March 2023

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Hybrid Colloquium: Cerebellar contributions to visual attention and working memory
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Abstract- The amount of sensory information we receive at any one moment far outstrips our brain’s ability to process this information. We can effortlessly withstand this deluge of sensory input due to our ability to prioritize and maintain the subset of information within our environment that is most relevant to our behavioral goals. Attention and working memory, the processes that enable this prioritization and maintenance, are thought to be supported by a network of cerebral cortical areas spanning visual, parietal, and frontal cortices. The cerebellum, a subcortical structure typically associated with the coordination of motor actions, has not been traditionally implicated in attention and working memory. In this talk, I will present evidence from a series of functional magnetic resonance imaging (fMRI) and psychophysical experiments for a cerebellar role in visual attention and working memory processes. In particular, I will present the findings of a recent study that examines whether the cerebellum encodes motor-independent stimulus-specific representations of items maintained in working memory. I will further discuss recent behavioral and eye-tracking work aimed at testing the hypothesis that the cerebellum is critical for the adaptive control of visual attention and working memory processes. https://lsa.umich.edu/psych/people/research-fellows-2/james-brissenden.html

Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)
 
 
 
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Hybrid Colloquium: The early life of an extraocular motor neuron: from birth to disease to function
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Abstract - Normal vision relies on exquisite control of the eye movements. Vertebrate extraocular motor neurons control the six muscles that move each eye. We know comparatively little about the development of extraocular motor neurons and the emergence of the behaviors they subserve. This gap constrains our ability to address developmental disorders of the oculomotor system. To make progress, we have developed the larval zebrafish as a model to study the development of the oculomotor system and the behaviors it subserves. Larval zebrafish are a small vertebrate with exceptional optical and genetic access to developing neural circuits. I’ll share highlights of our lab’s efforts to understand oculomotor development. Specifically, I’ll focus on the development of extraocular motor neurons in cranial nuclei nIII/nIV that are responsible for torsional/vertical eye movements such as those that comprise the gravito-inertial vestibulo-ocular reflex. I’ll begin with published findings establishing that an extraocular motor neuron’s “birthdate” predicts which muscle it will control and where its soma lies within nIII/nIV. Next, I’ll share unpublished progress on two fronts: First, we’re working to discover the molecular determinants responsible for proper development of extraocular motor neurons. In service of this aim, we’ve generated a mutant line that has lost phox2a expression. These fish lose extraocular motor neurons in nIII/nIV leaving only the lateral rectus motor neurons in nVI intact. The eyes deviate towards the ears, similar to human patients with CFEOM type 2, who have mutations in PHOX2A. Finally, I’ll end by showing how we use a new imaging technique (Tilt In Place Microscopy, or TIPM) to map the emergence of selectivity and sensitivity in the responses of individual extraocular motor neurons across development. https://med.nyu.edu/faculty/david-schoppik

Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)
 
 
 
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Hybrid Colloquium: Compensatory oculomotor strategies in central vision loss: Insights from simulated scotoma and visual training
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Abstract - Macular degeneration (MD) represents one of the main causes of vision loss and a serious health concern worldwide. Late-stage MD leads to the development of a region of retinal blindness (scotoma), forcing patients to adopt compensatory oculomotor strategies to perform everyday tasks such as reading, recognizing faces, and navigation. A common strategy involves functionally replacing the fovea with a portion of spare retina outside of the scotoma, called Preferred retinal locus (PRL).

However, the mechanisms underlying PRL development appear elusive, and progresses are complicated by practical issues inherent to MD research, including compliance, transportation to testing facilities, high heterogeneity, and comorbidity. Gaze-contingent simulation of central vision loss offers a potential framework for the study of compensatory oculomotor strategies in which many parameters, such as the onset, size, and shape of the scotoma can be precisely controlled.

I will present a simulated scotoma study aimed at understanding the development of compensatory oculomotor strategies: specifically, I will describe a method to extract relevant oculomotor metrics, show how these change with training, and discuss task-specific and individual differences in oculomotor behavior in conditions of simulated central vision loss.

Taken together, these results highlight how simulated scotomas may help understand oculomotor patterns following central vision loss, and potentially train eye movements in MD patients.

These studies are part of a larger framework that I am currently developing to characterize, evaluate and train central vision loss in an integrated model that addresses the far-reaching consequences of loss of central vision, including changes in low level vision, oculomotor control and higher-level visual functions. https://psychology.ucr.edu/about-our-department/postdoctoral-researchers/

Improving Zoom accessibility for people with hearing impairments People with hearing impairments often use lipreading and speechreading to improve speech comprehension. This approach is helpful but only works if the speaker’s face and mouth are clearly visible. For the benefit of people with hearing impairments on Zoom calls, please enable your device’s camera whenever you are speaking on Zoom, and face the camera while you speak. (Feel free to disable your camera when you aren’t speaking.)