Related Experiment Video
Updated: Aug 23, 2026
Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
Microstimulation of V1 delays the execution of visually guided saccades
Edward J Tehovnik1, Warren M Slocum, Peter H Schiller
1Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, E25-634, Cambridge, MA 02139, USA. tehovnik@mit.edu
Abstract:
Electrical stimulation delivered to V1 concurrently with the presentation of a visual target interferes with both the selection and the detection of targets positioned in the receptive field of the stimulated neurons. In the present study, we examined the temporal course of this effect by delivering electrical stimulation to V1 of rhesus monkeys at various times before the appearance of a visual target. Each trial was initiated by the appearance of a fixation spot that, once acquired, was followed by the presentation of a visual target in the receptive field of the stimulated neurons. A monkey was reward after making a saccadic eye movement to the target. A delay in saccade generation was obtained when stimulation was delivered while an animal maintained fixation on the fixation spot. No delay occurred when the visual target was placed outside the receptive field of the stimulated neurons. The best parameters for inducing the saccadic delay were: (i). anode-first pulses (as opposed to cathode-first pulses) and (ii). train durations greater than 40 ms and frequencies greater than 100 Hz. The lowest current threshold for producing a saccadic delay occurred at 1.5 mm below the top of superficial V1. The chronaxies of the directly stimulated elements mediating the delay ranged from 0.13 to 0.24 ms. These values overlap with those that have been described for phosphene induction in human V1. We discuss how the elements mediating the saccadic delay might interrupt a visual signal as it passes along the geniculostriate pathway.
Insights
Electrical stimulation of the primary visual cortex (V1) delays visual target selection. Anode-first pulses and specific train durations/frequencies were most effective in rhesus monkeys.
Area of Science:
- Neuroscience
- Visual Cortex Research
- Electrophysiology
Background:
- Electrical stimulation of the primary visual cortex (V1) can disrupt visual processing.
- Previous studies show concurrent stimulation interferes with target selection and detection.
Purpose of the Study:
- To investigate the temporal dynamics of V1 electrical stimulation's effect on visual target selection.
- To determine optimal stimulation parameters for inducing delays in saccade generation.
Main Methods:
- Electrical stimulation was applied to V1 in rhesus monkeys at varying times before visual target presentation.
- Saccadic eye movements towards the visual target were recorded.
- Stimulation parameters (pulse type, train duration, frequency, current threshold, location) were systematically varied.
Main Results:
- Stimulation during fixation delayed saccade generation to targets within the receptive field of stimulated neurons.
- Anode-first pulses, train durations >40 ms, and frequencies >100 Hz were most effective.
- The lowest current threshold was found at 1.5 mm below the superficial V1 surface.
- Chronaxies of stimulated elements ranged from 0.13 to 0.24 ms.
Conclusions:
- Electrical stimulation of V1 can transiently interrupt visual signal processing in the geniculostriate pathway.
- The timing and parameters of stimulation critically influence its effect on visual-guided behavior.
- Findings suggest V1 stimulation affects visual signal transmission, potentially by interfering with neural processing.
