To identify which specific brain areas are most active during a particular mental task

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Russell A. Poldrack

Departments of Psychology and Psychiatry & Biobehavioral Sciences, UCLA, Los Angeles, CA


Rusoffer A. Poldrack, Departments of Psychology and Psychiatry & Biobehavior Sciences, UCLA, Los Angeles, CA;

The goal of cognitive neuroscientific research is to identify the mapping between brain attribute and mental handling. In this paper, I examine the techniques that have actually been offered to identify such mappings, and also argue that they may be basically unable to identify selective structure-function mappings. I argue that in order to understand also the practical anatomy of mental processes, it will certainly be crucial to relocate from the brain mapping tactics that the field has employed in the direction of a search for selective associations. This will require a higher focus on the structure of cognitive procedures, which can be achieved via the breakthrough of formal ontologies that define the framework of psychological procedures. I outline the Cognitive Atlas job, which is arising such ontologies, and present exactly how this understanding could be provided in conjunction via data mining philosophies to more directly relate psychological procedures and brain feature.

You watching: To identify which specific brain areas are most active during a particular mental task


1 Introduction

Imagine that fMRI had actually been invented in the 1860s fairly than the 1990’s1. Instead of being based on modern-day cognitive psychology, neuroimaging would certainly instead be based on the faculty psychology of Thomas Reid and also Dugald Steward, which provided the mental “faculties” that Gall and also the phrenologists attempted to map onto the brain. Researchers would certainly have actually presumably jumped from phrenology to fMRI and perdeveloped experiments manipulating the engagement of specific psychological faculties, or researching individual differences in the strength of the faculties. They almost absolutely would certainly have actually uncovered brain areas that were reliably involved as soon as a particular faculty was engaged, and possibly would certainly also have actually uncovered areas whose task associated via the strength of each faculty across subjects. In assistance of this assertion, Table 1 gives a demonstration of some contemporary neuroimaging data that the intrepid post-phrenologist might have appeacaused in order to demonstrate the neural fact of his proposed faculties.


Table 1


A mapping of Galls 27 faculties (from Whye, 2004) to potentially related neuroimaging results


FacultyModern equivalentfor neuroimagingRegions implicatedReference
Impulse to propagationViewing of romantic lover versus other individualsBasal gangliaAron et al. (2005)
Tenderness for the off-spring, or parental loveMothers viewing own vs. other childAmygdala, insula, anterior cingulate, superior temporal gyrusLeibenluft et al. (2004)
friendly attachment or fidelityViewing frifinish vs. strangerR temporoparietal cortexSugiura et al. (2005)
valour, self-defensePunishment of defectors in financial gamesDorsal striatumde Quervain et al. (2004)
murder, carnivorousnessLess active in murderersPrefrontal cortexRaine et al. (1994)
sense of cunning
larceny, sense of propertyActivated in relation to hoarding behavior in OCDleft precentral gyrus and appropriate orbitofrontal cortexMataix-Cols et al. (2004)
pride, arrogance, love of authorityconcerned arrogance scoresPrefrontal cortexYang et al. (2005)
ambition and also vanityActivation for judgment around self versus othersMedial PFCOchsner et al. (2005)
circumspectionActivation associated via injury avoidanceNucleus accumbensMatthews et al. (2004)
aptness to receive an education, or the memoria realisactivation in the time of thinking tasks correlated through basic intelligenceParietal cortexLee et al. (2006)
sense of localityScenes vs. nonscenesParahippocampal cortexEpstein & Kanwisher (1998)
recollection of personscaused by judgments about face identity vs. occupationFusidevelop gyrusTurk et al. (2005)
faculty for words, verbal memoryUse of memory strategiesPrefrontal cortex, extrastriate visual cortexKirchhoff & Buckner (2006)
faculty of language
disposition for colouring, and also the delighting in coloursGreater activity in grapheme-shade synesthetesV4Hubbard et al. (2005)
feeling for sounds, musical talentactivation in MEG and gray issue volume correlated via musical aptitudeAuditory cortexSchneider et al. (2002)
arithmetic, counting, timeactivity correlated through arithmetic skillAngular gyrusMenon et al. (2000)
mechanical skillbetter activity for observing actions in expert vs. unexperienced groupsLeft premotor, intraparietal, exceptional temporalCalvo-Merino et al. (2005)
comparative perspicuity, sagacity
metaphysical perspicuity
wit, causality, sense of inferenceeven more active for viewing causal vs. non-causal eventsMT, STS, IPSBlakeeven more et al. (2001)
poetic talentgeneration of artistic vs. unimaginative narrativeRight medial frontalHoward-Jones et al. (2005)
Good-nature, compassion, ethical senseJudging personal versus impersonal ethical dilemmasMedial prefrontal, posterior cingulate, angular gyrusGreene et al. (2001)

Although few this day would host that nineteenth century faculty psychology is a precise description of the framework of the mind, we have the right to most likely all agree that if the phrenologists had produced task manipulations to isolate their proposed faculties making use of fMRI, something would have “lit up”. What would the patterns of activation associated with these faculties have looked like? If we think, as I think the majority of would certainly agree, that each of the phrenologists’ putative faculties depends in actuality upon a mix of standard psychological operations, then we would certainly most likely expect that the maps obtained for a offered faculty would certainly include a large collection of set off regions that would certainly tend to overlap throughout jobs intended to tap right into different faculties. Regardless, one have the right to be practically certain that Gall and his contemporaries would have actually taken these neuroimaging outcomes as evidence for the biological truth of his proposed faculties.

The allude of this instance is not to appeal to a specious analogy between phrenology and neuroimaging, however rather to suggest in the direction of a more standard worry. Neuroimaging research studies count upon a theory about the framework of the mind that states the component operations that make up psychological function, which I will certainly refer to as a cognitive ontology (Bilder et al., 2009; Price & Friston, 2005). This ontology explains the “parts” of the mind, which in the end are the points that cognitive neuroimaging aims to map onto brain framework, simply as biologists map cellular functions (e.g., translation) onto cellular structures (e.g., ribosomes). So lengthy as the assumed ontology is at somewhat correlated through the true ontology, regular structure-function mappings have the right to be uncovered, but these carry out not suggest that the underlying ontology is correct. Instead, correctness of the ontology would be reflected in selective association between structures and features. That is, if a specific framework or network is activated in association only one putative cognitive procedure, then one might argue that the truth of this process has actually been established.

A review of the neuroimaging literary works says that selective association in between psychological processes and brain frameworks is currently difficult to find. Although renowned accounts often suggest distinct structure-feature mappings (e.g., the amygdala is the “fear area”, the anterior cingulate is the “dispute area”), closer examicountry of practically eextremely such insurance claim uncovers counterexamples that are hard to reconcile through a selective structure-attribute mapping. Tbelow are a variety of feasible reasons for this lack of selective mapping. First, the underlying ontology might be incorrect. For instance, while we think that “functioning memory” is a distinct attribute enforced in the brain, it may be the situation that there is no such attribute enforced by the brain, and also that what we contact “working memory” is in fact a combination of some various other features. 2nd, it may be that the cognitive ontology is correct, however that the research studies are not appropriately isolating the fundamental operations (i.e., the mapping from job manipulations to psychological procedures is incorrect). Third, it might be that the assumption that mental features deserve to be mapped to individual brain structures is incorrect, such that tright here is selective mapping but it occurs at the level of netfunctions fairly than individual frameworks.

The goal of this paper is to research a set of concerns that aincrease from a consideration of these possibilities. First, I will ask whether current research methods might be problematic for the identification of selective associations also if they exist. Second, I will talk about the worry of cognitive ontologies, highlighting the require for an extra formal method to mapping of mental procedures to brain structures. I will certainly not directly resolve the question of localization in areas versus networks; it is a very vital issue, but it has actually been addressed in information by previous authors (e.g., McIntosh, 2000).


2 Neuroimaging study strategies

The most noticeable strategy within cognitive neuroimaging is what one might speak to the where strategy:

Design a manipulation that is thneed to modulate the engagement of some particular psychological procedure.

Analyze neuroimaging information to determine areas whose task is modulated by this manipulation.

Conclude that the active regions are associated in the manipulated procedure.

This was a common strategy in early on steras of neuroimaging; for example, the early on studies by (Petersen et al., 1988) identified that semantic handling relied upon the left inferior prefrontal cortex utilizing subtraction of word repetition from verb generation. This approach is regularly disparaged as “blobology” or “neo-phrenology”, though it’s not actually clear what various other technique one could use to bootstrap a new study enterprise.

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As neuroimaging has matured, the where strategy has actually given method to what one can contact the what strategy, which focuses more directly on characterizing the attribute of a details brain region:

Design a task that individually manipulates 2 or more various mental processes, among which is hypothesized to be performed by some certain region.

Examine the the imaging information to identify the family member response of the region in question to these manipulations.

Conclude that the region in question perdevelops a certain one of the manipulated procedures.

This strategy shows an incremental technique to reverse design of the attribute of individual brain regions. For instance, a variety of researches in the last ten years have actually examined the function of the left inferior prefrontal cortex in language handling. Early work-related said that it played a duty in the retrieval of expertise from semantic memory (Demb et al., 1995). However, succeeding occupational proposed that rather of perdeveloping retrieval, this area was associated in the selection of task-pertinent indevelopment across both semantic and non-semantic domain names (Thompson-Schill et al., 1997). This hypothesis was later on disconfirmed by Wagner et al. (2001), who confirmed that the region was involved in semantic retrieval even as soon as selection needs were assist constant.

This method has likewise in some cases caused what one could speak to the fractionation strategy:

Design a task that separately manipulates 2 or more different mental procedures.

Identify the regions that are independently involved by those different processes.

Conclude that the processes are perdeveloped by different regions.

For example, a variety of early neuroimaging researches examined the difference between processing of word interpretation (semantic processing) and also processing of word sounds (phonological processing). Based on an fMRI research that directly compared manipulations of these two forms of processing, along with a meta-analysis of previous research studies,Poldrack et al. (1999) proposed that semantic handling relied upon a more anterior portion of the inferior frontal gyrus, whereas phonological processing relied upon a much more posterior portion of the gyrus. This difference has been generally replicated, and also extfinished. In particular, there is an area in the middle of the left inferior frontal gyrus, in in between the areas engaged by semantic and phonological processing, that appears to play a different duty from these various other regions. One set of findings has highlighted the function of this mid-LIFG area in syntactic processing; a number of research studies (reperceived by Bookheimer, 2002) have actually displayed activation in this region for manipulations of the complexity of syntactic handling. Another result suggests that this mid-LIFG region may implement the selection operations proposed by Thompson-Schill et al. (1997). Badre et al. (2005) offered a set of converging manipulations together with aspect evaluation to determine the job determinants that modulated activation in the left inferior frontal gyrus. They discovered that whereas the anterior/inferior percentage of the LIFG was sensitive primarily to semantic retrieval demands, the middle portion of the LIFG was sensitive to a variable that indexed the require for selection among contending alternatives.

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These approaches have actually caused increasingly advanced functional characterizations of particular anatomical areas within relatively restricted domains. However, in many kind of situations the exact same area may be defined in this means across multiple extremely different domains. For example, one collection of studies has actually implicated the posterior percent of the left inferior frontal cortex in a much more basic process of tempdental sequencing (Gelfand also & Bookheimer, 2003). Yet another collection of research studies has suggested that this area forms part of a “mirror network” that is connected in the manufacturing and acknowledgment of actions (Iacoboni et al., 1999; Nishitani et al., 2005). Each of these gives an explacountry for some of the language sensations that have been previously linked via left inferior frontal gyrus task, but integrating every one of these findings right into a solitary concept is complex.

It’s instructive to task forward and think about what the ultimate outcome would certainly be from a number of years of scientific research utilizing the existing approach. It is tempting to conclude that this strategy would certainly aid us learn “what each brain area does”, yet the truth might be rather much less indevelopmental. In particular, while this strategy is likely to uncover a broad collection of attributes that depend upon each region, it is unlikely to identify a basic useful role in mental activity for a certain region (e.g., the basic computations that each area performs). As an analogy, imagine a team of people individually trying to understand the function of a knife blade. One perkid tests its capability to reduced peaches. Upon finding that the blade cuts via peach flesh but not through the pit, they conclude that the knife is specialized for peach flesh removal. Another perchild can test its ability to screw various kinds of screws; finding that the knife blade works well to screw flathead and Phillips screws however not allen screws, they can conclude that it is specialized for a subcollection of screwing functions. While each of these is a valid summary of the features that the knife participates in, neither seems to be a precise description of the standard function of a knife blade, which might be described as something choose “either cutting or manipulating objects relying on their hardness.”