This method proved itself in confirming the central postulate of direction selectivity, where special attention was paid to a particular set of amacrine-to-ganglion cell synapses. But it can also be used in less focused ways. For example, a patch of mouse retina 200 μm2, which is well within the capability of reconstruction technology, contains ∼1,500 bipolar cells (Jeon et al., 1998). On average, this would amount to 125 bipolar cells of each of 12 types, more than enough for an independent verification of the types defined using light microscopy and

an analysis of their synaptic connectivity. The same could be done for narrow www.selleckchem.com/PARP.html field amacrine and ganglion cells. I thank Dr. Steven

DeVries for the electrophysiological traces shown in Figure 3 and for reading the section on bipolar cells. Members of the Jakobs/Masland lab made helpful comments. The figures were made by Michael Becker. Susan Cardoza copyedited and helped with the references. The author is supported by NIH grant Doxorubicin concentration EY13399 and the Harvard Neurodiscovery Center. “
“Long ago defined by William James as “the focusing of the mind,” selective attention is simultaneously one of our most pervasive and most baffling cognitive functions. On one hand attention is recruited for nearly every behavior and has been investigated in humans, monkeys, mice, and rats. On the other hand despite this wealth of research, significant questions remain about the nature of attention, its purpose and neural mechanisms. In humans and nonhuman primates, much of our knowledge of the mechanisms of attention comes from the system of vision and eye movement control. Intensive research into this system has shown that attention affects sensory representations

at all levels of the visual hierarchy, starting from low-level areas such as the lateral geniculate nucleus, through high-level cortical areas in the inferior temporal lobe (Reynolds ADP ribosylation factor and Heeger, 2009; Saalmann and Kastner, 2011). These studies also suggest that the source of attentional modulations lies, at least in part, in sensorimotor areas associated with rapid eye movements (saccades). Two areas that have been particularly well investigated are the lateral intraparietal area and the frontal eye field (shown in Figure 1A for the macaque monkey brain). Neurons in these areas have spatial receptive fields and saccade-related responses and respond selectively to stimuli that are likely to attract attention in a variety of tasks. Not specifically sensory or motor, these cells seem to encode the specific act of target selection, and can provide feedback regarding this selection both to earlier visual areas and to downstream movement structures that generate shifts of gaze.