Response-related sensorimotor rhythms under scopolamine and MK-801 exposures in the touchscreen Visual Discrimination test in rats

Description

The human mu rhythm has been suggested to represent an important function in information processing. Rodent homologue rhythms have been assumed though no study has investigated them from the cognitive aspect yet. As voluntary goal-directed movements induce the desynchronization of mu rhythm, we aimed at exploring whether the touch-response-related brain activity during the touchscreen visual discrimination (VD) task is suitable to detect sensorimotor rhythms in healthy and cognitively impaired rats. Different doses of scopolamine or MK-801 were injected subcutaneously to male Lister Hooded rats, and epidural electroencephalography (EEG) was recorded during task performance. Arciform ~10 Hz oscillations appeared during visual processing, then two characteristic alpha/beta desynchronization-resynchronization patterns emerged predominating above the sensorimotor areas, serving different motor functions. Beyond causing cognitive impairment, both drugs supressed the touch-related upper alpha (10-15 Hz) reactivity for desynchronization. Reaction time positively correlated with movement-related alpha and beta power both in normal and impaired conditions. These results support the existence of a mu homologue rodent rhythm whose upper alpha component appeared to be modulated by cholinergic and glutamatergic mechanisms and its power change might indicate a potential EEG correlate of processing speed. The VD task can be utilized for the investigation of sensorimotor rhythms in rats.

Keywords

Funding

• Gedeon Richter Plc.
• Hungarian governmental grant 2017-1.2.1-NKP-2017-00002

Citation