The neural selection and the emergence of ‘beauty canons’ as signaling codes in co-evolving species

Widespread opinion wants beauty to be pleasant and aimless, this assumption biased Darwin's explanation of sexual selection. Conversely, Wallace hypothesized that showy and symmetric sexual traits correlate with vigor and health and he placed ‘aesthetic’ preferences within the natural selection. The controversy has continued until today. To understand the role of beauty canons in communication, the focus was on the flower-pollinator cooperative system as a model, were flower evolution embodies the natural history of pollinators' preferences.Optimum for a signal requires energy efficiency, high signal-to-noise ratio, and intelligibility. It involves pollinator perception mechanisms that, in turn, induce co-evolutionary feedback on signal traits. In fact, the flowers physical and hedonic properties correlate with the basic perceptual, motivational, emotional, and learning mechanisms of pollinators. It is proposed that pollinator behavior, unmasking a preference, reveals the ability to evaluate an expected benefit. Features such as a relative simplicity, redundancy, and regularity of stimuli facilitate perception and memorization and are essential elements for communication between co-evolving species. They improve signaling to satisfy the need for easy and fast recognition. With these properties, a stimulus is adaptive and rewarding per se and may be an ideal conditioned stimulus in associative learning. Among the most conspicuous signals, pollinators learn to recognize and choose those associated with nectar, thus favoring the evolution of flowers that are not only ‘beautiful’ but also ‘honest’ in reporting a reward. Beauty is an emergent property, and studying communication and perception we may understand the origin of some beauty canons.

The Neural Selection and Integration of Actions and Objects: An fMRI Study

There is considerable evidence that there are anatomically and functionally distinct pathways for action and object recognition. However, little is known about how information about action and objects is integrated. This study provides fMRI evidence for task-based selection of brain regions associated with action and object processing, and on how the congruency between the action and the object modulates neural response. Participants viewed videos of objects used in congruent or incongruent actions and attended either to the action or the object in a one-back procedure. Attending to the action led to increased responses in a fronto-parietal action-associated network. Attending to the object activated regions within a fronto-inferior temporal network. Stronger responses for congruent action–object clips occurred in bilateral parietal, inferior temporal, and putamen. Distinct cortical and thalamic regions were modulated by congruency in the different tasks. The results suggest that (i) selective attention to action and object information is mediated through separate networks, (ii) object–action congruency evokes responses in action planning regions, and (iii) the selective activation of nuclei within the thalamus provides a mechanism to integrate task goals in relation to the congruency of the perceptual information presented to the observer.

The neural selection and control of saccades by the frontal eye field

Recent research has provided new insights into the neural processes that select the target for and control the production of a shift of gaze. Being a key node in the network that subserves visual processing and saccade production, the frontal eye field (FEF) has been an effective area in which to monitor these processes. Certain neurons in the FEF signal the location of conspicuous or meaningful stimuli that may be the targets for saccades. Other neurons control whether and when the gaze shifts. The existence of distinct neural processes for visual selection and saccade production is necessary to explain the flexibility of visually guided behaviour.

R8 development in theDrosophilaeye: a paradigm for neural selection and differentiation

The Drosophila eye is an outstanding model with which to decipher mechanisms of neural differentiation. Paramount to normal eye development is the organized selection and differentiation of a patterned array of R8 photoreceptors – the founding photoreceptor of each ommatidium that coordinates the incorporation of all other photoreceptors. R8 development is a complex process that requires the integration of transcription factors and signaling pathways, many of which are highly conserved and perform similar functions in other species. This article discusses the developmental control of the four key elements of R8 development: selection, spacing, differentiation and orchestration of later events. New questions that have surfaced because of recent advances in the field are addressed, and the unique characteristics of R8 development are highlighted through comparisons with neural specification in other Drosophila tissues and with ganglion cell development in the mammalian retina.