Time, space, memory and brain–body rhythms

• Time and space are crucial concepts in neuroscience, because our personal memories are tied to specific events that occur ‘in’ a particular space and on a ‘timeline’. Thus, we seek to understand how the brain constructs time and space and how these are related to episodic memory. Place cells and time cells have been identified in the brain and have been proposed to ‘represent’ space and time via single-neuron or population coding, thus acting as hypothetical coordinates within a Newtonian framework of space and time. However, there is a fundamental tension between the linear and unidirectional flow of physical time and the variable nature of experienced time. Moreover, modern physics no longer views space as a fixed container and time as something in which events occur. Here, I articulate an alternative view: that time (physical and experienced) is an abstracted relational measure of change. Physical time is measured using arbitrary units and artificial clocks, whereas experienced time is linked to a hierarchy of brain–body rhythms that provide a range of reference scales that reflect the full span of experienced time. Changes in body and brain circuits, tied to these rhythms, may be the source of our subjective feeling of time.

Neurophysiology of Remembering

• By linking the past with the future, our memories define our sense of identity. Because human memory engages the conscious realm, its examination has historically been approached from language and introspection and proceeded largely along separate parallel paths in humans and other animals. Here, we first highlight the achievements and limitations of this mind-based approach and make the case for a new brain-based understanding of declarative memory with a focus on hippocampal physiology. Next, we discuss the interleaved nature and common physiological mechanisms of navigation in real and mental spacetime. We suggest that a distinguishing feature of memory types is whether they subserve actions for single or multiple uses. Finally, in contrast to the persisting view of the mind as a highly plastic blank slate ready for the world to make its imprint, we hypothesize that neuronal networks are endowed with a reservoir of neural trajectories, and the challenge faced by the brain is how to select and match preexisting neuronal trajectories with events in the world.

If I’m reading this right, bias is a function of neurophysiological alignment. Which is wild, but makes sense

Tasks

• Email to hotel – done
• Chores – done
• Laundry – done
• Groceries – done
• And a COLD, short ride.