Electrical self-stimulation

In 1954, experiments by Olds and Milner revealed that the brain has specialized centers for reward functions. In these studies electrical stimulation of certain brain sites was found to be highly rewarding in the sense that rats operantly respond for electrical stimulation of these brain sites, often to the exclusion of any other activity. A neurotransmitter system that is particularly sensitive to electrical self-stimulation is the mesolimbic dopamine projection that originates in the ventral tegmental area and projects to structures closely... 

Crow, T. J, (1972) Catecholamine containing neurones and electrical self-stimulation I. a review of some data. Psychol. Med., 2, 414. 

Another caution centers on studies combining in-vivo voltammetric electrochemistry with self-administered electrical brain stimulation reward in laboratory animals (Wightman and Garris 1996 Kruk et al. 

It has been reported that after withdrawal from twelve-to-twenty-four-hour binges of intravenous cocaine self-administration, current thresholds for electrical brain stimulation reward are elevated in animals (Markou and Koob 1991,1992). In addition, levels of extracellular DA are decreased in Acb following withdrawal from prolonged cocaine self-administration (Weiss et al. 1992b). Long-term cocaine use can decrease tyrosine hydroxylase levels, leading to decreased DA synthesis (Trulson et al. 1987). 

Moolten, Marjorie, and Conan Komctsky. 1990. "Oral Self-Administration of Ethanol and Not Experimenter-Ad ministered Ethanol Facilitates Rewarding Electrical Brain Stimulation." Alcohol 7 221-25. 

Nakahara D, Fuchikami K, Ozaki N, Iwasaki T, Nagatsu T (1992) Differential effect of self-stimulation on dopamine release and metabolism in the rat medial frontal cortex, nucleus accumbens and striatum following electrical stimulation of the median forebrain bundle. Brain Res 674 164-170. 

Intracranial Self-Stimulation Self-Delivered Electrical Stimulation... 

Richardson, D.E. and H. Akil, Pain reduction by electrical brain stimulation in man. Part 2 Chronic self-administration in the periventricular gray matter. /. Neurosurg., 1977,47 184—194. 

The development of some of the secondary models such as conditioned place preference and electrical brain stimulation which do not require intravenous drug injections will continue to occur (for complete descriptions of the conditioned place preference paradigm and validation data, see Bardo and Bevins (2000) or Cunningham et al. (2006, 2011) for a complete description of the electrical brain stimulation model, also see O Neill and Todtenkopf (2010) or McBride et al. (1999)). A better understanding of the predictivity of these models and correlation with the traditional self-administration model will be required for these models to assume a mainstream position in abuse potential assessment. The self-administration model s predictive correlation to abuse potential in humans has been well characterized but new models will have to be characterized and published to have equal impact in future abuse potential testing. 

Sensitivity to Other Non-Social Exteroceptive Stimuli - Several studies indicate that PCPA increases various behavioral or neurological effects of electrical stimulation. Thresholds of current required to reinforce selfstimulation behavior are lowered by PCPA in rats,46 and PCPA has been reported to cause strong excitatory effects on intracranial self-stimulation rates in rats 3 days after treatment.47 5-HT-depleted animals have been reported to be more active than controls under conditions of extra environmental stimulation, particularly "novel" stimulation.18b,19c Cats "overreact to slight noises,"48 sensory thresholds are lowered,29 the responsiveness to a startle stimulus of rats with low basal responsiveness Is Increased,49 and habituation to an audltory-ellcited startle response, as measured by cortical electrical responses. Is reduced.50... 

Skeletal muscle is neurogenic and requires stimulation from the somatic nervous system to initiate contraction. Because no electrical communication takes place between these cells, each muscle fiber is innervated by a branch of an alpha motor neuron. Cardiac muscle, however, is myogenic, or self-excitatory this muscle spontaneously depolarizes to threshold and generates action potentials without external stimulation. The region of the heart with the fastest rate of inherent depolarization initiates the heart beat and determines the heart rhythm. In normal hearts, this "pacemaker region is the sinoatrial node. 

---