Title: Data associated with Allison, TA et al., 2020, Lingual electrotactile discrimination ability is associated with the presence of specific connective tissue structures (papillae) on the tongue surface

Abstract: Electrical stimulation of nerve endings in the tongue can be used to communicate information to users and has been shown to be highly effective in sensory substitution applications. The anterior tip of the tongue has very small somatosensory receptive fields, comparable to those of the fingertips, allowing for precise two-point discrimination and high tactile sensitivity. However, perception of electrotactile stimuli varies significantly between users, and across the tongue surface. Despite this, previous studies all used uniform electrode grids to stimulate a region of the dorsal-medial tongue surface. In an effort to customize electrode layouts for individual users, and thus improve efficacy for sensory substitution applications, we investigated whether specific neuroanatomical and physiological features of the tongue are associated with enhanced ability to perceive active electrodes. Specifically, the study described here was designed to test whether fungiform papillae density and/or propylthiouracil sensitivity are positively or negatively associated with perceived intensity and/or discrimination ability for lingual electrotactile stimuli. Fungiform papillae number and distribution were determined for 15 participants and they were exposed to patterns of electrotactile stimulation (ETS) and asked to report perceived intensity and perceived number of stimuli. Fungiform papillae number and distribution were then compared to ETS characteristics using comprehensive and rigorous statistical analyses.  Our results indicate that fungiform papillae density is correlated with enhanced discrimination ability for electrical stimuli. In contrast, papillae density, on average, is not correlated with perceived intensity of active electrodes. However, results for at least one participant suggest that further research is warranted. Our data indicate that propylthiouracil taster status is not related to ETS perceived intensity or discrimination ability. These data indicate that individuals with higher fungiform papillae number and density in the anterior medial tongue region may be better able to use lingual ETS for sensory substitution. 

Contact: Leslie Stone-Roy	

Email: Leslie.Stone-Roy@ColoState.EDU

Phone: 970-491-3801

Recommended data citation: Allison, T.S., Moritz, J., Turk, P., Stone-Roy, L.M. (2020) Data associated with "Lingual electrotactile discrimination ability is associated with the presence of specific connective tissue structures (papillae) on the tongue surface." Colorado State University. Libraries. http://dx.doi.org/10.25675/10217/210898

Format of data files: .csv

Location where data were collected: Fort Collins, Colorado

Time period during which data were collected: 2016-2018

File information:
This dataset includes two data files:
	1. Compiled fungiform papillae counts.csv contains information about fungiform distribution and density 
	2. Compiled data ETS PROP Papillae.csv contains information about participant perceptions of electrotactile stimulation, fungiform density, and reported perception of propylthiouracil taste (PROP) 
In addition, the consent form signed by participants is included as a PDF file:
	1. Consent form 2018.pdf

The data used to create manuscript figures 2, 3, 4, 6, 7, 8, 9 came from the Compiled data ETS PROP Papillae dataset and the data used to create figure 5 came from the Compiled fungiform papillae counts dataset. More details for each figure are described below:

Figure 2 uses perceived intensity data from the data set from subject 5 and subject 11 (average perceived intensity data over all distances and orientations for each of those participants).
Figure 3 uses all perceived intensity and discrimination distance data from all participants in the dataset.
Figure 4 uses data from the data set on the minimum vertical discrimination distances for subject 3 and subject 9.
Figure 5 uses the data from the Compiled fungiform papillae counts dataset.
Figure 6 uses the data from all subjects averaged over Location, Subarray, Distance and Orientation.
Figure 7 uses the data from all subjects and data from subject 5. 
Figure 8 uses the average perceived intensity data (over all distances and orientations) for subject 5, with overlayed locations of individual fungiform papillae from subject 5.
Figure 9 uses data from all subjects to determine the typical, average subject, and the calculated observed means for each subject.

Definitions & explanations of abbreviations:

Compiled data ETS PROP Papillae file:
* Taste - reported taste intensity to the bitter compound propylthiouracil using the General Labeled Magnitude Scale ranging from 1-100, with 100 being the most intense sensation.
* Subject - indicates each individual that was tested.
* Location  1 cm strip of tongue with Location 1 being the most anterior (or tip of the tongue).
* Subarray  1 cm strips of the tongue running parallel to the long axis of the tongue. Subarray 1 is the most left, Subarray 4 is the most right and Subarrays 2 and 3 are left/middle and right/middle respectively. 
* Distance  distance in mm between active electrodes on the device mouthpiece. These range from 2- 8 mm apart.
* Orient  refers to the orientation of the active electrodes. H = horizontal, V = vertical (parallel to long axis of tongue).
* SubSamp - refers to which of the rows or columns in a specific 1 cm2 region defined by Location and Subarray, that were activated for that data point. Individual subsample data were used to create tongue maps, but for statistical analyses, subsamples were treated as repeated samples for each 1 cm2 region. 
* PerInt  Perceived intensity on a scale of 1-10 with 10 being more intense.
* PerNum  Perceived number of active electrodes during experiment.
* Pap - average number of fungiform papillae in a specific 1 cm2 area defined by Location and Subarray.
* Discrim  represents whether 2 electrodes were discriminated, 1 represents yes and 0 represents no.

Compiled fungiform papillae counts file:
* Subject # - indicates each individual that was tested
* FP  Fungiform Papillae
* FP - L1S2  1 cm2 area defined by Location 1 Subarray 2 (most anterior cm and just left of the tongue midline)
* FP - L1S3  1 cm2 area defined by Location 1, Subarray 3 (most anterior cm and just right of the tongue midline)
* FP - L2S2  1 cm2 area defined by Location 2, Subarray 2 (starting 1 cm away from anterior edge of tongue and just left of the midline)
* FP - L2S3  1 cm2 area defined by Location 2, Subarray 3 (starting 1 cm away from anterior edge of tongue and just right of the midline)

For related information and methods refer to the following published articles: 

1. Allison, T.S., Moritz, J., Jr, Turk, P., Stone-Roy, L.M. (2020) Lingual electrotactile discrimination ability is associated with the presence of specific connective tissue structures (papillae) on the tongue surface. PLoS ONE 15(8): e0237142. https://doi.org/10.1371/journal.pone.0237142
2. Moritz, J., Turk, P., Williams, J., Stone-Roy, L.M. (2017) Perceived intensity and discrimination ability for lingual electrotactile stimulation depends on location and orientation of electrodes. Frontiers in Human Neuroscience. 11:186 doi: 10.3389/fnhum.2017.00186.

