Brain-machine interfaces

CSGnet Archive CSG2004
1

from Phil Runkel on 18 Jan 04, replying to Rick Marken’s of 17 Jan 04 at 08:28:29:

Thanks for your story about using GSR to control your perception of the size of a square on a computer screen and for your use of it to comment on the news item about the monkey who was doing something similar. I have not read the original article(s) about the monkey (and I guess neither have you), so maybe we are speculating beyond our facts, but after reading your message, I had a thought that I want to ask about.

Neural sensors detect changes in electrical voltage. Voltage can be affected by electrical potentials produced by neurons, and also by the conductivity of local chemicals (as in GSR). When I read that the experimenters were using neural sensors, I thought of all the “experiments” in which the experimenters ask the subject to watch a movie of a football game (let’s say), and find that the electrical voltage in the XYZ area is changing, and declare that they now know that football is controlled, or mediated, or processed, in the XYZ area.

As you pointed out, your excited thoughts produced changes in your GSR. Maybe if you attached a GSR sensor in your armpit, and watched an exciting football game, you could announce that the area for control, or mediation, or processing of football is the armpit!

Am I oversimplifying?

--Phil R.

2

Martin Taylor 2004.01.19.0107]

From Phil Runkel on 18 Jan 04, replying to Rick Marken's of 17 Jan
04 at 08:28:29:

Thanks for your story about using GSR to control your perception of
the size of a square on a computer screen and for your use of it to
comment on the news item about the monkey who was doing something
similar.....
As you pointed out, your excited thoughts produced changes in your
GSR. Maybe if you attached a GSR sensor in your armpit, and watched
an exciting football game, you could announce that the area for
control, or mediation, or processing of football is the armpit!

Am I oversimplifying?

Probably. It's a matter of degrees of freedom.

Many years ago, I watched a demonstration of controlling the location
of a cursor on a screen using head-mounted sensors (EEG). You
couldn't do that with GSR, because it's a 2-dimensional problem.

But your point is reasonable. Activity in an area only shows that
there is some correlation, not that the area is THE functional area
for the behaviour studied. Activity there might only be an
inconsequential side-effect of the real important brain work.

Martin

3

[From Rick Marken (2004.01.19.0900)]

From Phil Runkel on 18 Jan 04, replying to Rick Marken�s of 17 Jan 04 at
08:28:29:

Thanks for your story about using GSR to control your perception of the
size of a square on a computer screen and for your use of it to comment
on the news item about the monkey who was doing something similar. I
have not read the original article(s) about the monkey (and I guess
neither have you), so maybe we are speculating beyond our facts, but
after reading your message, I had a thought that I want to ask about.

I think I saw a news report on this work. As I recall, it showed the hookup
between monkey's and cursor (the monkey's did a one dimensional tracking
task) and it also showed a monkey controlling the cursor by "brain waves".

The interesting part of the work is that the researchers manage to transfer
the monkeys from controlling the cursor using their hand to controlling it
using their brain. I think they gradually decrease the influence of the
monkeys' hand and increase the influence of the monkeys' brain waves on the
cursor. It's quite an impressive demonstration of animal training.

I forget whether, when the cursor is influenced only by brain waves, the
monkey stops using the hand. My guess is that some monkeys do stop using the
hand and some don't, even though it is ineffective. It would depend on where
reorganization end up. If someone knows what happens maybe they could let us
know. I think it would be an interesting test of the reorganization model of
PCT. I think the prediction of the reorganization model would be that
continued use of the hand would occur in about 1/2 the monkeys.

Neural sensors detect changes in electrical voltage. Voltage can be
affected by electrical potentials produced by neurons, and also by the
conductivity of local chemicals (as in GSR). When I read that the
experimenters were using neural sensors, I thought of all the
�experiments� in which the experimenters ask the subject to watch a
movie of a football game (let�s say), and find that the electrical
voltage in the XYZ area is changing, and declare that they now know that
football is controlled, or mediated, or processed, in the XYZ area.

As you pointed out, your excited thoughts produced changes in your GSR.
Maybe if you attached a GSR sensor in your armpit, and watched an
exciting football game, you could announce that the area for control, or
mediation, or processing of football is the armpit!

As Martin Taylor said, it is a degrees of freedom issue. When gross measures
of the amplitude of physiological activity, GSR or brain waves, is used as
the means of influencing the controlled variable, there is really only one
df (amplitude) available for control.

Always great to hear from you, Phil.

Best regards

Rick

···

--
Richard S. Marken
MindReadings.com
Home: 310 474 0313
Cell: 310 729 1400

4

To Martin Taylor and Rick Marken: Thanks for your replies to my query
about the armpit. Helps keep me reasonably close to the track. --P

5

[From Dick Robertson,2004.01.19.1830CDT]

Philip Runkel wrote:

   Part 1.1 Type: Plain Text (text/plain)
From Phil Runkel on 18 Jan 04, replying to Rick Marken�s of 17 Jan 04
at
08:28:29:

Thanks for your story about using GSR to control your perception of
the
size of a square on a computer screen and for your use of it to
comment
on the news item about the monkey who was doing something similar....

As you pointed out, your excited thoughts produced changes in your
GSR.
Maybe if you attached a GSR sensor in your armpit, and watched an
exciting football game, you could announce that the area for control,
or
mediation, or processing of football is the armpit!

I love it. Thanks, Phil

Best,

Dick R

···