Blake W. Johnson

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Recent electrophysiological studies have shown that the human electroencephalographic mu rhythm is suppressed during the observation of actions performed by other persons, an effect that may be functionally related to the behaviour of so-called "mirror neurons" observed in area F5 of nonhuman primates. Because mirror neuron activity has been reported to be(More)
OBJECTIVE We characterised the spectral response of the EEG to median nerve stimulation using wavelet analysis, and compared the relative magnitudes of effect of several different action-observation conditions on the beta and mu 'rebound' rhythms. METHODS EEG responses to median nerve stimulation were recorded from 8 normal adult subjects during baseline(More)
We recorded 128-channel EEG from 16 participants while they observed, imitated, and self-initiated the precision grip of a manipulandum. Mu rhythm amplitudes were significantly lower during observation of a precision grip than during observation of a simple hand extension without object interaction. Scalp topographies for subtractions of observation,(More)
We investigated the role of cerebral motor structures during mental hand rotation. Neural activity was measured with event-related potentials (ERPs) in 16 healthy participants while they performed handedness judgments of visually presented hands. Mental rotation was associated with ERP amplitude modulations as early as 170 ms but most strongly during a time(More)
Long-term potentiation (LTP) is a candidate synaptic mechanism underlying learning and memory that has been studied extensively at the cellular and molecular level in laboratory animals. To date, LTP has only been directly demonstrated in humans in isolated cortical tissue obtained from patients undergoing surgery, where it displays properties identical to(More)
OBJECTIVES The aim of this study was to examine the N300 and N400 effect to pictures that were semantically incongruous to a prior object name. Based upon theories of object identification, the semantic incongruity was manipulated to occur early or late in the object processing stream. METHODS High-density visual event-related potentials were measured in(More)
Neuroimaging studies have shown that the neural mechanisms of motor imagery (MI) overlap substantially with the mechanisms of motor execution (ME). Surprisingly, however, the role of several regions of the motor circuitry in MI remains controversial, a variability that may be due to differences in neuroimaging techniques, MI training, instruction types, or(More)
When inverted, thatcherized faces appear normal. This may be due to a decrease in configural and an increase in featural processing. It is not known whether this processing is continuous or reflects two distinct processing systems. Using event-related potentials (ERPs), we investigated the Thatcher effect on thatcherized and normal faces at varying(More)
Reaction times, accuracy and 128-channel event-related potentials (ERPs) were measured from 14 normal, right-handed subjects while they performed two different parity-judgment tasks that require transformations of mental images: a relatively simple task requiring a single transformation (mental letter rotation), and a more complex task involving a(More)
A neural biomarker that can be applied to studies of oral communication disorders would provide a boon to researchers. While there has been much research conducted on manual response inhibition, very few studies have examined vocal response inhibition. To date, no study has examined the temporal aspects of vocal inhibition. Therefore, the present study(More)