diff --git a/src/fmri/ActivityAnimation.cpp b/src/fmri/ActivityAnimation.cpp
index 16605e1..8257271 100644
--- a/src/fmri/ActivityAnimation.cpp
+++ b/src/fmri/ActivityAnimation.cpp
@@ -5,6 +5,8 @@
 #include <caffe/util/math_functions.hpp>
 #include "Range.hpp"
 #include "ActivityAnimation.hpp"
+#include "RenderingState.hpp"
+#include "glutils.hpp"
 
 using namespace std;
 using namespace fmri;
@@ -29,11 +31,13 @@ ActivityAnimation::ActivityAnimation(
             const std::vector<std::pair<DType, std::pair<std::size_t, std::size_t>>> &interactions,
             const float *aPositions, const float *bPositions, ColoringFunction coloring)
         :
-        bufferLength(3 * interactions.size())
+        bufferLength(3 * interactions.size()),
+        delta(bufferLength)
 {
     CHECK(coloring) << "Invalid coloring function passed.";
     startingPos.reserve(bufferLength);
-    delta.reserve(bufferLength);
+    vector<float> endPos;
+    endPos.reserve(bufferLength);
     colorBuf.reserve(interactions.size());
 
     for (auto &entry : interactions) {
@@ -44,9 +48,16 @@ ActivityAnimation::ActivityAnimation(
 
         for (auto i : Range(3)) {
             startingPos.emplace_back(aPos[i]);
-            delta.emplace_back(bPos[i] - aPos[i] + (i % 3 ? 0 : LAYER_X_OFFSET));
+            endPos.emplace_back(bPos[i] + (i % 3 ? 0 : LAYER_X_OFFSET));
         }
     }
+
+    caffe::caffe_sub(endPos.size(), endPos.data(), startingPos.data(), delta.data());
+    startingPos.insert(startingPos.end(), endPos.begin(), endPos.end());
+    for (auto i : Range(interactions.size())) {
+        lineIndices.push_back(i);
+        lineIndices.push_back(i + interactions.size());
+    }
 }
 
 void ActivityAnimation::draw(float timeScale)
@@ -60,5 +71,11 @@ void ActivityAnimation::draw(float timeScale)
     glVertexPointer(3, GL_FLOAT, 0, vertexBuffer.data());
     glDrawArrays(GL_POINTS, 0, bufferLength / 3);
     glDisableClientState(GL_COLOR_ARRAY);
+    if (RenderingState::instance().renderInteractionPaths()) {
+        glColor4f(1, 1, 1, 0.1);
+        glVertexPointer(3, GL_FLOAT, 0, startingPos.data());
+        glDrawElements(GL_LINES, lineIndices.size(), GL_UNSIGNED_INT, lineIndices.data());
+        checkGLErrors();
+    }
     glDisableClientState(GL_VERTEX_ARRAY);
 }
diff --git a/src/fmri/ActivityAnimation.hpp b/src/fmri/ActivityAnimation.hpp
index dca62d2..8d1f534 100644
--- a/src/fmri/ActivityAnimation.hpp
+++ b/src/fmri/ActivityAnimation.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstddef>
+#include <functional>
 #include <memory>
 #include <vector>
 #include "Animation.hpp"
@@ -30,5 +31,6 @@ namespace fmri
         std::vector<std::array<float, 3>> colorBuf;
         std::vector<float> startingPos;
         std::vector<float> delta;
+        std::vector<int> lineIndices;
     };
 }
diff --git a/src/fmri/RenderingState.cpp b/src/fmri/RenderingState.cpp
index 02c924f..23fc5ba 100644
--- a/src/fmri/RenderingState.cpp
+++ b/src/fmri/RenderingState.cpp
@@ -94,6 +94,10 @@ void RenderingState::handleKey(unsigned char x)
             reset();
             break;
 
+        case 'p':
+            toggle(options.renderInteractionPaths);
+            break;
+
         case 'o':
             toggle(options.activatedOnly);
             break;
@@ -254,6 +258,7 @@ void RenderingState::renderOverlayText() const
                        "l: toggle layers visible\n"
                        "i: toggle interactions visible\n"
                        "o: toggle activated nodes only\n"
+                       "p: toggle interaction paths visible\n"
                        "q: quit\n";
     }
 
@@ -312,3 +317,8 @@ bool RenderingState::renderActivatedOnly() const
 {
     return options.activatedOnly;
 }
+
+bool RenderingState::renderInteractionPaths() const
+{
+    return options.renderInteractionPaths;
+}
diff --git a/src/fmri/RenderingState.hpp b/src/fmri/RenderingState.hpp
index 77033e1..96287ec 100644
--- a/src/fmri/RenderingState.hpp
+++ b/src/fmri/RenderingState.hpp
@@ -43,6 +43,7 @@ namespace fmri
          * @return Whether the network should only render activated nodes, rather than all of them.
          */
         bool renderActivatedOnly() const;
+        bool renderInteractionPaths() const;
 
         static RenderingState& instance();
 
@@ -53,6 +54,7 @@ namespace fmri
             bool renderLayers = true;
             bool renderInteractions = true;
             bool activatedOnly = false;
+            bool renderInteractionPaths = false;
         } options;
         std::array<float, 3> pos;
         std::array<float, 2> angle;
diff --git a/src/fmri/main.cpp b/src/fmri/main.cpp
index 8e76afd..282d148 100644
--- a/src/fmri/main.cpp
+++ b/src/fmri/main.cpp
@@ -54,7 +54,7 @@ int main(int argc, char *argv[])
     google::InstallFailureSignalHandler();
 
     glutInit(&argc, argv);
-    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
+    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA);
     glutCreateWindow(argv[0]);
 
     // Prepare data for simulations
@@ -77,7 +77,7 @@ int main(int argc, char *argv[])
     glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
     glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
     glEnable(GL_BLEND);
-    glBlendFunc(GL_DST_ALPHA,GL_ONE_MINUS_DST_ALPHA);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
     // Start visualisation
     glutMainLoop();
diff --git a/src/fmri/utils.cpp b/src/fmri/utils.cpp
index f16ce36..c0a0d6a 100644
--- a/src/fmri/utils.cpp
+++ b/src/fmri/utils.cpp
@@ -21,7 +21,7 @@ const std::vector<float> & fmri::animate(const std::vector<float> &start, const
     static std::vector<float> vertexBuffer;
     vertexBuffer = delta;
     caffe::caffe_scal(vertexBuffer.size(), time, vertexBuffer.data());
-    caffe::caffe_add(start.size(), vertexBuffer.data(), start.data(), vertexBuffer.data());
+    caffe::caffe_add(vertexBuffer.size(), vertexBuffer.data(), start.data(), vertexBuffer.data());
 
     return vertexBuffer;
 }