Letter to nephew, 11/30/1881

Handwritten letter from Daniel D. Whedon to nephew, Daniel Avery Whedon. Dated November 30, 1881.

Letter to Ruth Merritt 11/10/1818

Handwritten letter from Timothy Merritt to sister (?) Ruth Merritt regarding her loss of religious conviction. Dated Nov. 10, 1818.

Letter to Rev. Epaphras Kibby. 01/11/1801

Handwritten letter from Timothy Merritt to Rev. Epaphras Kibby regarding lodging and preaching schedule. Sent in care of Mr. Lambert. Dated Jan. 11, 1801, Bath, ME.

Letter to nephew, 11/14/1881

Three page handwritten letter to nephew, Daniel Avery Whedon, from Daniel D. Whedon. Dated 11/14/1881.

Letter to nephew, 12/11/1868

Letter from Daniel Whedon to nephew, Daneil Avery Whedon. Dated December 11 1868.

Cortical Dynamics of Visual Motion Perception: Short-Range and Long Range Apparent Motion

This article describes further evidence for a new neural network theory of biological motion perception that is called a Motion Boundary Contour System. This theory clarifies why parallel streams Vl-> V2 and Vl-> MT exist for static form and motion form processing among the areas Vl, V2, and MT of visual cortex. The Motion Boundary Contour System consists of several parallel copies, such that each copy is activated by a different range of receptive field sizes. Each copy is further subdivided into two hierarchically organized subsystems: a Motion Oriented Contrast Filter, or MOC Filter, for preprocessing moving images; and a Cooperative-Competitive Feedback Loop, or CC Loop, for generating emergent boundary segmentations of the filtered signals. The present article uses the MOC Filter to explain a variety of classical and recent data about short-range and long-range apparent motion percepts that have not yet been explained by alternative models. These data include split motion; reverse-contrast gamma motion; delta motion; visual inertia; group motion in response to a reverse-contrast Ternus display at short interstimulus intervals; speed-up of motion velocity as interfiash distance increases or flash duration decreases; dependence of the transition from element motion to group motion on stimulus duration and size; various classical dependencies between flash duration, spatial separation, interstimulus interval, and motion threshold known as Korte's Laws; and dependence of motion strength on stimulus orientation and spatial frequency. These results supplement earlier explanations by the model of apparent motion data that other models have not explained; a recent proposed solution of the global aperture problem, including explanations of motion capture and induced motion; an explanation of how parallel cortical systems for static form perception and motion form perception may develop, including a demonstration that these parallel systems are variations on a common cortical design; an explanation of why the geometries of static form and motion form differ, in particular why opposite orientations differ by 90°, whereas opposite directions differ by 180°, and why a cortical stream Vl -> V2 -> MT is needed; and a summary of how the main properties of other motion perception models can be assimilated into different parts of the Motion Boundary Contour System design.