Ratio schedules of reinforcement

Andrews. J.S., and Holtzman, S.G. The interaction of ti-amphetamine and naloxone differs for rats trained on separate fixed-interval or fixed-ratio schedules of reinforcement. Pharmacol Biochem Behav 26 167-171, 1987. Angrist, B.M., and Gershon, S. Amphetamine abuse in New York City, 1966-1968. Semin Psychiatry 1 195-207, 1969. 

Monkey (Rhesus) 7-8 yr 1 x/d (C) 1.5 (altered performance on a fixed-interval-fixed-ratio schedule of reinforcement at age 7-8 years) Rice 1992 PbAc... 

Ranaldi, R., Wise, R.A. Intravenous self-administration of methamphetamine-heroin (speedball) combinations under a progressive-ratio schedule of reinforcement in rats. Neuroreport. 11 2621, 2000. 

Roberts DCS, Bennett SAL (1993) Heroin self-administration in rats under a progressive ratio schedule of reinforcement. Psychopharmacology 111 215-218 Shelton KL (2007) Inhaled toluene vapor as a discriminative stimulus. Behav Pharmacol 18 219-229... 

There are four simple schedules of reinforcement the fixed interval (FI) and the variable interval (VI), both of which are temporally based reinforcement schedules, and the fixed ratio (FR) and the variable ratio... 

Figure 9 Schematic cumulative records of performance on the fixed ratio (FR), variable ratio (VR), fixed interval (FI), and variable interval (VI) schedules of reinforcement. Responses are cumulated vertically over time. Each downward deflection of the pen represents reinforcement delivery horizontal lines indicate pausing. (Reproduced from Seiden LS and Dykstra LA (1977) Psychopharmacology A Biochemical and Behavioral Approach. New York, NY Van Nostrand Reinhold.)...

Like the VI, the pattern of responding on the VR schedule reflects the lack of predictability of reinforcement availability. Since reinforcement availability may always be imminent, pausing would delay reinforcement. The high rates characteristic of VR and FR schedules are thought to be due to the ratio basis of reinforcement in that the faster the response requirement is completed, the faster reinforcement is available. Increases in rates of responding on interval-based schedules such as the FI and VI cannot accelerate the availability of reinforcement one must still wait for the time interval to end. 

Performance generated by intermittent schedules of reinforcement has played an important role in behavioral pharmacology and is proving a useful tool in behavioral toxicology. On an intermittent schedule, an animal is not reinforced for every response but for a number of responses according to certain rules . Most intermittent schedules are based on reinforcing the organism as a function of the number of responses emitted, some temporal requirement for emission of responses, or a combination of these. For example, a fixed ratio (FR)... 

Fixed ratio schedule delivers reinforcement after a fixed number of responses... 

Solinas M, Panlilio LV, Antoniou K, Pappas LA, Goldberg SR. The cannabinoid CB 1 antagonist N-piperidinyl-5-(4-chlorophenyl)-l-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide (SR-141716A) differentially alters the reinforcing effects of heroin under continuous reinforcement, fixed ratio, and progressive ratio schedules of drug self-administration in rats. J. Pharmacol. Exp. Ther. 306, 93-102 (2003). 

Another indicator of the reinforcing effectiveness of a test substance can be the amount of work an animal will perform to obtain the test substance. This can be investigated with a progressive ratio schedule whereby the response requirement increases for every infusion (Solinas et al. 2004) or after a fixed period of time (Wilcox et al. 2000) until the animal ceases to lever-press for a pre-determined interval,... 

Each process provides capabilities such as meeting production quantity (small to large quantities and/or shapes), performance requirements, proper ratio of reinforcement to matrix, fiber orientation, reliability/ quality control, surface finish, materials used, quantity, tolerance, time schedule, and so forth versus cost (equipment, labor, utilities, etc.). There are products when only one process can be used but there can be applications where different processes can be used. 

In the habit modality, response is mainly controlled by stimuli that precede rather than follow it (outcomes) (Dickinson, 1994). As a result of this, devaluation of response outcome fails to impair habit responding. Habit responding takes place as a result of exhaustive training on high ratio schedules or under variable interval schedules where reinforcement is loosely related to response (Dickinson, 1994). 

Evidence for a role of NAc DA in cocaine reinforcement has been provided by studies of the effect of 6-OHDA lesions on cocaine self-administration. Thus, 6-OHDA lesions of the DA innervation of the nucleus accumbens result in extinction-like effects on responding for cocaine in FR schedules (Roberts et al., 1977 Roberts et al., 1980, Pettit et al., 1984) and in a decrease in break point in progressive ratio schedules (Koob et al.,... 

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