Our research
Role and genesis of fixational eye movements
Microsaccades are extremely small versions of the saccadic eye movements that we employ in everyday life, but they never displace retinal images of the objects we are looking at away from the fovea. Slow ocular drifts are even smaller smooth rotations of the eyeball during fixation. We use a variety of techniques to explore brain control over microsaccades and slow ocular drifts, as well as to understand when/why these movements are triggered.
Perception and eye movements
High-resolution vision in humans is only limited to a small area of the visual field. Despite this, humans have the perception of a vivid, clear scene throughout the visual field, and this is because humans are active observers. One of our goals is to understand how eye movements support such clear, stable percepts.
visual attention and eye movements
Related to the interplay between perception and eye movements is an equally important interaction between attention/decision making/target selection on the one hand and eye movements on the other. Our lab investigates the neural mechanisms that underlie such interaction.
SELECTED PUBLICATIONS
Willeke, K. F.*, Tian, X.*, Buonocore, A.*, Bellet, J., Ramirez-Cardenas, A. & Hafed, Z. M. (2019). Memory-guided microsaccades. Nature Communications, 10: 3710, doi: 10.1038/s41467-019-11711-x. Chen, C. -Y., Hoffmann, K.-P., Distler, C., & Hafed, Z. M. (2019). The foveal visual representation of the primate superior colliculus. Current Biology, 29: 2109-2119, doi: 10.1016/j.cub.2019.05.040. Chen, C. -Y., Sonnenberg, L., Weller, S., Witschel, T., & Hafed, Z. M. (2018). Spatial frequency sensitivity in macaque midbrain. Nature Communications, 9: 2852, doi: 10.1038/s41467-018-05302-5. Hafed, Z. M. & Chen, C. -Y. (2016). Sharper, stronger, faster upper visual field representation in primate superior colliculus. Current Biology, Vol. 26, pp. 1647-1658. Hafed, Z. M., Chen, C. -Y., & Tian, X. (2015). Vision, perception, and attention through the lens of microsaccades: mechanisms and implications. Frontiers in Systems Neuroscience (Special Research Topic on Perisaccadic Vision), 9:167. doi: 10.3389/fnsys.2015.00167 Chen, C. -Y., Ignashchenkova, A., Thier, P., & Hafed, Z. M. (2015). Neuronal response gain enhancement prior to microsaccades. Current Biology, Vol. 25, pp. 2065-2074. Hafed, Z. M. (2013). Alteration of visual perception prior to microsaccades. Neuron, Vol. 77, pp. 775-786. Hafed, Z. M., Goffart, L., & Krauzlis, R. J. (2009). A neural mechanism for microsaccade generation in the primate superior colliculus. Science, Vol. 323, No. 5916, pp. 940-943. Hafed, Z. M. & Krauzlis, R. J. (2006). Ongoing eye movements constrain visual perception. Nature Neuroscience, Vol. 9, No. 11, pp. 1449-1457. Hafed, Z. M. & Clark, J. J. (2002). Microsaccades as an overt measure of covert attention shifts. Vision Research, Vol. 42, No. 22, pp. 2533-2545.
our team
news & thoughts
Sensing LOOPS retreat 2024
Our lab participated in the first annual retreat of the Sensing LOOPS (SPP 2411). Sensing LOOPS is a Priority Programme of the German Research Foundation, and our lab has a funded project in this program. At the retreat, Tong and Tanya presented their work. Tong gave a great talk on signaling of prediction error by[…]
33rd MüTüZü Oculomotor and Vestibular System Meeting – in Tübingen
We hosted this year’s annual Oculomotor and Vestibular System Meeting. This is a meeting that originated by neurologists and scientists in the Münich, Zürich, and Tübingen regions who were interested in the oculomotor and vestibular systems. The meeting rotates between these three locations annually, and it was our turn to host it this year. The[…]
Deep dive into the properties of the smallest possible image-shifting eye movements
We have a new paper now published in the Journal of Neuroscience. In it, we explored a phenomenon that we recently documented about ocular position drifts that occur during maintained gaze fixation. Ocular position drifts are generally the smallest known eye position displacements that cause retinal image shifts. These eye movements displace images on the[…]
Express detection of visual objects by primate superior colliculus neurons
We have a new paper just published in Scientific Reports! In this new paper, we tackled the question of whether superior colliculus (SC) neurons have an ability to detect visual objects in their very initial spiking responses to image onsets (occurring within ~50 ms from presenting a visual stimulus to the eyes). It has long[…]
Cortical and subcortical mechanisms of active vision at the 2023 Society for Neuroscience Meeting
Our lab members are in Washington, DC this week to present their latest work on active vision, with a focus on how the primary visual cortex (V1) relates to the midbrain superior colliculus (SC) when it comes to generating rapid saccadic eye movements. Comparison of the physiological properties of visual responses in primary visual cortex[…]
More on the inevitability of visual interruption
We have a new paper now published in the Journal of Neurophysiology! In it, we continued our studies of visual interruption. During natural visual behavior, we continuously generate saccadic eye movements. Whenever a visual transient occurs in the environment, the likelihood of saccade generation suddenly drops to almost zero within less than 100 ms from[…]
Like a race car driver “feeling the road” through the gas pedal: new study by the lab shows how eye movement commands in the brain simultaneously sense the visual appearance of the environment
We have a new and exciting paper now published in the Proceedings of the National Academy of Sciences! In this paper, we tackled one of the most classic notions in systems neuroscience: that superior colliculus (SC) neurons in the midbrain issue a motor command that triggers and controls the trajectories of rapid eye movements (called[…]
Graduate student conference – NeNa 2023
Our lab is represented at this year’s junior neuroscientists’ conference by Carlotta Trottenberg! She presents updates on our work relating visual detection of stimuli and variability in saccadic reaction times. Carlotta explored visual responses of neurons in the primary visual cortex (V1) and superior colliculus (SC), and she related how different parameters of visual responses[…]
Eye movements and brainstem neurophysiology at the European Conference for Visual Perception (ECVP) 2023
Our lab participated in this year’s European Conference on Visual Perception (ECVP), taking place in Cyprus. The conference has a long tradition, being organized since more than 40 years. At this year’s conference, we tackled the neurophysiological mechanisms associated with slow ocular position drifts. These are tiny, slow changes in eye position (even smaller than[…]
Peri-saccadic visual performance and neural sensitivity are higher in the upper visual field, unlike in the absence of rapid eye movements
We have a new paper just published in the Journal of Neuroscience. In this paper, we investigated visual field anisotropies, but specifically when visual stimuli appeared in the temporal vicinity of rapid saccadic eye movements. Past work has shown that visual perceptual performance is either the same or significantly better (depending on the stimulus conditions)[…]