Retinal SD wave segment propagating (blue arrows) with free open ends that grow (red arrow) and therefore curl in to form a double spiral.

<p>At lower susceptibility values, reaction-diffusion models of SD predict that open ends retract (green arrows) and the wave vanishes.</p

Creation of an SD wave segment with free open ends in submerged chicken retina.

<p>(a) Mechanical stimulation with sharp glass needle s, (b) circular SD wave evolves, (c)–(d) local application of Mg²⁺ via pipette p, (e) wave propagation is locally blocked and consequently SD front brakes open and curls in to form a spiral at the lower open end, while the upper open end is guided by the Mg2+-pipette to the border of the retina where it attaches.</p

3D form of primary visual cortex (V1).

<p>The representation of the azimuthal coordinate of the two visual hemifields is given by the hue, value, saturation color model: (a) right V1 (b) left visual hemifield (c) left V1 (d) right visual hemifield. The current position of the visual field defect, occurring during two different migraine aura attacks and each exclusively in one visual hemifield, are indicated by white lines, with numbers denoting the time in minutes after onset.</p

Schematic view of the spatio-temporal course of a reaction-diffusion wave for different tissue susceptibility values σ: wave front (red), recovery phase (yellow), blue arrows indicate normal velocity, future location is dashed (red).

<p>(a) sustained wave, (b) retracting wave, indicated by green arrow heads, (c) collapsing wave, (d) no spread. The gray σ interval is defined as weakly susceptible.</p

Lateral exploration as a function of developmental age.

<p>For each child, the results of the 4 protocol items are displayed separately.</p

The Older Adult Positivity Effect in Evaluations of Trustworthiness: Emotion Regulation or Cognitive Capacity?

<div><p>An older adult positivity effect, i.e., the tendency for older adults to favor positive over negative stimulus information more than do younger adults, has been previously shown in attention, memory, and evaluations. This effect has been attributed to greater emotion regulation in older adults. In the case of attention and memory, this explanation has been supported by some evidence that the older adult positivity effect is most pronounced for negative stimuli, which would motivate emotion regulation, and that it is reduced by cognitive load, which would impede emotion regulation. We investigated whether greater older adult positivity in the case of evaluative responses to faces is also enhanced for negative stimuli and attenuated by cognitive load, as an emotion regulation explanation would predict. In two studies, younger and older adults rated trustworthiness of faces that varied in valence both under low and high cognitive load, with the latter manipulated by a distracting backwards counting task. In Study 1, face valence was manipulated by attractiveness (low /disfigured faces, medium, high/fashion models’ faces). In Study 2, face valence was manipulated by trustworthiness (low, medium, high). Both studies revealed a significant older adult positivity effect. However, contrary to an emotion regulation account, this effect was not stronger for more negative faces, and cognitive load increased rather than decreased the rated trustworthiness of negatively valenced faces. Although inconsistent with emotion regulation, the latter effect is consistent with theory and research arguing that more cognitive resources are required to process negative stimuli, because they are more cognitively elaborated than positive ones. The finding that increased age and increased cognitive load both enhanced the positivity of trustworthy ratings suggests that the older adult positivity effect in evaluative ratings of faces may reflect age-related declines in cognitive capacity rather than increases in the regulation of negative emotions.</p></div

Duration and frequency of episodes of gaze directed toward a face.

<p>Duration and frequency of episodes of gaze directed toward a face.</p

Analysis of gaze directed toward faces.

<p><i>in FoV</i>: Percentage of time a face was in the broad field of view. <i>in CV</i>: Percentage of time a face was in central vision.</p

2-way ANCOVAs on the variables <i>Mean Elevation</i> and <i>Lateral Exploration</i>.

*<p>lines in bold correspond to significant effects.</p

Schema of the events recorded.

<p>Whenever a face appeared in a frame, one or more of these events occurred. <i>in FoV</i>: a face (rectangle) is present in the broad field of view; <i>in CV</i>: a face is inside a 10^° radius of the Central Vision (crosshair).</p