Anja Pahor

The influence of theta transcranial alternating current stimulation (tACS) on working memory storage and processing functions.

The study aimed to explore the role of the fronto-parietal brain network in working memory function--in temporary storage and manipulation of information. In a single blind sham controlled experiment 36 respondents solved different working memory tasks after theta transcranial alternating current stimulation (tACS) was applied to left frontal, left parietal and right parietal areas. Both verum tACS protocols stimulating parietal brain areas (target electrodes positioned at location P3, or P4) had a positive effect on WM storage capacity as compared with sham tACS, whereas no such influence was observed for the stimulation of the left frontal area (target electrode positioned at location F3). A second finding was that left parietal theta tACS had a more pronounced influence on backward recall than on forward recall, which was not related to task content (spatial or verbal). The influence of theta tACS on WM executive processes was most pronounced for right parietal stimulation. The results are discussed in the broad theoretical framework of the multicomponent model of working memory.

The effects of theta transcranial alternating current stimulation (tACS) on fluid intelligence

The objective of the study was to explore the influence of transcranial alternating current stimulation (tACS) on resting brain activity and on measures of fluid intelligence. Theta tACS was applied to the left parietal and left frontal brain areas of healthy participants after which resting electroencephalogram (EEG) data was recorded. Following sham/active stimulation, the participants solved two tests of fluid intelligence while their EEG was recorded. The results showed that active theta tACS affected spectral power in theta and alpha frequency bands. In addition, active theta tACS improved performance on tests of fluid intelligence. This influence was more pronounced in the group of participants that received stimulation to the left parietal area than in the group of participants that received stimulation to the left frontal area. Left parietal tACS increased performance on the difficult test items of both tests (RAPM and PF&C) whereas left frontal tACS increased performance only on the easy test items of one test (RAPM). The observed behavioral tACS influences were also accompanied by changes in neuroelectric activity. The behavioral and neuroelectric data tentatively support the P-FIT neurobiological model of intelligence.

The Mystery of Intelligence

Intelligence is a precious asset, highly valued in society. It is not surprising that bold claims, which on the one side, stress the genetic influences on intelligence and, on the other side, state that it can be raised via cognitive training, cause fierce discussions among scientists and catch the attention of media and the general public. Several hypotheses have tried to explain why, in the history of human evolution, no organ has grown faster than the brain. It is likely that a combination of social and ecological factors promoted the proliferation of neural precursor cells, making our brain the most complex organ. Intelligence has been linked to academic performance and career success, therefore in the 20th century much energy has been devoted to the design of preschool and early school interventions that would raise intelligence. In contrast, new age approaches are mainly conducted in controlled laboratory experiments showing promising results, although a definite conclusion is still out of reach.

Once Upon a Time We Were on the Moon

Does being more intelligent pay off? Counting the pros and cons definitively gives a yes as an answer. Intelligence has made us the dominant species on Earth, with no natural enemies, except ourselves. However, problems from the past such as hunger, poverty, and wars have not disappeared. On the contrary, our intelligence has created new ones like pollution, extinction of species, global warming, and population growth, to name just a few. Can a higher IQ solve them?

Other Approaches: From Neurofeedback to Cognitive-Enhancing Drugs

A number of alternative approaches can affect cognitive function. Presently, there is no evidence that neurofeedback can be used to enhance intelligence in healthy individuals; however, it presents a promising tool for improving specific cognitive processes, such as attention and memory. The development of new methods that enable self-regulation of functional connectivity between regions of interest may provide a platform for enhancing performance on tests of intelligence. Research suggests that adhering to a healthy lifestyle, which involves a balanced diet, regular exercise, and stress management, has neuroprotective effects. Moderate intensity physical activity seems to be one of the best methods currently available to promote brain health, and counteract age-related cognitive decline. While there is substantial evidence for meditation-related reduction in psychological stress and anxiety, and some evidence for improvement in various components of attention, no conclusions can be drawn with respect to its effect on measures of intelligence. Finally, nutrition plays an important role in the child’s intellectual development; multiple micronutrient supplementation to infants and children who have micronutrient deficiencies can improve fluid intelligence. Certain dietary supplements may also help preserve cognitive function in the elderly. The use of drugs for the purpose of improving cognitive functions by healthy individuals raises several concerns with respect to medical safety and ethics. Prescription stimulants can produce short-term improvements in memory and executive function in healthy individuals; however, the long-term effects of the use of cognitive enhancers remain unknown.