A comparison of event-related potentials of humans and rats elicited by a serial feature-positive discrimination task

Event-related potentials evoked by passive visuospatial perception in rats and humans reveal common denominators in information processing

In the human cortex, event-related potentials (ERPs) are triggered in response to sensory, cognitive or motor stimuli. Due to the inherent difficulties of conducting invasive mechanistic studies in human subjects, little is known as to the precise neurophysiological mechanisms that lead to their manifestation. By contrast, although much is known about synaptic and neural mechanisms that underlie information processing in rodents, very few studies have addressed to what extent ERPs are comparable in rodents and humans. Here, we explored this by triggering ERPs in both species during the passive observation of visuospatial imagery, shown in an oddball-like manner, using an experimental design that was equivalent. Several ERP-components were identified in the rodent cohort, corresponding, for example, to the human P1, N1, and P2. ERPs that are likely to reflect a rodent N2 and P300 were also detected. Deviance, as well as repetition effects were evident in both species, whereby rodent ERPs displayed more immediate response alterations to repeated stimuli and humans showed more gradual response shifts. These results indicate that humans and rodents may implement similar strategies for the passive perception and initial processing of visuospatial imagery, despite clear differences in their sensory and cognitive capacities.

Simultaneous monitoring of electroencephalographic characteristics in animals subjected to behavioral tests: a preclinical investigation

Drug-induced changes in electroencephalographic (EEG) characteristics in animals may be used to predict central activity of drugs in humans. Previous studies have established that drugs affect EEG characteristics in humans and rodents in a similar manner. However, there has been little work to establish correlations between drug effects on behavioral and EEG characteristics in rats. In the current study, we have simultaneously monitored EEG characteristics during a novel object recognition task (NORT) or open field (OF) test in rats. EEG was monitored using telemetric device from epidural and hippocampal regions during the choice trial in the NORT after treatment with scopolamine (0.1 mg/kg, intraperitoneal) alone or in combination with donepezil (0.3 mg/kg, subcutaneous). Power changes across spectral frequency bands during exploration of novel and familiar object were assessed separately. Amphetamine (2 mg/kg, intraperitoneal) was used to monitor effects on locomotor activity and EEG changes in the OF test. In the NORT, scopolamine impaired object recognition, but no differences were observed in the power densities across spectral bands during exploration of novel and familiar objects. Treatment with donepezil reversed scopolamine-induced cognitive impairment, and the power density in the theta frequency band was increased during exploration of the novel object. In OF, amphetamine increased locomotion and produced an overall decrease in the power densities of all frequency bands. Overall, the results indicate that EEG characteristics are closely related to behavioral changes in the NORT and OF in rodents.

"Wesley says": a children's response inhibition playground training game yields preliminary evidence of transfer effects

Recent studies suggest that the response inhibition ability of children can be modified through training. Based on the notion of embodied cognition, we investigated transfer effects of a 7-day training program using a game named "Wesley says" in 8- to 12-year-old children (n = 15). The game consists of providing commands for performing simple body actions, the actual execution of which is conditional upon the preceding verbal expression "Wesley says." Training effects were assessed with a computer-based visual go/no-go task and the Stroop color-word interference task. Relative to a control group playing other games mainly involving physical exercise (n = 15), the trained group showed a performance improvement on the go/no-go task, but not on the Stroop task. These results suggest the potential of an easy-to-use and ecologically valid training game to improve the inhibition capacity of children on related response inhibition tasks but not on tasks measuring other aspects of inhibition, such as interference control.

Cholinergic drugs affect novel object recognition in rats: relation with hippocampal EEG?

This study examined the role of cognitively enhancing cholinergic drugs on both object memory and brain activity in rats, as well as the possible relation between the two measures. A group of twenty-four animals was used for assessing object recognition. In another group of eight rats, an electrode was implanted into the dorsal hippocampus to record an electroencephalogram (EEG) and auditory evoked potentials (AEP). In both groups, animals were treated with saline, 0.1 mg/kg scopolamine, 0.1 mg/kg methylscopolamine, 3 mg/kg donepezil, donepezil combined with scopolamine, 0.1 mg/kg nicotine, and nicotine combined with scopolamine. Scopolamine, but not methylscopolamine, impaired object recognition. Both donepezil and nicotine reversed this impairment. The N1 and N2 components of the AEP became closer to baseline after scopolamine, which was not reversed by donepezil or nicotine. Scopolamine increased the theta frequency in the EEG. When combined with donepezil, theta increased even more. Conversely, nicotine reversed the theta increment to control level. It is suggested that scopolamine caused a decrement in arousal in this study. Furthermore, the current results suggest a relation between EEG and object memory after cholinergic drug treatment. However, there was a clear dissociation between memory performance and EEG after combined treatment with drugs, which makes additional research where EEG and performance measures are co-registered imperative.