diff --git a/README.md b/README.md
index a7fe0b72..b5d91860 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,19 @@ We provide a Binder environment for BrainPy. You can use the following button to
 
 [![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/brainpy/BrainPy-binder/main)
 
+## Brain Dynamics Programming Ecosystem
+
+We are building an ecosystem for bain dynamics programming (BDP), evolving from our previously experimental [BrainPy package](https://github.com/brainpy/BrainPy).
+
+The BDP ecosystem is a collection of tools, libraries, and frameworks that can be used to build brain dynamics models and applications.
+
+The BDP ecosystem is designed to be modular, so you can use as much or as little of it as you need.
+
+The details for this ecosystem please see: https://ecosystem-for-brain-dynamics.readthedocs.io/
+
+We welcome contributions from the community, so if you have an idea for a new tool or library, please let us know! Please email us at: <chao.brain@qq.com>.
+
+
 
 ## Ecosystem
 
diff --git a/brainpy/_src/math/pre_syn_post.py b/brainpy/_src/math/pre_syn_post.py
index bc978569..06976a35 100644
--- a/brainpy/_src/math/pre_syn_post.py
+++ b/brainpy/_src/math/pre_syn_post.py
@@ -56,7 +56,7 @@ def pre2post_event_sum(events,
     for i in range(pre_num):
       if events[i]:
         for j in range(idnptr[i], idnptr[i+1]):
-          post_val[post_ids[i]] += values
+          post_val[post_ids[j]] += values
 
   When ``values`` is a vector (with the length of ``len(post_ids)``),
   this function is equivalent to
@@ -70,7 +70,7 @@ def pre2post_event_sum(events,
     for i in range(pre_num):
       if events[i]:
         for j in range(idnptr[i], idnptr[i+1]):
-          post_val[post_ids[i]] += values[j]
+          post_val[post_ids[j]] += values[j]
 
 
   Parameters
diff --git a/requirements-doc.txt b/requirements-doc.txt
index 3c4a3ae6..5c6d440e 100644
--- a/requirements-doc.txt
+++ b/requirements-doc.txt
@@ -10,7 +10,7 @@ braintaichi
 # document requirements
 pandoc
 Jinja2
-sphinx>=5, <7.4.0
+sphinx>=5, <8.2.0
 myst-nb
 sphinx_thebe
 sphinx-autodoc-typehints