Purchase this article with an account.
Julio Martinez-Trujillo, Roberto Gulli, Guillaume Doucet, Benjamin Corrigan; Dissociable effects of saccades on hippocampal local field potential power and phase. Journal of Vision 2017;17(10):1151. doi: 10.1167/17.10.1151.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Saccadic eye movements to reorient gaze are critical to efficient scene exploration in primates. During saccades, neural activity in visually responsive areas is suppressed, leading to widespread perturbation in local field potentials (LFPs) known as phase resetting. Saccade-aligned phase resetting has been observed in primate hippocampal LFPs (4-12 Hz) during visual scene exploration, and analogously aligned to object sniffing in rodents completing an associative learning task. To disambiguate motor-activity related changes and object-sampling related changes in primate LFPs during 2D and 3D exploration, we trained two monkeys to complete three tasks while we recorded eye movements and hippocampal LFPs. In a visually guided saccade task (VGS), monkeys were rewarded for making saccades to small white dots on a gray screen. The remaining two tasks required free navigation in a novel virtual reality environment using a joystick. In the virtual foraging task, animals searched for, and navigated to, a red volume which was randomly relocated within the environment. In the virtual associative memory task, monkeys learned a reversed two-context, three-object reward value hierarchy. Eye movements and intra-hippocampal LFPs were simultaneously recorded in each task in a total of 93 channels over 41 sessions. In all tasks, saccade-aligned phase resetting was observed between 4-16 Hz 80-100 ms after saccade onset. Interestingly, the consistency of saccade aligned phase resetting was lowest during VGS in the 8-12 Hz range, and under no circumstances correlated with saccade amplitude. Conversely, gamma range (~64-111Hz) power was elevated ~20ms around the saccade onset in all tasks, and gamma power correlated positively with saccade amplitude across all tasks. These results illustrate dissociable and frequency specific signatures of saccade features on hippocampal LFP power and phase. Phase resetting may be critical for coordination of hippocampal networks during visual exploration of simple scenes and navigable environments.
Meeting abstract presented at VSS 2017
This PDF is available to Subscribers Only