Sven Braeutigam

Neuroeconomics—From neural systems to economic behaviour

Neuroeconomics is a new and highly interdisciplinary field. Drawing from theories and methodologies employed in both economics and neuroscience, it aims at understanding the neural systems supporting and affecting economically relevant behaviour in real-life situations. Although incomplete, the evidence is beginning to clarify with the possibility that neuroeconomic methodology might eventually trace whole processes of economically relevant behaviour. This paper accompanies the authors ConNEcs 2004 keynote speech on applications of neuroeconomic research.

What can advertisers learn from neuroscience

The insights of neuroscience are only just becoming available for the study of advertising. This paper seeks to consolidate the contribution so far. Advertising works in two ways: it may trigger some immediate response and/or change the respondent’s brand memories in some way that influences later behaviour. This paper addresses the latter process. In other words, advertising first changes brand equity, and brand equity, in turn, later affects behaviour. The paper outlines the four main techniques of functional brain imaging and reported research in this area, its limitations and the opportunities for new research. Whether the contribution to date is seen as modest or substantive is a lesser question than what neuroscience could do for our longer-term understanding of how advertising works. Neuroscientists and advertisers need to work together so that research investigates how ads are processed, how brand memories are stored and the subsequent behaviour effects relative to the intentions of the advertisers.

COMT Val(158)Met genotype determines the direction of cognitive effects produced by catechol-O-methyltransferase inhibition

Background Catechol-O-methyltransferase (COMT) metabolizes dopamine. The COMT Val158Met polymorphism influences its activity, and multiple neural correlates of this genotype on dopaminergic phenotypes, especially working memory, have been reported. COMT activity can also be regulated pharmacologically by COMT inhibitors. The inverted-U relationship between cortical dopamine signaling and working memory predicts that the effects of COMT inhibition will differ according to COMT genotype. Methods Thirty-four COMT Met158Met (Met-COMT) and 33 COMT Val158Val (Val-COMT) men were given a single 200-mg dose of the brain-penetrant COMT inhibitor tolcapone or placebo in a randomized, double-blind, between-subjects design. They completed the N-back task of working memory and a gambling task. Results In the placebo group, Met-COMT subjects outperformed Val-COMT subjects on the 2- back, and they were more risk averse. Tolcapone had opposite effects in the two genotype groups: it worsened N-back performance in Met-COMT subjects but enhanced it in Val-COMT subjects. Tolcapone made Met-COMT subjects less risk averse but Val-COMT subjects more so. In both tasks, tolcapone reversed the baseline genotype differences. Conclusions Depending on genotype, COMT inhibition can enhance or impair working memory and increase or decrease risky decision making. To our knowledge, the data are the clearest demonstration to date that the direction of effect of a drug can be influenced by a polymorphism in its target gene. The results support the inverted-U model of dopamine function. The findings are of translational relevance, because COMT inhibitors are used in the adjunctive treatment of Parkinsons disease and are under evaluation in schizophrenia and other disorders.

Abnormal activation of face processing systems at early and intermediate latency in individuals with autism spectrum disorder: a magnetoencephalographic study

The neurological basis of developmental psychopathology in autism is a matter of intense debate. Magnetoencephalography (MEG) was used to study the neuronal responses associated with the processing of faces in 12 able adults with autism spectrum disorders (ASD), performing image categorization and image identification tasks. The neuromagnetic data were analysed using nonparametric time‐series analysis and equivalent current dipole estimation. Comparison data were obtained from 22 normally developing adults. In individuals with ASD, the neural responses to images of faces, observed in right extrastriate cortices at ≈ 145 ms after stimulus onset, were significantly weaker, less lateralized and less affected by stimulus repetition than in control subjects. Early latency (30–60 ms) responses to face images, over right anterior temporal regions, differed significantly between the two subject groups in the image identification task. No such difference was observed for images of mugs or meaningless geometrical patterns. These findings suggest that, during the course of development in individuals with ASD, the cortical activity associated with the processing of human faces assumes a different‐from‐normal localization in extrastriate brain regions. This abnormal localization may be associated with unusual, but nevertheless face‐specific, fast processing pathways.

Task-dependent early latency (30-60 ms) visual processing of human faces and other objects

Electrophysiological responses to previously seen faces reportedly differ from those to novel faces at shorter latencies than generally associated with complex visual analysis. It is unclear, however, whether such observations are unique to faces, and which stages of visual processing they reflect. MEG was used in 21 normal adults to record neural responses to images of faces, other objects and abstract patterns presented individually as part of a classification task and in sequential pairs as part of an image comparison task. The amplitudes of the short latency responses (30–60 ms) to the first image in pairs of faces were significantly greater than the responses to both the second faces and the individual face images. These early responses were recorded over predominantly right hemisphere parietal and occipito-temporal cortical regions including areas that, at longer latencies, have been associated with face specific activity. The differences in the responses within pairs were less for non-face objects and absent for abstract geometrical patterns. No early neuronal activity was observed in the classification task. The results indicate the existence of early latency neural networks that are sensitive to both stimulus type and task and are strongly activated by faces.

Contextual integration the unusual way: a magnetoencephalographic study of responses to semantic violation in individuals with autism spectrum disorders

Autism is a neurodevelopmental disorder associated with deficits in language and social communication. Behavioural studies indicate abnormal semantic organization in individuals with autism, but little is known about the neural mechanism underlying the processing of language in context. Magnetoencephalography was used to record neural responses in 11 able adults with autism spectrum disorders reading meaningful sentences and sentences ending with a semantically incongruous word (e.g. ‘He sent a photo to the trumpet’). Spatially extended evoked signals at 400 ms (N4) and 750 ms (LPC), as well as synchronized gamma‐oscillations, provided clear evidence for specific neuronal processes sensitive to sentence context that differed in individuals with autism compared with typically developing individuals (11 healthy volunteers). Amongst other differences, N4 responses following incongruous words were weaker over left temporal cortices, whereas LPC responses to incongruous words and long‐latency gamma‐oscillations following congruous words were stronger over central and prefrontal regions in individuals with autism compared with the control group. Also, incongruous words elicited long‐lasting gamma‐oscillations above 40 Hz in the clinical group, but not in typically developing subjects. These findings may indicate unusual strategies for resolving semantic ambiguity in autism. Moreover, the observed gamma‐band responses provide evidence for sustained cortical synchronization across segregated areas in individuals with autism, contrary to claims that a general deficit in either temporal binding or long‐range connectivity may explain autism.

Magnetoencephalographic Signals Identify Stages in Real-Life Decision Processes

We used magnetoencephalography (MEG) to study the dynamics of neural responses in eight subjects engaged in shopping for day-to-day items from supermarket shelves. This behavior not only has personal and economic importance but also provides an example of an experience that is both personal and shared between individuals. The shopping experience enables the exploration of neural mechanisms underlying choice based on complex memories. Choosing among different brands of closely related products activated a robust sequence of signals within the first second after the presentation of the choice images. This sequence engaged first the visual cortex (80-100 ms), then as the images were analyzed, predominantly the left temporal regions (310-340 ms). At longer latency, characteristic neural activetion was found in motor speech areas (500-520 ms) for images requiring low salience choices with respect to previous (brand) memory, and in right parietal cortex for high salience choices (850-920 ms). We argue that the neural processes associated with the particular brand-choice stimulus can be separated into identifiable stages through observation of MEG responses and knowledge of functional anatomy.

Face‐ and gaze‐sensitive neural responses in children with autism: a magnetoencephalographic study

Face and gaze processing were studied using magnetoencephalography in 10 children with autism and 10 normally developing children, aged between 7 and 12 years. The children performed two tasks in which they had to discriminate whether images of faces presented sequentially in pairs were identical. The images showed four different categories of gaze: direct gaze, eyes averted (left or right) and closed eyes but there was no instruction to focus on the direction of gaze. Images of motorbikes were used as control stimuli. Faces evoked strong activity over posterior brain regions at about 100 ms in both groups of children. A response at 140 ms to faces observed over extrastriate cortices, thought to be homologous to the N170 in adults, was weak and bilateral in both groups and somewhat weaker (approaching significance) in the children with autism than in the control children. The response to motorbikes differed between the groups at 100 and 140 ms. Averted eyes evoked a strong right lateralized component at 240 ms in the normally developing children that was weak in the clinical group. By contrast, direct gaze evoked a left lateralized component at 240 ms only in children with autism. The findings suggest that face and gaze processing in children with autism follows a trajectory somewhat similar to that seen in normal development but with subtle differences. There is also a possibility that other categories of object may be processed in an unusual way. The inter‐relationships between these findings remain to be elucidated.

Abnormal intrinsic and extrinsic connectivity within the magnetic mismatch negativity brain network in schizophrenia: A preliminary study

Altered neuroplasticity is increasingly invoked as a mechanism underpinning dysconnectivity in schizophrenia. We used Dynamic Causal Modelling to compare connectivity during the magnetic auditory Mismatch Negativity (MMN), an index of error prediction, between schizophrenia patients and controls. Patients showed reduced intrinsic connectivity within the primary auditory cortex suggestive of impaired local neuronal adaptation and disrupted forward and backward extrinsic connectivity throughout the MMN network indicative of reduced higher order input in disambiguating activity in lower network nodes. Our study provides the first empirical description of the dysplastic changes underpinning dysconnectivity between primary sensory and higher order cortical areas in schizophrenia.

Face and gaze processing in normally developing children: a magnetoencephalographic study.

Magnetoencephalography (MEG) was used to study the neural mechanisms underlying face and gaze processing in ten normally developing boys aged between 8 and 11 years and 12 adult males. The participants performed two tasks in which they had to decide whether images presented sequentially in pairs, depicted the same person or the same motorbike. In the first task, the participants saw pictures of faces in which the eyes were either open or shut and pictures of motorbikes. In the second task, participants saw pairs of faces with gaze averted to the left or right. In children there was no evidence of the face sensitive, low amplitude short latency (30–60 ms) activity seen previously in adults. A strong, midline posterior response at approximately 100 ms was observed in children, which was earlier and somewhat stronger to faces than to motorbikes; in adults the signal at this latency was weak. A clear face sensitive response was seen in adults at 135 ms, predominantly over the right inferior occipito‐temporal regions. Although activity was observed in the children at the same latency, it was less prominent, not lateralized and was evoked similarly by faces and motorbikes. Averted gaze conditions evoked strong right‐lateralized activity at approximately 245 ms in children only. These findings indicate that even in middle childhood the neural mechanisms underlying face processing are less specialized than in adults, with greater early activation of posterior occipital cortices and less specific activation of ventral occipito‐temporal cortex.