Processing Speed

Cerebellum

Coordination and timing, and increasingly recognised as carrying part of cognitive processing speed as well as movement. Included because motor slowing shows up in the drug literature on anti-estrogens and has nowhere else to point.

Cerebral White Matter

The wiring between the processors. It carries the speed at which regions can talk to each other, so damage here presents as slowness and poor coordination between functions.

Iron

Carries oxygen in haemoglobin and sits in the active site of several enzymes. Absorption is the bottleneck, ahead of intake, which is why so much of the absorption layer points here.

Myelination

The insulation on axons that sets how fast signals travel. It is maintained continuously, and it is sensitive to thyroid hormone and to sex steroids, both of which these protocols move.

Sleep Quality

How restorative sleep is, as opposed to how much of it there is. Deep and REM sleep are where growth hormone is released and where memory is consolidated, so this is the measure that connects a sleep effect to a memory effect. A person can sleep eight hours and get almost none of this.