Reduced Neural Selectivity Increases fMRI Adaptation with Age during Face Discrimination

Key project finally published! This took quite a while, but it was worth it.

[Link to article if you have journal access]
[Link to Pubmed abstract access]

By Joshua O., Goh , Atsunobu, Suzuki , Denise C., Park
Beckman Institute, University of Illinois, Urbana-Champaign, IL, USA; Center for Vital Longevity, University of Texas, Dallas, TX, USA.

Ventral-visual activity in older adults has been characterized by dedifferentiation, or reduced distinctiveness, of responses to different categories of visual stimuli such as faces and houses, that typically elicit highly specialized responses in the fusiform and parahippocampal brain regions respectively in young adults (Park et al., 2004). In the present study, we demonstrate that age-related neural dedifferentiation applies to within-category stimuli (different types of faces) as well, such that older adults process less distinctive representations for individual faces than young adults. We performed a functional magnetic resonance imaging adaptation experiment while young and older participants made same-different judgments to serially presented face-pairs that were Identical, Moderate in similarity through morphing, or Different. As expected, older adults showed adaptation in the fusiform face area (FFA), during the Identical as well as the Moderate conditions relative to the Different condition. Young adults showed adaptation during the Identical condition, but minimal adaptation to the Moderate condition. These results indicate that older adults' FFA treated the morphed faces as Identical faces, reflecting decreased fidelity of neural representation of faces with age.

NeuroImage, In Press, Accepted Manuscript, Available online 6 February 2010

Cognitive abilities in kindergartners and first graders: A comparison, evaluation, and extension of models using data from Robinson et al. (1996)

Paper submitted for final in structural equation modeling class, Spring 2009, UIUC Psychology. This paper is a critique of Robinson et al.'s (1996) paper on "The structure of abilities in math-precocious young children: Gender similarities and differences", published in the Journal of Educational Psychology (Vol. 88, Iss. 2, p341-352). This current paper, though, focuses on the age differences in abilities of kindergartners and first graders.

It is known that very young children show less differentiated cognitive abilities. Children who perform well in tests such as those involving math, tend to have correlated performance in other tests such as in verbal tests. As children age and progress towards adolescence, however, their cognitive abilities becomes differentiated so that abilities such as math and verbal abilities are not necessarily equally developed in the child.

Presumably, this occurs because when children are very young, they are untrained and unaffected by external factors such as education and related experiences (e.g. streaming into majors). Thus, the best predictor of the child's performance is the individual difference or a general factor. With age, the child undergoes specialization where children start to develop more specific knowledge in selective domains. Some children become more trained at math, while others at language. Importantly, these abilities aren't always equally developed. This may be the underlying reason for differentiated abilities in older children.

This current paper is a methodological exploration of the data in Robinson et al. (1996) using various modifications of the basic structural equation model. The main results are consistent with differentiated abilities in first graders relative to kindergartners. Some discrepancies in Robinson et al.'s (1996) paper are noted as well.

[Download pdf of paper]

VSS Conference Day 4: My Poster

This poster was presented at VSS Conference 2009 [link to VSS website], morning session [download poster pdf]. This study investigated the effect of task instructions on repetition suppression in the brain. Repetition suppression refers to the phenomenon that the brain response to repeated stimuli is usually reduced or attenuated. It is thought that such reduction in brain response reflects less neuronal recruitment, and hence, a more "efficient" way of processing the same information.
In this study, however, I postulated that under certain circumstances, the brain requires more neuronal recruitment in order to effectively process information for task demands. That is, repetition suppression becomes inefficient because it reduces the degrees of freedom that the brain can use to manipulate existing representations.

The study evaluated brain response in the fusiform region to face-pairs morphed at different levels of similarity. The idea is that the more similar face-pairs are, the more repetition suppression should be observed in the fusiform face area. Participants viewed the face-pairs under two different task instructions. The first task made face-pair similarity irrelevant. In this task, repetition suppression was observed to repeated faces. In the second task, face-pairs were made critical as participants had to make same-different judgments about the pairs. In this task, repetition suppression was eliminated.

The idea here is that in the same-different judgment task, the brain has to represent faces as distinctinctively as possible so that subtle morph differences can be detected. Thus, repetition suppression is prevented, possibly from executive function areas that process task instruction and exert a top-down modulatory control in the fusiform area.

The study also shows that there are individual differences in participants ability to exert this top-down modulation to regulate repetition suppression in the fusiform regions. This study was also performed in older adults, which will be reported in a subsequent research article. Briefly though, it is thought that older adults show declines in behavioral performance because of less distinctiveness in cognitive representations. This design is thus useful as a means to measure and related distinctinveness of representations in the brain and how that affects behavior.

Age and Culture Modulate Face, House Processing in Ventral Visual Areas

This is the powerpoint (hosted on Google Docs; leave comment if buggy) for the presentation of this research work given at a talk during the Society for Neuroscience Annual Meeting, Washington DC, 2009.

Aging increases fMR-Adaptation to repeated faces and limits discrimination ability

Age-related ventral-visual activity is characterized by reduced selectivity between categories of visual stimuli such as faces and houses that typically elicit highly specialized responses in the fusiform and parahippocampal brain regions respectively of young adults (Park et al., 2004). This study demonstrates that older adults’ less selective neural response (dedifferentiation) to faces is due to a coarser neural representation than that of young adults for individual faces. In this event-related fMRI adaptation study, 20 young and 20 older participants made same-different judgments to serially presented face-pairs that were either identical (repetition of the same face), moderately different (second face was morphed with 40% of prior face), or completely different (faces from two individuals). In the fusiform regions, older adults showed greatest adaptation during the exact-repetition condition and intermediate adaptation during the moderately-different condition relative to the completely-different condition. Young adults showed a similar pattern of adaptation, but with reduced adaptation magnitudes. This suggests that older adults’ fusiform area was not able to represent facial differences at the same level of sensitivity as young adults. Individual subjects’ adaptation magnitudes positively correlated with behavioral face discrimination thresholds for morphed faces (r = .38). Greater age-related adaptation during the exact-repetition condition suggests older adults’ fusiform face region is particularly sensitive to similarity, whereas young adults have a neural response that is more sensitive to facial differences. The data provide strong evidence for an age-related decrease in representational contrast in the fusiform area that is linked to behavioral differences during perceptual discrimination. [pdf]

Publications

Articles, Chapters and Reviews

1. Goh, J. O. S. (2010). Functional dedifferentiation and altered connectivity in older adults: Neural accounts of cognitive aging. Aging and Disease, 1(2), [epub ahead of print] http://aginganddisease.org/A&D-Joshua%20Goh.pdf.
   
2. Goh, J. O. S, Leshikar, E., Sutton, B. P., Tan, J. C., Sam, S., Hebrank, A., & Park, D. (2010). Culture differences in neural processing of faces and houses in ventral visual cortex. Social, Cognitive and Affective Neuroscience, 5(2-3), 227-235.
   
3. Suzuki, A., Goh, J. O. S., Hebrank, A., Sutton, B., Jenkins, L., Flicker, B., & Park, D. C. (in press). Sustained happiness? Lack of repetition suppression in right ventral visual cortex for happy faces. Social, Cognitive and Affective Neuroscience.
   
4. Chee, M., Zheng, H., Goh, J., & Park, D. (in press). Brain structure in
   young and old East Asians and Westerners: Comparisons of structural volume
   and cortical thickness. Journal of Cognitive Neuroscience.
   
5. Goh, J. O. S., Suzuki, A., & Park, D. C. (2010). Reduced neural selectivity increases fMRI adaptation with age during face discrimination. NeuroImage, 51(1), 336-344.
6. Jenkins, L. J., Yang, Y. J., Goh, J., Hong, Y. Y., Park, D. C. (2010). Cultural differences in the lateral occipital complex while viewing incongruent scenes. Social, Cognitive and Affective, Neuroscience, Advanced Access published online January 18, 2010, doi:10.1093/scan/nsp056.
7. Goh, J. O. S., Tan, J. C., Park, D. C. (2009). Culture modulates eye-movements to visual novelty. Public Library of Science ONE, 4(12), e8238.
8. Goh, J. O., Park, D. C. (2009). Culture sculpts the perceptual brain. Progress in Brain Research, 178, 95-111.
9. Goh, J., Park, D. C. (2009). Neuroplasticity and cognitive aging: The scaffolding theory of aging and cognition. Restorative Neurology and Neuroscience, 27, 391-403.
10. Park, D. C., & Goh, J. O. S. (2009). Successful aging. In J. Cacioppo & G. Berntson (Eds.), Handbook of Neuroscience for the Behavioral Sciences (pp. 1203-1219). Hoboken, NJ: John Wiley & Sons.
    
11. Sutton, B., Goh, J., Hebrank, A., Welsh, R. C., Chee, M. W. L., Park, D., (2008). Investigation and validation of intersite fMRI studies using the same imaging hardware. Journal of Magnetic Resonance Imaging, 28(1), 21-28.
12. Gutchess, A., Hebrank, A., Sutton, B., Leshikar, E., Chee, M. W. L., Tan, J. C., Goh, J., Park, D., (2007). Contextual Interference in Recognition Memory with Age. NeuroImage, 35(3), 1338-1347.
13. Goh, J., Chee, M. W. L., Tan, J. C., Venkatraman, V., Hebrank, A., Leshikar, E., Jenkins, L., Sutton. B., Gutchess, A., Park, D., (2007). Age and Culture Modulate Object Processing and Object-Scene Binding in the Ventral Visual Area. Cognitive, Affective and Behavioral Neuroscience, 7(1), 44-52.
14. Chee, M. W. L., Goh, J., Venkatraman, V., Tan, J. C., Gutchess, A., Sutton, B., Hebrank, A., Leshikar, E., Park, D., (2006). Age-Related Changes in Object Processing and Contextual Binding Revealed using fMR Adaptation. Journal of Cognitive Neuroscience, 18(4), 495-507.
15. Goh, J., Soon, C. S., Park, D., Gutchess, A., Hebrank, A., Chee, M. W. L., (2004). Cortical Areas Involved in Object, Background and Object-Background Processing Revealed with fMR-A. Journal of Neuroscience, 24(45), 10223-10228.
16. Chee, M. W. L., Goh, J., Lim, Y., Graham, S., Lee, K., (2004). Recognition Memory For Studied Words Is Determined by Cortical Activation Differences at Encoding But Not During Retrieval. NeuroImage, 22, 1456-1465.
17. Chee, M. W. L., Westphal, C., Goh, J., Graham, S., Song, A. W., (2003). Word frequency and subsequent memory effects studied using event-related fMRI. NeuroImage, 20(2), 1042-1051.
18. Chee, M. W. L., Hon, N. H. H., Caplan, D., Lee, H. L.,Goh, J., (2002). Frequency of Concrete Words Modulates Prefrontal Activation during Semantic Judgments. NeuroImage, 16(1), 259-268.

Abstracts

1. Goh, J. O., Yu, G., Sutton, B., Park, D. (2010). Aging reduces ventral visual diffusivity: Effects on face discrimination and fMRI adaptation. [291]. Presented at Human Brain Mapping Conferences, Barcelona, Spain. [pdf]
   
2. Goh, J. O., Suzuki, A., Park, D. (2010). Aging reduces attentional modulation on selectivity in fusiform face area. [Session 1, 11]. Presented at the Cognitive Aging Conference, Atlanta, GA, USA. [pdf]
   
3. Leshikar, E. D., Goh, J. O., Hebrank, A. C., Jenkins, L. J., Chee, M. W., Park, D. (2009). Frontal compensation for default network suppression deficits in older adults during scene encoding. [17.3]. Presented at the Society for Neuroscience Annual Meeting, Chicago, IL, USA.
4. Goh, J., Suzuki, A., Park, D. (2009). Attending to face-pair similarity decreases face adaptation in the fusiform area. [43.445]. Presented at the Vision Science Society Annual Meeting, Naples, FL, USA. [pdf]
   
5. Goh, J., Suzuki, A., Park, D. (2008). Aging reduces neural selectivity and increases face adaptation. [G94]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA. [pdf]
6. Jenkins, L., Yang, Y., Goh, J., Hong, Y., Park, D. (2008). Cultural differences in the processing of incongruous scenes revealed using fMR adaptation. [B21]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA.
7. Suzuki, A., Goh, J., Sutton, B., Hebrank, A., Jenkins, L., Flicker, B., Park, D. (2008). Emotional faces produced less repetition suppression than neutral faces. [E19]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA.
8. Goh, J., Chee, M., Tan, J.C., Park, D. (2007). Aging and cultural differences in eye-movements during complex picture viewing. [D7]. Presented at the Cognitive Neuroscience Society Annual Meeting, New York, NY, USA.[blog entry][pdf]
9. Goh, J., Chee, M., Tan, J.C., Venkatraman, V., Leshikar, E., Hebrank, A., Jenkins, L., Sutton, B., Park, D. (2006). Aging and culture modulate fMR-Adaptation in the ventral visual area. Abstract No. 359. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA. Available online at http://www.cogneurosociety.org/content/CNS2006_Abstracts.xls. [blog entry][pdf]
10. Gutchess, A., Hebrank, A., Sutton, B., Leshikar, E., Chee, M., Tan, J.C., Goh, J., Park, D. (2005). Prefrontal compensation with age for contextual interference. Program No. 127.8. 2005 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2005. Online.
11. Chee, M., Goh, J., Tan, J.C., Gutchess, A., Sutton, B., Hebrank, A., Leshikar, E., Park, D. (2005). FMR adaptation shows that age and culture modulate visual processing of complex pictures. Program No. 127.4. 2005 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2005. Online.
12. Chee, M., Goh, J., Lim, Y., Graham, S. (2003). Event-related fMRI of incidental encoding of episodic retrieval of high and low frequency words. [17649]. Presented at the 9th International Conference on Functional Mapping of the Human Brain, June 18-22, 2003, New York, NY, USA. Available on CD-Rom in NeuroImage, Vol. 19, No. 2
13. Chee, M., Goh, J., Lim, Y., Graham, S. (2003). Neural correlates of the effect of word frequency at encoding and retrieval. Program No. 288.15. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.
14. Chee, M., Soon, C., Westphal, C., Lee, H., Goh, J. (2002). Printed word frequency effects on semantic judgment: a comparison between event-related and block designs. [10110]. Presented at the 8th International Conference on Functional Mapping of the Human Brain, June 2-6, 2002, Sendai, Japan. Available on CD-Rom in NeuroImage, Vol. 16, No. 2

Unpublished Work

1. Cognitive abilities in kindergartners and first graders: A comparison, evaluation, and extension of models using data from Robinson et al. (1996). Joshua Goh. Paper in fulfillment of class on Structural Equation Modelling at the University of Illinois at Urbana-Champaign, 2009. [blog entry][pdf manuscript]
   
2. Morphed Faces. Joshua Goh. Stimuli collection, PAL Face Database. Available at https://pal.utdallas.edu/facedb/request/index/Morph, sourced 4th April 2009.
3. Extension of the Von Der Malsburg Self-Organized Visual Cortex Model. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007. [blog entry][pdf manuscript][R code - network][R code - hexagonal plot]
4. Backpropagation in a non-linear layered network: learning from past mistakes. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007. [blog entry][pdf manuscript][R code - train network][R code - test network]
5. Hopfield Network. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007. [blog entry][pdf manuscript][R code - train network][R code - test network]
6. GLM for Dumbos, fMRI Training Course 2005, Presented at the Cognitive Neuroscience Lab, Singapore. [pdf]
7. BrainVoyager for Dumbos, , fMRI Training Course 2005, Presented at the Cognitive Neuroscience Lab, Singapore. [pdf]
8. 3T Allegra for Dumbos, fMRI Training Course 2005, Presented at the Cognitive Neuroscience Lab, Singapore. [pdf]
9. Individual differences in interrogative suggestibility: finding an ERP correlate of recognition memory. Joshua Goh. Thesis in fulfillment of Honour’s degree at the National University of Singapore, Singapore, 2002

Curriculum Vitae

Full document available for [download], hosted on Google docs.

EDUCATION

1. National University of Singapore (1998-2001), majored in Psychology and English Language, minored in Philosophy, Bachelor of Social Sciences 2001.
2. National University of Singapore (2002), Bachelor of Social Science with Honors (2nd Upper) in Psychology.
3. University of Texas at Austin (Fall 1999), exchange program, majored in Psychology and Linguistics.
4. Talent Development Program (1998-2002), National University of Singapore.
5. Currently enrolled in University of Illinois at Urbana-Champaign (since Fall 2005), Psychology PhD program
6. Highest level attained: Masters in Psychology

MILITARY SERVICE

1. National Service (1996 – 1998)

EMPLOYMENT

1. Research coordinator at Singapore General Hospital, Cognitive Neuroscience Laboratory (2001-2005)
2. Part-time research coordinator at Singapore General Hospital, Cognitive Neuroscience Laboratory (2001)
3. Part-time research assistant at NUS Department of Geography (2000)
4. Part-time autistic therapy assistant at NUS Department of Psychology (1999)

APPOINTMENTS

1. Editor, Talent Development Program magazine (2000-2001)
2. Contact Group Leader, Varsity Christian Fellowship (1999-2001)

HONORS AND AWARDS

1. Incomplete List of Teachers Listed as Excellent by their Students, University of Illinois, Urbana-Champaign, IL, Fall 2008.
2. Departmental Travel Award, Psychology, University of Illinois, Urbana-Champaign, IL, Fall 2008.

MEMBERSHIP IN SOCIETIES

1. Varsity Christian Fellowship (1998-2002), National University of Singapore
2. Photographic Society (1998-2002), National University of Singapore
3. Dartmouth Summer Institute in Cognitive Neuroscience (2005)

PUBLICATIONS

Articles, Chapters and Reviews

1. Goh, J., Suzuki, A., Park, D., (in preparation). Attending to face-pair similarity reduces fMR-Adaptation to repeated faces.
2. Goh, J., Chee, M. W. L., Hebrank, A., Sutton, B., Abdi, H., Dunlop, J., Krishnan, A., Park, D., (in preparation). Culture modulates age-related ventral-visual selectivity.
3. Goh, J., Suzuki, A., Park, D., (in preparation). Reduced neural selectivity increases face adaptation with age.
4. Goh, J., Chee, M. W. L., Hebrank, A., Sutton, B., Park, D., (in preparation). Culture modulates ventral-visual selectivity to faces and houses.
5. Goh, J., Tan, J. C., Park, D., (in preparation). Culture modulates eye-movements to visual novelty.
6. Leshikar, E. D., Goh, J., Hebrank, A., Jenkins, L., Chee, M., Park, D., (submitted). Frontal compensation for default network suppression deficits in older adults during scene encoding.
7. Jenkins, L. J., Yang, Y. J., Goh, J., Hong, Y. Y., Park, D. C. (in press). Cultural differences in the lateral occipital complex while viewing incongruent scenes. Social, Cognitive, Affective, Behavioral Neuroscience.
8. Goh, J., Park, D. (in press). Neuroplasticity and cognitive aging: The scaffolding theory of aging and cognition. Restorative Neurology and Neuroscience.
9. Park, D., Goh, J., (in press). Healthy aging: a neurocognitive perspective. Eds. J. Cacioppo & G. Bernston, Handbook of Cognitive Neuroscience.
10. Sutton, B., Goh, J., Hebrank, A., Welsh, R. C., Chee, M. W. L., Park, D., (2008). Investigation and validation of intersite fMRI studies using the same imaging hardware. Journal of Magnetic Resonance Imaging, 28(1), 21-28.
11. Gutchess, A., Hebrank, A., Sutton, B., Leshikar, E., Chee, M. W. L., Tan, J. C., Goh, J., Park, D., (2007). Contextual Interference in Recognition Memory with Age. NeuroImage, 35(3), 1338-1347.
12. Goh, J., Chee, M. W. L., Tan, J. C., Venkatraman, V., Hebrank, A., Leshikar, E., Jenkins, L., Sutton. B., Gutchess, A., Park, D., (2007). Age and Culture Modulate Object Processing and Object-Scene Binding in the Ventral Visual Area. Cognitive, Affective and Behavioral Neuroscience, 7(1), 44-52.
13. Chee, M. W. L., Goh, J., Venkatraman, V., Tan, J. C., Gutchess, A., Sutton, B., Hebrank, A., Leshikar, E., Park, D., (2006). Age-Related Changes in Object Processing and Contextual Binding Revealed using fMR Adaptation. Journal of Cognitive Neuroscience, 18(4), 495-507.
14. Goh, J., Soon, C. S., Park, D., Gutchess, A., Hebrank, A., Chee, M. W. L., (2004). Cortical Areas Involved in Object, Background and Object-Background Processing Revealed with fMR-A. Journal of Neuroscience, 24(45), 10223-10228.
15. Chee, M. W. L., Goh, J., Lim, Y., Graham, S., Lee, K., (2004). Recognition Memory For Studied Words Is Determined by Cortical Activation Differences at Encoding But Not During Retrieval. NeuroImage, 22, 1456-1465.
16. Chee, M. W. L., Westphal, C., Goh, J., Graham, S., Song, A. W., (2003). Word frequency and subsequent memory effects studied using event-related fMRI. NeuroImage, 20(2), 1042-1051
17. Chee, M. W. L., Hon, N. H. H., Caplan, D., Lee, H. L.,Goh, J., (2002). Frequency of Concrete Words Modulates Prefrontal Activation during Semantic Judgments. NeuroImage, 16(1), 259-268.

Abstracts

1. Goh, J., Suzuki, A., Park, D. (2009). Attending to face-pair similarity decreases face adaptation in the fusiform area. [43.445]. Presented at the Vision Science Society Annual Meeting, Naples, FL, USA.
2. Goh, J., Suzuki, A., Park, D. (2008). Aging reduces neural selectivity and increases face adaptation. [G94]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA.
3. Jenkins, L., Yang, Y., Goh, J., Hong, Y., Park, D. (2008). Cultural differences in the processing of incongruous scenes revealed using fMR adaptation. [B21]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA.
4. Suzuki, A., Goh, J., Sutton, B., Hebrank, A., Jenkins, L., Flicker, B., Park, D. (2008). Emotional faces produced less repetition suppression than neutral faces. [E19]. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA.
5. Goh, J., Chee, M., Tan, J.C., Park, D. (2007). Aging and cultural differences in eye-movements during complex picture viewing. [D7]. Presented at the Cognitive Neuroscience Society Annual Meeting, New York, NY, USA.
6. Goh, J., Chee, M., Tan, J.C., Venkatraman, V., Leshikar, E., Hebrank, A., Jenkins, L., Sutton, B., Park, D. (2006). Aging and culture modulate fMR-Adaptation in the ventral visual area. Abstract No. 359. Presented at the Cognitive Neuroscience Society Annual Meeting, San Francisco, CA, USA. Available online at http://www.cogneurosociety.org/content/CNS2006_Abstracts.xls
7. Gutchess, A., Hebrank, A., Sutton, B., Leshikar, E., Chee, M., Tan, J.C., Goh, J., Park, D. (2005). Prefrontal compensation with age for contextual interference. Program No. 127.8. 2005 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2005. Online.
8. Chee, M., Goh, J., Tan, J.C., Gutchess, A., Sutton, B., Hebrank, A., Leshikar, E., Park, D. (2005). FMR adaptation shows that age and culture modulate visual processing of complex pictures. Program No. 127.4. 2005 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2005. Online.
9. Chee, M., Goh, J., Lim, Y., Graham, S. (2003). Event-related fMRI of incidental encoding of episodic retrieval of high and low frequency words. [17649]. Presented at the 9th International Conference on Functional Mapping of the Human Brain, June 18-22, 2003, New York, NY, USA. Available on CD-Rom in NeuroImage, Vol. 19, No. 2
10. Chee, M., Goh, J., Lim, Y., Graham, S. (2003). Neural correlates of the effect of word frequency at encoding and retrieval. Program No. 288.15. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.
11. Chee, M., Soon, C., Westphal, C., Lee, H., Goh, J. (2002). Printed word frequency effects on semantic judgment: a comparison between event-related and block designs. [10110]. Presented at the 8th International Conference on Functional Mapping of the Human Brain, June 2-6, 2002, Sendai, Japan. Available on CD-Rom in NeuroImage, Vol. 16, No. 2

TALKS

1. Cross-Cultural Perspectives on Perception. Invited talk presented at the Osher Lifelong Learning Institute, Spring 2009 course on Cognition and Personality Across the Lifespan: Only as Old as You Think You Are, University of Illinois, Urbana-Champaign, IL.
2. Aging, Culture, and Ventral Visual Selectivity. Presented at the 2008 Society for Neuroscience Annual Meeting, Washington, DC.
3. Age and Culture Modulate the Ventral Visual Area. Presented at the Advanced Sensory Developmental Neuroscience Seminar, 2008, 17th March, University of Illinois, Urbana-Champaign, IL.
4. Aging in Different Cultural Environments: Visual Brain Activity and Eye-Movements. Presented at the Beckman Graduate Student Seminar 2008, March 26th, University of Illinois, Urbana-Champaign, IL.
5. Age Differences in Activations of a Frontal-Parietal Network Associated with Categorical and Coordinate Judgments. Presented at the 2007 Regional Symposium on MRI, University of Michigan, Ann Arbor, MI.
6. Word Frequency and Subsequent memory Studied Using Event-Related fMRI. Presented at the Annual Scientific Meeting, 2003, Singapore General Hospital.

TEACHING EXPERIENCE

1. Psychological and Educational Statistics, Teaching Assistant, University of Illinois, Urbana-Champaign, IL, Fall 2008.
2. Lab training on functional brain imaging analysis, University of Illinois, Urbana-Champaign, IL, 2007.
3. Lab training on functional brain imaging analysis, Cognitive Neuroscience Laboratory, Singapore, 2005.

UNPUBLISHED WORK

1. Cognitive abilities in kindergartners and first graders: A comparison, evaluation, and extension of models using data from Robinson et al. (1996). Joshua Goh. Paper in fulfillment of class on Structural Equation Modelling at the University of Illinois at Urbana-Champaign, 2009.
2. Morphed Faces. Joshua Goh. Stimuli collection, PAL Face Database. Available at https://pal.utdallas.edu/facedb/request/index/Morph, sourced 4th April 2009.
3. Extension of the Von Der Malsburg Self-Organized Visual Cortex Model. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007.
4. Backpropagation in a non-linear layered network: learning from past mistakes. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007.
5. Hopfield Network. Joshua Goh. Project in fulfillment of class on Neural Network at the University of Illinois at Urbana-Champaign, 2007.
6. Individual differences in interrogative suggestibility: finding an ERP correlate of recognition memory. Joshua Goh. Thesis in fulfillment of Honour’s degree at the National University of Singapore, Singapore, 2002.

ART WORK

1. Cover art, “Birthday Girl”, Journal of Cognitive Neuroscience, 18(4), 2006.
2. Cover art, “Sam’s Brain”, Mind and Brain. Innovation: The Magazine of Research and Technology, 5(3), 2005.

PRESS COVERAGE

1. Pickens Gift Propels Brain Health Research. Dallas Business Business Journal, Dave Moore, 15th to 21st February 2008.
2. Culture May Make and Impression. The DANA Foundation, Nicky Penttila, Released 4th June 2007. Available at http://www.dana.org/news/features/detail.aspx?id=8008, sourced on 4th April 2009.
3. Culture Sculpts Neural Responses to Visual Stimuli, New Research Indicates. News Bureau, University of Illinois at Urbana-Champaign, Released 1st May 2007. Available at http://news.illinois.edu/news/07/0501culture.html, sourced on 4th April 2009.

COMPUTER SOFTWARE SKILLS

1. Fluent in Windows, Mac, Linux operating systems.
2. Brain imaging analysis: BrainVoyager, SPM
3. Other analysis software: Matlab, SPSS and AMOS, R

Talks

1. Cross-Cultural Perspectives on Perception. Invited talk presented at the Osher Lifelong Learning Institute, Spring 2009 course on Cognition and Personality Across the Lifespan: Only as Old as You Think You Are, University of Illinois, Urbana-Champaign, IL. [pdf]
2. Aging, Culture, and Ventral Visual Selectivity. Presented at the 2008 Society for Neuroscience Annual Meeting, Washington, DC. [blog entry][Google docs]
3. Age and Culture Modulate the Ventral Visual Area. Presented at the Advanced Sensory Developmental Neuroscience Seminar, 2008, 17th March, University of Illinois, Urbana-Champaign, IL.
4. Aging in Different Cultural Environments: Visual Brain Activity and Eye-Movements. Presented at the Beckman Graduate Student Seminar 2008, March 26th, University of Illinois, Urbana-Champaign, IL.
5. Age Differences in Activations of a Frontal-Parietal Network Associated with Categorical and Coordinate Judgments. Presented at the 2007 Regional Symposium on MRI, University of Michigan, Ann Arbor, MI.
6. Word Frequency and Subsequent memory Studied Using Event-Related fMRI. Presented at the Annual Scientific Meeting, 2003, Singapore General Hospital.

Press Release: Culture and Aging fMRI Study

Culture, Aging fMR-Adaptation press release in UIUC News Bureau.

http://www.news.uiuc.edu/news/07/0501culture.html

Culture, Age and Eye-Movements

We repeated the same experiment as in the culture and aging adaptation fMRI study. Only this time, we were recording subject eye-movements. We know that there were already cultural differences in old adults in terms of brain activity. Specifically, old East Asian adults did not engage the object processing regions to the same degree as Old Westerners. But how do we really know for sure that this was related to visual processing and not some other form of cognitive operations at work. A way to understand this better was to use eye-tracking. Which is what mainly motivated this study. In parallel, this eye-tracking version of the paradigm allowed to examine three main questions:

1. Cultural experience with age predicts that individuals become more different as they become more developed in their culture (assuming that the cultures are different on some dimensions and levels). However, aging also leads to a phenomena called de-differentiation, which refers to the fact that cognitive processing in older adults becomes less individually distinct due to general decline and increased variability in performance. So it would seem these two forces are in opposition. Thus, one question was whether cultural difference diverge or converge with age.

2. Another question was whether these cultural differences are robust to environmental biases. Cultural biases are such that East Asians are context-oriented and Westerners are object-oriented. These are sweeping statements of course, and should in no way be understood as stereotypical. However, there is evidence that suggests that, for whatever reason, there are visual processing differences that are related to the cultural background of individuals, including this current study. The question though is if we were exposed to visual environments that biased us to attend to objects or backgrounds, how would we behave given our own cultural biases to one component over the other?

3. Finally, the last question is whether these cultural biases in visual processing is just an inconsequential behavior, or if it does indeed have impact on other cognitive processes, perhaps an obviously important process such as memory.

In sum, we found that cultural differences diverge with age, these cultural biases remain despite environmental biases, at least in a passive viewing case, and these biases also impact on memory such that the item we attend to less is subsequently less well remembered.

[CNS Poster 2007.pdf]

Cultural effects on visual processing as a function of age

Evidence shows that Westerners are more object-focused, being more individualistic, whereas East Asians are more context-focused, being more holistic. These differences are probably due to the larger historical cultural developmental influence exerted on individuals throughout their life experiences. Such influences permeate from the larger societal forces down to the everyday inter-relational communications, even to the physical habitational environment as an outward expression of these internal thoughts. With age, therefore, there is greater experience with one's own cultural development. We sought to examine these neural correlates of cultural experience with age.

The same study previously conducted with East Asians was conducted with Westerners. In summary, we found that Westerners showed similar object, background, and binding processing regions. These regions showed reduced expression with age. The most interesting contrast, however, was that Older East Asians did not show typical object processing (as measured using our adaptation paradigm; see subsequent follow-up experiments) while Young East Asians, Young Westerners and Old Westerners all showed object processing in the lateral occipital complex (LOC). This was related to changes in attentional resources with age. Furthermore, the difference was consistent with cultural expectations because the Old Westerners showed preserved object processing engagement, reflecting the more object-focused cultural background.

This study is currently in press in Cognitive, Affective, Behavioral Neuroscience journal. CNS 2006 abstract available for download.

So now, we know that differences in experiences over lifetime lead to differences in engagement of visual processing regions, and these differences are at the neural systems level as well. The next question how these patterns of neural engagement relate to what these people are actually looking at. This is important for understanding what is the actual visual information being attended. This has implications on developmental experience as a top-down modulator of the bottom-up visual information being input into higher cognitive processes. The other aspect is how external experience interacts with biological or cognitive changes related to aging.

What processes are specific to aging only? What processes are specific to long-term experience within the external developmental environment? Can short-term training alleviate processes that decline with age? What are the long-term experiences that lead to beneficial aging neural, cognitive outcomes?

This study had since had a press release [article].

Aging effects on visual object, background and binding processing

Earlier, we saw different brain regions involved in object, background and binding processing. Now, we see if these regions might be engaged differently in older adults. Older adults typically show poorer episodic memory but relatively preserved item processing that does not require episodic or contextual access. Might this be due to a reduced engagement of binding processes in the MTL of older adults?

We found that not only is MTL reduced, but older adults seemed to not process the entire visual stimuli in the same way as young adults. In particular, older adults seem to process only background components of the pictures while somewhat treating the objects less attentively. Abstract: Age-related changes in object processing and contextual binding revealed using fMR adaptation.

So we know that at least part of the changes in aging might be related to the partial processing of the entire picture rather than the entire central item and context. Next, we turn to consider what are some of the factors that might lead to these changes with age.

Binding information about items and their contexts

So we know frequency has bearing on how the brain works during semantic judgments, encoding, and retrieval. Now, we take a look more specifically at how the brain does the work of binding the item to information about its occurrence for subsequent memory. Previously, we showed that if you had to engage the brain more during encoding, you are more likely to remember the item's occurrence. Now, we are interested in where in the brain this occurrence information or contextual information about the item is processed.

We looked at pictures for this inquiry instead of words because they afforded more relevant ways of manipulating the stimuli, as well as the ability to test these items more easily in other sample groups of people as will become apparent later on.

When looking at pictures of objects in background scenes, we are able to process information about the identity of the object, the content or spatial layout of the background. Furthermore, we form the binding between object and background that relates to information about their co-occurrence. The brain regions involved in these respective processes are the lateral occipital complex (LOC), the parahippocampal place area (PPA), and the medial temporal regions (MTL) that includes a different region of the parahippocampal gyrus and the hippocampus. Abstract: Cortical areas involved in object, background, and object-background processing revealed with functional magnetic resonance adaptation.

Thus, we know that the brain processes the component item information and their contextual binding in seperate regions. These then give us clues about how these different regions might operate differently across people groups that show different memory behavior and/or processing of visual stimuli.

Frequency, memory formation, memory retrieval or access

Once we know that the brain works differently when making semantic judgments about words encountered with different frequencies, we can ask how the brain processes these words so that information about them can be accessed later. So, with regards to frequency, why is it that when asked to recall word lists, we tend to recall more frequent items, whereas when asked to recognize word lists, we do it better for less frequent items. Clearly, something about the previous history of these words of different frequency of encounters has an affect on the way information about a specific encounter of these words is retrieved later.

First, we can look at what the brain does differently for words of high and low frequency that leads to different memory access. In sum, the brain seems to be more active during semantic judgments for words that are later recognized. Furthermore, these words that are more active tend to be the low frequency words. Perhaps, because we have to work harder at making semantic distinctions for such words, we end up enhancing their recent representation. This makes it easier for them to be retrieved later for recogntion. Abstract: Word frequency and subsequent memory effects studied using event-related fMRI.

Next, we look at how the brain handles these words during recognition itself. Perhaps during this stage, other processes additively or interactively affect the resulting recognition response. The mechanism might operate in this manner: the top-down criteria is made active (words that appeared at a particular point in time), probe words are encountered and identified, information for these words are matched to the active set, a decision is made about the recognition memory for the word. In sum, word frequency of the test words seen during encoding did not affect brain activity differentially, however, word frequency of new words not seen at encoding did make a difference to brain activity. That is, high frequency novel words activated the parietal region more than low frequency words when subjects recognized them as such. Abstract: Recognition memory for studied words is determined by cortical activation differences at encoding but not during retrieval.

So once we encode the word recently, the word frequency does not matter anymore, at least to the recognition judgment. What matters in the recognition is trace of recency or specific time information associated with the probe word. This, presumably, is not dependent on the frequency history of the word. However, if the word is not encountered before, word frequency seems to make a difference in the parietal area, an area that is involved in attention modulation and visualization. Perhaps, the higher activity for high frequency words in this case marks the more connected representation of high frequency words compared to low frequency words. Sort of an automatic engagement of the relatively wider spread of activation for high frequency words.

Word Frequency and brain activity

One of the basic forms of information that our brains are sensitive to, is the number of times we encounter an external event. This is most easily seen in examples of learning. Such as, the more we practice doing something, it becomes easier, we get faster at doing it, and even more accurate. Another example is that the more we encounter a specific information about an item or concept, we know a little more about it, maybe in a different way, maybe in a clearer way. Prior knowledge is updated.

The brain probably represents this frequency information in terms of changes in individual neuronal activity and inter-neuronal connectivity. In terms of internal neuronal changes, neurons may form more synapses that facilitate the generation of an action potential. There might also be reductions in synapses, leading to inhibitory type responses or de-potentiation. In terms of inter-neuronal connectivity, neurons may form more synapses with other neurons, axons may travel along certain paths in order to reach target brain regions, neuronal branching becomes more dense, or even less dense depending on the nature of the stimulation and connection. In all these cases, frequency of encountering stimuli, represented as frequency of individual neurons and networks of neurons being stimulated, leads to changes in neuronal structure and activity.

We start with an evaluation of how frequency of encountering words changes the way our brains respond when trying to access semantic information about those words. By semantic information, we typically refer to all associative information (neuronal connections) that are involved when we make an inclusion/exclusion categorizing judgment. In theory, we make these judgments by first evoking a set of semantic restrictions that define the target categories and keep this set active. We then identify the words, retrieve connections of these words, then match these retrieved connections to the active restriction set. This can proceed in a top-down/bottom-up competition type mechanism whereby bottom-up perceptual information about the word representation (lexical features, semantic associative strength and density) have to be resolved with the top-down imperative to match or not match the active semantic set relevant to the task.

In sum, the brain has to work harder for words encountered less frequently during such semantic judgments. Abstract: Frequency of concrete words modulates prefrontal activation during semantic judgments.

Perhaps, while low frequency should have fewer connections than high frequency words, since they have not had that much opportunity to form these connections due to the sparsity of their occurrence, the brain compensates their lack of obvious semantic associations by engaging more neuronal processing (particularly in the frontal regions). This may mark the recurrent search or matching effort to decide the category for the probe word.