HoloDBS is an application that simulates fiber pathway activation during deep brain stimulation (DBS). DBS electrodes can be placed within an atlas brain model and a simple representation of an activation volume can be associated with the electrode contacts. The streamlines intersecting the activation volume can be displayed to provide an approximation of fiber pathway activation for a given electrode location. References: CIT168 Atlas Brain: Pauli WM, Nili AN, Tyszka JM. A high-resolution probabilistic in vivo atlas of human subcortical brain nuclei. Sci Data. 2018 Apr 17;5:180063. Axonal Pathways: Petersen MV, Mlakar J, Haber SN, Parent M, Smith Y, Strick PL, Griswold MA, McIntyre CC. Holographic Reconstruction of Axonal Pathways in the Human Brain. Neuron. 2019 Dec 18;104(6):1056-1064. DBS Simulation: Noecker AM, Frankemolle-Gilbert AM, Howell B, Petersen MV, Beylergil SB, Shaikh AG, McIntyre CC. StimVision v2: Examples and Applications in Subthalamic Deep Brain Stimulation for Parkinson's Disease. Neuromodulation. 2021 Feb;24(2):248-258. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Instructions for Use -Brain models can be turned on and off and displayed as transparent or opaque using the menu on the left side of the interactive user interface. -Electrodes can be placed 1) using the stereotactic controls on the interactive user interface, 2) using control buttons which become accessible when pointing at the active electrode within the model, or 3) with a manual pinch and place action. In order to place an electrode manually, the user must point to the active electrode, click the “Controls” button with the three bars to display the electrode control buttons (these may be easier to see with the nuclei set to transparent), and click the button with the rectangle at the upper left corner of the electrode control buttons. This results in a “cage” surrounding the active electrode. When the cage is visible, that electrode can be moved by pinching the cage between the thumb and forefinger and placing it within the brain model. For extra control of where the electrode is released, the user can say the command “DROP” and wait a moment before releasing the pinch. -Image slices can be displayed by selecting the T1 or T2 button, and selecting the checkbutton corresponding to the axial, coronal, sagittal, probe, or free slice that the user wants to display. Once visible, an image slice can be moved by pinching the edge of the image between the thumb and forefinger and placing it where desired. For extra control of where the image slice is released, the user can say the command “DROP” and wait a moment before releasing the pinch. -The active contact on the electrode can be selected by using the contact arrow buttons on the interactive user interface and the activation volume can be increased or decreased in size using the slider or by entering the diameter (in mm) manually. -The streamlines of the fiber pathways that overlap the activation volume can be displayed by checking the “Only Activated” checkbox. Otherwise, all of the streamlines (designated as visible) will be displayed.