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Making brains run faster: Are they becoming smarter? Norbert Jaušovec http://increasingintelligenc e.blogspot.si/

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Page 1: Madrid  making brains run faster

Making brains run faster: Are

they becoming smarter?

Norbert Jaušovec

http://increasingintelligence.blogspot.si/

Page 2: Madrid  making brains run faster

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?

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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).

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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

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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.

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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

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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).

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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

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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

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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.

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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)

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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

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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

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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)

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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

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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.

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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.