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Posts Tagged ‘prefrontal cortex’

Brain Disease and Creativity

31/05/2012 2 comments

Readers of this blog probably know I’m very interested in creativity. Recently, I came across a very interesting  review paper on artistry in brain disease by Schott.  Even though, many studies focus on the loss of various abilities as result of brain injury or disease, this review is focused on cases where brain disease resulted in enhanced artistic creativity in people with an interest in art or emergence of artistic creativity in art naive patients. Pictures created spontaneously by patient with brain disease sometimes present an excellent opportunity for studying that disease and revealing underlying mechanisms of cerebral dysfunction. It can also provide some useful information about creative processes in the healthy brain.

Dementia and stroke are very common. However, cases of patients who exhibit enhanced artistic output in these and other neurological disorders are rare or very rare. Miller et al. (2000) showed that enhanced artistry is probably more common but it is often under-reported, since new or preserved visual or musical ability was found in 17% of 69 patients with frontotemporal dementia.
In fact, frontotemporal dementia seems to be the brain disease more closely associated with increased creativity. Miller et al. (1996) were the first to report a patient with frontotemporal dementia that had developed new artistic creativity in the face of advancing dementia. A number of papers (Tanabe et al., 1996; Snowden et al., 1996), as well as Miller at al.’s seminal letter in the Lancet published in the same year brought more attention to the subject of preserved or increased artistic creativity in the presence of brain disease. Miller et al. (1996) described a 68-year-old male with a 12-year history of frontotemporal dementia,who, at the age of 56 years, started to paint having had no previous interest in art.

Patients with Alzheimer’s disease have also been reported to exhibit enhance artistic creativity. Professional painter, Danae Chambers, whose dementia started at around the age of 49 years (Fornazzari, 2005) is a striking example. Even though she was diagnosed with Alzheimer’s disease and her MRI scan revealed mild to moderate brain atrophy, there was no effect on her talent and creativity. However, it should be noted that typically during the progression of the disease stylistic changes leading to frank deterioration and eventual cessation of painting have been reported, especially in professional artists (see Crutch and Rossor, 2006).

In the case of autism there have been several cases of even very young autistics who could produce impressive works of art. A famous example is Stephen Wiltshire, who was able to draw astonishingly faithful architectural representations at the age of 7 years (Sacks, 1995).

According to Schott unexpected artistic creativity experienced by many patients has many features that suggest compulsive behaviour. Moreover, emergence of artistry after brain disease reflects innate rather than learned skills.

The brain correlates of emergent artistic creativity are rather obscure. It appears that dysfunction of the anterior temporal lobes is important if not crucial for the production of unexpectedly enhanced artistry, but the findings are often inconsistent. In some cases frontal lobe involvement is present too (Seeley et al., 2008).  Thus creative drive is thought to increase not only with abnormalities of temporal lobe function and ‘release’ of frontal lobe-mediated creativity, but also by involvement of the dopaminergic mesolimbic system (Flaherty, 2005)

One might wonder; is this emergence of artistic talent observed in patients with various brain diseases really creativity?

De Souza et al. (2010) then concluded: ‘The emergence of artistic talent in patients with fvFTLD is explained by the release of involuntary behaviors, rather than by the development of creative thinking’, and also recommended avoiding consideration of ‘pseudo-creative production, or the emergence of “artistic talent”, as a mastered mental production’.

The author, however, disagrees and concludes:

…the notion of pseudo-creation and identification of ‘artistic talent’ create more difficulties than enlightenment; rather, they emphatically confirm the importance of patients’ pictures. The evidence for creativity surely lies in the creation itself rather than in perfusion patterns or psychological tests.

ResearchBlogging.orgSchott, G. (2012). Pictures as a neurological tool: lessons from enhanced and emergent artistry in brain disease Brain, 135 (6), 1947-1963 DOI: 10.1093/brain/awr314

Investigating the Anatomical Relationship Between Primary Sensory and Prefrontal Cortices in the Human Brain

11/10/2011 1 comment

People experience the world in slightly different ways. Philosophers have been writing about this for years and, recently, studies using psychophysics and neuroimaging provide further support for this. A classic example is the way we perceive visual illusions; there is variability in the responses of people about the extent they experience various illusions. Schwarzkopf et al. (2010) showed that inter-individual differences in the surface area of V1 predict individual differences in conscious perception, such as how big something looks.

A study by Chen et al. that was published on the  JoN used a novel approach that combined non-invasive cortical functional mapping with whole-brain voxel-based morphometric analyses to investigate the anatomical relationship between the functionally mapped visual cortices and other cortical structures in healthy humans. Chen et al. found an interesting correlation between the size of V1 and primary auditory cortex. This relationship could be explained in terms of our everyday multisensory experience of the world. However, the size of those areas was anticorrelated with the size of the anterior prefrontal cortex (aPFC), the frontopolar part of the frontal cortex. In a few words, individuals with larger primary visual cortex had larger primary auditory cortex but smaller aPFC. This anticorrelation was only found for the primary sensory cortices and not for other visual cortices (e.g. V2, V3).

According to Chen et al.

…while one might expect a positive correlation between the whole-brain gray matter volume and the volume of its components, instead we found a striking anticorrelation for primary visual cortex: individuals with larger brains tended to have smaller primary visual cortices. In contrast, anterior prefrontal cortex was the single most enlarged region in a larger brain.

The aPFC is a particularly fascinating area. Apart from having many names (anterior PFC, the frontal pole, frontopolar cortex, rostral prefrontal cortex, BA 10…), aPFC is larger relative to the rest of the brain (Semendeferi et al., 2001) and is significantly different in humans compared to other primates (Semendeferi et al., 2001), suggesting that this region may contribute to the unique human behaviour. Furthermore, it is one of the last brain areas to mature in humans (Dumontheil et al., 2008) and has been recently identified as the region with the greatest relative prediction power about brain maturity over development (Dosenbach et al., 2011). Evidence from previous studies suggest that this particular area has a role in higher-order cognitive functions (including prospective memory)

The pairing between the expansion of anterior prefrontal cortex and the contraction of primary sensory cortices reflects a common ground for the formation of anatomically and phylogenetically remote cortical regions, and suggests the existence of a reciprocal link between high-order cognition and low-level sensation.

Future studies will attempt to further investigate this relationship and examine what the effects of these structural differences are on function and performance on various tests thought to tap on those areas.

ResearchBlogging.orgSong C, Schwarzkopf DS, Kanai R, & Rees G (2011). Reciprocal anatomical relationship between primary sensory and prefrontal cortices in the human brain. The Journal of neuroscience : the official journal of the Society for Neuroscience, 31 (26), 9472-80 PMID: 21715612

Schwarzkopf DS, Song C, & Rees G (2011). The surface area of human V1 predicts the subjective experience of object size. Nature neuroscience, 14 (1), 28-30 PMID: 21131954

Coren S, & Porac C (1987). Individual differences in visual-geometric illusions: predictions from measures of spatial cognitive abilities. Perception & psychophysics, 41 (3), 211-9 PMID: 3575080

Dumontheil I, Burgess PW, & Blakemore SJ (2008). Development of rostral prefrontal cortex and cognitive and behavioural disorders. Developmental medicine and child neurology, 50 (3), 168-81 PMID: 18190537

Semendeferi, K., Armstrong, E., Schleicher, A., Zilles, K., & Van Hoesen, G. W. (2001). Prefrontal cortex in humans and apes: a comparative study of area 10 American journal of physical anthropology, 3 (114), 224-241

Dosenbach NU, Nardos B, Cohen AL, Fair DA, Power JD, Church JA, Nelson SM, Wig GS, Vogel AC, Lessov-Schlaggar CN, Barnes KA, Dubis JW, Feczko E, Coalson RS, Pruett JR Jr, Barch DM, Petersen SE, & Schlaggar BL (2010). Prediction of individual brain maturity using fMRI. Science (New York, N.Y.), 329 (5997), 1358-61 PMID: 20829489

Your brain on improv

08/01/2011 3 comments

Charles Limb is a surgeon and musician who is investigating the neural correlates of musical creativity. You might remember his very cool fMRI study of jazz improvisation. You can read it here. He talks about this and other projects he’s working on in his recent TED talk. We need more studies like these!

Behavioural Effects of Early Focal Damage to Prefrontal Cortex

18/04/2010 2 comments

ResearchBlogging.orgAnderson et al. (2007) report a case of a 14 month boy (PF1) who sustained damage to his right inferior dorsolateral prefrontal cortex due to resection of a vascular malformation on day 3 of life. After a successful surgery he exhibit normal behaviour and reached developmental milestones at a normal rate. Also, his performance on various clinical tests was normal, as well as his social and communication skills as rated by his mother. Compared to a sample of healthy controls PF1 was impaired significantly in the regulation of emotion and engagement of attention, specifically in unstructured conditions.
In particular, Anderson et al. (2007) report that:

PF1 showed
markedly high positive affectivity and low restraint
relative to his peers. This was particularly evident
in his intense and positive affective expressions
during free-flowing interactions, his unrestrained
approach of desirable but prohibited stimuli, and to
a lesser extent in his mildly atypical levels of anger
and resistance when physically restrained. Faced
with problem-solving tasks, when most of his peers
displayed affectively neutral expressions and
focused on finding the solutions, PF1 initially
responded with strong and under-regulated positive
emotion that interfered with attentional engagement
on the task at hand.

According to the writers the results of the study provide useful information about the impact that early damage in the prefrontal cortex may have on emotional and cognitive behaviour. I’m looking forward to their future reports on this particular case as the boy grows up.

Anderson SW, Aksan N, Kochanska G, Damasio H, Wisnowski J, & Afifi A (2007). The earliest behavioral expression of focal damage to human prefrontal cortex. Cortex; a journal devoted to the study of the nervous system and behavior, 43 (6), 806-16 PMID: 17710831

Executive Functions in ASD

braincopyThere are three key theories that attempt to explain the links between brain and behaviour in Autistic spectrum disorders (ASD): the Theory of Mind Deficit Hypothesis (for a review see Baron-Cohen, 2001), the Weak Central Coherence (Happé & Frith, 2006) and that of Executive Dysfunction (Hill, 2004).

Executive functions is an umbrella term for a number of cognitive and behavioural capacities such as planning, working memory, inhibition, mental flexibility, multitasking, initiation and monitoring of action (Gilbert & Burgess, 2008). Executive functions are usually impaired in patients with frontal lobe damage and in many neurodevelopmental disorders like ADHD, OCD, schizophrenia and ASD.  These disorders are likely to involve deficits in the frontal lobes.

Autistic people seem to be impaired only in some tests of executive functions, especially those involving multitasking (“Six Element Test”, Hill & Bird, 2006), planning (“Tower of London”, Ozonoff et al, 1991) and Inhibition (“Go/No-Go task” ,  Ozonoff & Strayer, 1997). Deficits have also been shown in planning and abstract problem solving tasks (Hill & Bird, 2006). On other tests their performance is equal or superior to control groups (Minshew, Goldstein & Siegel, 1997). It’s worth noting that ASD individuals are mostly impaired in newer tests rather than classical tests of executive functions (Hill & Bird, 2006, Gilbert et al., 2008). These findings could be due to the heterogeneity of different tests of executive function (Gilbert et al., 2008).

Most of the tasks in which ASD individuals show deficits are thought to be mediated by the frontal lobes. A number of studies have identified several several cortical, subcortical abnormalities and functional differences (Kawakubo et al., 2009; Schmitz et al., 2005).

The theory of cortical underconnectivity  posits a deficit in integration of information at the neural and cognitive levels (Just et al., 2006). Findings from neuroimaging studies such as the thinning of the corpus callosum and the reduced connectivity, especially with the frontal areas and also the fusiform face area in ASD people support the theory of underconnectivity (Hughes, 2007). Recently, increased activation in medial rostral prefrontal cortex (BA 10) during tasks of stimulus-oriented versus stimulus-independent attention has been found in people with ASD (Gilbert et al., 2008). Previous studies has shown the importance of rPFC in selection between stimulus-oriented and stimulus-independent thought (Gilbert, Frith & Burgess, 2005; Ramnani & Owen, 2004). On the same task the control group showed greater activity primarily in bilateral occipital cortex. According to Gilbert et al.:

“This suggests that the control group were able to modulate activity in early visual cortex according to the attentional demands of the task to a greater degree than the ASD group. The stimuli were matched between the two conditions, suggesting attentional modulation rather than an effect of stimulus-category. This finding is consistent with the suggestion of functional underconnectivity in ASD”

Further Readings

Happé, F., & Frith, U. (1996). The neuropsychology of autism.Brain, 19, 1377-1400.

White, S., O’Reilly, H., & Frith, U. (2009). Big heads, small details and autism. Neuropsychologia, 47(5), 1274-1281.‎

Mundy, P. (2003). The Neural Basis of Social Impairments in Autism: The Role of the Dorsal Medial-Frontal Cortex and Anterior Cingulate System. Journal of Child Psychology & Psychiatry, 44, 793-809

Happé, F., Booth, R., Charlton, R. & Hughes, C. (2006) Executive function deficits in Autism Spectrum Disorders and Attention-Deficit/Hyperactivity Disorder: Examining profiles across domains and ages. Brain and Cognition.

Baron-Cohen, S., & Swettenham, J. (1998) Theory of mind in autism: Its relationship to executive function and central coherence. In D.J. Cohen & F.R. Volkmar (Eds.), Handbook of autism and pervasive developmental disorders (2nd ed., pp. 880–893). New York: Wiley.

Martin, I. and McDonald, S. (2003). Weak coherence, no theory of mind, or executive dysfunction? solving the puzzle of pragmatic language disorders. Brain and language, 85(3):451-466.

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