Reduced approach motivation, indexed by reduced emotional responding to pleasant stimuli, and increased cognitive elaboration of unpleasant stimuli, are increasingly considered putative risk factors for depression. A novel approach to simultaneously examine these two processes is to examine time-frequency delta and theta power while participants are exposed to emotional pictures. Indeed, delta power appears to have a functional role in monitoring the motivational relevance of affective cues and in the identification of pleasant/rewarding stimuli and is generated by subcortical regions involved in the motivational system. Whereas theta power reflects the processing of salient events and can be employed to assess cognitive processing during the viewing of affective content.

The study ‘Recovery of neural dynamics criticality in personalized whole brain models of stroke‘ published in Nature Communications, fruit of an international collaboration among physicists, neurologists, psychologists, and PNC members Samir Suweis, Marco Zorzi and Maurizio Corbetta, proposes the theory of brain criticality to explain brain-behavior relationships in neurological patients.

Criticality is a physical state at the transition between order and disorder, and previous studies had shown that healthy brains work at criticality.

This study shows that patients affected by stroke present at three months decreased levels of neural activity, decreased entropy, and decreased strength of functional connections.

To date, there is no consensus on how to semi-quantitatively assess brain amyloid PET.

Researchers used data from 85 patients who underwent dual time-point PET/MRI acquisitions. The correlations with a gold standard (SI) were computed and the methods compared with the visual assessment.

Each quantifier exhibited excellent agreement with visual assessment and strong correlation with SI (average AUC = 0.99, ρ = 0.91). Among the other methods, TDr came closest to the reference with less implementation complexity.

The ability of techniques integrating blood perfusion to depict age-related variations in amyloid load in amyloid-negative subjects demonstrates the goodness of the estimate.

What are the cognitive abilities of a newly hatched zebrafish? A research from the University of Padova found that hatchings are able to associate a visual stimulus with presence of food. Learning occurs much faster in larvae than in adult zebrafish, requiring less than 48h to establish an association.

This feature was exploited to assess the capacity of larval zebrafish to recognize objects. Larvae can easily discriminate two objects by their color or shape. They can also perceive more complex visual properties, being able to discriminate two identical objects with a different spatial orientation or an object from its mirror image.