Schall Laboratory - Schall Laboratory at YorkU

Schall’s research program seeks to understand how the brain guides, controls, and monitors behavior. To address these fundamental mechanisms of decision-making, we must understand how to translate between multiple scales of description. With neurophysiological and electrophysiological data we seek explanations at neural, biophysical, and computational scales.

Through other scholarship Schall also translates between research and application at the intersection of law and neuroscience,

Our group is multigender-multiracial-multicultural-multinational. We practice the method of multiple hypotheses in research and in life. We avoid the blinding influence of personal and petty affections. We debate ideas and respect people. We know that the best science flourishes in a liberal society. We value each other. We value you.

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RESEARCH & SCHOLARSHIP TOPICS

One research theme seeks to understand how the brain locates and selects the target for an eye movement during visual search tasks. This problem is a tractable instance of the larger problem of decision making. Focusing on the frontal eye field with the superior colliculus and midlevel extrastriate area V4, we have described how the brain distinguishes a target from distractors and how this relates to covert attention and overt saccade production.

Another research theme seeks to understand how the brain controls whether and when to shift gaze during visual stop signal (countermanding) tasks. This problem is a tractable instance of the larger problem of the origin of voluntary movements. Focusing on the frontal eye field with the superior colliculus, we have described how the brain initiates responses when the stochastic activation of certain neurons rises to a threshold. We have also described how the brain accomplishes response inhibition.

A related research theme seeks to understand how the brain monitors performance and exerts executive control during search and countermanding tasks. This problem is a tractable instance of the larger problem of intentional action. Focusing on the supplementary eye field and the middle cingulate cortex, we have described how the brain signals errors, detects conflict among response processes, times task events, maintains task goals, and determines whether or not earned reward is received.

A collaboration with Gordon Logan and Tom Palmeri seeks to bridge the explanatory gap between neural events, task performance, and cognition by formulating neuro-computational models of stochastic decision mechanisms. We have formulated models of response inhibition, evidence accumulation, and evidence creation named Interactive race, GAM, and SCRI. We have also explored the scaling problem of how ensembles of accumulators arrive at a decision in a simulation called EPU.

A collaboration with Jorge Riera and Geoff Woodman seeks to bridge the explanatory gap between neural events and signals observed in EEG by describing associations between intracranial neurophysiological and cranial electrophysiological measures through statistical and biophysical models. We have focused on the mechanisms underlying the N2pc, the CDA, the ERN, and the N2/P3.

Through a variety of collaborations we seek to make our basic research efforts applicable in clinical settings. In collaboration with Sohee Park and Katherine Thakkar we have explored gaze control associated with psychopathology. In collaboration with Charles Caskey we explored how focused ultrasound influences neural processes. In collaboration with Nelleke van Wouwe and Joseph Neimat and others we have contributed to interpretation of deep brain stimulation effects.

A collaboration with Owen Jones and Francis Shen has produced the first coursebook in the emerging field of law and neuroscience.