Altered Cognitive Flexibility and Synaptic Plasticity in the Rat Prefrontal Cortex after Exposure to Low ( ≤15 cGy) Doses of 28Si Radiation.

This study has established the impact that 1-15 cGy 600 MeV/n 28Si radiation had on cognitive flexibility performance, glutamatergic synaptic transmission and plasticity in the prelimbic area (PrL) of the medial prefrontal cortex (mPFC) of ∼10-month-old (at the time of irradiation) male Wistar rats. Exposure to 1 cGy 600 MeV/n 28Si ions resulted in significantly impaired performance in the simple (SD) and compound discrimination (CD) stages of the attentional set shifting (ATSET) task. However, there was a pronounced non-linear dose response for cognitive impairment. Should similar effects occur in astronauts, the impairment of SD performance would result in a decreased ability to identify and learn the "rules" required to respond to new tasks/situations, while the impaired CD performance would result in a decreased ability to identify and maintain focus on relevant aspects of the task being conducted. The irradiated rats were also screened for performance in a task for unconstrained cognitive flexibility (UCFlex), often referred to as creative problem solving. Exposure to 1, 5 and 10 cGy resulted in a significant reduction in UCFlex performance, in an apparent all-or-none responsive manner. Importantly, performance in the ATSET test was not indicative of UCFlex performance. From a risk assessment perspective, these findings suggest that a value based on a single behavioral end point may not fully represent the cognitive deficits induced by space radiation, even within the ...
Source: Radiation Research - Category: Physics Authors: Tags: Radiat Res Source Type: research