Understanding alcohol use disorders with neuroelectrophysiology.

Visual oddball event-related potential (ERP) and corresponding event-related oscillations using time frequency transformation. (Data from Jones et al., 2006.)(A) Responses to rare targets in a visual oddball task at the vertex (Cz electrode): Typical grand mean waveform from 100 normal control subjects showing the major sequential ERP components and their topography, namely N100 (N1), P200 (P2), N200 (N2), and P300 (P3). These components are discussed in the text and described here:The N1 (N100) component, a negative deflection occurring around 100 ms, is involved in an early attentional selection process; it is dampened to unattended stimuli and enhanced to attended ones (Hillyard et al., 1973; Nataanen et al., 1978). The vertex P200 component has been associated with visual feature discrimination (O’Donnell et al., 1997) and is sensitive to salient features of target stimuli (Luck and Hillyard, 1994a). The posterior N200 reflects the degree of attention required for processing stimuli and is sensitive to target probability (Folstein and Van Petten, 2008). The P3 (P300) is a large positive deflection seen 300–700 ms after a rare stimulus embedded in a series of unattended standard stimuli. It is proposed to reflect attentional allocation and context updating (Polich and Herbst, 2000) and cognitive closure (Desmedt, 1980; Verleger, 1988), while its time of occurrence (latency) reflects mental processing speed; the earlier and larger the P3, the easier the processing. Evidence indicates that P3 has multiple sources, with contributions from frontal cortex (including anterior cingulate) and hippocampus (Halgren et al., 1980; Menon et al., 1997; Kiehl and Liddle, 2001; Ardekani et al., 2002).(B) Time–frequency transformation using the S-transform (same data from top panel), illustrating the distribution of power over time during processing of the target. The white boxes indicate time–frequency regions of interest (TFROI) in specific band widths and their topography in the head plots at the bottom. It can be seen that during target detection theta (4–7 Hz) has a frontal distribution while delta (1–2 Hz) has a posterior distribution (Jones et al., 2006b).

Event-related potential waveforms and source localization of N2 component with low-resolution brain electromagnetic tomography (LORETA). (Data from Pandey et al., 2012.)(Top panel) Waveforms from response inhibition task (Go/NoGo) comparing alcoholics and normal controls showing enhanced N2 wave and a frontal P3 during response inhibition (NoGo). Reduced N2 amplitudes are seen to both Go and NoGo condition, particularly for NoGo at frontal (Fz) lead.(Bottom panel) sLORETA images for controls (A) and alcoholics (B) indicating areas in the brain which are significantly more activated for NoGo when compared to Go. Controls show a strong bilateral activation of anterior cingulate and also right medial frontal cortex. Alcoholics show a much smaller region of activation in anterior cingulate that does not involve bilateral areas.

Event-related potential, event-related oscillations, and theta topography in a gambling paradigm. (Data from Kamarajan et al., 2012.)(A) Waveforms to loss and gain feedback stimuli in a gambling task showing erroneous responses (ERN)/outcome-related negativity (ORN) component and the outcome-related positivity (ORP) (P3) component in male controls (n = 38)and male alcoholics (n = 38).(B) Time–frequency transformation of electroencephalogram epochs describing the total power in controls and alcoholics for loss and gain trials. Box indicates the region of interest – theta (3–7 Hz) band, 200–500 ms.(C) Theta band response corresponding to the event-related potential traces in the above panel. Note differences between normal controls and alcoholics in the gray-shaded area.(D) Theta power topography: note the sharply anterior peak for loss and a more diffuse slightly posterior spread for gain. Alcoholics have lower theta power, and the reduction is of greater magnitude for loss.

Event-related potential waveforms from the semantic priming task. (Data from Roopesh et al., 2009, 2010.)Waveforms from a semantic decision task for primed and unprimed words. The dotted circle marks the N400 component that is prominent in the case of unprimed words and highly attenuated for primed words, as seen in controls (n = 57) and low-risk (n = 28) individuals; alcoholics (n = 87) and high-risk (n = 23) individuals have less attenuation of this component.N400 is a negative response seen between 200 and 600 ms in response to semantic incongruency (Kutas and Federmeier, 2011). The semantic priming task has been one of the most extensively used event-related potential paradigms to study the effect of priming on N400 (Bentin, 1989).