Related Experiment Video
Updated: Aug 14, 2026

Patterned Photostimulation with Digital Micromirror Devices to Investigate Dendritic Integration Across Branch Points
Published on: March 2, 2011
Intensity-dependent spatial summation
Abstract:
Psychophysical evidence indicates that, in the human retina, the size of the spatial-summation area decreases as illuminance increases. Such a relationship would be beneficial for the detection of spatial contrast in the presence of photon noise. We analyze an image-processing mechanism in which the area of a strictly positive point-spread function varies inversely with local illuminance while its volume remains constant. In addition to its expected effect of improving spatial resolution as illuminance increases, this mechanism also yields center-surround antagonism and all other manifestations of bandpass filtering and accounts for Ricco's law and Weber's law--including the failures of both laws as a function of test conditions. The relationship between this mechanism and lateral inhibition is analyzed.
Related Concept Videos
Long-term Potentiation
The Role of Ion Channels in Neuronal Computation
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Long-term Potentiation
Hebbian LTP
LTP can occur when presynaptic neurons...
Graded Potential
Graded potentials fall into two categories: depolarizing and hyperpolarizing. Depolarizing graded potentials typically occur when sodium (Na+) or calcium...
Integration of Synaptic Events

