Jamie Mazer PhD
Associate Professor of Neurobiology and of Psychology
Vision; Attention; Cortex; Sensory processing; Coordinate systems; Neuroethology
- Efficient coding of visual stimuli in early visual cortex.
- Non-linear processing of complex natural stimuli in extrastriate cortex.
- Attentional modulation of neural selectivity during visual search.
- Visual and attentional stability during natural vision.
The Mazer lab studies the role of extrastriate visual cortex in natural, visually guide behavior. We are interested in how cortical microcircuits support complex behavior. Current work in the lab focuses on three issues: (1) Characterizing neuronal responses to spectrally complex natural scene stimuli. This work uses modern linear and non-linear system identification methods to estimate the receptive field properties of visual neurons based on neuronal responses to natural visual stimuli. (2) Identifying the sources and circuits underlying top-down modulation of visual selectivity using neurophysiological methods.
We use visual search tasks in conjunction with single neuron recordings to investigate how attention and memory interact with visual processing during complex behavior to facilitate target detection. (3) Exploring interactions between visual processing and oculomotor behavior. These studies seek to clarify the relationship between spatial attention and the oculomotor planning processes by studying how saccadic eye movements affect the locus of spatial attention.
Extensive Research Description
Neuroscientists have identified more than 30 distinct cortical and sub-cortical areas in the primate brain that contribute to visual processing. However, we really only understand the specific contributions a small number of the areas make to visual perception.
In my laboratory we use a combination of neurophysiological, psychophysical, and computational methods to study the contributions of occipital and parietal cortex to visual perception and action. We use nonlinear system identification techniques to analyze both single neuron responses in extrastriate cortex and psychophysical performance data from subjects performing attentionally demanding visual search tasks. These data are used to construct visual selectivity profiles for both single neurons and individual subjects.
By using similar methods to study both single neurons and perception we can accurately estimate the contributions of single neurons to perception and action. The primary focus of this research is characterizing the effects of top-down modulatory signals on visual perception and to determine how the visual system influences the oculomotor system to guide eye movements during natural visual exploration of the world around us.