METABOLIC CONTROL OF HIGH-FREQUENCY GAMMA OSCILLATIONS IN THE BRAIN

Abstract

A high-frequency electrical activity across the range of 30–100 Hz, known as gamma rhythms, is observed in many regions of the brain. This phenomenon serves to synchronize the activity of various neural networks intended to process, transmit, store and receive information. Gamma rhythms play a key role in such processes of higher nervous activity as attention, sensory perception and memory formation. Impairment of gamma rhythms is a common symptom of diseases associated with cognitive impairment, including Alzheimer’s disease, epilepsy and schizophrenia. Recent studies have shown that a particular population of GABAergic-inhibiting neurons, i.e. parvalbumin-positive (PV+) interneurons, is the source of high-frequency oscillations. Maintenance of gamma rhythms is an extremely energy-intensive process that relies on a high rate of oxidative phosphorylation in the mitochondria of neurons and is limited by the presence of glucose. Insulin may be involved in the metabolic control of gamma oscillations, since PV+ interneurons selectively express the insulin-dependent glucose transporter GLUT4, which can provide an additional glucose influx under near-limit functioning conditions as in the case of high-frequency gamma oscillations. This review generalized available literature data on the relationship between metabolism and a high-frequency electrical brain activity, with an emphasis on the possible contribution of central insulin resistance to disturbances of gamma rhythms in the brain.