Research Groups

[3] Functional Anatomy of Higher Cognitive Processes

The main research interests of the Psychiatric Neuroimaging Unit concern the functional anatomy of higher cognitive processes related to voluntary action, attention, and memory, and the study of cerebral dysfunction occurring in various frequent and incapacitating psychiatric disorders: psychosis (mainly schizophrenia), depression and neurodegenerative diseases (mainly Alzheimer disease). There are two leading themes:

1) Functional neuroanatomy of higher cognitive processes
We focus on the links between perception and action, in an attempt to understand human behavior and its alterations. The integration of the sensory signals (visual, somatosensory and auditory) and the covert processes underlying action are studied using electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) techniques. We plan to use neurofeedback techniques to test experimental hypothesis on sensorimotor control. On a clinical point of view, our objective is to test whether a dysfunction of perceptual processing, such as hallucinatory episodes in schizophrenic patients, is the result of abnormal integration of sensory signals, or could associate inadequate internal modeling of action.

Three projects utilizing fMRI and/or EEG techniques are part of this theme:

- The cortical network of voluntary action in schizophrenia: links between perception and action.
- The functional substrate of visuo-spatial attention in normal observers and in schizophrenic patients.
- The identification of early dysfunction of corticocortical circuits in mild cognitive impairment and Alzheimer's disease. In collaboration with Pr. Giannakopoulos (Principal Investigator), Psychogeriatric clinic, HUG.

2) Cerebral metabolism and neurotransmission in neuropsychiatric diseases
In neuropsychiatric disorders, it has been proposed that there is an abnormal regulation of different neurotransmitter systems. In mood disorders for example, the action mechanism of anti-depressive drugs is imperfectly known. A double methodological approach is used to study brain metabolism and neurotransmission dysfunction in neuropsychiatric diseases:
a) A fundamental approach in animal (rat or mouse) uses a new device, a beta probe similar to PET. This technique is applied to in vivo kinetic studies of serotonin receptors, evaluating their modifications under various experimental pharmacological conditions (mainly the action of Serotonin Reuptake Inhibitor drugs)
b) A clinical approach, using PET in humans, is employed to carry out kinetic studies and measure neurotransmitter receptor density in neuropsychiatric patients.

There are three ongoing projects :
- In vivo quantification of 5-HT1A receptors and their modulation after serotonin reuptake inhibitor drugs.
- Quantification and parametric mapping of GabaA receptor density using PET and SPECT.
- Brain metabolism in rats: in vivo measurement and comparison with autoradiography

Group Publications