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M Terman

Publications and source records attributed to M Terman.

62 records · Page 4Linked to original sources
PubMed1975

Control of the rat's sniffing behavior by response-independent and dependent schedules of reinforcing brain stimulation.

The rat's sniffing response occurs in continuous bursts, at approximately 5-11 Hz. In the present experiments, the analog signal from a thermo-couple probe in the nasal cavity was digitized to provide a discrete logic pulse, defining a sniff, and permitting on-line presentations of reinforcing brain stimulation contingent on momentary sniffing patterns. Schedules of reinforcer presentation included response-independent fixed interval (temporal conditioning), continuous reinforcement (CRF), and differential reinforcement of low rates (DRL 10 sec). Under temporal conditioning, bursts of sniffing were observed immediately after stimulation, and an acceleration in sniffing developed preceding stimulation. Under CFR, operant rate-intensity functions were found to be similar to traditional bar-press data. Under DRL, sniffs were effectively paced by the criterion interval, and interresponse time analyses revealed evidence of temporal discrimination. The behavioral patterns were interpreted in terms of the interplay of operant and respondent functions.

Animals↗
PubMed1973

Latency differentiation of hits and false alarms in an operant-psychophysical test.

Rats detected the luminance difference of standard and comparison stimuli in a go/no-go procedure. A key press was reinforced by brain stimulation only when the key's luminance was 10.53 ft-L (36.01 cd/m(2)), and key presses to dimmer comparison values produced a 5-sec timeout. These asymmetrical reinforcement contingencies maximized the bias toward hits and false alarms ("yes" reports), and thus the number of latencies available for analysis. False alarm latencies exceeded hit latencies, with the magnitude of differentiation proportional to luminance difference, demonstrating stimulus control on the very occasions that errors (key presses to comparison luminances) were emitted. Overall latencies decreased when the standard-comparison luminance difference was made smaller, suggesting a reduction in observing time when the stimuli became indiscriminable.

Animals↗
PubMed1970

Circadian rhythm of brain self-stimulation behavior.

Under constant conditions of light, sound, temperature, and humidity, rats exhibited circadian rhythmicity in rate of bar-pressing with hypothalamic and septal reinforcing brain stimulation. Variations in reinforcer magnitude aflected absolute levels of operant response emission but not the frequency of the circadian rhythm. In long sessions, the time of peak responding deviated systematically from a strict 24-hour period. Such data show marked similarity to free-running rhythms of motor activity.

Animals↗
PubMed1970

Detection of brief tones in noise by rats.

Two rats were trained to detect brief 8000-Hz tones centered in a one-third octave band of noise. The procedure was analogous to the yes-no method of human psychophysics in that one response was defined as correct and reinforced if the tone were present in the noise, and another response was correct and reinforced if the tone were absent. The percentage of correct responses was determined principally by the energy in the tone for the range of durations studied (75 to 600 msec): if the tone's duration were halved, for example, its power had to be doubled to keep the percentage of correct responses about the same. The ratio of the energy in the tone to the power per cycle of the noise needed to maintain 75% correct responses was about 36 db for one animal and 41 db for the other. Although the two responses were similar, and their consequences equal, biases in responding were sometimes observed.

Animals↗
PubMed1970

Discrimination of auditory intensities by rats.

Rats were trained to press one of two keys when a standard intensity value of a 4.0-kHz sine tone (70 or 100 db re 2 x 10(-4) microbar) was presented from a centrally located loudspeaker. Pressing the other key was reinforced when comparison intensity values (as much as 30 db less than the standard value) were presented. The animals initiated tone presentations by breaking a light beam at the rear of the chamber. Correct choices produced brain-stimulation reinforcement, and errors produced a timeout. A procedure designed by Jenkins was used to partial out choice data under potential control of sequential cues in the stimulus series. When the standard-comparison intensity difference was varied, the rats showed similar psychometric functions despite wide differences in response bias (relative position preference). A signal detection analysis showed that response biases for individual animals remained fairly consistent during psychophysical testing. The trend of decreasing choice accuracy at small intensity differences was described by the cumulative normal probability function. The similarity of psychometric functions obtained with 70- and 100-db standards supported Weber's law. There was some evidence that response latencies were controlled by intensity differences even when choice behavior was undifferentiated.

Animals↗
PubMed1968

Discrimination of brightness differences by rats with food or brain-stimulation reinforcement.

Rats were trained to respond to the brighter of two keys. Four animals were trained with food pellets and four with electrical brain stimulation. Each discrimination sequence was initiated when the animal broke a light beam at the rear of the chamber, turning on the key lights and starting a 30-sec reinforcement period. An initial response on the brighter key was immediately reinforced, and further responses on the brighter key were then intermittently reinforced. Any time the dimmer key was pressed, a 30-sec timeout was introduced. During timeout, no response had any programmed consequence. When the reinforcement period or the timeout ended, a new discrimination sequence could be initiated. Daily 1-hr training sessions were conducted, and after seven or eight sessions, all animals were at or near errorless performance levels. The luminance of the brighter key was then systematically reduced, in seven steps, with two 30-min test sessions at each step. Orderly psychometric functions were generated for individual animals. Initial acquisition, once position preferences were broken, was equally rapid for food and for brain-stimulation animals, and the two reinforcement procedures yielded comparable levels of brightness discriminability.

Animals↗