JFK's Head Snap and the Implausible Jet-Effect and Neurospasm Theories

[Michael T. Griffith]

What does Mr. SPersonivan say:

No where does Mr. SPersonivan say that first reaction of the goat is the “decerebrate rigidity”, which he observes happening about one second after the shot. He is saying that the last movement of the goat takes place 1,000 milliseconds after the impact of the bullet.

So, when is the soonest reaction of the goat observed? Later he states:

His entire HSCA testimony is on the following website:

https://mcadams.posc.mu.edu/russ/jfkinfo/hscastur.htm

It doesn’t matter if the film is shot at 24 frames per second or 2,400 frames per second. Four one-hundredths of a second is still four one-hundredths of a second. Or 40 milliseconds. 40 milliseconds after impact, the back legs start to go out.

Ah-ahhh ! ! !


So, yes, I confess. If we define the length of time that the goat starts to react as being the last time the goat moved at all, then the goat reaction time is 1,000 milliseconds. Damm, that is one slow goat. But if we define the length of time that the goat starts to react as being the first time he starts to move, the goat’s reaction time is 40 milliseconds.

If I can define JFK’s reaction time the same way Mr. Griffith does, when the backward movement of JFK stopped, at frame 321, then JFK’s reaction time was 490 milliseconds. Well within the possible reaction time of Dr. Zacharko, Dr. Mantik and all of his other experts.

Ah-ahhhhh !!!!!!!!!!!!!!!!

Keep trying, but you haven’t got my goat yet.

Oh boy oh boy. Apparently you do not know what "decerebrate" means and what a "decerebrate reaction" is. Apparently you don't understand that when SPersonivan talked about the beginning and end (terminus) of the "decerebrate reaction," he was referring to the neuromuscular reaction. Instead, you're assuming that when SPersonivan said "and that takes places about a second after the shot," he was only talking about half of the actions he had just described, because you think that the decerebrate reaction is separate from the neuromuscular reaction. First, let's read SPersonivan again:

The first sequence will be a normal 24-frame-per-second view of this. This is a real time. First, we will observe the neuromuscular reaction, the goat will collapse then, and by the wiggling of his tail and the tenseness of the muscles we will see what I think has sometimes been called the decerebrate rigidity, and that takes place about a second after the shot and then slowly dissipates and you will see the goat slump, obviously dead.

The decerebrate reaction and terminus of the decerebrate reaction. (1 HSCA 416)

Now let's see what "decerebrate" means:

. . . the arms and legs being held straight out, the toes being pointed downward, and the head and neck being arched backward. The muscles are tightened and held rigidly. This type of posturing usually means there has been severe damage to the brain.

That is exactly the reaction that SPersonivan describes seeing in the 2400 fps film, and he calls it "the neuromuscular reaction that I described," which could only refer to the description of the real-time film:

. . . then the neuromuscular reaction that I described begins to happen; the back legs go out, under the influence of the powerful muscles of the back legs, the front legs go upward and outward, that back arches, as the powerful back muscles overcome those of the abdomen. (1 H 417)

SPersonivan knew what "decerebrate reaction" means, and he used it synonymously with "neuromuscular reaction." His syntax could have been a little clearer, but if you know what "decerebrate" means, you can see he was not saying that the decerebrate reaction was different from the neuromuscular reaction--he knew enough not to make such a fundamental error.

Now that we have that point cleared up, you need to deal with his observation that in "real time" the neuromuscular reaction began about 1000 milliseconds after bullet impact.

[Joe Elliott]

Just to make sure that I'm understanding you right, by Z-314.5 you mean what we know as Z315?

No. I am not measuring time to the nearest frame, but to the nearest tenth of a frame. Each tenth of a frame is roughly 5 milliseconds long.

z-312.0 is when the shutter opens for frame 312. Roughly 27 milliseconds later the shutter closes at z-312.5. Frame z-312 shows images from time z-312.0 through z-312.5.

I believe the bullet struck at z-312.5, or there abouts, right when the shutter closed or very shortly after. Below is a possible, approximate, time scale. Basically, my best very rough estimate:

Vis    Time    Time
able    in      in
        sec.    Zap         Event
----  -----    -------     ---------------
       0.000   z-312.5   Shutter closes.
       0.000   z-312.5   Bullet impact.
       0.001   z-312.5   Bullet leaves head,
                                momentum has been deposited into head,
                                the head starts moving at a steady speed forward.
       0.027   z-313.0   Shutter opens.
vis   0.027   z-313.0       Head is now 1 inch in front of z-312 position, same steady speed
vis   0.055   z-313.5       Head is now 2 inches in front of z-312 position, same steady speed
       0.055   z-313.5   Shutter closes.
       0.077   z-314.0   Shutter opens.
vis   0.082   z-314.1   Neuromuscular spasm commences,
vis                                 Head starts moving back, initially slowly.
vis   0.110   z-314.5   Head is now 1.5 inches ahead of 312.5 position.
       0.110   z-314.5   Shutter closes.

“vis” refers to events that may be visible, because the shutter was open.

Again, this is not to represent exact locations. I don’t have the timing down to the nearest 5 milliseconds. Just a possible scenario consistent with what the Zapruder film shows and William Hoffman’s data.

In this scenario, the neuromuscular spasm started 82 milliseconds after the bullet impact. The real time  of reaction could be a little more, or less.

[Joe Elliott]

Oh boy oh boy. Apparently you do not know what "decerebrate" means and what a "decerebrate reaction" is. Apparently you don't understand that when SPersonivan talked about the beginning and end (terminus) of the "decerebrate reaction," he was referring to the neuromuscular reaction. Instead, you're assuming that when SPersonivan said "and that takes places about a second after the shot," he was only talking about half of the actions he had just described, because you think that the decerebrate reaction is separate from the neuromuscular reaction. First, let's read SPersonivan again:

What does Mr. SPersonivan mean when he says:

Four one-hundredths of a second after that impact then the neuromuscular reaction that I described begins to happen; the back legs go out, under the influence of the powerful muscles of the back legs, the front legs go upward and outward, that back arches, as the powerful back muscles overcome those of the abdomen.

Don’t change the subject. Don’t quote a different portion of the testimony.

Just give me your interpretation of this sentence.


My interpretation is that 40 milliseconds after the impact of the bullet, the goat’s body starts to move.


The section you quote is ambiguous. Does it mean the “decerebrate reaction” starts after one second? Does he mean the wiggling of the tail stops after one second? It is ambiguous. You ignore the clear, unmistakable sentence, and focus and a statement that is ambiguous, and insist on interpreting it your way. If your interpretation is correct, then the later clear sentence, which I focus on, does not make sense. That is why I draw your attention to, and everybody else’s attention, to the clear, unmistakable sentence.

[Michael T. Griffith]

In this scenario, the neuromuscular spasm started 82 milliseconds after the bullet impact. The real time  of reaction could be a little more, or less.

Amazing. For the past week or so you have repeatedly said that JFK's head began to move backward 55 milliseconds after bullet impact. I trust I don't need to quote you to yourself. But, well, now that you realize you need that movement to start later--much later--to allow for the mere possibility that it was caused by a neurospasm, you suddenly decide that it might have begun 82 milliseconds after impact, an increase of 48%.

[Tim Nickerson]

Oh boy oh boy. Apparently you do not know what "decerebrate" means and what a "decerebrate reaction" is. Apparently you don't understand that when SPersonivan talked about the beginning and end (terminus) of the "decerebrate reaction," he was referring to the neuromuscular reaction. Instead, you're assuming that when SPersonivan said "and that takes places about a second after the shot," he was only talking about half of the actions he had just described, because you think that the decerebrate reaction is separate from the neuromuscular reaction. First, let's read SPersonivan again:

Now let's see what "decerebrate" means:

That is exactly the reaction that SPersonivan describes seeing in the 2400 fps film, and he calls it "the neuromuscular reaction that I described," which could only refer to the description of the real-time film:

SPersonivan knew what "decerebrate reaction" means, and he used it synonymously with "neuromuscular reaction." His syntax could have been a little clearer, but if you know what "decerebrate" means, you can see he was not saying that the decerebrate reaction was different from the neuromuscular reaction--he knew enough not to make such a fundamental error.

Now that we have that point cleared up, you need to deal with his observation that in "real time" the neuromuscular reaction began about 1000 milliseconds after bullet impact.

SPersonivan may have been using "decerebrate reaction" synonymously with "neuromuscular reaction" ,but you err in assuming that he was using "decerebrate rigidity" synonymously with "neuromuscular reaction". He used "terminus of the decerebrate reaction" synonymously with "decerebrate rigidity".

[Joe Elliott]

Amazing. For the past week or so you have repeatedly said that JFK's head began to move backward 55 milliseconds after bullet impact. I trust I don't need to quote you to yourself. But, well, now that you realize you need that movement to start later--much later--to allow for the mere possibility that it was caused by a neurospasm, you suddenly decide that it might have begun 82 seconds after impact, an increase of 48%.

I have no need to increase it. The goat starts moving after 40 milliseconds. I only meant to clarify that 55 milliseconds is an approximate time. I don’t know if it was 49 milliseconds, 64 milliseconds or 82 milliseconds. I never meant the 55 milliseconds to be some sort of precise estimate. Anymore than I mean 82 milliseconds is a precise estimate.

[Michael T. Griffith]

What does Mr. SPersonivan mean when he says:

Don’t change the subject. Don’t quote a different portion of the testimony.

Don't change the subject?! You erroneously assumed that SPersonivan was describing two separate reactions in the real-time film because you didn't know what "decerebrate" meant! But now you want to ignore that gaffe and ignore that SPersonivan said the neuromusuclar reaction occurred in about 1000 milliseconds in real time.

Just give me your interpretation of this sentence. My interpretation is that 40 milliseconds after the impact of the bullet, the goat’s body starts to move.

Then please explain what SPersonivan meant when he stated in pretty plain English that in "real time" the reaction took about 1,000 milliseconds. Is "real time" really not real time? Did SPersonivan just egregiously misspeak?

[Tim Nickerson]

No. I am not measuring time to the nearest frame, but to the nearest tenth of a frame. Each tenth of a frame is roughly 5 milliseconds long.

z-312.0 is when the shutter opens for frame 312. Roughly 27 milliseconds later the shutter closes at z-312.5. Frame z-312 shows images from time z-312.0 through z-312.5.

I believe the bullet struck at z-312.5, or there abouts, right when the shutter closed or very shortly after. Below is a possible, approximate, time scale. Basically, my best very rough estimate:

Vis    Time    Time
able    in      in
        sec.    Zap         Event
----  -----    -------     ---------------
       0.000   z-312.5   Shutter closes.
       0.000   z-312.5   Bullet impact.
       0.001   z-312.5   Bullet leaves head,
                                momentum has been deposited into head,
                                the head starts moving at a steady speed forward.
       0.027   z-313.0   Shutter opens.
vis   0.027   z-313.0       Head is now 1 inch in front of z-312 position, same steady speed
vis   0.055   z-313.5       Head is now 2 inches in front of z-312 position, same steady speed
       0.055   z-313.5   Shutter closes.
       0.077   z-314.0   Shutter opens.
vis   0.082   z-314.1   Neuromuscular spasm commences,
vis                                 Head starts moving back, initially slowly.
vis   0.110   z-314.5   Head is now 1.5 inches ahead of 312.5 position.
       0.110   z-314.5   Shutter closes.

“vis” refers to events that may be visible, because the shutter was open.

Again, this is not to represent exact locations. I don’t have the timing down to the nearest 5 milliseconds. Just a possible scenario consistent with what the Zapruder film shows and William Hoffman’s data.

In this scenario, the neuromuscular spasm started 82 milliseconds after the bullet impact. The real time  of reaction could be a little more, or less.

Thanks for clarifying.

I think that we have been wrongly assuming that the start of the backward head movement was the initiation of the neuromuscular spasm. That backward motion was from the jet effect and the neuromuscular reaction initiated a couple of frames later.