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[Neuroscience] Re: Brain and awarness

feedbackdroids at yahoo.com feedbackdroids at yahoo.com
Thu Mar 30 14:07:16 EST 2006


Glen M. Sizemore wrote:
> Ohhhhh! I see. We couldn't just say that the person responds, in part, to
> the pitcher's motion. A copy of the pitcher's motion has to get inside the
> brain where the homunculus can see it. Right Dan?
>
>


A single-celled protozoan has a "lightspot" [actually, an aggregation
of light-sensitive molecules] on one side right next to its flagellum
base. Apparently they cause production of some chemical which
stimulates the flagellum to move. Do you think the protozoan could hit
a baseball pitch? If not, why not?

Hint: it doesn't have the necessary "internal" sensory and motor
mechanisms.



>
> <feedbackdroids at yahoo.com> wrote in message
> news:1143741168.024219.135950 at e56g2000cwe.googlegroups.com...
> >
> > tehgabriel at web.de wrote:
> >> Hi!
> >> The average reaction time of humans is around 1 s (e.g. time one needs
> >> to initiate braking his car after the perception of a red light).
> >> Training and expectation (you know that a certain event will happen)
> >> can lower the reaction time to 0.1 to 0.4 s. So, definitivley below 0.5
> >> s.
> >>
> >> Concerning your example with the pitcher (I am not familiar with
> >> baseball) i would assume what enables one to hit the ball properly is
> >> the ability to predict a chain of subsequent events. One can predict
> >> (note that precision of prediction increases with experience/practise):
> >> how the pitcher will move  =>  at which point the ball will leave his
> >> hand  =>  the way of the ball
> >>
> >> Regards,
> >> Thomas
> >>
> >
> >
> > This is exactly correct. Nothing in cognition [ala brain operation]
> > simply starts and stops at specific times. Rather all operations are
> > performed in the context of "on-going" foreground and background
> > activity. In the end, I think, people will come to realize that this is
> > the key issue involved in the correct interpretation of Libet's
> > experiments, too.
> >
> > Eg, if you look at the P300 alerting wave, it doesn't simply exist at
> > one point in time, with a clearcut beginning and end. Rather, it builds
> > up steadily over a 100-200 msec time span, and than wanes over an
> > additional 500-800 msec. It just happens to "peak" at about 300 msec.
> > What this indicates is that neural activity persists in internal neural
> > feedback loops for much longer than simple 1-to-1 transmission between
> > neurons, which will take only 10-20 msec. For activity to last upwards
> > to 800-msec, it must involve multiple passes around the internal loops,
> > while first more and then less neural tissue is being recruited into
> > the process.
> >
> > All of this internal activity is taking place within the brain during
> > any cognitive or behavioral task. This is continually performed
> > internally while the external events are taking place. As the pitcher
> > gets ready to throw, winds up, stretches, and then releases the ball,
> > all of these external activities are reflected by internal brain
> > operations in the batter in preparation to hit the ball. Each step
> > involves updating internal predictions of where the ball will go.
> > Without these internal predictions, the batter couldn't possibly hit
> > the ball. Every nuance of the pitcher's activity will change the
> > internal predictions in some way, before the pitch. After the ball is
> > pitched, its trajectory will further modify the internal predictions,
> > and the movement of the muscles to hit the ball. Finally, batters can
> > modify the bat trajectories even as they swing, based upon where they
> > predict the ball will be going as the flight ensues.
> >
> > The best pitchers either throw the ball so fast that the batter's
> > predictive [and probably motor] machinery cannot keep up, or else are
> > able to throw balls with so much spin that the balls suddenly change
> > course too late for the batters to be able to respond. Eg, balls that
> > come relatively straight but then suddenly sink over the plate at the
> > last instant, as the spin effects build up. Spin effects are pretty
> > cool. When I bowled the 3 or 4 times I ever bowled, I had a wicked hook
> > on the ball. It would fly down the edge of the lane, first relatively
> > straight due to forward momentum, and then at the last instant curve
> > around and into the pins, and spin took over from forward momentum.
> > Neat.
> >
> > For a 100 MPH pitch [the fastest recorded], and 90' to the plate, it
> > only takes about 0.6 sec for the ball to travel the distance, so
> > without an entire spectrum of one-after-another perceptual cues and
> > especially internal predictive mechanisms, the batter could never ever
> > hit the ball.
> >



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