Posts tagged Frontal lobe

Cognitive control: when less is more!

ResearchBlogging.org

Yesterday I wrote a post about ADHD and creativity and how the frontal lobes hypo-function and dopamine may be the mediating factors involved.  Today I serendipitously came across this article by Thomson-Schill et al in which they posit that frontal cortex hypofunction during childhood is beneficial, on average, as it enables convention learning and thus linguistic acquisition.

What they basically mean is that frontal cortex has been found to be involved in cognitive control i.e. in higher cognitive functions like planning, flexible thinking etc ; and the frontal cortex does this by biasing the competitive responses elicited by a stimuli by goals /existing beliefs / other task related information that is maintained in the working memory. To take an example, cognitive control is often measured by tasks such as the stroop task. the strrop task measures how well you are able to suppress the prepotent response tendency of naming the color-term itself by the task-relevant constraint that you name the color of the term instead. when a color term like ‘green’ is presented in Red color, then the green as well as red linguistic response compete with each other. In the absence of frontal biasing in teh direction of color ie.e red, we are apt to name the color-term itself i.e green by default which is the habitual response. Children , who have less well-developed frontal cortices generally perform poorer at the stroop task than adults as their frontal cortex does not bias or tilt the scales in favor of the color used rather than the color-term presented.

The authors claim that this inability to bias results on the basis of pre-existing knowledge/beliefs leads to a greater ability to learn. They posit that learning conditions (that maximize competition )  are different from performance conditions (where one response needs to be selected or competition minimized) and the child’s brain is optimized for learning by not having frontal inhibition and control. An example they give is filtering noise form signal which the child are able to do, but adults can’t. for eg. if a new language has a phrase ‘et tu brute’ and 75 % of times it is in this form and 25% of times it is of the form ‘et tu vous Brute’, then adults will tend to probability match and select the utterance/ utter themselves phrase ‘et tu brute’ 75% of times and ‘et tu vous Brute’ 25 % of times. This is because when they want to utter the phrase their existing knowledge that sometimes the other phrase is also used, makes them sensitive to variations. In child’s brain on the other hand a competition between the two phrases takes place and as there is no moderating influence involved, the outcome hundred percent of the time is ‘et tu brute’. Thus, they are able to learn conventional meaning of a phrase/word etc more easily than an adult who gets bogged down by variations. Thus sometimes, less is more!

However the reason I got hooked to this study is the implications they draw for ADHD/Autism and creativity. I’ll quote them verbatim on the issue:

Central to our proposal is the claim that the timing of PFC development has been the target of selection and, therefore, that variations in timing are functionally meaningful. Recent neuroimaging studies have revealed potentially important differences in the timing of PFC development across typical and atypical individuals. Variations in the trajectory of PFC maturation (based on repeated measures of cortical thickness) have been associated with cognitive measures in typically developing children (Shaw et al., 2006). Children with attention-deficit hyperactivity disorder (ADHD) exhibit a delay in cortical maturation that is most prominent in the PFC (Shaw et al., 2007). In contrast, children with autism spectrum disorders (ASD) undergo early maturation of the PFC (Carper, Moses, Tigue, & Courchesne, 2002). A better understanding of the implications of these timing changes for both learning and performance may illuminate some of the behavioral and cognitive patterns associated with these diagnoses (e.g., impaired acquisition of social conventions in ASD), as well as offer a fertile ground for testing the validity of our hypothesis that typical PFC development involves a trade-off in favor of learning to the detriment of performance in infancy and early childhood.

This gels quite nicely with what I have been speculating for some time, that ADHD and Autism are opposed and that ADHD is childhood equivalent of psychosis. ADHD kids are bound to be good learners, more divergent creative and have better social and linguistic skills. Autistic kids on the other hand would be better performers (say child prodigies in memory etc) , more convergent thinkers, and have less social and linguistic skills- one mechanism of which may be lesser ability to learn social and linguistic conventions- like the usage of metaphorical terms.

On creativity this is what the authors say:

Creativity—the ability to approach an object or a situation from an alternative perspective—may benefit from the unsupervised competition that occurs in the absence of prefrontal control. Consider one common assessment of creative thinking, the Alternative Uses Task: When attempting to think of ways to use an object in some atypical way, adults struggle. In this case, an active PFC might, paradoxically, hinder flexible thinking, because the representation of the object is sculpted by prior experience and expectations. Interestingly, young children are immune to this kind of functional fixedness (German&Defeyter, 2000). Successful performance in similar tasks of ideational fluency has been associated with EEG changes in prefrontal regions (e.g., Mo¨lle, Marshall, Wolf, Fehm, & Born, 1999). Furthermore, patients with PFC damage solve insight-problemsolving tasks better than do their healthy counterparts (Reverberi, Toraldo, D’Agostini, & Skrap, 2005). This apparent flexibility of behavior can be interpreted as a stimulus-driven response: A mind that is at the mercy of its environment is not shaped by expectations or beliefs. This interpretation highlights a parallel between functional fixedness and probability matching, in that both of these ‘‘adult’’ phenomena involve biasing stimulus–response associations based on expectations. This proposal suggests new avenues of investigation into the processes that support creative thought and into putative relations between creativity and psychological disorders associated with hypometabolic prefrontal function (i.e., a state of lower energy consumption in the PFC, as in bipolar disorder, for example).

The above analysis of creativity in terms of hypofunction of frontal cortex bodes well for my theories of creativity-ADHD relationships as well as creativity-psychosis (bipolar etc) relationship, both of which involve developmental or functional hypofucnction of frontal cortex.

Thompson-Schill, S., Ramscar, M., & Chrysikou, E. (2009). Cognition Without Control: When a Little Frontal Lobe Goes a Long Way Current Directions in Psychological Science, 18 (5), 259-263 DOI: 10.1111/j.1467-8721.2009.01648.x

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Creativity-psychosis linkage via reduced white matter /myelination

ResearchBlogging.org
I have been following, and am passionate about, the positive psychology movement for quite some time, but was surprised to discover that there was something called positive neuroscience also in place. I recently came across this new scientist article about the research paper of Rex Jung et al and was pleased to discover that Jung was working on the frontier of applying latest in neuroscience research to Positive brain states and substrates like that involved in creativity.

The article is in PLOSOne, an open access journal and is lucidly written , so you should go and read it now. I’ll anyway like to summarize their study results. First a bit of background about creativity psychopathology linkage.

Some research reports positive correlations between various definitions of creativity and a diagnosis of psychopathology [1], [2], [3], [4]. Other studies report that psychopathology is rarely, if ever, associated with creative insight, capacity, or productivity [5]. When artists are studied more carefully, certain personality characteristics appear to reside upon a continuum of both normal behavior and psychopathology. For example, creative expression in the visual arts and poetry has been linked with the overlapping personality traits of schizotypy and Openness to Experience (Openness), and particularly to self-reports of “unusual experiences” and “unconventional nonconformity”, but not the “introvertive anhedonia” characteristic of schizophrenia [6].

This is inline with what we have been covering at mouse trap regarding association of creativity with the psychotic spectrum especially the creativity that is artistic or revolutionary in nature rather than scientific and methodical in nature. This is how the authors distinguish between types of creativity inline with my views that one type of creativity is autistic (cognitive) in nature while the other is psychotic (emotional) and these are on a continuum.

First, there does not exist one “creativity”; rather, this construct is hypothesized to reside upon a continuum between cognitive (i.e., scientific) and emotional (i.e., artistic) behavioral domains [41], [42]. Thus, when comparing scientists and artists directly, researchers have found lower lifetime rates of psychopathology for: 1) scientists compared to artists, 2) natural scientists compared to social scientists, 3) nonfiction writers compared to fiction writers and poets, and 4) formal artists compared to “expressive” artists [3], [4], [43]. These findings have led researchers to hypothesize a hierarchical structure of creativity across disciplines [42], which echoes the notions of “paradigmatic” (i.e., a fundamental model of events) versus “revolutionary” (i.e., rejection of doctrines) approaches as applied to the sciences [44]. The benefits of working within the lines of a given field appear to be lower levels of psychopathology; alternately, individuals with lower levels of psychopathology may be attracted to such endeavors. Similarly, there is increasing evidence that the cost of “revolutionary” approaches to creative endeavors, whether it is in the arts or sciences, may be associated with increased levels of psychopathology although, again, causative links are weak at best.

So that fits in with broader creativity/ psychopathology linkage, but to get back to the current study the authors had already established earlier that performance on Divergent Thinking (DT) (a measure of creativity) “exhibited significant inverse relationships with both cortical thickness in frontal lobe regions and metabolite concentration of N-acetyl-aspartate (NAA) in the anterior cingulate cortex in normal young subjects “. Thus, some theoretical relationship between creativity and underlying brain circuitry in the frontal reagion was available a priori. Also, research by other researchers has already established that ” Both schizophrenic and bipolar patients have been shown to have reduced fractional anisotropy (FA) in the anterior thalamic radiation [12], [13] and uncinate fasciculus [14] within frontal brain regions. Similarly, reduced FA was observed within the uncinate fasciculus of a cohort with schizotypal personality disorder, providing strong support for the hypothesis that similar neural phenotypes may not result in full-blown clinical symptoms [15]. Finally, in normal subjects, the Neuroregulin-1 (NRG1) single nucleotide polymorphisms (SNP’s) SNP8NRG243177 and SNP8NRG221533 were found to predict lower FA in the left anterior thalamic radiation [16]. As NRG1 has been found to predict higher risk of schizophrenia [17], [18] and bipolar disorder [19], and is linked with axonal myelination and migration [20], these authors hypothesize a mechanistic link between NRG1 within the anterior thalamic radiation and risk for psychotic disorders [16].”

Thus, from the above it is easy to see that there should be a inverse relationship between Fractional Anisotropy (a construct related to myelination of axons) in the frontal regions and creativity if one assumes that creativity and psychopathology are related and are on one end of a continuum. And this inverse relationship between creativity and FA is exactly what they found:

Our results suggest a convergence between a cognitive measure of divergent thinking, a personality measure of Openness, and a white matter integrity measure within the inferior frontal lobes. We found that normal young subjects with lower levels of FA within predominantly left inferior frontal white matter (i.e., regions overlapping the uncinate fasciculus and anterior thalamic radiation) scored higher on the CCI; similarly subjects with lower levels of FA within the right frontal white matter (i.e., regions overlapping the uncinate fasciculus and anterior thalamic radiation) scored higher on self-reported measures of Openness. These two regions of white matter overlap with those reported by other researchers who found lower FA in both schizophrenia and bipolar disorder [13], [14], [30].

They could also nail the reduced FA to reduced myelination as radial diffusion was affected more than axial diffusion. As reduced myelination has been shown as a diatheisis for psychosis, this fits in with previous research linking risk factors common to psychosis and creativity.

Whereas more neural resources are often associated with higher intellectual capacity in a parieto-frontal network of brain regions [39], studies in DT appear to suggest that less is often better in a different network of brain regions, particularly fronto-cingulate-subcortical networks linked via white matter loops [40].

One can speculate that frontal region, more concerned with executive control , when with reduced activity or functional connectivity , may not inhibit the other brain regions that much, and may thus lead to flowering of inherent creativity and cross-talk amongst different brain regions. On the other hand too much white matter/ gray matter in this region may lead to too much control and leave little room for flexibility and creativity.

However, while lower FA is commonly seen in diseases where both cognition and white matter integrity are impaired (e.g., Traumatic Brain Injury, Schizophrenia, Alzheimer’s disease) [45], [46], [47], evidence is accumulating that higher FA in particular brain regions may also be associated with clinical disorders including post-traumatic stress disorder [48], obsessive-compulsive disorder [49], panic disorder [50], synaesthesia [51], and Williams syndrome [52].

It is interesting to note that enhanced FA is associated with clinical disorder of Williams syndrome, which is associated with Autism; on the other end of continuum, reduced FA in particular brain region is associated with psychosis proneness, thus providing another convergent linkage of autism and psychosis as opposites.

Jung, R., Grazioplene, R., Caprihan, A., Chavez, R., & Haier, R. (2010). White Matter Integrity, Creativity, and Psychopathology: Disentangling Constructs with Diffusion Tensor Imaging PLoS ONE, 5 (3) DOI: 10.1371/journal.pone.0009818

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