Brain correlates of aesthetic expertise: A parametric fMRI study [Link]

2008, Brain and Cognition, Ulrich Kirk, Martin Skov, Mark Schram Christensen and Niels Nygaard

1. Introduction

Q: Dose art experts use different neural processes for determining aesthetic evaluation than non-expert?

1. Psychological model of aesthetic experience/ Behaviour studies
Expertise à Preference

2. Imaging studies

a. for expertise (London taxi driver, Musicians) / b. Aesthetic preference
: Subcortical areas implicated in the processing of reward: Striatum, OFC, ACC
Hypothesis: these regions à modulation of aesthetic assessment according to level of expertise

2. Methods & Analysis

Full-size image

3. Results: Behaviour

Full-size image
image regend: A. Aesthetic rating B. Reaction time C. Distribution, building D. Distribution, face

1. Stimuli difference judged as aesthetic between two subject groups.(Two-way ANOVA:  no significantly different)

2. Frequency difference  of each rating bin between two subject groups (2-sample t test:  no significantly different ,C,D)

3. Response time difference (ANOVA:  no significantly different, B)

4. Results: fMRI

4-1. Correlation between the BOLD and linear aesthetic ratings

Full-size image

To focus on voxels - difference between the responses for the 2 stimulus conditions varied across the 2 subject groups.

•       Activation in ACC, OFC: experts >> non-experts  - Building stimuli than Face when aesthetic judgment

•       ACC: Positive correlation in experts, Negative correlation in non-experts

•       OFC: Positive correlation in both, activation level: experts >> non-experts

•       Nuisance process on recognition preference, ‘familiarly effects’

4-2. Correlation between the BOLD and non-linear aesthetic ratings

Full-size image

Comparing responses the maximal for appealing and unappealing stimuli to the neutrally rated stimuli

•       No significant difference between groups

•       l.Nacc: from Group conjunction analysis - left NAcc plays a role in encoding high and low aesthetic values that is not modulated by expertise or stimulus modality

4-3. Correlation between the BOLD signal and expertise irrespective of aesthetic ratings

Full-size image (Hippocampus) | Full-size image (Fusiform)

To identify voxels that responded differentially in the two groups per se - irrespective of aesthetic rating

•       l. hippocampus, l. precuneus and cerebellum: when aesthetic judgment to building stimuli, experts >> non-experts

•       bilateral  fusiform gyrus and bilateral calcarine gyrus : when aesthetic judgment to building stimuli, non-experts >> experts

•       PPA(parahippocampal place area) : when aesthetic judgment to building stimuli, both groups

5. Discussion

5-1. Relative to ‘Reward’ processing influenced by the expertise

Regions: ventral tegmental area, ventral striatum, amygdala, OFCà only part of system are modulated by expertise during aesthetic judgment (OFC, subcallosal cingulate gyrus(ACC))

1.  OFC, experts>>non-experts
- Sensitivity to the magnitude of aesthetic value
- medial OFC may be engaged under conditions where behavioural decision making based on stimulus reward value is required

[PREVIOUS STUDIES on OFC]

•     relative reward value of stimuli is reflected by the amplitude of neural activity in OFC

•     medial OFC represents the hedonic attributes involved in preference judgments of various stimulus types

•     medial OFC responses can be modulated by top-down information
- the price of a wine, brand information and visual word descriptors influence preference for odours

2.  ACC, experts (+) correlation | non-experts (-) correlation- cingulate gyrus and OFC : contribute distinct component processes to decision making
- [H1] Interface between OFC and premotor cortex: selecting appropriate motor responses

- [H2] emotional processing of happy autobiographical memories

[PREVIOUS STUDIES on ACC]

•     Making decision how to act

•     Emotional  processing: [1] memory related, [2] musical pleasure, monitoring autonomic interoceptive states

*. Possible reasons of Discrepancy: Neural activity – Behaviour

1.Rating method: Not enough sensitive to measure the aesthetic state

2.Set of building stimuli lack perceptual properties (between experts : non-experts)

5-2. Relative to ‘Reward’ processing

1.  l. NAcc (in Ventral Striatum), regardless of group or stimuli difference

- if salience high, activation in left NAcc. increased when both conditions: anticipated loss and gain
- if salience low, activation in left NAcc. increased when anticipated gain | decreased when anticipated gain loss

à However, neither manipulated the salience of the pictures nor the relation between anticipation and reward, so this remains conjecture (In this study)

[PREVIOUS STUDIES on NAcc]

•     NAcc.: Prediction of reward and compute variance between reward expectation and actual reward
(whereas, OFC: process reward outcome)

•     NAcc.: activation increased when positive prediction error, activation decreased when negative prediction error

•     Valence theory, 2. Salience theory, 3. Interaction between Valence and Salience theory

5-3. Difference in perception

1.  Precuneus, Hippocampus, Cerebellum: experts >> non-experts, for expert-stimuli (buildings) compared to control (faces)

- Precuneus: play a role in integrating the current input with prior established knowledge, episodic memory retrieval
- Hippocampus: subjects correctly recollect contextual information compared to conditions where they do not

- Considering: Ruled out familiarity effects in the data

à Experts may have attempted to organize new information into a framework of prior knowledge and use this information to guide and bias aesthetic judgments.

àThe possibility that the hippocampus and the precuneus are specifically involved in biasing preference judgments based on recruitment of episodic memory has also been suggested by other studies  (Symmetrical - Aesthetic, Cultural factor – Drink preference)