music increases frontal eeg coherence during verbal learning
DESCRIPTION
Music increases frontal EEG coherence during verbal learning. David A. Peterson a , b , c , ∗, Michael H. Thaut b , c a Department of Computer Science, Colorado State University b Program in Molecular, Cellular, and Integrative Neuroscience Colorado State University - PowerPoint PPT PresentationTRANSCRIPT
Music increases frontal EEG coherence during verbal
learning
David A. Peterson a,b,c, , Michael H. Thaut b∗ ,ca Department of Computer Science, Colorado State Universityb Program in Molecular, Cellular, and Integrative Neuroscience Colorado State Universityc Center for Biomedical Research in Music, Colorado State University
Ranelle Johnson
Neuroscience Letters 412 (2007) 217-221
Introduction (others said…)• Memory may be subserved by oscillations
in recurrent networks within and between brain regions (in theory)
• Increased multi band spectral power in the EEG during encoding is associated with successful subsequent word recall
Introduction• In an earlier study…
– verbal learning is associated with broadband increases in EEG power spectra
– Music influences the topographic distribution of the increased spectral power
• Present study…– examining spatial coherence in EEG
measured during learning phase
Independent Variable
• Treatment Groups– Learning to recall in conventional speaking
voice– Learning to recall while singing to melody
Dependent Variable
Theoretical Construct- verbal learning
Operational Definition- Transition from not being able to recall to being able to recall a word that is repeatedly presented in the AVLT
Dependent Variable
• Theoretical Construct– Learning related changes in coherence
(LRCC)• Operational Definition
– Percent increase or decrease in coherence comparing “first recalled” words to the same words not recalled during the immediately preceding trial (all pairs of not learned/learned words)
Hypothesis
• Learning that persists over short- and long- delays will be associated with “learning related change in coherence” (LRCC) in frontal EEG
Hypothesis
• The temporally structured learning template provided by music will strengthen LRCC patterns in frontal EEG compared to conventional spoken learning.
Subjects
• 16 healthy right-handed volunteers– Normal hearing– No history- neurological or psychiatric conditions
• Randomly assigned to one of two experimental conditions in a in between-subjects design
• Age range– 18-26 (mean=19.8, SD=2.8)– 18-21 (mean=19.0, SD=1.0)
• Each group contained 7 females
Method
• Rey’s Auditory Verbal Learning Test (AVLT)– 15 semantically unrelated words – Repeated in 5 learning trials– Subjects free recalled as many words as
possible after each recall– 6th trial- distracter list, 20 minute visual
Method
Fig. 1. Rey’s Auditory Verbal Learning Test (AVLT) and the operational definitions of:• learning (thickest arrows, during the learning trials—e.g. words 2, 14, 15);• short-delay memory (medium thick arrows to M1—e.g. words 2, 15);• long-delay memory (thinnest arrows to M2—e.g. word 2).
Method
• Pre-recorded female voice (both conditions)
• Music condition- sang simple, repetitive and unfamiliar melody
• Made both groups’ list of words same durations (15sec)
Method
• Electroencephalogram (EEG)– Continuous EEG from continuous 32 scalp
electrodes – Neuroscan’s QuickCap using low- and high-
frequencies 1 and 100 Hz, 1kHz sampling frequency
– Computed interelectrode coherence over 500 ms window 250ms after each word’s onset
• For electrode pairs in theta, alpha, gamma frequency bands
Analysis
• Computed coherence for– left and right prefrontal areas, within and
between• LRCC for each group- compared to no
change using one-tailed t-test, alpha=.05• LRCC between the two groups- compared
using two-tailed t-test, alpha=.05• Bonferroni adjustment by factor of 3 for
multiple comparison
Results (performance)
• Both groups recalled about 6 more words on the last learned trial than on the first– mean=11 & 4.9 (spoken) – mean=9.7 & 4.3 (music)
• Significant improvement in performance– t(16)= 9.6 & 6.3, p<0.0001
• Recall was not significantly different between spoken and musical groups on any trial – t(16)<1.4, p>0.1
Results (spoken)
• Involves a mix of (+) & (-) LRCC• None of LRCC values differed significantly
from zero• Except…
– Negative right frontal gamma LRCC– t(42)=2.2, p=.03 and t(36)= 2.2, p=.03
Results (musical)
• Involved (+) LRCC within & between the hemispheres
• Short-delays– Increased frontal coherence significant for left
gamma, t(39)=2.6, p=.003– Interhemispheric theta, t(39)=2.6, p=.01
Results (musical)• Between Group Comparisons
– Higher LRCC for music group in all 3 frequency bands– Music showed greater increase in theta coherence for
short- & long- delay learning • t(81)=2.1, p=.04 (short- delay)
– Music showed increase and spoken a decrease for right alpha coherence (both short- and long- delay)
• t(66)=2.5, p=.01 (long delay learning)– Music showed greater increase (spoken decrease) in
right gamma coherence in b/t groups for long- delay learning
• t(66)=2.7, p=.009
Results
In each cell: .Values are mean coherence relative to previous unlearned trial (i.e. 100 is no change in coherence). Boldvalues indicates p < 0.05 in one-tailed T-test after Bonferroni correction. Highlighted values indicates p < 0.05 in between-group, two-tailed T-test after Bonferronicorrection.
Results
Fig. 2. Learning-related change in coherence (LRCC). Left: LRCC for short-delay recall; right: LRCC for long-delay recall. Scale bar is percent change. Straightline and box overlays indicate absolute changes in LRCC greater than 5%: box for local quadrant LRCC, and line for interquadrant (interhemispheric) LRCC. Thinbox (e.g. spoken group’s long-delay right frontal gamma LRCC) indicates a decrease of greater than 5%.
Discussion
• Music condition had increased frontal coherence whereas spoken condition had no significant change
• Music group had stronger temporal synchronization in frontal areas
Discussion
• Lack of coherence in spoken condition may be due to form of measure
• Spoken learning involves more focal changes
• Musical learning shows more topographical broader network synchronization
Discussion
• Performance effect “nullified”• Transfer appropriate processing theory
– Subjects asked to recall material in different way that it was encoded
• Physiological results not due to differences in performance
• Physiological results not due to different sensory processing (music vs. spoken stimuli)– Data for LRCC measured with recalled word
compared to the same word not recalled in previous trial
Discussion
• How does music effect synchronization then?– Early attentional mechanism
• Selective attention associated with greater coherence with multiple spatial skills
– Music is known to form expectancy, listeners can predict musical aspects, this could increase coherence
– Studies suggest that music related processing involves more widely distributed subcortical and cortical networks
What do I think?
• Uuuuuummmmm???• I don’t know enough about the interpretations of
EEG to really be able to criticize a whole lot…• But like they said, use more subjects• They could try testing performance by having
the words sung back and see if it makes a difference on performance
• I don’t understand how you can measure a not recalled word
BUT MOST IMPORTANTLY….
– widely distributed
z, t, F =