Glossary

agonist A drug that activates the same receptor as does the natural neurotransmitter.

antagonist A drug that blocks the activation of a receptor.

electroencephalograph The electrical activity of the brain measured from the surface of the scalp.

G protein-coupled receptors Cell surface receptors that are activated by substances in the synaptic cleft but are coupled to channels by multiple chemical messengers that open the channels from within the cell.

ligand-gated receptors Cell surface receptors that are activated by chemical substances in the synaptic cleft (ligands) and are coupled directly to channels in the cell's membrane.

neuromodulator transmitter A neuroactive substance found in the peripheral or central nervous system that causes long-lasting changes in excitability of the postsynaptic cell.

Arousal is the ability to mobilize metabolic energy to meet environmental or internal demands on behavior. As such, it is an organismal property that is found throughout the animal kingdom, including those species with very rudimentary nervous systems. For example, in jellyfish, arousal may be produced by the diffusion of activating substances within the body wall that increase metabolic activity. In insects, activating substances may be generally mobilized within ganglia and released onto specific target structures from single neurons. In marine mollusks, repeated application of a noxious stimulus to the skin causes a withdrawal response that grows in magnitude over time. Although termed sensitization, it is associated with global changes in metabolism and is probably the precursor to the arousal response in higher organisms. The anatomy and physiology of arousal are similar among primitive vertebrates and highly complex mammals. Although the arousal response in humans is present at birth, research suggests that some components of the response are recognizable in utero. Arousal responses in neonates are frequent and associated with hunger and discomfort. The soothing voice of the parent is usually the first external stimulus to exert control over the arousal response. The major developmental changes in the arousal response are the growth of inhibitory processes that control and shape the response and an increase in the range of internal and environmental stimuli that activate these processes.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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