Topic: Episode #359

[Steven Novella]

Interview with Debbie Feldman
This Day in Skepticism: Bridget Bishop
News Items: Medical Zombies, Science of Reruns, Leakey on Evolution
Who's That Noisy
Your Questions and E-mails: Local Darkmatter Followup
Science or Fiction    This week's topic is:
What's the Harm?
Connect with the

[Trinoc]

Thanks folks. WTN starts at 34:40.

Surely it can't be as simple as a normal heartbeat or pulse heard through a stethoscope, or even detected by ultrasound or laser, so I wonder what the special thing about it is.

Edit: Maybe some sort of quack healing sound loop, like this? (Though this isn't it.)

Healing Heart Pulse - (Mind Entrainment + Developmental Heartbeat) V2

[chexuma]

WTN: I'm going to go with a pulsar. Though a mystical space baby's heartbeat seems reasonable too.

[mwilley]

It's the signal from vega in the movie of Carl Sagan's book 'Contact'.
Jodi Foster sits upright and clamps her earphones on, eyes widening. All of a sudden the film gets interesting for a short while. 

[Evil Eye]

WTN guess. The sound of a Quasar from the series Cosmos.

EDIT next day... CRAP! I meant to say PULSAR.

[mwilley]

Did anyone notice an edit when Steve was talking about Scientology. It's as if he was going to say something criticising the church, but then there was a blip and a jump cut and he was talking about something else.
Is there something going on that we, the listeners, don't know about?  Have the lawyers gotten to the SGU?

[mmmichael]

Did anyone notice an edit when Steve was talking about Scientology. It's as if he was going to say something criticising the church, but then there was a blip and a jump cut and he was talking about something else.
Is there something going on that we, the listeners, don't know about?  Have the lawyers gotten to the SGU?

It's a conspiracy! Haha, but really, I noticed the blip as well. I notice them a semi-frequently, actually. My guess would be that this and most edits are made for less dubious reasons.

[Hanes]

Madness!  Total Recall is an awesome movie.  Of course it's bad, but it was never good.  It's great for what it is, which is an Arnold Scifi flick.

[stretcher]

Man, the bit about cannibalism... I was in line for food, almost lost my appetite.

[Crusafontia]

My hypothesis on the shrinking brain:

It may be that rather than more intelligence as a consequence of a larger brain, the reverse is true--that as an evolutionary response to greater intelligence and our reliance on it, we evolved a larger brain.

Since brain size has been linked to longevity, in smaller, preliterate cultures, longer-lived elders would conserve and contribute to the cultural pool of knowledge.  Note that all that is necessary is longevity in certain lucky individuals as opposed to average lifetime of the entire community (maximum useful lifespan vs. average life expectancy).  In other words, having a few lucid elders as repositories would be crucial to maintain the benefits of experience, customs, expertise and technological innovation. 

Another thing to remember is that the brain cannot repair itself like the rest of the body.  We may be able to continuously regenerate skin cells, but we can't grow a new brain since we must maintain existing neuronal relationships in order to preserve memory and who we are.  Brain growth must begin early, then stabilize as maturity is reached.  At that point we have a lifetime reserve of brain cells that, in case of injury or disease, neuronal redundancy serves to mitigate the damage.

If brain size is decreasing while intelligence is stable, perhaps it is our softer lifestyle, but it could also be that older age individuals as repositories are no longer necessary with literate populations and mass culture.

To sum up:

1 Larger brain is an evolutionary product of greater intelligence and reliance on it, not the commonly believed reverse.
2 A brain must maintain integrity with redundancy as opposed to regeneration
3 A modern decrease in size is due to less need of individual older people as repositories of culture as they were in small preliterate communities
4 Larger brains have been linked to greater longevity in mammals in general and specifically in primates. (see refs below) 

Brain weight and life-span in primate species.
J Allman, T McLaughlin, and A Hakeem

Hofman MA. Energy metabolism, brain size and longevity in mammals. Q Rev Biol. 1983 Dec;58(4):495–512. [PubMed]

[GodSlayer]

does the guest's voice remind anyone else of Eliza Dushku?

[GodSlayer]

re minute 59

how do these groups get around mandatory education for ages 5-15 (or whatever it is) laws?

[Ice Wolf]

WTN : I think it is a heart beat .

Sounds a lot like a pleural rub but speed is too quick for breath sounds .

Best guess is that it's a pericardial rub.

Ice Wolf

[Trinoc]

Another thing to remember is that the brain cannot repair itself like the rest of the body.  We may be able to continuously regenerate skin cells, but we can't grow a new brain since we must maintain existing neuronal relationships in order to preserve memory and who we are.  Brain growth must begin early, then stabilize as maturity is reached.  At that point we have a lifetime reserve of brain cells that, in case of injury or disease, neuronal redundancy serves to mitigate the damage.

Hasn't this recently been found to be a myth, and that new brain cells do grow in later life? How memories are stored is obviously still largely a mystery, but I think it's pretty much accepted that it is a distributed process so that, for instance, knocking out one particular bunch of cells will not erase my memory of the cat I had as a child while leaving associated memories intact. I think some research also suggests that memories are is a sense rewritten (a bit like some sorts of computer memory) when they are accessed, to the extent that (say) traumatic memories can be partly erased by getting the subject to recall them and then causing a major distraction which prevents the memory from getting written back reliably. This suggests that, at least for memories we recall periodically, these could get copied into new nerve cells, leaving behind any dead cells which formerly formed part of the memory.

That's my amateur take on the subject. I'm sure Steve could put me right on a lot of things.

[cyclosarin]

WTN: Sounds like auscultation of a heartbeat with a systolic murmur, classically a "pansystolic" murmur would be due to mitral valve regurgitation or a ventricular septal defect.