madrid making brains run faster
TRANSCRIPT
Making brains run faster: Are
they becoming smarter?
Norbert Jaušovec
http://increasingintelligence.blogspot.si/
I will talk about:
• A possible theoretical background of the relation between individual alpha frequency (IAF) and g.
• The correlation between IAF and psychological constructs like g, short-term and working memory.
• Increasing IAF – increasing IQ?
The rhythm • Dominates the EEG power spectrum during relaxed
wakefulness• power – number of synchronously discharging neurons.• frequency – white matter structure such as fiber density,
axonal diameter, myelination (Jann et al., 2010; 2012; Valdés-Hernández et al., 2010):o P – FIT neurobiological theroy of intelligence (Jung and Haier, 2007).o Intelligence is the periodicity of neural oscillation in the action
potentials of the brain and central nervous system (Jensen 2011; p. 173).
o Positive correlation between white matter integrity and intelligence (Clayden et al. 2012; Chiang et al., 2009; 2011; Dunst et al., 2014; Haász et al., 2013; Li et al., 2009; Navas-Sánchez et al., 2014; Ritchie et al., 2015; Tamnes et al., 2010).
Correlation IAF – IQ
• Reduced IAF in clinical individuals• Research before 1960 (e.g. review: Vogel and
Broverman,1964): EEG indices seem to be more strongly related to mental age (MA) than to IQ.
• Mundy-Castle (1960) r = 0.34 between alpha frequency and IQ (WAIS).
Nature, 1960, 185; p.184
Correlation IAF – IQ
• Jaušovec and Jaušovec (2000) and Posthuma et al.,(2001) no significant correlations between IAF and IQ (Wechsler adult intelligence test).
• Anokhin and Vogel (1996) correlations between IAF and Raven’s matrices.
Correlation IAF – IQ
Grandy et al.,(2013) structural equation modelling correlation between g (Berlin Intelligence Structure test – BIS) and composed eyes open/closed IAF was .40
NeuroImage 79 (2013) 10–18
Study 1
1. Objective: correlation between IAF (anterior/posterior) and full scale IQ (performance/verbal) – moderator sex. (N = 417; females = 248).
2. Objective: correlation between IAF and lower order factors (rotation–verbal/focus–diffusion of attention; Johnson & Bouchard, 2005). (N = 188; females = 117).
Study 1
1. As predicted, none of the correlation coefficients reached significance. Further, no differences in relation to sex or location could be observed.
2. Whole sample, correlations between IAF verbal-rotation and focus-diffusion no significant differences.
a) Males: rotation-verbal factor and posterior IAF (r = .43; FDR p<.01).
b) Males: focus-diffusion factor and anterior IAF (r = .25; FDR p<.07).
c) Females all correlations were negative, pointing to a reverse trend, although not reaching significance.
Variable
Whole sample (N = 188) Male (n = 71) Female (n = 117)
IAFant IAFpost IAFant IAFpost IAFant IAFpost
VE-ROT .03 (.65) .10 (.16) .22 (.07) .43 (.00)* – .14 (.13) – .11 (.22)
FOC-DIFF .06 (.39) – .01 (.87) .25 (.03)† .18 (.13) –.08 (.39) – .11 (.24)
* FDR p<.01; † FDR p <.07
IAF – Working Memory
• Correlations between IAF and performance on memory tests (Angelakis, et al., 2004; Clark et al., 2004; Klimesch, et al., 1993).
• The relation between working memory (WM) and intelligence
• WM – neurocognitive perspective
Correlations IAF – WM • Clark and colleagues (2004): correlation IAF (eyes-
closed) with backward digit span(N = 550; age 11 – 70 years).
• Angelakis et al. (2004): correlation between performance on the memory test and resting state eyes-closed IAF (determined immediately prior to test administration).
• Klimesch et al. (1993) demonstrated that: o Increased memory load led to a drop in IAF o IAF of good performers remained at a constant level as
task demands increased, whereas in bad performers a decrease was observed.
Study 2
1. Objective: explore the relation between IAF and measures of (a) verbal, (b)spatial WM capacity and (c)scope of attention.
2. Objective: explore (a)endophenotypic characteristics (eyes-closed) and (b) state-based characteristics (eyes-open)
Study 2• Subjects: 115 right-handed students (75
females)• Procedure:
o First day: EEG (eyes closed); forward and backward Corsi block-tapping tasks; Forward and backward digit-span tasks.
o Second day: visual-array comparison task while EEG was recorded
Study 2• No significant correlations between IAF and
the four memory-span tests.• IAF during task performance 0.81 hz lower
than during the interval preceding stimulus onset – more pronounced in anterior than posterior location
• Women higher posterior and lower frontal IAF than males
Study 2
High performers lower drop in IAF
Variable
Whole sample (N = 113) Male (n = 38) Female (n = 75)
Z-diffant Z-diffpost Z-diffant Z-diffpost Z-diffant Z-diffpost
VACT – .25 (.007)* – .17 (.066) – .42 (.008)* – .21 (.215) – .11 (.353) – .15 (.178)
VACT-RT .18 (.057) .02 (.860) – .03 (.843) .17 (.301) .31 (.007)* – .00 (.974)
Study 3
• Objective – establish a causal relation between IAF and fluid intelligence
• Method: o 18 right-handed students (11 females); o Sham/verum tACS; resting eyes closed EEG;
RAPAM test (two parallel forms with 25 items)o Analysis of behavioral data; ERD/ERS and ErCoh
Study 3
• Results:o No differences between participants’ sensations
sham/verum tACSo Significant influence of tACS on IAF in verum
setting.o GLM behavioral data – sex tACS interaction: In
males tACS decreased RAPM performance; in females tACS increased RAPM performance.
Study 3
• Results:o tACS ERD/ERS effect in the upper alpha band –
increased ERD.o tACS ErCoh upper alpha and theta band –
dissociation over a hub in the right temporo-parietal area.