Related by context. Frequent words. (Click for all words.) 76 electrical impulses 65 muscle contractions 63 electrical pulses 63 chemical messengers 61 nerve cells 61 vagus nerve 59 sensory input 59 auditory nerve 58 neurotransmitters 58 nerve fibers 57 cochlea 57 neuronal activity 56 peripheral nerves 55 excitatory 55 neurons 55 biochemical reactions 55 neurones 55 Neurons 54 neural pathways 54 neuron 54 electrical currents 54 autonomic nervous system 54 NMDA receptors 53 synapse 53 chemical serotonin 53 neurotransmitter 53 skeletal muscles 53 nerve endings 53 thalamus 52 external stimuli 52 neurotransmitter dopamine 52 acetylcholine 52 electrical stimulation 52 glutamate 52 brain circuitry 51 motor neurons 51 oxygenated blood 51 biochemical pathways 51 sweat glands 51 motor neuron 51 endocytosis 51 axons 51 signaling molecules 50 biochemical pathway 50 dopamine 50 metabolism 50 forebrain 50 neural circuits 50 synapses 50 chemical dopamine 50 pineal gland 49 dopamine neurons 49 facial muscles 49 hormone insulin 49 electromagnetic waves 49 cilia 49 messenger RNA 49 neurochemical 49 axon 49 signaling pathways 49 neural 49 inhibitory 49 calcium ions 49 serotonin 49 biochemical processes 49 blood vessels 48 brainstem 48 thyroid hormones 48 modulate 48 cerebellum 48 cochlear 48 ventricles 48 cytoskeleton 48 cell membranes 47 norepinephrine 47 dendrites 47 vestibular 47 orexin 47 hypothalamus 47 cortex 47 visual cortex 47 retinal cells 47 brain 47 Nitric oxide 47 Wnt 47 neuromuscular 47 Cortisol 47 Abnormalities 47 signaling molecule 47 ion channels 47 molecular pathways 47 prostaglandins 47 olfactory bulb 47 mitochondria 47 neuronal 47 atria 46 synaptic 46 endorphins 46 molecular pathway 46 oligodendrocytes 46 NMDA receptor