diff --git a/src/miv_simulator/optimization.py b/src/miv_simulator/optimization.py
index 7416bb3..4a70691 100644
--- a/src/miv_simulator/optimization.py
+++ b/src/miv_simulator/optimization.py
@@ -370,15 +370,20 @@ def update_run_params(env, param_tuples):
 def network_features(env, t_start, t_stop, target_populations):
     features_dict = dict()
 
-    temporal_resolution = float(env.stimulus_config["Temporal Resolution"])
-    time_bins = np.arange(t_start, t_stop, temporal_resolution)
+    analysis_config = env.analysis_config
+    if analysis_config is None:
+        analysis_config = {}
+    fr_inference_config = analysis_config.get("Firing Rate Inference", {})
+    
+    temporal_resolution = float(fr_inference_config.get("Temporal Resolution", 2.0))
+    time_bins = np.arange(t_start, t_stop, temporal_resolution).astype(np.float32)
 
     pop_spike_dict = spikedata.get_env_spike_dict(env, include_artificial=False)
 
     for pop_name in target_populations:
         n_active = 0
         spike_density_dict = spikedata.spike_density_estimate(
-            pop_name, pop_spike_dict[pop_name], time_bins
+            pop_name, pop_spike_dict[pop_name], time_bins, return_time_bins=False
         )
         for gid, dens_dict in spike_density_dict.items():
             mean_rate = np.mean(dens_dict["rate"])
diff --git a/src/miv_simulator/optimize_network.py b/src/miv_simulator/optimize_network.py
index e24a346..2ba819a 100644
--- a/src/miv_simulator/optimize_network.py
+++ b/src/miv_simulator/optimize_network.py
@@ -2,7 +2,7 @@
 """
 Network model optimization script for optimization with dmosopt
 """
-
+import gc
 import os
 import sys
 import datetime
@@ -410,9 +410,9 @@ def compute_objectives(local_features, operational_config, opt_targets):
                     sum_mean_rate_local += mean_rate
                 ip_rate = np.interp(
                     fr_time_centers,
-                    dens_dict["time"].astype(np.float32),
+                    time_bins_ref,
                     dens_dict["rate"].astype(np.float32),
-                )
+                ).astype(np.float32)
                 active_per_bin = ip_rate > active_threshold
                 sum_active_per_bin += active_per_bin
 
@@ -439,17 +439,19 @@ def compute_objectives(local_features, operational_config, opt_targets):
         )
 
         all_features_dict[f"{pop_name} mean fraction active per time bin"] = (
-            mean_fraction_active_per_bin
+            float(mean_fraction_active_per_bin)
         )
         all_features_dict[f"{pop_name} std fraction active per time bin"] = (
-            std_fraction_active_per_bin
+            float(std_fraction_active_per_bin)
         )
-        all_features_dict[f"{pop_name} fraction active"] = fraction_active
-        all_features_dict[f"{pop_name} firing rate"] = mean_rate
+        all_features_dict[f"{pop_name} fraction active"] = float(fraction_active)
+        all_features_dict[f"{pop_name} firing rate"] = float(mean_rate)
 
         rate_constr = mean_rate if mean_rate > 0.0 else -1.0
         constraints.append(rate_constr)
 
+    gc.collect()
+
     objective_names = operational_config["objective_names"]
     feature_dtypes = [(feature_name, np.float32) for feature_name in objective_names]
 
@@ -470,7 +472,7 @@ def compute_objectives(local_features, operational_config, opt_targets):
         features.append(feature_val)
 
     result = (
-        np.asarray(objectives),
+        np.asarray(objectives, dtype=np.float32),
         np.array([tuple(features)], dtype=np.dtype(feature_dtypes)),
         np.asarray(constraints, dtype=np.float32),
     )
diff --git a/src/miv_simulator/spikedata.py b/src/miv_simulator/spikedata.py
index 6e249c7..15c1963 100644
--- a/src/miv_simulator/spikedata.py
+++ b/src/miv_simulator/spikedata.py
@@ -295,6 +295,7 @@ def spike_density_estimate(
     trajectory_id=None,
     output_file_path=None,
     progress=False,
+    return_time_bins=True,
     inferred_rate_attr_name="Inferred Rate Map",
     **kwargs,
 ):
@@ -339,7 +340,7 @@ def make_spktrain(lst, t_start, t_stop):
     spk_rate_dict = {
         ind: baks(spkts / 1000.0, time_bins / 1000.0, **baks_args)[0].reshape((-1,))
         if len(spkts) > 1
-        else np.zeros(time_bins.shape)
+        else np.zeros(time_bins.shape, dtype=np.float32)
         for ind, spkts in seq
     }
 
@@ -360,13 +361,14 @@ def make_spktrain(lst, t_start, t_stop):
             output_file_path, population, attr_dict, namespace=namespace
         )
 
-    result = {
-        ind: {"rate": rate, "time": time_bins} for ind, rate in spk_rate_dict.items()
-    }
-
-    result = {
-        ind: {"rate": rate, "time": time_bins} for ind, rate in spk_rate_dict.items()
-    }
+    if return_time_bins:
+        result = {
+            ind: {"rate": rate, "time": time_bins} for ind, rate in spk_rate_dict.items()
+        }
+    else:
+        result = {
+            ind: {"rate": rate} for ind, rate in spk_rate_dict.items()
+        }
 
     return result
 
diff --git a/src/miv_simulator/utils/utils.py b/src/miv_simulator/utils/utils.py
index 0112a81..0009199 100644
--- a/src/miv_simulator/utils/utils.py
+++ b/src/miv_simulator/utils/utils.py
@@ -984,7 +984,7 @@ def baks(spktimes, time, a=1.5, b=None):
 
     threshold = 6.0
     h = (gamma(a) / gamma(a + 0.5)) * (sumnum / sumdenom)
-    rate = np.zeros((len(time),))
+    rate = np.zeros((len(time),), dtype=np.float32)
     for j in range(n):
         time_diff = time - spktimes[j]
         abs_diff = np.abs(time_diff)