Jacqueline N. Wood

Politics on the brain: an FMRI investigation.

Abstract We assessed political attitudes using the Implicit Association Test (IAT) in which participants were presented with faces and names of well-known Democrat and Republican politicians along with positive and negative words while undergoing functional MRI. We found a significant behavioral IAT effect for the face, but not the name, condition. The fMRI face condition results indicated that ventromedial and anterior prefrontal cortices were activated during political attitude inducement. Amygdala and fusiform gyrus were activated during perceptual processing of familiar faces. Amygdala activation was also associated with measures of strength of emotion. Frontopolar activation was positively correlated with an implicit measure of bias and valence strength (how strongly the participants felt about the politicians), while strength of affiliation with political party was negatively correlated with lateral PFC, lending support to the idea that two distinct but interacting networks—one emphasizing rapid, stereotypic, and emotional associative knowledge and the other emphasizing more deliberative and factual knowledge—co-operate in the processing of politicians. Our findings of ventromedial PFC activation suggests that when processing the associative knowledge concerned with politicians, stereotypic knowledge is activated, but, in addition, the anterior prefrontal activations indicate that more elaborative, reflective knowledge about the politician is activated.

Brain activation in processing temporal sequence: An fMRI study

Structured event complexes (SECs) are stored representations of sequential event knowledge, and represent sequences of activities that have been described elsewhere as scripts or schemas. Previous studies have shown that the prefrontal cortex is involved in temporal sequencing. The present study investigates the involvement of the prefrontal cortex in temporal order and membership judgments of script and category items by using functional magnetic resonance imaging. In this experiment, stimuli were either script events or category items. In experimental trials, subjects classified stimuli according to temporal order or membership category. Results show that the script order task and the chronological order task (relative to their respective memberships tasks) were associated with different patterns of PFC activation. Both order tasks activated the middle frontal gyrus bilaterally; however, script order tasks showed additional activation in right inferior frontal gyrus, and the chronological order tasks in left inferior frontal gyrus. These results suggest that while the middle frontal gyri are activated bilaterally in both script and chronological temporal ordering tasks, there are different, though largely overlapping, neural substrates for script and chronological representations during temporal ordering.

Category-Specific Representations of Social and Nonsocial Knowledge in the Human Prefrontal Cortex

Complex social behavior and the relatively large size of the prefrontal cortex are arguably two of the characteristics that distinguish humans from other animals. Grafman presented a framework concerning how the prefrontal cortex (PFC) controls complex behavior using stored structured event complexes (SECs). We report behavioral and imaging data from a modified go/no-go paradigm in which subjects had to classify words (semantic) and phrases (SEC) according to category. In experimental trials, subjects classified items according to social or nonsocial activity; in control trials, they classified items according to font. Subjects were faster to classify social than nonsocial semantic items, with the reverse pattern evident for the social and nonsocial SEC items. In addition, the conditions were associated with different patterns of PFC activation. These results suggest that there are different psychological and neural substrates for social and nonsocial semantic and SEC representations.

Representation of attitudinal knowledge: role of prefrontal cortex, amygdala and parahippocampal gyrus

It has been proposed that behavior is influenced by representations of different types of knowledge: action representations, event knowledge, attitudes and stereotypes. Attitudes (representations of a concept or object and its emotional evaluation) allow us to respond quickly to a given stimulus. In this study, we explored the representation and inhibition of attitudes. We show that right dorsolateral prefrontal cortex mediates negative attitudes whereas left ventrolateral prefrontal cortex mediates positive attitudes. Parahippocampal regions and amygdala mediate evaluative processing. Furthermore, anxiety modulates right dorsolateral prefrontal activation during negative attitude processing. Inhibition of negative attitudes activates left orbitofrontal cortex: a region that when damaged is associated with socially inappropriate behavior in patients. Inhibition of positive attitudes activates a brain system involving right inferior frontal gyrus and bilateral anterior cingulate. Thus, we show that there are dissociable networks for the representation and inhibition of attitudes.

Integral calculus problem solving : an fMRI investigation

Only a subset of adults acquires specific advanced mathematical skills, such as integral calculus. The representation of more sophisticated mathematical concepts probably evolved from basic number systems; however its neuroanatomical basis is still unknown. Using fMRI, we investigated the neural basis of integral calculus while healthy participants were engaged in an integration verification task. Solving integrals activated a left-lateralized cortical network including the horizontal intraparietal sulcus, posterior superior parietal lobe, posterior cingulate gyrus, and dorsolateral prefrontal cortex. Our results indicate that solving of more abstract and sophisticated mathematical facts, such as calculus integrals, elicits a pattern of brain activation similar to the cortical network engaged in basic numeric comparison, quantity manipulation, and arithmetic problem solving.

Neural correlates of script event knowledge: a neuropsychological study following prefrontal injury.

Scripts sequentially link information about daily activities and event knowledge. Patients have difficulty sequencing script events following lesions of the prefrontal cortex while showing intact access to selective aspects of script knowledge. It has been suggested that the sequencing impairment is due to a deficit in an inhibitory gating mechanisms that usually enables selection of an item from competing alternatives. If this is the case, then an inhibitory task should reveal script processing impairments on a script categorization task that is not normally associated with poor performance following prefrontal damage. To test this hypothesis, we administered a simple untimed classification task and a modified Go/NoGo task in which subjects classified events from social and non-social activities (e.g., read the menu, order the food) and related semantic items (e.g., menu, order) in terms of whether they belonged to a target activity. Participants were patients with lesions of the prefrontal cortex and matched controls. The results showed that damage to the right orbitofrontal cortex was associated with social item classification errors in the simple untimed classification task. In addition, the damage to the right prefrontal cortex was associated with increased response times to respond correctly to Go trials in the modified Go/NoGo task. The data demonstrate that damage to the right orbitofrontal cortex results in impairment in the accessibility of script and semantic representations of social activities. This impairment is exacerbated by an inefficient inhibitory gating mechanism.

New Meat Begets a New Appetite: Advice for the Functional Neuroimaging Dieter

William R. Uttal’s The New Phrenology is the third in a series of volumes that have attempted to take to task the “cognitive establishment” in order to persuade cognitive psychologists and students to return to the friendly confines of an observable behavioral science. In this volume, Uttal asks the question: can psychological processes be localized in the brain? His answer(s) are to say the least pessimistic. His stated goal in tackling this question is to be a constructive gadfly. For example, he implies that it should be clear to anyone conducting cognitive neuroscience research that the major scientific journals have rushed to publish functional neuroimaging papers with localization findings that are often either theoretically dubious or, at best, replications of previous “lesion” research – hardly the usual criteria for publishing in cutting-edge journals. We, like Uttal, believe that this rush to feature functional neuroimaging studies in the scientific press has led to a significant number of scientific and financial diversions. While the effects of a new technology on the political climate of a scientific enterprise may not be unique to cognitive neuroscience, a voice of reason in the midst of ecstatic endorsement is useful. Does Uttal’s volume provide such a voice? Well, yes and no. Uttal’s assertions about the failures of cognitive neuroscience may be criticized by some reviewers because he comes from another era and area (perception) within psychological science. That is a specious criticism that would only distract us from debating his main criticisms. It is clear, however, from this volume that Uttal is both a reductionist and a behaviorist and this approach to psychological science colors many of his commentaries in this volume and occasionally distracts the reader from his more cogent commentaries. We will return to this point later in our review.