M a i n  S o u r c e s  o f  R e s e a r c h  F u n d i n g

Work in the lab is currently funded by grants from The Royal Society (~£12,000) and BBSRC (New Investigator Grant, ~£380,000 fEC) to Narender Ramnani

• Comparative anatomy and evolution of the primate cerebellum
• Symbolic information processing in the human cerebellum
• Cerebellum and automatic processing of routine of cognitive and motor operations
• Reward processing in the human nucleus accumbens
• Modeling the BOLD impulse-response function: Insufficiency of canonical basis functions

S e l e c t e d  W o r k

Cortico-cerebellar information processing...

Ramnani N. (2006) "The Primate Cortico-Cerebellar System", Nature Reviews Neuroscience, 7(7):511-22

Evidence has been accumulating that the primate cerebellum contributes not only tomotor control, but also to higher ‘cognitive’ function. However, there is no consensus about how the cerebellum processes such information. The answer to this puzzle can be found in the nature of cerebellar connections to areas of the cerebral cortex (particularly the prefrontal cortex) and in the uniformity of its intrinsic cellular organization, which implies uniformity in information processing regardless of the area of origin in the cerebral cortex. With this in mind, the relatively well-developed models of how the cerebellum processes information from the motor cortex might be extended to explain how it could also process information from the prefrontal cortex.

The figure shows the cerebellar cortical terminations of projections from the primary motor cortex and prefrontal cortex in monkeys (top) and homologous areas in the human cerebellar cortex.

Ramnani et al. (2006) "The Evolution of Prefrontal Inputs to the Cortico-pontine System: Diffusion Imaging Evidence from MacaqueMonkeys and Humans"

This study determed the areas of the cerebral cortex which contribute projections to the cortico-cerebellar system using probabilistic diffusion tractography. Information from the cerebral cortex is conveyed to the cerebellum by topographically arranged fibres in the cerebral peduncle — an important fibre system in which all cortical outputs spatially converge on their way to the cerebellum via the pontine nuclei. Here we contrasted their organization in humans and macaque monkeys. There was a dominant contribution of the cortical motor areas to the macaque monkey cerebral peduncle. However, there was a relatively large prefrontal contribution to the human cortico-ponto-cerebellar system in the cerebral peduncle. These findings suggest the selective evolution of prefrontal inputs to the human cortico-ponto-cerebellar system.

The figure shows  the origin of tracts from the human prefrontal cortex in both hemispheres. Tracts generated in human cases were spatially registered into a common stereotaxic coordinate system and rendered onto the canonical brain of the ICBM series.

Prefrontal cortex...

Ramnani N and Owen AM (2004), 'The Anterior Prefrontal Cortex: What can functional imaging tell us about function?', Nature Reviews: Neuroscience 5, 184-194.

The anterior prefrontal cortex (aPFC), or Brodmann area 10, is one of the least well understood regions of the human brain. Work with non-human primates has provided almost no indications as to the function of this area. In recent years, investigators have attempted to integrate findings from functional neuroimaging studies in humans to generate models that might describe the contribution that this area makes to cognition. In all cases, however, such explanations are either too tied to a given task to be plausible or too general to be theoretically useful. Here, we use an account that is consistent with the connectional and cellular anatomy of the aPFC to explain the key features of existing models within a common theoretical framework. The results indicate a specific role for this region in integrating the outcomes of two or more separate cognitive operations in the pursuit of a higher behavioural goal.

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