Questions tagged [signal-processing]
For questions about signal processing theory and its applications in psychology and cognitive neuroscience.
34
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Interpreting signal from plethysmography sensor
I have a plethysmography sensor by ADI Instruments, connected to a Biosemi ActiveTwo device. My goal is to measure heart rate, in the context of a social psychology lab experiment to investigate ...
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Hanning window size in EEG power spectrum
I must compute the power spectrum density of sleep EEGs. I was told by an experienced scientist that the process goes as follows:
Artifact detect/reject the EEG
Compute the power spectrum for every 2 ...
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Slow-wave EEG artifact removal
If we want to study a sleep EEG signal in any way (e.g. compute its power spectrum), do we need to remove artifacts from the whole EEG signal, or do we simply need to extract those epochs that ...
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Frequency band comparison between two groups
I am a beginner in signal processing. I have two resting eye closed data groups with group 1 having 40 data samples and group 2 having 100 samples. Both are taken from different devices with different ...
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Why is Electric Artefact still present in my recording?
I carried out EEG and EP studies on a daily basis. I occasionally electric artefact present within my studies, despite having my notch filter applied, low impedance, and subjects well grounded.
I ...
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Does the brain have code? [duplicate]
I am not sure if the brain is totally analogous to a computer but it certainly behaves like one in some respects. It seems to take input information from the environment, process that signal, store ...
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How to handle single trial ERP (P300)
I am learning to work with EEG data in young and elderly subjects. The goal is to find differences in P300 (amplitude & latency) between both age groups during learning. I analyzed the data based ...
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48
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Requirements and development of depth and spatial orientation sensing
I'm trying to understand from the signal processing perspective how the perception of depth and the ability of spatial orientation is calculated by our brains. One possible explanation seems to be ...
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3
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343
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Why are biosignals from the body said to be continuous?
Whether we talk about EEG, ECG or EKG aren't all these signals discrete as we are reading the voltages from the electrodes that are due to certain bio-chemical or bio-electrical activities. I do not ...
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How to chose which filter to design for EEG signal? [closed]
I am currently working on the EEG Grasp Dataset from Kaggle. I am aware that I need to filter the EEG signal as it is visually noisy (is there any way to mathematically show it's noisy?). How do I ...
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Reference signal when measuring EEG
When performing EEG, a number of electrodes are placed on the scalp to measure the electric potential difference between those locations and a reference. In the unipolar configuration, the reference ...
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208
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The number of things we can focus on at once
In terms of computer science, a programming runtime like JavaScript can be assumed to have 1 thread, or one thing to focus on at a time. The processor moves sequentially through instructions, ...
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What does fMRI data look like after pre-processing?
I wish to know what fMRI data looks like after preprocessing.
My Understanding
My understanding is that fMRI is MRI in time dimension that is we have repeated scans of brain volume. A voxel is a ...
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202
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Features for blink detection in real-time single channel EEG
I am looking to detect blink events in real-time single channel EEG. Classification of a moving window of samples to determine whether a blink artifact exists requires feature extraction (except when ...
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EEG segmentation and denoising which one should done first?
Because of EEG nature, in EEG analysis often researcher use Windowing/segmentation method.
As i currently work on sleep study, and in my study i need to analysis EEG data, i came to a problem.
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How do I determine whether my EEG signal needs denoising?
I recently start to work on sleep study.
For my research i download sleep EEG data from physionet. The EEG data has 100 HZ sampling rate and was recorded from 2 bipolar EEG site.
When i start the ...
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702
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Can a bipolar EEG signal be converted to a monopolar (unipolar) one?
I have bipolar EEG signal of Fpz-Cz of EEG sleep data which I have downloaded from physionet. I would like to have Fpz signal for my sleep study.
Is there any way I could convert a bipolar EEG signal ...
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What happens at sampling rates lower or higher that the Nyquist rate?
I do understand that for a signal to be properly sampled, it has to be done on the Nyquist sampling rate. What I do not understand is, what happens at sampling rates lower rate than the Nyquist rate, ...
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How do I measure ratio of EEG frequency band for a few electrodes in decibels?
I wanted to calculate the ratio of Theta/Beta ($\Theta$/$\beta$) in decibels for a couple of electrodes in AF3 AF4 and Cz
I was able to get these in microvolts, but would like to convert them to ...
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668
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EEGlab: power spectral density from a single EEG lead
I was trying to get power spectral density of a time-series data. The sleep recording software we use, doesn't allow to export EDF format of an interval, only of the whole record, but it allows to ...
4
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Noise free EEG signal data base
I am working on a research paper regarding EEG signal preprocessing. The first stage includes denoising the signal. However, since I need to evaluate the performance of the method I am using, I ...
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Window and noverlap values in pwelch function of Matlab
Could anyone please suggest what values to be used for Window and noverlap inputs of pwelch function in Matlab. I am using a 200 ms EEG signal with sampling frequency 1000 (so total samples 200) to ...
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How to map EEG time-series and visualize meditative states frequencies?
I came across this research article "Case Study of Ecstatic Meditation: fMRI and EEG Evidence of Self-Stimulating a Reward System" about the brainwaves when a Yogi went into a meditative level.
I ...
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249
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How is the biological error signal in predictive coding computed?
I am quite inspired by the results obtained by PredNet, which implements a predictive coding model using artificial neural networks. They compute the prediction error as a simple subtraction, and then ...
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143
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Oblique EPI in afni
It is my very first time with afni and I am having problems with the creation of the afni dataset from dicom images.
I runned:
...
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What are the methods to reject ocular artifacts in the EEG?
Is there any way to remove ocular artifacts from an EEG signal, other than applying independent component analysis, or manual rejection?
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997
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What is the meaning of the peak polarity in EEG data?
I wish to define neuronal activities by analyzing the peaks of each channel in EEG signals. Some papers use the negative peaks as a measure of neuronal activity and others deploy the positive peaks. ...
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48
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Library (or manual creation) of ERP components
I'm looking to test some computational models using ERP components as inputs (eg. p300, n170)
I'm wondering if there is an existing library anywhere that would have a bank of wave/component examples ...
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229
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Is there a reasonably easy way to get emotions from EEG?
I am building a project to visualise brain data from EEG, specifically emotions. I have found a significant numbers of papers that describe methods that include pre-processing, feature extraction and ...
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188
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Method/Unit for measuring activity in specific frequency band for EEG
This may be more of a signal processing question but I'm looking to measure and compare activity in different frequency bands for each sensor. Unfortunately, all papers I've looked at simply refer to "...
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75
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High Density Signal Meaning
When I was reading an article, I found that it describes the EEG signal as a high-density signal. So what is that mean?
EMG is high temporal resolution and moderate spatial resolution
(...
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422
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Python MNE - reading EEG data from array [closed]
I have EEG data that comes in the form of a 3D numpy array (epoch * channel * timepoint). timepoint is a 256 element array containing each sampled timepoint (1s total, at 256Hz). epoch is an ...
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What are proper EEG frequency bands and electrode placements for imagined speech?
I am doing an EEG experiment about imagined speech recognition. Which frequencies will have the most relevant information? I chose the frequency band [4-40] Hz as a start, mainly because of signal ...
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184
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How to analyze auditory steady state responses?
How does one usually go about analyzing the auditory steady state response (ASSR)? I have data where speech was amplitude modulated to a 40 Hz sine tone. There's 3.5 minutes of data; should I just ...
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