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In the flocculus of pigeons, as in other species, there are two major types of Purkinje cell responses to rotational optokinetic stimuli. One type prefers rotation about the vertical axis (VA neurons) whereas the other prefers rotation about an horizontal axis oriented at 135 degrees ipsilateral azimuth (H-135 neurons). In this study, we injected the(More)
In the nodulus and ventral uvula of pigeons, there are four parasagittal zones containing Purkinje cells responsive to patterns of optic flow that results from self-translation along a particular axis in three-dimensional space. By using a three-axis system to describe the preferred direction of translational optic flow, where +X, +Y, and +Z represent(More)
The ectostriatum is a large visual structure in the avian telencephalon. Part of the tectofugal pathway, the ectostriatum receives a large ascending thalamic input from the nucleus rotundus, the homolog of the mammalian pulvinar complex. We investigated the effects of bilateral lesions of the ectostriatum in pigeons on visual motion and spatial-pattern(More)
Functional mapping and microstimulation studies suggest that recovery after stroke damage can be attributed to surviving brain regions taking on the functional roles of lost tissues. Although this model is well supported by data, it is not clear how activity in single neurons is altered in relation to cortical functional maps. It is conceivable that(More)
The pretectum, accessory optic system (AOS), and vestibulocerebellum (VbC) have been implicated in the analysis of optic flow and generation of the optokinetic response. Recently, using drifting sine-wave gratings as stimuli, it has been shown that pretectal and AOS neurons exhibit spatiotemporal tuning. In this respect, there are two groups: fast neurons,(More)
Spinal cord transection leads to elimination of brain stem-derived monoamine fibers that normally synthesize most of the monoamines in the spinal cord, including serotonin (5-hydroxytryptamine, 5-HT) synthesized from tryptophan by enzymes tryptophan hydroxylase (TPH, synthesizing 5-hydroxytryptophan, 5-HTP) and aromatic l-amino acid decarboxylase (AADC,(More)
Microglia have been implicated in disease progression for several age-related brain disorders. However, while microglia's contribution to the progression of these disorders is accepted, the effect of aging on their endogenous cellular characteristics has received limited attention. In fact, a comprehensive study of how the structure and function of(More)
Elevation of intracellular Ca2+ in astrocytes can influence cerebral microcirculation and modulate synaptic transmission. Recently, in vivo imaging studies identified delayed, sensory-driven Ca2+ oscillations in cortical astrocytes; however, the long latencies of these Ca2+ signals raises questions in regards to their suitability for a role in short-latency(More)
Previous studies in pigeons have shown that the neurons in the medial column of the inferior olive respond best to patterns of optic flow resulting from self-rotation. With respect to the axis of rotation, there are two functional groups: rVA neurons prefer rotation about the vertical axis, whereas rH45 neurons respond best to rotation about an horizontal(More)
The responses of neurons in the medial column of the inferior olive to translational and rotational optic flow were recorded from anaesthetized pigeons. Panoramic translational or rotational flowfields were produced by mechanical devices that projected optic flow patterns onto the walls, ceiling and floor of the room. The axis of rotation/translation could(More)