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Abstract Alcohol consumption has been identified as a causal factor promoting changes in different molecular and cellular mechanisms resulting in neurodegeneration. This process is specific to certain brain regions and its effects on different areas of the brain can result in a variety of deleterious consequences. The prefrontal cortex (PFC) appears to be particularly sensitive to alcohol-induced neurodegeneration; this region is quite complex, as it is responsible for high order mental processes such as decision making. Thus, it is important to have precise and unbiased data of neuronal morphology parameters to understand the real effects of alcohol on the PFC. This study aimed to investigate alcohol-induced neurodegeneration in the PFC by utilizing behavioral and stereological methods. In the first phase of the study, we utilized eighteen animals, six controls and twelve alcohol-treated, that were submitted to voluntary chronic alcohol ingestion for four or eight weeks. Their brains were analyzed by design-based stereology methods to assess number and volume parameters regarding neuronal integrity in regions of the PFC (prelimbic - PL, infralimbic - IL and anterior cingulate - ACC). In the second phase of the study, six animals were utilized as controls and eight animals were submitted to the same alcohol ingestion protocol and to a behavioral decision-making test. In conclusion, our findings indicate that chronic alcohol consumption promotes a decrease in volume in the prelimbic and in the anterior cingulate, a decrease of mean neuronal volume in the anterior cingulate cortex and a decrease of total volume of neurons in the IL area. We did not observe changes in decision-making behavior in either of the two periods of alcohol intake. This shows that morphological changes occur in specific regions of the prefrontal cortex, a noble area of cognitive functions, induced by chronic alcohol consumption. [ABSTRACT FROM AUTHOR]

Background: Complex walking conditions (e.g. dual tasking) have been associated with increased prefrontal (PFC) activity. However, most paradigms include a predictable environment, specifically, a predictable walking terrain. In the present study we investigate PFC activity under an unusual walking condition where each foot placement was on unexpected terrain, thus causing a mismatch between visuospatial perception and lower-extremity proprioception.Research Objective: To assess whether PFC activity increases under unstable unpredictable conditions compared to unstable but predictable conditions.Methods: This was a prospective study involving twenty healthy adults. Participants walked in two conditions: unstable but predictable, and unstable and unpredictable. To assess walking stability, both stride-time (ST) and stride-time variability (CV) were measured. To assess PFC activity, two wireless near-infrared spectroscopy devices were used. The group hemodynamic response (GHR) was calculated for each condition. For statistical analysis, a linear-mixed-effects model was used.Results: Walking with unpredictable perturbations did not change the ST (t = 0.51, p = 0.61) but significantly increased the parameter CV (t = 11.74, p < 0.001). The GHR of both conditions indicated brief per-initiation PFC activity that was similar across conditions. However, when GHRs were calculated relative to normal walking (i.e., the participants' own shoes), continuous activity was evident. Compared to the predictable condition, the unpredictable condition significantly increased this activity during steady-state walking (t = 2.13, p = 0.033).Significance: Observations from the present study suggest that at least two neural components are present in the measured signal-a brief one, occurring per-initiation, and a continuous one, sensitive to the predictability of the terrain. The second component was accompanied by a decrease in walking stability. These results may contribute to our understanding of the control mechanism underlying gait and future planning of rehabilitation protocols. [ABSTRACT FROM AUTHOR]