Mixtures of strategies underlie rodent behavior during reversal learning.

In reversal learning tasks, the behavior of humans and animals is often assumed to be uniform within single experimental sessions to facilitate data analysis and model fitting. However, behavior of agents can display substantial variability in single experimental sessions, as they execute different blocks of trials with different transition dynamics. Here, we observed that in a deterministic reversal learning task, mice display noisy and sub-optimal choice transitions even at the expert stages of learning.

Cortical-subcortical interactions in goal-directed behavior.

Flexibly selecting appropriate actions in response to complex, ever-changing environments requires both cortical and subcortical regions, which are typically described as participating in a strict hierarchy. In this traditional view, highly specialized subcortical circuits allow for efficient responses to salient stimuli, at the cost of adaptability and context specificity, which are attributed to the neocortex. Their interactions are often described as the cortex providing top-down command signals for subcortical structures to implement; however, as available technologies develop, studies increasingly demonstrate that behavior is represented by brainwide activity and that even subcortical structures contain early signals of choice, suggesting that behavioral functions emerge as a result of different regions interacting as truly collaborative networks.

Negative Lymph Node Count and Lymph Node Ratio Are Associated With Survival in Male Breast Cancer.

Background: Male breast cancer (MBC) is usually diagnosed at late stages and therefore has a worse prognosis than female breast cancer (FBC). MBC is also more likely to have lymph node (LN) involvement than FBC.

Materials And Methods: We sought to determine the prognostic role of the examined lymph node (LN), negative LN (NLN), and positive LN counts and the LN ratio (LNR), defined as (positive LNs/ENLs), on the survival rate among MBC patients.

Orthodontic care in suburban Cuyahoga County, Ohio: who provides treatment and whom do they treat?

It has been reported that orthodontic services are being provided to a larger segment of the population by an increasing number of providers. The present study surveyed the dental and orthodontic experiences of 10th grade students attending 16 public and two parochial high schools in suburban Cuyahoga County, Ohio, as well as two schools from the city of Cleveland. Questionnaires were distributed in the classroom and data obtained for 2808 students.