Alpha frequency

Electrophysiological Tobacco smoking produces cortical activation on the EEG. Broadly, it reduces slow-wave activity (theta and delta) and increases activity in alpha and beta frequency bands (Knott et al. 1998 Pritchard et al. 1999). Other studies have found more isolated effects in alpha frequencies (Domino and Matsuoka 1994 Foulds et al. 1994). 

HPPD has been studied with quantitative EEC. Compared to controls, people with HPPD show a faster alpha frequency and shorter visual-evoked-response latency, consistent with LSD-induced cortical disinhibition (Abraham and Duffy 1996). Conversely, the auditory-evoked-response latency is increased. Analyses indicate that these differences are predominant in temporal and left parietal regions. 

Foulds J, McSorley K, Sneddon J, Feyerabend C, Jarvis MJ, Russell MA. (1994). Effect of subcutaneous nicotine injections of EEG alpha frequency in nonsmokers a placebo-controlled pilot study. Psychopharmacology (Berlin). 115(1-2) 163-66. 

For each hour the mean relative power (% of total spectral power) in the subfrequency bands delta, theta, alpha, beta and gamma are estimated during treadmill-on phases. In addition, the ratios between fast (beta and gamma) and slow (delta, theta and alpha) frequencies for the same phases are calculated. 

In Donald s experiments (D16, D17), those not reaching a convulsive end point showed a tendency toward a slight increase in beta activity and increased synchronization of delta activity in the EEG. Coupled with this was a decrease in the amount and voltage of the dominant alpha frequency (6-12 cps). Single high-voltage spikes appeared infrequently these were symmetrical and bilateral. 

There are two parts to the EEG analysis in Huang, et al. s research (2008). At first, the researchers analyzed the EEG data to make sure that the participants emotional responses really were induced. The EEG data from task C (neutral affect) was the baseline of the EEG waveform for individual participants. If the participants showed more positive than neutral affect, the power value of the alpha frequency band would be higher. In contrast, if the participants showed more negative than neutral affect, the power value of the alpha frequency band would be lower (Huang et al., 2008). The data which did not reflect the expected emotions were rejected. Second, the data which were accepted were analyzed to identify changes in the power value of the theta frequency band. The theta frequency band is always identified as the indicator to assess creativity. 

Palva, S. and J.M. Palva, 2007. New vistas for [alpha]-frequency band oscillations. Trends Neurosci., 30(4) 150-158. 

Fig. 3 Power of alpha frequency band (value x 10 T/cm) from total averaged data of all subjects at left right frontal and left parietal region...

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