Brain and quality of experience are important; for example, there is substantial evidence that animals raised in enriched environments have thicker cerebral cortices, indicating a higher density of synaptic connections, than animals whose levels of stimulation are restricted. The functions of the brain depend on the ability of neurons to transmit electrochemical signals to other cells, and their ability to respond appropriately to electrochemical signals received from other cells. The electrical properties of neurons are controlled by a wide variety of biochemical and metabolic processes, most notably the interactions between neurotransmitters and receptors that take place at synapses. Neurotransmitters are chemicals
Electrical brain stimulation motor and sensory territories). EBS remains inextricably entwined with the work of Dr. Robert Galbraith Heath, Dr. Jose Delgado and Dr. Wilder Penfield. It's of interest that during cerebral localization studies, neurosurgeon Penfield could not elicit emotional reactions in humans, either by observing spontaneous epilepsy or by electrically stimulating the surface of the cerebral cortex. Neurophysiologist Dr. Jose Delgado noted a few exceptions to this rule. In contrast, EBS, via deeply implanted electrodes in localized areas of the brain (deep brain stimulation; DBS), elicited both pleasurable and aversive responses in laboratory animals and man as previously described. EBS could elicit