The neural mechanisms of object processing

Neuroimaging studies have identified several regions in the brain that respond to different complex objects such as human bodies, faces, places, and objects. Findings from recent studies suggest that, not only are the locations distinct, but that the neural mechanisms may also differ. This study aims to investigate these differences further to determine whether the neural mechanisms for faces are distinct from those for other classes of objects. We are seeking to recruit 20 adult participants with normal or corrected-to-normal vision to take part in an fMRI scan. By recording your brain activity, we will be able to identify the brain areas involved in the perception and recognition of complex objects. Participation in this study will last approximately 1.5hrs. During this time we will take a structural image of your brain, followed by functional scans in which you will be shown images of different categories of complex objects and faces. Subjects should be between 18-35yrs of age, and will be compensated $15 for taking part in this study. This experiment takes part at the UBC hospital.

Please email Jodie Davies-Thompson to ask any questions, or to register your interest in this study.

Eye-movements during face processing

Eyes are major sensory organs that help us communicate with the world. Moving our eyes allows us to visually explore our environments and gather the information used to make decisions and take action. In my experiments, I study eye movements in response to various visual stimuli to understand how processes differ between neurologically healthy people and various disease populations, and in the future help in developing effective early diagnosis and possibly even treatment. We are currently running a study to understand how face processing occurs in the absence of the complete visual field ? a condition broadly called anopia. In anopia, a patient is unable to see a part of their visually field, and we want to understand if this affects the speed of face processing. In patients with brain damage, it is difficult to determine if a symptom ? such as slower face processing ? is due to the brain damage or because of absence of a part of the visual field alone. We are recruiting subjects with no history of neurological issues, between the ages of 50 and 60. As a subject, you will be asked to view images of faces presented on a computer screen, during which a camera will track your eyes movements. You may be asked to make manual responses (verbal/mouse click/keyboard entry). The experiment is ~45 minutes long and takes place at the Eye Care Centre at the Vancouver General Hospital (2550 Willow Street).

Please email Jaya Viswanathan to ask any questions, or to register your interest in this study.

Holistic processing of facial identity, expression and gender in patients with acquired prosopagnosia: common or independent mechanisms?

Behavioral studies have demonstrated that recognition of facial identity relies on a holistic perception of the entire face rather than on an analytical perception of its parts. Recent findings show that expression recognition and gender categorization also rely on a holistic representation. This suggests that a common holistic representation is used for most types of face processing. However, brain-damaged prosopagnosic patients (individuals who cannot recognize faces) are reported to have intact expression and gender perception, suggesting dissociation between identity and expression/gender processing, which may suggest separate mechanisms. We propose to study holistic processing of identity, expression and gender in these patients, to determine if there are separate holistic mechanisms for all three that can be differentially affected by disease, or if there is a single holistic mechanism that is impaired in all, with residual expression and gender perception supported by alternative mechanisms, such as processing of individual facial features. This will provide important information about the nature of face representations and how they are affected by disease. We have already studied brain-damaged prosopagnosic patients using a range of behavioural tests, and structural and functional neuroimaging. For this study, we also require 15 healthy participants who have normal or corrected-to-normal vision. Subjects should have no history of neurological or psychiatric disease and be between 30-60 years of age.

Please email Thomas Busigny to ask any questions, or to register your interest in this study.

Volitional control of actions

A great number of psychiatric conditions suffer from dysfunctional volitional action control i.e. performing behaviors against better knowledge. We are currently investigating the fundamental cognitive processes underlying volitional control of actions by testing healthy volunteers. We use simple eye movement tasks to assess the time healthy subjects need to program different types of volitional eye movements. By that we hope to gain further insight in how the brain computes volitional actions enabling us to better understand how the volitional action generation is altered in patients with psychiatric conditions. If you want to participate as a subject, you should be between 18-35 years, have normal or corrected to normal vision and no history of neurological or psychiatric diseases. Study takes place at the Eye Care Center, 2550 Willow Street.

Please email Lisa Kloft to ask any questions, or to register your interest in the study.