brainbox.population.decode
Population functions.
Code from https://github.com/cortexlab/phylib/blob/master/phylib/stats/ccg.py by C. Rossant. Code for decoding by G. Meijer Code from sigtest_pseudosessions and sigtest_linshift by B. Benson
Functions
Classify trial identity (e.g. 

Return the number of spikes in a sequence of time intervals, for each neuron. 

Use linear discriminant analysis to project population vectors to the line that best separates the two groups. 

Perform linear regression to predict a continuous variable from neural data 

Uses a provably conservative Linear Shift technique (Harris, Kenneth Arxiv 2021, https://arxiv.org/ftp/arxiv/papers/2012/2012.06862.pdf) to estimate significance level of a statistical measure. 

Estimates significance level of any statistical measure following Harris, Arxiv, 2021 (https://www.biorxiv.org/content/10.1101/2020.11.29.402719v2). 

Compute all pairwise crosscorrelograms among the clusters appearing in spike_clusters. 
 get_spike_counts_in_bins(spike_times, spike_clusters, intervals)[source]
Return the number of spikes in a sequence of time intervals, for each neuron.
 Parameters
spike_times (1D array) – spike times (in seconds)
spike_clusters (1D array) – cluster ids corresponding to each event in spikes
intervals (2D array of shape (n_events, 2)) – the start and end times of the events
 Returns
counts (2D array of shape (n_neurons, n_events)) – the spike counts of all neurons ffrom scipy.stats import sem, tor all events value (i, j) is the number of spikes of neuron neurons[i] in interval #j
cluster_ids (1D array) – list of cluster ids
 xcorr(spike_times, spike_clusters, bin_size=None, window_size=None)[source]
Compute all pairwise crosscorrelograms among the clusters appearing in spike_clusters.
:param : :type : param spike_times: Spike times in seconds. :param : :type : type spike_times: arraylike :param : :type : param spike_clusters: Spikecluster mapping. :param : :type : type spike_clusters: arraylike :param : :type : param bin_size: Size of the bin, in seconds. :param : :type : type bin_size: float :param : :type : param window_size: Size of the window, in seconds. :param : :type : type window_size: float :param Returns an (n_clusters: :param n_clusters: :param winsize_samples) array with all pairwise: :param crosscorrelograms.:
 classify(population_activity, trial_labels, classifier, cross_validation=None, return_training=False)[source]
Classify trial identity (e.g. stim left/right) from neural population activity.
 Parameters
population_activity (2D array (trials x neurons)) – population activity of all neurons in the population for each trial.
trial_labels (1D or 2D array) – identities of the trials, can be any number of groups, accepts integers and strings
classifier (scikitlearn object) –
 which decoder to use, for example Gaussian with Multinomial likelihood:
from sklearn.naive_bayes import MultinomialNB classifier = MultinomialNB()
cross_validation (None or scikitlearn object) –
 which crossvalidation method to use, for example 5fold:
from sklearn.model_selection import KFold cross_validation = KFold(n_splits=5)
return_training (bool) – if set to True the classifier will also return the performance on the training set
 Returns
accuracy (float) – accuracy of the classifier
pred (1D array) – predictions of the classifier
prob (1D array) – probablity of classification
training_accuracy (float) – accuracy of the classifier on the training set (only if return_training is True)
 regress(population_activity, trial_targets, regularization=None, cross_validation=None, return_training=False)[source]
Perform linear regression to predict a continuous variable from neural data
 Parameters
population_activity (2D array (trials x neurons)) – population activity of all neurons in the population for each trial.
trial_targets (1D or 2D array) – the decoding target per trial as a continuous variable
regularization (None or string) – None = no regularization using ordinary least squares linear regression ‘L1’ = L1 regularization using Lasso ‘L2’ = L2 regularization using Ridge regression
cross_validation (None or scikitlearn object) –
 which crossvalidation method to use, for example 5fold:
from sklearn.model_selection import KFold cross_validation = KFold(n_splits=5)
return_training (bool) – if set to True the classifier will also return the performance on the training set
 Returns
pred (1D array) – array with predictions
pred_training (1D array) – array with predictions for the training set (only if return_training is True)
 lda_project(spike_times, spike_clusters, event_times, event_groups, pre_time=0, post_time=0.5, cross_validation='kfold', num_splits=5, prob_left=None, custom_validation=None)[source]
Use linear discriminant analysis to project population vectors to the line that best separates the two groups. When crossvalidation is used, the LDA projection is fitted on the training data after which the test data is projected to this projection.
 spike_times1D array
spike times (in seconds)
 spike_clusters1D array
cluster ids corresponding to each event in spikes
 event_times1D array
times (in seconds) of the events from the two groups
 event_groups1D array
group identities of the events, can be any number of groups, accepts integers and strings
 cross_validationstring
 which crossvalidation method to use, options are:
‘none’ No crossvalidation ‘kfold’ Kfold crossvalidation ‘leaveoneout’ Leave out the trial that is being decoded ‘block’ Leave out the block the tobedecoded trial is in ‘custom’ Any custom crossvalidation provided by the user
 num_splitsinteger
** only for ‘kfold’ crossvalidation ** Number of splits to use for kfold cross validation, a value of 5 means that the decoder will be trained on 4/5th of the data and used to predict the remaining 1/5th. This process is repeated five times so that all data has been used as both training and test set.
 prob_left1D array
** only for ‘block’ crossvalidation ** the probability of the stimulus appearing on the left for each trial in event_times
 custom_validationgenerator
** only for ‘custom’ crossvalidation ** a generator object with the splits to be used for cross validation using this format:
 (
(split1_train_idxs, split1_test_idxs), (split2_train_idxs, split2_test_idxs), (split3_train_idxs, split3_test_idxs),
…)
 n_neuronsint
Group size of number of neurons to be subselected
 Returns
lda_projection – the position along the LDA projection axis for the population vector of each trial
 Return type
1D array
 sigtest_pseudosessions(X, y, fStatMeas, genPseudo, npseuds=200)[source]
Estimates significance level of any statistical measure following Harris, Arxiv, 2021 (https://www.biorxiv.org/content/10.1101/2020.11.29.402719v2). fStatMeas computes a scalar statistical measure (e.g. R^2) between the data, X, and the decoded variable, y. pseudosessions are generated npseuds times to create a null distribution of statistical measures. Significance level is reported relative to this null distribution.
 X2d array
Data of size (elements, timetrials)
 y1d array
predicted variable of size (timetrials)
 fStatMeasfunction
takes arguments (X, y) and returns a statistical measure relating how well X decodes y
 genPseudofunction
takes no arguments () and returns a pseudosession (same shape as y) drawn from the experimentally known nulldistribution of y
 npseudsint
the number of pseudosessions used to estimate the significance level
 Returns
alpha (pvalue e.g. at a significance level of b, if alpha <= b then reject the null) – hypothesis.
statms_real (the value of the statistical measure evaluated on X and y)
statms_pseuds (array of statistical measures evaluated on pseudosessions)
 sigtest_linshift(X, y, fStatMeas, D=300)[source]
Uses a provably conservative Linear Shift technique (Harris, Kenneth Arxiv 2021, https://arxiv.org/ftp/arxiv/papers/2012/2012.06862.pdf) to estimate significance level of a statistical measure. fStatMeas computes a scalar statistical measure (e.g. R^2) from the data matrix, X, and the variable, y. A central window of X and y of size, D, is linearly shifted to generate a null distribution of statistical measures. Significance level is reported relative to this null distribution.
 X2d array
Data of size (elements, timetrials)
 y1d array
predicted variable of size (timetrials)
 fStatMeasfunction
takes arguments (X, y) and returns a scalar statistical measure of how well X decodes y
 Dint
the window length along the center of y used to compute the statistical measure. must have room to shift both right and left: len(y) >= D+2
 Returns
alpha (conservative pvalue e.g. at a significance level of b, if alpha <= b then reject the) – null hypothesis.
statms_real (the value of the statistical measure evaluated on X and y)
statms_pseuds (a 1d array of statistical measures evaluated on shifted versions of y)