We describe methods and software resources for a bioimpedance measurement technique, “trans-radial electrical bioimpedance velocimetry” that allows for the non-invasive monitoring of relative cardiac contractility and stroke volume, proxies of sympathetic cardiac tone. In addition to describing the general recording methodology, which requires impedance measurements of the forearm, we provide open source Jupyter based software (operable on most computers) for deriving cardiac contractility from the impedance measurements. We demonstrate the ability of this bioimpedance measurement for tracking event related contractility in a maximal grip force production task. Critically, the results demonstrate both a reactive increase in cardiosympathetic drive with force production as well as a learned increase in drive prior to grip onset, consistent with allostatic autonomic regulation. The method and software should be of broad utility for investigations of event related cardio-sympathetic regulation in psychophysical studies.

Oscillations in the alpha frequency band (~8-12 Hz) of the human electroencephalogram play an important role in supporting selective attention to visual items and maintaining their spatial locations in working memory (WM). Recent findings suggest spatial information maintained in alpha is modulated by interruptions to continuous visual input, such that attention shifts, eye-closure and backward-masking of the encoded item causes reconstructed representations of remembered locations to become degraded. Here, we investigated how another common visual disruption - eye-movements - modulates reconstructions of behaviorally relevant and irrelevant item locations held in WM. Participants completed a delayed estimation task, where they encoded and recalled either the location or color of an object after a brief retention period. During retention, participants either fixated at center or executed a sequence of eye-movements. Electroencephalography (EEG) was recorded at the scalp and eye-position monitored with an eye-tracker. Inverted encoding modeling (IEM) was applied to reconstruct location-selective responses across multiple frequency bands during encoding and retention. Location-selective responses were successfully reconstructed from alpha activity during retention where participants fixated at center, but these reconstructions were disrupted during eye-movements. Recall performance decreased during eye-movement conditions but remained largely intact, and further analyses revealed that under specific task conditions it was possible to reconstruct retained location information from lower frequency bands (1-4 Hz) during eye-movements. These results suggest that eye-movements disrupt maintained spatial information in alpha in a manner consistent with other acute interruptions to continuous visual input, but this information may be represented in other frequency bands.