity of this region was beginning to be understood in terms of a rostrocaudal axis of columnar anatomical organization also reflecting functional differentiation [7]. Nevertheless, the PAG was still viewed as involved in rather basic defensive, autonomic, and antinociception processes, among others — essentially a ‘behavioral expression’ or output nucleus.

One of

Control, goals, and decision-making ‘here and now’

The integration of information in the service of carrying out goals that go beyond the ‘here and now’ is a hallmark of cognition as usually conceptualized to involve the cortex — and the prefrontal cortex in particular. Here, I proposed that it is beneficial to conceptualize cognition more broadly as organized along a spatiotemporal proximity spectrum (Figure 1). The proposal thus builds upon ideas developed in ethological research, such as the predator imminence continuum [3] and modern

Declaration of Competing Interest

I have no conflict of interest.

Acknowledgements

The author’s research received support from the National Institute of Mental Health (MH071589). Thanks to Trang Nguyen for help with figures and Sydni Sobers for assistance with references.

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