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Hopkins, Bill

Research Description

Our laboratory is broadly focused on examining brain-behavior relationships in nonhuman primates with a specific emphasis on chimpanzees and other great apes.  A central focus on our research is on the evolution of language and speech but also other dimensions of higher order cognitive and motor functions.  We use non-invasive imaging technologies including magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) and positron emission tomography (PET) to visual brain structure and function. We also conduct a variety of behavioral and cognitive studies that can be correlated with individual differences in brain structure and function as well as different genes.   There are four major ongoing projects in our laboratory.

One current research focus in our laboratory is on the role of genetic and non-genetic mechanisms on cortical development with specific reference to asymmetries in the brain.   Many have argued that population-level brain and behavioral asymmetries are unique to humans and fundamentally linked to the genetic factors associated with the evolution of language.   We are currently testing these theories by determining heritability of asymmetries for a variety of brain regions in chimpanzees and comparing them to estimates from human populations.  In collaboration with Dr. Chet Sherwood, we are also assessing asymmetries at the cellular level of analysis from post-mortem chimpanzee brains. 

A second research focus on our laboratory is on neuroanatomical and neurofunctional correlates of individual differences in joint attention.  Prior to the development of speech, many children go through stage of non-verbal communication which involves the integration of pointing with alternation o gaze between the referent and social agent (i.e., joint attention).  Studies suggest that children at risk for the development of autism have poorly developed joint attention skills. Chimpanzees also engage in joint attention but there are considerable individual differences.  The aim of these studies is to identify potential neuroanatomical predictors of variation in joint attention skills and to assess how the brain changes when chimpanzees are specifically trained on joint attention tasks.

A third set of funded studies are examining the role of prefrontal cortex on inhibitory control in monkeys, apes and humans.  Grey and white matter volumes as well as connectivity within the prefrontal cortex are being quantified from MRI and DTI in and each species.  Inhibitory control is quantified using several behavioral measures including delayed gratification and reverse contingency, tasks that have shown pronounced species differences in performance.   

Lastly, in collaboration with Dr. Larry Young at the Yerkes National Primate Research Center, we are examining the role of the AVPR1A as well OXTR genes on social behavior and cognition in chimpanzees.  Vasopressin and oxytocin play important roles in the formation and social relationships in many mammals and previous studies have shown that chimpanzees show a very unique polymorphism in the AVPR1A gene.  Whether this polymorphism can explain individual differences in social behavior and cognition is the central focus of these studies.