On Monday, September 2, 2013 6:11:51 PM UTC-4, chris peck wrote: > > Hi Craig > > Highlighting the word 'spontaneous' with astereixes doesnt show anything. > Here 'spontaneous' just means 'originates in the brain in the absence of > external stimuli'. This kind of activity is often refered to as 'task > unrelated' which is to say it is not activity that is bound to some > external task. Daydreaming and remembering past events are common examples. > You shouldn't confuse it with the idea of uncaused activity which evidently > you have done. > > I highlighted them to show that the word is not being used in any cryptic specialized sense, but rather it is used often, and in the general sense of being wholly unanticipated. Spontaneous in this case means originating in the brain in the absence of external stimuli but it also means originating in the brain in the absence of any known cause. The study goes to considerable lengths to make this clear.. note the gist of the headings:
Intrinsic Activity Accounts for Behaviorally Relevant Left SMC BOLD Variance Ruling Out Evoked Activity Ruling Out Stimulus-Evoked Activity Ruling Out Attention and Anticipation and finally, to directly address your claim: "Ruling Out Other Potential Confounds While sensory evoked activity and attention/anticipation are the most concerning potential confounds, other mechanisms should be considered. For example, global arousal might cause fluctuations in neuronal activity and behavior. *However, our BOLD-behavior effect should then be present in all regions or at least regions implicated in arousal (Critchley et al., 2000), not localized to the somatomotor system*. Similarly, after-effects such as the BOLD undershoot could persist from the previous trial, influencing early BOLD time points and confounding our results (Buxton et al., 1998). However, this possibility is excluded by the lack of a relationship between our BOLD measurement and ISI." Do daydreaming and remembering take place in the somatomotor system? Probably not. Another conclusion from the study: " Finally, it provides support for the intrinsic perspective on brain function, showing that the brain not only exhibits intrinsic organized fluctuations in neuronal activity, but that these fluctuations impact brain function and behavior in interesting and important ways." Not really anything there to support anything that you are claiming. Thanks, Craig > All the best. > > --- Original Message --- > > From: "Craig Weinberg" <whats...@gmail.com <javascript:>> > Sent: 3 September 2013 2:48 AM > To: everyth...@googlegroups.com <javascript:> > Subject: Re: Spontaneous Brain Activity Controls Behavior > > "Finally, there was a pronounced difference in the effect of regressing > out *spontaneous* activity on the left SMC BOLD-behavior relationship > with instructed versus *spontaneous *force variability. With > *spontaneous*force variability, regression of > *spontaneous* (right SMC) activity all but eliminated the left SMC > BOLD-behavior relationship. In contrast, with instructed force variability > regressing out *spontaneous* activity increased the significance of the > left SMC BOLD-behavior effect. This improvement in significance suggests > that regression of *spontaneous* activity removed noise that was > independent of the BOLD-behavior effect in the instructed condition. This > finding is important as it shows that an ipsilateral response alone is not > sufficient to eliminate the BOLD-behavior effect by regression as seen with > * spontaneous* force variability. > > *In summary, there are three pronounced differences between spontaneous > and instructed force variability in the current experiment: (1) the > reversal of the time course magnitudes, (2) the difference in the timing of > the significant BOLD-behavior effect, and (3) the difference in the effect > of regressing out spontaneous activity. As such, we can be relatively > confident that spontaneous and instructed force variability represent > distinct phenomena in the current experiment. "* > > > The study speaks for itself. What I think it means is what the researchers > also think it means. I don't know what you could imagine it would mean > otherwise. Spontaneous is used here in an ordinary way, not in some obscure > medical jargon which somehow actually means "anything but spontaneous". The > whole experiment is about isolating spontaneous activity from other types > of activity which respond to known conditions. > > You are welcome to explain exactly what you think this study shows in your > terms, but don't bother if you are just going to throw out unsupported > opinions. > > Thanks, > Craig > > > On Monday, September 2, 2013 11:18:31 AM UTC-4, stathisp wrote: > > > > The article doesn't show what you think it shows. "Spontaneous" doesn't > mean what you think it means. > > On 02/09/2013, at 12:35 PM, Craig Weinberg <whats...@gmail.com> wrote: > > > http://ac.els-cdn.com/S0896627307006666/1-s2.0-S0896627307006666-main.pdf?_tid=4e78eb70-1321-11e3-bc23-00000aab0f01&acdnat=1378052132_997e220cfcf62a6d02d5ccd22660a221 > > > The resting brain is not silent, but exhibits organized fluctuations in > neuronal activity even in the absence of tasks or stimuli. This intrinsic > brain activity persists during task performance and contributes to > variability in evoked brain responses. What is unknown is if this intrinsic > activity also contributes to variability in behavior. In the current fMRI > study, we identify a relation- ship between human brain activity in the > left somatomotor cortex and spontaneous trial-to-trial variability in > button press force. We then demonstrate that 74% of this brain-behavior > relationship is attributable to ongoing fluctuations in intrinsic activity > similar to those observed during resting fixation. > > The resting brain is not silent, but exhibits organized fluctuations in > neuronal activity even in the absence of tasks or stimuli. This intrinsic > brain activity persists during task performance and contributes to > variability in evoked brain responses. What is unknown is if this intrinsic > activity also contributes to variability in behavior. In the current fMRI > study, we identify a relation- ship between human brain activity in the > left somatomotor cortex and spontaneous trial-to- trial variability in > button press force. We then demonstrate that 74% of this brain-behavior > relationship is attributable to ongoing fluctuations in intrinsic activity > similar to those observed during resting fixation - See more at: > http://s33light.org/post/60036139333#sthash.sgzmIpwx.dpuf > The resting brain is not silent, but exhibits organized fluctuations in > neuronal activity even in the absence of tasks or stimuli. This intrinsic > brain activity persists during task performance and contributes to > variability in evoked brain responses. What is unknown is if this intrinsic > activity also contributes to variability in behavior. In the current fMRI > study, we identify a relation- ship between human brain activity in the > left somatomotor cortex and spontaneous trial-to- trial variability in > button press force. We then demonstrate that 74% of this brain-behavior > relationship is attributable to ongoing fluctuations in intrinsic activity > similar to those observed during resting fixation - See more at: > http://s33light.org/post/60036139333#sthash.sgzmIpwx.dpuf > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-li...@googlegroups.com. > To post to this group, send email to everyth...@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-li...@googlegroups.com <javascript:>. > To post to this group, send email to everyth...@googlegroups.com<javascript:> > . > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
