Actually I'm just posting this because I can never find this policy on the SfN meeting site when I am looking to cite it. And I always remember seeing something like this during the registration process so, here's the policy.
First, the funny bit. You have to assent to this in order to be registered for the meeting.
Photo and Video Release
By registering for Neuroscience 2013 or its associated events, you hereby understand that you may be photographed, videotaped, or digitally recorded, as may be your voice, and hereby waive any objection, condition, limit, or right you may have to the photographs or recordings.
By registering for Neuroscience 2013 or its associated events, you hereby authorize SfN to use any such photographs, videotapes or other recordings of yourself and your guests for any promotional purposes and to license other relevant people/organizations to use them. You hereby indemnify and hold the Society harmless for any such licensed or unlicensed use.
Don't image us, we'll image you. Heh.
Moving on, the actual policy of interest regarding taking photographs of the presentations.
Photography Policy during Scientific Sessions
Photography of scientific presentations, including posters presentations, is prohibited without the specific consent of the presenter(s)/author(s). Individuals who do not comply will be asked to leave the session. In addition, the use of cameras and recording devices (to include cell phones with camera capabilities) are prohibited in the Exhibit Hall. If you have any questions regarding this policy, please contact the annual meeting Press Room.
Personally I have yet to see someone asked to leave a slide session for taking photos, even when it is as egregious as standing up with a full-frame camera and snapping ever damn slide. So yeah. Of course, what do I know, maybe the presenters gave specific consent.
"prohibited in the Exhibit Hall". That means the poster sessions. No snapping pictures of your friends or trainees at their very first poster. Nuh-uh. Can't do it.