@cristi This show, while not popsci does tend to leave off alot of jargon. The suprachiasmatic nuclei or SCN is part of the overall system they are speaking to when they talk about "as the brain ages, the speed at which your brain is able to synthesize information starts to drop off".
That part of the brain is essentially the "clock signal" for the rest of the brain. But on a more generalized basis. So not like the CPU timer crystal, but more like the clock in the bios.

So they talked about it, just not by name and not at length.
Interesting tidbit and I'm speaking from personal experience here...

There is a form of epilepsy, which can originate within the SCN in certain patients. Patients who have seizures with a focus there will often report time being in a "disordered state". This is especially true if the seizure activity is able to spread to primary processing areas of the brain involved in other time sensitive tasks such as synthesizing audio processing and visual processing.

There is mounting evidence that there is no single center in the brain where everything about anything is occurring. Instead of just the SCN, there are numerous "clocks" within the brain. Various regions doing various tasks and shuttling information back and forth into a shared memory.

The perception of conscious thought appears to be the result of exchange between each of these in a massively parallel manner. Everything that defines your subjective experience is essentially a pattern or a wave function of information.