The Olfactory System and Autism

A Boston Club titled “Social Cognition and the Olfactory Brain” was held on June 15, 2006. This meeting was aimed at understanding the structure and function of the primary and accessory olfactory systems with a special emphasis on social behaviors. Dysfunction of these systems in autism is speculative, but testable hypotheses can already be generated to investigate the impact of these systems on autistic behavior.

Social cognition is widely recognized as a core element that appears to go awry in autism; however, few attempts have been made to determine the origin of this malfunction. The ability to interact with a social group is important for survival among most mammals. The systems involved in processing, representing, and acting on social cues are likely to be some of the oldest in primate evolution, but also contain multiple pathways acquired later during phylogenesis. It is tempting to speculate that some of the evolutionary steps in creating the human social cognitive brain are recapitulated during ontogenetic development. In primates, these systems are centered on older olfactory and paraolfactory brain activities, and the visual system. Perhaps, the pathway to socialization in human beings is also centered on chemical signals during early brain development. Learning from olfactory and visual stimuli depends on bottom-up mechanisms relying mainly on salience and on top-down mechanisms linked to executive and memory functions. In young children, bottom-up processes are dominant, but innate top-down processes falling within the category of appetitive functions also play a crucial role, and joined by later developing executive top-down mechanisms, come to dominate over social cognitive development. The social deficit in autism might lie in the appetitive functions that regulate the actions and development of the toolboxes that have evolved for social interactions, such as speech, face analysis, analysis of emotional gestures, etc. It seems reasonable at this point in autism research to focus on the midline and ventral brain, through which appetitive systems work, including olfactory and paraolfactory systems.

Susan Birren, Ph.D., Brandeis University

Odors and social perception
Richard Doty, Ph.D., University of Pennsylvania

Olfaction and social behavior: a comparative approach
Heather Eisthen, Ph.D., Michigan State University

Ventral Midline Brain Contributions to Human Social Cognition
John Gabrieli, Ph.D., Massachusetts Institute of Technology

The Olfactory System and Autism: Nidor, ergo sum?
Albert Galaburda, MD, Harvard Medical School

Tal Kenet, Ph.D., Massachusetts General Hospital

Early Olfactory/Tactile Experience
Michael Leon, Ph.D., University of California Irvine

Damon Page, Ph.D., Massachusetts Institute of Technology

Susan Santangelo, Sc.D., Massachusetts General Hospital

Luca Turin, Ph.D., Flexitral, Inc.

2006

The Nancy Lurie Marks Family Foundation, Wellesley, MA