# Problem in generating the hippocampal volume source space **URL:** \ **Category:** Mailing List Archive (read-only)\ **Tags:** list-archive\ **Created:** [April 3, 2018, 12:04pm UTC](https://mne.discourse.group/t/problem-in-generating-the-hippocampal-volume-source-space/1472 "2018-04-03T12:04:12Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 3, 2018, 12:04pm UTC](https://mne.discourse.group/t/problem-in-generating-the-hippocampal-volume-source-space/1472/1 "2018-04-03T12:04:12Z")
Hello, I used the program given in the link, [https://martinos.org/mne/stable/auto\_examples/forward/plot\_left\_cerebellum\_volume\_source.html](https://martinos.org/mne/stable/auto_examples/forward/plot_left_cerebellum_volume_source.html) . Instead of Cerebellum i tried to generate the hippocampus volume source space. The final output gives the inappropriate structure of hippocampus. I mean that the hippocampal surface is downsampled to higher extent. I wanted to know how can i control the downsampling rate in the code given in the link above. Which parameters are to be altered? The program also setup the sources within and on the hippocampal surface. Is there any way that i can get the sources only on the surface of hippocampus? Thank You ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 3, 2018, 8:02pm UTC](https://mne.discourse.group/t/problem-in-generating-the-hippocampal-volume-source-space/1472/2 "2018-04-03T20:02:13Z")
hi Pooja, you should reduce the value of the pos parameter in setup\_volume\_source\_space (eg make it 2) to position more densely sources. HTH Alex