Ghana's evolving protein economy

This paper provides an initial analysis of Ghana's protein economy in the light on current debates about nutritional transition and livestock revolution. Ghana's strong economic growth and reducing levels of poverty make it a particularly interesting case. Protein-rich foods, including fish and livestock products, supply 20-40 percent of protein consumed. Overall fish is becoming less important and poultry more important; but there also are large difference in household expenditure on protein-rich foods across wealth categories, regions and areas. Specifically, the protein element of the nutritional transition and the consumption side of the livestock revolution would appear to be unfolding at different speeds and in different ways, along an axis that is urban-south-non-poor at one end, and rural-north-poor at the other. We explore the policy and political economy dimensions of these change

Distributed Fading Memory for Stimulus Properties in the Primary Visual Cortex

The brain has a one-back memory for visual stimuli. Neural responses to an image contain as much information about the current image as it does about another image presented immediately before

A neurodynamical model of brightness induction in V1

Brightness induction is the modulation of the perceived intensity of an area by the luminance of surrounding areas. Recent neurophysiological evidence suggests that brightness information might be explicitly represented in V1, in contrast to the more common assumption that the striate cortex is an area mostly responsive to sensory information. Here we investigate possible neural mechanisms that offer a plausible explanation for such phenomenon. To this end, a neurodynamical model which is based on neurophysiological evidence and focuses on the part of V1 responsible for contextual influences is presented. The proposed computational model successfully accounts for well known psychophysical effects for static contexts and also for brightness induction in dynamic contexts defined by modulating the luminance of surrounding areas. This work suggests that intra-cortical interactions in V1 could, at least partially, explain brightness induction effects and reveals how a common general architecture may account for several different fundamental processes, such as visual saliency and brightness induction, which emerge early in the visual processing pathway.Publisher PDFPeer reviewe

Neuronal Functional Diversity and Collective Behaviors

A major question in today’s neuroscience is how the brain’s complex operations and organization emerge from individual components. The robustness of neuronal properties with flexible linkages between regulatory processes conceivably accounts for the adaptive, tunable, multistable dynamics; the coding schemes; and the complexity of neuronal functional (sub)systems. Interneurons and neurotransmitter diversity, resonance phenomena due to properties of the cell, time/frequency-dependent activation of dedicated neuronal assemblies, and code- and frequency-specific oscillations interact in determining the brain functional setup and operations. Such an arrangement would also provide the functional requirements for access to neural mechanisms, dedicated neuronal circuitry and the proper timing allowing for the selective differentiation among cortical neurons due to performing in different tasks. No comprehensive theory or systematic methodological approach appears yet conceivable. The scenario, however incomplete and incompletely characterized, is nevertheless promising and warrants further investigation