diff --git a/backend/ks_search_tool.py b/backend/ks_search_tool.py
index 3004a02..b093aff 100644
--- a/backend/ks_search_tool.py
+++ b/backend/ks_search_tool.py
@@ -10,6 +10,90 @@
 from difflib import SequenceMatcher
 
 
+
+def rerank_results_using_metadata(results: List[dict]) -> List[dict]:
+    """
+    Re-rank search results based on metadata signals:
+    - More recent datasets are preferred
+    - Higher citation count is preferred
+    - Trusted sources can be boosted
+    """
+    def score_result(r: dict) -> float:
+        score = r.get("_score", 1.0)  # original search score
+        meta = r.get("metadata", {})
+
+        # Example 1: Boost newer datasets
+        year = meta.get("publication_year") or meta.get("year")
+        if year:
+            try:
+                score += float(year) / 10000  # small boost for recent years
+            except:
+                pass
+
+        # Example 2: Boost by citations if available
+        citations = meta.get("citations") or meta.get("citation_count")
+        if citations:
+            try:
+                score += float(citations) / 100  # small boost
+            except:
+                pass
+
+        # Example 3: Boost trusted sources
+        trusted_sources = ["Allen Brain Atlas", "GENSAT", "EBRAINS"]
+        source_name = r.get("datasource_name") or meta.get("source") or ""
+        if any(ts.lower() in str(source_name).lower() for ts in trusted_sources):
+            score += 0.5  # boost for trusted source
+            print(f"Result: {r.get('title') or r.get('title_guess')} | Score: {score}")
+        return score
+
+    return sorted(results, key=score_result, reverse=True)
+
+
+
+
+
+
+
+
+
+
+# Query Expansion Code 
+# --- Query Expansion for Neuroscience terms ---
+QUERY_SYNONYMS = {
+    "mouse brain": ["Rattus norvegicus", "somatosensory cortex", "cortex", "hippocampus"],
+    "memory": ["hippocampus", "synaptic plasticity"],
+    "hippocampus": ["CA1", "CA3", "dentate gyrus"],
+    # add more phrases and synonyms as needed
+}
+
+
+def expand_query(query: str) -> str:
+    query_lower = query.lower()
+    expanded = [query_lower]  # original query
+
+    # Keep track of added terms to avoid duplicates
+    added_terms = set(expanded)
+
+    # Phrase match
+    for phrase, synonyms in QUERY_SYNONYMS.items():
+        if phrase in query_lower:
+            for syn in synonyms:
+                if syn not in added_terms:
+                    expanded.append(syn)
+                    added_terms.add(syn)
+
+    # Word match
+    for word in query_lower.split():
+        if word in QUERY_SYNONYMS:
+            for syn in QUERY_SYNONYMS[word]:
+                if syn not in added_terms:
+                    expanded.append(syn)
+                    added_terms.add(syn)
+
+    return " ".join(expanded)
+
+
+
 def tool(args_schema):
     def decorator(func):
         func.args_schema = args_schema
@@ -334,6 +418,8 @@ async def general_search_async(query: str, top_k: int = 10, enrich_details: bool
         if enrich_details and normalized_results:
             print("  -> Using parallel async enrichment...")
             normalized_results = await enrich_with_dataset_details_async(normalized_results, top_k)
+            normalized_results = rerank_results_using_metadata(normalized_results)
+
         return {"combined_results": normalized_results[:top_k]}
     except Exception as e:
         print(f"  -> Error during async general search: {e}")
@@ -376,6 +462,7 @@ def general_search(query: str, top_k: int = 10, enrich_details: bool = True) ->
             print("  -> Enriching results with detailed dataset information (parallel)...")
             # Use sync enrichment for now - we'll make the whole function async later
             normalized_results = enrich_with_dataset_details(normalized_results, top_k)
+            normalized_results = rerank_results_using_metadata(normalized_results)
         return {"combined_results": normalized_results[:top_k]}
     except requests.RequestException as e:
         print(f"  -> Error during general search: {e}")
@@ -439,7 +526,9 @@ def _perform_search(data_source_id: str, query: str, filters: dict, all_configs:
                     "metadata": src,
                 }
             )
+        out = rerank_results_using_metadata(out)
         return out
+
     except requests.RequestException as e:
         print(f"  -> Error searching {data_source_id}: {e}")
         return []
@@ -452,7 +541,7 @@ def smart_knowledge_search(
     data_source: Optional[str] = None,
     top_k: int = 10,
 ) -> dict:
-    q = query or "*"
+    q = expand_query(query) if query else "*"
     if filters:
         config_path = "datasources_config.json"
         if os.path.exists(config_path):
@@ -463,3 +552,39 @@ def smart_knowledge_search(
                 results = _perform_search(target_id, q, dict(filters), all_configs)
                 return {"combined_results": results[:top_k]}
     return general_search(q, top_k, enrich_details=True)
+
+
+# Test code
+
+
+
+# if __name__ == "__main__":
+#     test_queries = ["mouse brain", "memory", "hippocampus"]
+
+#     for q in test_queries:
+#         print(f"Searching for: {q}")
+#         results = smart_knowledge_search(q, top_k=3)
+#         for i, r in enumerate(results.get("combined_results", [])):
+#             print(f"  {i+1}. {r.get('title') or r.get('title_guess')} - {r.get('primary_link')}")
+#         print("-" * 50)
+
+def test_rerank():
+    mock_results = [
+        {"title_guess": "Dataset A", "_score": 1.0, "metadata": {"year": 2020, "citations": 5, "source": "GENSAT"}},
+        {"title_guess": "Dataset B", "_score": 1.0, "metadata": {"year": 2023, "citations": 2, "source": "OtherSource"}},
+        {"title_guess": "Dataset C", "_score": 1.0, "metadata": {"year": 2019, "citations": 10, "source": "EBRAINS"}},
+    ]
+
+    print("Before rerank:")
+    for r in mock_results:
+        print(r["title_guess"], r["_score"])
+
+    ranked = rerank_results_using_metadata(mock_results)
+
+    print("\nAfter rerank:")
+    for r in ranked:
+        print(r["title_guess"], r["_score"])
+
+if __name__ == "__main__":
+    test_rerank()
+