This BARTH_CMC_README.txt file was generated on 2020-10-06 by BRADLEY BARTH



GENERAL INFORMATION

1. Title of Dataset: Data from: The control of colonic motility using electrical stimulation to modulate enteric neural circuitry 

2. Author Information
	A. Principal Investigator Contact Information
		Name: Warren Grill
		Institution: Duke University
		Email: warren.grill@duke.edu

	B. Alternative Contact Information
		Name: Bradley Barth
		Institution: Duke University
		Email: bradley.barth@duke.edu

	C. Co-investigator Contact Information
		Name: Nick Spencer
		Institution: Flinders University
		Email: nicholas.spencer@flinders.edu.au                       

	E. Alternative Contact Information
		Name: Lee Travis
		Institution: Flinders University
		Email: lee.travis@flinders.edu.au

3. Date of data collection (single date, range, approximate date):
    Start: 2019-09-13
    End: 2020-10-06

4. Geographic location of data collection:
    Duke University, Durham, NC, 27710 USA
    Flinders University, Bedford Park, South Australia, 5042, AUSTRALIA 

5. Information about funding sources that supported the collection of the data: 
    This work was conducted at Duke University and Flinders University with financial support from NIDDK R01DK119795 (WMG), NHMRC #1156416 (NJS), ARC DP190103628 (NJS), and the Department of Biomedical Engineering at Duke University.



DATA & FILE OVERVIEW

1. File List: 
    2b_MC_interval.csv: The interval before CMCs and the duration of CMCs in the isolated mouse colon for spontaneous CMCs and CMCs evoked by electrical stimulation
    2c_median_MC_interval.csv: The median values for each preparation and type of CMC (spontaneous or evoked) from 2b_MC_interval.csv        
    3c_refractory_period_at_1T.csv: The refractory period at stimulation threshold for CMCs evoked by electrical stimulation after spontaneous or after evoked CMCs
    3d_relative_refractory_period.csv: The refractory period after spontaneous CMCs at stimulation threshold or at 40% above stimulation threshold
    3e_absolute_refractory_period.csv: The refractory period as a function of stimulus amplitude
    4_entrainment.csv: The duration of entrainment and number of successfully evoked CMCs with closed-loop electrical stimulation delivered after a delay following the previous CMC
    8f_propagation_velocity.csv: The actual and apparent velocity of contraction propagation for different locations of electrical stimulation along the colon
    supplementary_fig_1.pdf: Increasing diameter of distension reduces the MC interval. The mean interval between the onset of an MC and the cessation of the prior MC is significantly lower for maintained physiological distension at 2.6 mm compared to 2.1 mm, determined by an unpaired t-test (p = 0.0100, n = 7).
    supplementary_fig_2.pdf: Interval preceding spontaneous and evoked MCs. The interval between the onset of an MC and the cessation of the prior MC was collected from the experiments to measure the refractory period after spontaneous MCs. The first MCs to occur after a stimulus (red) and all subsequent MCs (black) are plotted as spontaneous (x) or evoked (o) MCs (n = 8).

2. Relationship between files, if important: 
    The median data from 2b_MC_interval.csv are reported in 2c_median_MC_interval.csv. The median duration and interval for each preparation (mouse) and type of CMC (spontaneous or evoked) are reported in 2c_median_MC_interval.csv. 

3. Are there multiple versions of the dataset? yes/no
    Not as of 2020-10-06
  A. If yes, name of file(s) that was updated: 
		i. Why was the file updated? 
		ii. When was the file updated? 



METHODOLOGICAL INFORMATION           

1. Description of methods used for collection/generation of data: 
    Myoelectric activity in the isolated mouse colon was recorded from the serosal surface opposite of the mesenteric border using one or two suction electrodes. Experiments were conducted using two different experimental rigs with similar, but not identical equipment. Rig 1 recorded AC-coupled and DC-coupled EMG separately using ISO-80 (World Precision Instruments, Sarasota, FL, USA) and DAM-50 (World Precision Instruments) amplifiers, respectively. Both signals were processed with a HumBug 50 Hz low-pass filter (Quest Scientific, North Vancouver, BC, Canada). Rig 2 recorded DC-coupled EMG using a SR560 low noise amplifier (Stanford Research Systems, Sunnyvale, CA, USA) with 1kHz low-pass filter and a 50 Hz digital low-pass filter. The DC-coupled recordings were transformed into AC-coupled recordings with digital high-pass filters at 0.5 Hz. Both rigs acquired data at 1kHz sampling rate in LabChart 8 using PowerLab (AD Instruments, Colorado Springs, CO, USA). 
    
    Electrical stimulation was delivered as 100 pulses with 400 µs per phase at 20 pulses per second. Rig 1 used voltage-controlled stimulation (S48 and SIU5B, Grass Instruments) to deliver 50 V monophasic pulses via tungsten electrodes. Rig 2 used current-controlled stimulation to deliver symmetric, biphasic pulses at varying amplitudes via suction electrodes. At Rig 2, stimulating current was isolated (Model 2200, A-M Systems, Sequim, WA, USA) dc-filtered, and monitored across a 1kO resistor. The threshold was coarsely determined in 0.1 mA increments as the minimum current necessary to evoke an MC. Preparations in which electrical stimulation delivered at threshold and 30 s after the end of the preceding MC did not evoke an MC were excluded from this study (n = 1). Electrical stimulation was defined to evoke an MC successfully if the onset of an MC was detected within 20 s of the beginning of electrical stimulation.

2. Methods for processing the data: 
    We measured the actual and apparent velocity of the contraction wavefront in sham stimulation and with electrical stimulation delivered in the proximal, middle, and distal colon. The actual velocity was calculated as the mean velocity of the contraction while it was propagating, before and after the temporary arrest induced by electrical stimulation. The apparent velocity was calculated as the net velocity for the continuous propagation from the oral to aboral end of the preparation. 


              
DATA-SPECIFIC INFORMATION FOR: 2b_MC_interval.csv

1. Number of variables: 4

2. Number of cases/rows: 171

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Type: Referring to either Spontaneous or Evoked CMCs
    Duration (s): Duration, in seconds, of the CMC
    Interval (s): Interval, in seconds, between the end of the previous CMC and the onset of this CMC


              
DATA-SPECIFIC INFORMATION FOR: 2c_median_MC_interval.csv

1. Number of variables: 4

2. Number of cases/rows: 14

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Type: Referring to either Spontaneous or Evoked CMCs
    median(Duration (s)): median Duration, in seconds, of the CMC, from 2b_MC_interval.csv
    median(Interval (s)): meidan Interval, in seconds, between the end of the previous CMC and the onset of this CMC, from 2b_MC_interval.csv
     

              
DATA-SPECIFIC INFORMATION FOR: 3c_refractory_period_at_1T.csv

1. Number of variables: 6

2. Number of cases/rows: 13

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Type: Referring to either Spontaneous or Evoked CMCs
    Threshold (mA): Minimum current, in milliamps, necessary to evoke a CMC
    Amplitude (mA): Current amplitude, in milliamps, used to evoke CMCs
    Amplitude (T): Current amplitude normalized to threshold (unitless)
    Refractory Period (s): Measured refractory period, in seconds      
     

              
DATA-SPECIFIC INFORMATION FOR: 3d_relative_refractory_period.csv

1. Number of variables: 7

2. Number of cases/rows: 14

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Type: Referring to either Spontaneous or Evoked CMCs
    Threshold (mA): Minimum current, in milliamps, necessary to evoke a CMC
    Amplitude (mA): Current amplitude, in milliamps, used to evoke CMCs
    Amplitude (T): Current amplitude normalized to threshold (unitless) 
    Amplitude Group: Whether low or high current amplitude was used
    Refractory Period (s): Measured refractory period, in seconds    
     

              
DATA-SPECIFIC INFORMATION FOR: 3e_absolute_refractory_period.csv

1. Number of variables: 7

2. Number of cases/rows: 30

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Type: Referring to either Spontaneous or Evoked CMCs
    Threshold (mA): Minimum current, in milliamps, necessary to evoke a CMC
    Amplitude (mA): Current amplitude, in milliamps, used to evoke CMCs
    Amplitude (T): Current amplitude normalized to threshold (unitless)
    Refractory Period (s): Measured refractory period, in seconds     
    Outlier: Indicates if a value is an outlier by stimulus amplitude group    
     

              
DATA-SPECIFIC INFORMATION FOR: 4_entrainment.csv

1. Number of variables: 8

2. Number of cases/rows: 16

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Refractory Period (s): Measured refractory period, in seconds     
    Delay (s): Delay, in seconds, between the end of the previous CMC and the start of electrical stimulation
    Delay (R): Delay normalized to refractory period (unitless)
    Delay Group: Whether low or high delay was used
    Duration of Entrainment (min): The duration, in minutes, of continued entrainment, measured from the start of the first stimulus train to evoke a CMC to the start of the first stimulus train that failed to evoke a CMC
    Evoked CMCs: The number of CMCs that were evoked consecutively
    Exlcuded: Indicates if a preparation met the exclusion criteria for this study
     

              
DATA-SPECIFIC INFORMATION FOR: 8f_propagation_velocity.csv

1. Number of variables: 4

2. Number of cases/rows: 40

3. Variable List:
    Mouse: Unique identifier for each preparation of isolated mouse colon
    Stimulus: Location of electrical stimulus along colon; none if no stimulus delivered
    Actual Velocity (mm/s): The mean velocity, in millimeters per second, of the contraction wavefront while the wavefront was moving                                               
    Apparent Velocity (mm/s): The mean velocity, in millimeters per second, of the contraction wavefront averaged over the duration of propagation