[Eeglablist] Measuring clusters using numerical integration/ area under the curve

[Makoto Miyakoshi]

Dear Elizabeth,

Steve Luck must be such a kind person. Good for you.

Makoto

On Sat, Dec 10, 2016 at 3:22 PM, Elizabeth J Kirkham <
ekirkham1 at sheffield.ac.uk> wrote:

> Dear Makoto,
>
> Thank you for your advice. I actually tried emailing the ERPLAB list after
> emailing the EEGLAB list and got a helpful response from Steve Luck. So I
> don't think my email to the EEGLAB list needs to go out anymore.
>
> Best wishes,
> Elizabeth
>
> On 8 December 2016 at 02:52, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
>
>> Dear Elizabeth,
>>
>> While waiting for other experts in this list write you back, why don't
>> you write to ERPLAB mailing list too if you haven't.
>> http://erpinfo.org/erplab/erplab-email-list
>>
>> Personally I have no experience with it so I can't help you, sorry. I
>> hope other researchers here can help you.
>>
>> Makoto
>>
>> On Mon, Dec 5, 2016 at 11:52 AM, Elizabeth J Kirkham <
>> ekirkham1 at sheffield.ac.uk> wrote:
>>
>>> Dear all,
>>>
>>> I am using the area under the curve methodology to measure my ERP
>>> waveforms. To do this, I am using ERPLAB's Measurement tool function, with
>>> the settings "Numerical Intergration/Area between two fixed latencies",
>>> "Rectified area (negative values become positive)".
>>>
>>> I want to examine the waveform over two clusters of electrodes (P5, P7
>>> and TP7; and P6, P8 and TP8).
>>>
>>> There are two ways for me to examine these clusters, either (1) create
>>> the cluster in ERPLAB (ERPLAB > ERP operations > ERP channel operations),
>>> and then use the Measurement tool to find the Numerical Integration values
>>> for the cluster, or (2) use the Measurement tool to find the Numerical
>>> Integration values for each electrode separately, and then average them
>>> together later (for example in Excel).
>>>
>>> I have found that these measures produce different output values. The
>>> values are not the same in absolute terms, or in relative terms. (For
>>> example, the values for one participant in conditions 1 and 2 are 0.523 and
>>> 0.630 using the first method, and 1.698 and 1.641 using the second method.)
>>>
>>> I don't know if these different values are because I have made a
>>> mistake, or if differences in output are to be expected when using
>>> numerical integration?
>>>
>>> If it is the case that I have not made a mistake, is there a best
>>> practice in terms of which way round to carry out the procedures? Should I
>>> average the channels in ERPLAB, and then take the measurement, or take the
>>> measurement for each channel separately, and then average the output
>>> together?
>>>
>>> Thanks in advance,
>>> Elizabeth
>>>
>>>
>>> --
>>> Elizabeth Kirkham
>>> PhD Researcher
>>>
>>> Department of Psychology
>>> The University of Sheffield
>>> Floor E
>>> Cathedral Court
>>> 1 Vicar Lane
>>> Sheffield
>>> S1 2LT
>>> UK
>>>
>>>
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>>
>>
>>
>> --
>> Makoto Miyakoshi
>> Swartz Center for Computational Neuroscience
>> Institute for Neural Computation, University of California San Diego
>>
>
>
>
> --
> Elizabeth Kirkham
> PhD Researcher
>
> Department of Psychology
> The University of Sheffield
> Floor E
> Cathedral Court
> 1 Vicar Lane
> Sheffield
> S1 2LT
> UK
>
>


-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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