Mental and Social Disabilities in Agenesis of the Corpus Callosum

Investigators: 
Warren S. Brown, Ph.D., Fuller Professor of Psychology (Vitae)
Lynn K. Paul, Ph.D., Senior Research Fellow, Caltech

Project Description:
Agenesis of the corpus callosum (ACC) is a congenital condition in which corpus callosum of the brain is absent from birth.  The corpus callosum is the largest neural pathway in the brain, composed of over 200 million axons that interconnect the right and left cerebral hemispheres.  In agenesis of the corpus callosum, this pathway can be either completely or partially absent.

Since 1992, the laboratory of Warren S. Brown at the Travis Research Institute (Fuller Graduate School of Psychology) has been studying the cognitive and psychosocial consequences of agenesis of the corpus callosum.  This project has been studying individuals with ACC who have normal IQs with respect to their functioning in three domains:

  • interhemispheric interactions
  • cognitive capacities
  • psychosocial abilities

Research has shown that individuals with callosal agenesis have subtle-to-marked deficits in all 3 domains.

In 2007, Brown published (with our collaborators from Caltech and UCSF) a major review of ACC research in Nature Reviews Neuroscience.  [Paul, L.K., Brown, W.S., Adolphs, R., Tyszka, J.M., Richards, L.J., Mukherjee, P., and Sherr, E.H. (2007) Agenesis of the corpus callosum:  Genetic, developmental, and functional aspects of connectivity. Nature Reviews Neuroscience. 8, 287-299.]

Conclusions From the Results of Current Research on ACC

Results of Studies of Interhemispheric Interactions:

  • Individuals with ACC show an absence of early evoked EEG responses over the ipsilateral (same side) visual cortex to visual stimuli presented exclusively to one side of the visual field of view.  Since images the left visual field project solely to the right visual cortex (and right visual field to the left cortex), this result indicates that the corpus callosum is necessary for transmission of visual sensory information from one cerebral hemisphere to the other.
  • Individuals with ACC have normal interhemispheric color-word (Stroop) interference.  That is, when a patch of color to be named is presented in one visual field there is a slower and less accurate response if a different (interfering) color word is presented simultaneously in the other visual field.  This result suggests that despite callosal absence, there is still some remaining interhemispheric transfer of information.  The anterior commissure (a very much smaller interhemispheric pathway present in the majority of individuals with ACC) is the most likely route for residual interhemispheric transfer in ACC.
  • Individuals with ACC have difficulty quickly and accurately coordinating the activity of the two hands in the Bimanual Coordination Task. [see the abstract in the text box on this page].
  • Persons with ACC are slow in shifting their visual attention from one side of the visual field to the other.
  • Difficulty responding accurately to tactile stimulation of the fingers of one hand by using the finger of the other hand is also seen in persons with ACC.

Results of Studies of Mental Capacities:

  • Individuals with ACC may have a normal Intelligence Quotient (IQ; as measured by the Wechsler intelligence scales).  Some individuals have even tested in the above-average range.
  • When there is a discrepancy between Verbal and Performance IQ, there is no consistency in the direction of this difference – either verbal or spatial skills could be stronger in a particular individual with ACC.
  • By the time individuals with ACC reach adolescence, basic academic achievement scores (e.g. Reading, Spelling, and Math) are typically in the normal range (presuming a normal-range IQ), but math scores tend to be lowest. 
  • Individuals with ACC have reduced overall information processing speed.
  • Persons with ACC have deficiencies on tasks which demand complex novel mental processing and problem solving.  This we believe to be the core cognitive deficit related to absence of the corpus callosum.
  • ACC is associated with difficulty comprehending second-order meaning in language (that is, difficulty adequately understanding proverbs, nonliteral statements, some forms of humor, and irony).
  • There is not evidence for problems in basic memory capacity in ACC.  However, some difficulty remembering may occur when the task demands imposing some sort of mental organization on the material to be remembered.

Results of Studies of Psychosocial Abilities:

  • Persons with ACC often have difficulty in processing and interpreting social cues and, thus, may appear naïve or gullible.
  • ACC is associated with difficulty imaging and anticipating the consequences of actions in complex social situations, such as making a particular remark in a particular social context, or not showing up for an appointment.
  • It is difficulty for persons with ACC to construct adequate imaginary social narratives based on single pictures of people interacting.
  • Persons with ACC have a reduced ability to infer the intentions and states of mind of other people, particularly when the inference demands integrating information from previous social contexts.
  • Individuals with ACC have difficulty recognizing more subtle emotions in expressions in faces.
  • Persons with ACC have limitations in insight into their own emotional responses and about their own social skills.

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Posters presented at INS 2011

Erickson, R. L., Paul, L. K., & Brown, W. S. (February, 2011). Deficient Delayed Memory on the CVLT-II in Individuals with Agenesis of the Corpus Callosum. Paper presented at the 39th annual meeting of the International Neuropsychological Society, Boston, MA.  Click here for abstract.

Harrell, K. M., Marco, E., Paul, L. K., Sherr, E., & Brown, W. S. (February 2011). Verbal and Design Fluency in Agenesis of the Corpus Callosum. Paper presented at the 39th annual meeting of the International Neuropsychological Society, Boston, MA. Click here for abstract.

Legardy, S. N., Paul, L. K. & Brown, W. S. (February, 2011). Longitudinal Study of Crystallized versus Fluid Intelligence in Agenesis of the Corpus Callosum.  Paper presented at the 39th annual meeting of the International Neuropsychological Society, Boston, MA. Click here for abstract.

Pazienza, S. R., Brown, W. S., & Paul, L. K. (February, 2011). Emotional Expressiveness and Somatization in Agenesis of the Corpus Callosum.  Paper presented at the 39th annual meeting the International Neuropsychological Society, Boston, MA. Click here for abstract. 

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Published Papers: Agenesis of the Corpus Callosum

Brown, W. S., Bjerke, M. D., and Galbraith, G. C. (1998). Interhemispheric transfer in normals and acallosals: Latency adjusted evoked potential averaging. Cortex, 34, 677-692. Click here for abstract.

Brown, W. S., Jeeves, MA, Dietrich, R., and Burnison, D. S. (1999). Bilateral field advantage and evoked potential interhemispheric transmission in commissurotomy and callosal agenesis. Neuropsychologia, 37, 1154-1180. Click here for abstract.

Brown W. S. and Paul L.K., (2000). Psychosocial deficits in agenesis of the corpus callosum with normal intelligence. Cognitive Neuropsychiatry, 5, 135-157. Click here for abstract.

Brown, W. S., Thrasher, E. D., and Paul, L. K. (2001). Interhemispheric Stroop effect in partial and complete agenesis of the corpus callosum. Journal of the International Neuropsychological Society, 7, 302-311. Click here for abstract.

Hines, R. J., Paul, L. K. and Brown, W. S. (2002). Spatial attention in agenesis of the corpus callosum: Shifting attention between visual fields. Neuropsychologia. 40, 1804-1814. Click here for abstract.

Brown, W. S. (2003). Clinical neuropsychological assessment of callosal dysfunction: Multiple sclerosis and dyslexia. In E. Zaidel, and M. Iacoboni (Eds.). The Parallel Brain: The Cognitive Neuroscience of the Corpus Callosum. Cambridge: MIT Press.

Paul, L. K., Van Lancker, D., Schieffer, B. and Brown, W. S. (2003). Communicative deficits in individuals with agenesis of the corpus callosum: Nonliteral language and affective prosody. Brain and Language, 85, 313-324. Click here for abstract.

Paul, L. K., Schieffer, B., and Brown, W. S. (2004). Social Processing Deficits in Agenesis of the Corpus Callosum: Narratives from the Thematic Apperception Test. Archives of Clinical Neuropsychology, 19, 215-225. Click here for abstract.

Brown, W. S., Paul, L. K., Symington, M., and Dietrich, R. (2005). Comprehension of Humor in Primary Agenesis of the Corpus Callosum. Neuropsychologia, 43, 906-916. Click here for abstract.

Brown, W. S., Symington, M., VanLancker, D., Dietrich, R. and Paul, L. K. (2005). Paralinguistic processing in children with Callosal Agenesis: Emergence of neurolinguistic deficits. Brain and Language, 93,135-139. Click here for abstract.

Paul, L. K., Lautzenhiser, A., Brown, W. S., Spezio, M., Neumann, D., and Adolphs, R. (2006). Emotional arousal in agenesis of the corpus callosum. International Journal of Psychophysiology, 61, 47-56. Click here for abstract.

Paul, L. K., Brown, W. S., Adolphs, R., Tyszka, J. M., Richards, L. J., Mukherjee, P., and Sherr, E. H. (2007). Agenesis of the corpus callosum: Genetic, developmental, and functional aspects of connectivity. Nature Reviews Neuroscience, 8, 287-299. Click here for abstract.

Badaruddin, D. H. Andrews, G. L., Bölte, S., Schilmoeller, K. J., Schilmoeller, G., Paul, L. K. and Brown, W. S. (2007). Social and behavioral problems of children with agenesis of the corpus callosum. Child Psychiatry and Human Development, 38, 287-302. Click here for abstract.

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Published Papers: Human Cognition and Interhemispheric Interactions

Brown, W. S. and Jeeves, M. A. (1993). Bilateral field advantage and evoked potential interhemispheric transfer time. Neuropsychologia, 31, 1267-1281. Click here for abstract.

Brown, W. S., Larson, E. B., and Jeeves, M. A.. (1994). Directional asymmetries in interhemispheric transfer time: Evidence from visual evoked potentials. Neuropsychologia, 32, 439-448. Click here for abstract.

Moore, L. H., Brown, W. S., Markee, T. E., Theberg, D. C., and Zvi, J. (1995). Bimanual coordination in dyslexia. Neuropsychologia, 33, 781-793. Click here for abstract.

Steese-Seda, D., Brown, W. S., and Caetano, C. (1995). Development of bimanual visuomotor coordination in school aged children: The Bimanual Coordination Task. Developmental Neuropsychology, 11, 181-199.

Moore, L. H., Brown, W. S., Markee, T. E. Theberge, D. C., and Zvi, J. C. (1996). Callosal transfer of finger localization information in phonologically dyslexic adults. Cortex, 32, 311-322.

Markee, T. E., Brown, W. S., Moore, L. H., Theberge, D. C., and Zvi, J. C. (1996). Callosal function in dyslexia: Evoked potential interhemispheric transfer time and bilateral field advantage. Developmental Neuropsychology, 12, 409-428.

Larson, E. B. and Brown, W. S. (1997). Bilateral field interactions, hemispheric specialization and evoked potential interhemispheric transmission time. Neuropsychologia, 35, 573-581. Click here for abstract.

Brown, W. S. and Banich, M. T. [Special Issue Guest Editors] (2000). Development of the corpus callosum and interhemispheric interactions. Developmental Neuropsychology, 18.

Banich, M. T. and Brown, W. S. (2000). A lifespan perspective on interaction between the cerebral hemispheres. Developmental Neuropsychology, 18, 1-10. Click here for abstract.

Hagelthorn, K. M., Brown, W. S., Amano, S., and Asarnow, R. (2000). Normal development of bilateral field advantage and evoked potential interhemispheric transmission time. Developmental Neuropsychology, 18, 11-32. Click here for abstract.

Larson, E. B., Burnison, D. S. and Brown, W. S. (2002). Callosal function in multiple sclerosis: Bimanual Motor Coordination. Cortex, 38, 201-214. Click here for abstract.

Marion, S. D., Killian, S. C., Naramor, T., and Brown, W. S. (2003). Normal Development of Bimanual Coordination: Visuomotor and Interhemispheric Aspects. Developmental Neuropsychology, 23, 399-421. Click here for abstract.

Lee, G. P., Meador, K. J., Loring, D. W., Allision, J. D., Brown, W. S., Paul, L. K., et al. (2004). Neural substrates of emotion as revealed by functional magnetic resonance imaging. Cognitive and Behavioral Neurology, 17, 9-17. Click here for abstract.

Roebuck-Spencer, T. M., Mattson, S. N., DeBoard Marion, S., Brown, W. S., and Riley, E. (2004). Bimanual coordination in alcohol-exposed children: Role of the corpus callosum. Journal of the International Neuropsychological Society, 10, 536-548. Click here for abstract.

Moes, P., Brown, W. S., and Minnema, M. (2007). Individual differences in interhemispheric transfer time (IHTT) as measured by event related potentials. Neuropsychologia, 45, 2626-2630. Click here for abstract.

Kilian, S., Brown, W. S., Hallam, B. J., McMahon, W., Lu, J., Bigler, E. D., and Lainhart, J. E. (2008). Regional callosal morphology in autism and macrocephaly. Developmental Neuropsychology, 33, 74-99. Click here for abstract.

Hallam, B. J., Brown, W. S., Ross, C., Buckwalter, J. G., Bigler, E. D., Tschanz, J. T., et al. (2008). Regional Atrophy of the Corpus Callosum in Dementia. Journal of the International Neuropsychological Society, 14, 414-423. Click here for abstract.

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