In rats, sighs correlate with relief.

A deep breath, i.e., a sigh, in mammals is a ubiquitous respiratory phenomenon, whose function is to prevent airlessness (atelectasis) in hypoventilated parts of lungs.

22-kHz ultrasonic vocalization in rats as an index of anxiety but not fear: behavioral and pharmacological modulation of affective state.

Ultrasonic vocalization (USV) was found useful for differentiating fear and anxiety in rats. These affective states were established through a Pavlovian conditioning procedure. Danger stimulus, preceding unavoidable tail shock, elicited acute fear.

Apparatus for studying behavior and learning in restrained rats.

A new treadmill/stand apparatus for a rat is described. It will be useful in behavioral experiments when control of the animal's position in the training chamber is required while considerable freedom of movement, including locomotion, is desired. The position and distance relative to sources of stimuli are thus kept constant.

Structure/function studies of QS-21 adjuvant: assessment of triterpene aldehyde and glucuronic acid roles in adjuvant function.

QS-21, a purified Quillaja saponaria saponin immunologic adjuvant, contains two functional groups that we hypothesized to be involved in the adjuvant mechanism of action through charge or Schiff base interaction with a cellular target. Derivatives, prepared by modification of these sites, were prepared and tested for their ability to augment the immunogenicity of the antigen ovalbumin (OVA) in C57BL/6 mice. QS-21 derivatives that were modified at the carboxyl group on an anionic sugar, glucuronic acid, retained adjuvant activity for antibody stimulation, inducing relative increases in antibody titers similar to those induced by QS-21, although the minimum adjuvant dose required for this stimulation was increased several fold relative to the dose of unmodified QS-21.

Adjuvant activity of QS-21 isomers.

QS-21, a reverse-phase purified triterpene glycoside from the South American tree Quillaja saponaria, can be further resolved into two peaks when chromatographed by high performance hydrophilic interaction chromatography. These two peaks demonstrated identical pseudomolecular ion weights and fragmentation patterns when analyzed by fast atom bombardment-mass spectroscopy. Carbohydrate analysis by monosaccharide composition and linkage analysis showed that a terminal apiose in the major peak was replaced by another pentose residue in the minor peak.

Ontogeny of conditioned inhibition of conditioned respiratory suppression in kittens.

Excitatory and inhibitory classical conditioning were examined in 4-week-old, 8-week-old, and 12-week-old kittens. Conditioned respiratory suppression (CRS) was a measure of conditioned fear. The inhibitory conditioning procedure was designed to model the schedule of events that normally accompanies successful coping behavior: The safety signal predicted the cancellation of shock that would otherwise follow the danger signal, rather than simply the absence of shock.

Regulation of the butyryl-CoA dehydrogenase by substrate and product binding.

Until now, workers in the field of fatty acid metabolism have suggested that the substrates are isopotential with the enzymes and that the reactions are forced to completion by the formation of charge-transfer complexes [Gustafson, W. G., Feinberg, B.

The effects of reversible freezing inactivation and inhibitor binding on redox properties of L-amino-acid oxidase.

We measured the redox potentials of frozen inactivated L-amino-acid oxidase (L-amino-acid:oxygen oxidoreductase (deaminating), EC 1.4.3.

Oxidation-reduction potentials of butyryl-CoA dehydrogenase.

In order to obtain butyryl-CoA dehydrogenase from Megasphaera elsdenii in pure enough form to perform redox studies, the existing purification procedures first had to be modified and clarified [Engel, P. (1981) Methods Enzymol. 71, 359-366].

Pharmacological manipulations of the nucleus accumbens: effects on classically conditioned responses and locomotor activity in the cat.

Agonists and antagonists of dopamine, acetylcholine, and glutamate were injected bilaterally into the nucleus accumbens in 5 adult cats, and their effects on classically conditioned responses and locomotor activity were observed. Dopamine reduced conditioned consummatory responses (leg flexion and vocalization) and conditioned changes in respiration rate, but did not affect other conditioned preparatory responses (changes in heart rate and respiration amplitude). The cholinergic agonist oxotremorine reduced both conditioned and unconditioned leg flexion.

Early coping experience and later aversive conditioning in cats.

Kittens were given differential early experience in order to compare an objective coping behavior with the result of an inescapable aversive experience. Separate groups of kittens were treated in a shock motivated runway task at either 4 or 12 weeks of age, by allowing one member of a weight matched sibling pair to acquire an escape behavior, while the other member was confined; a third subject served as a handled control. Escape behavior was significantly different for 4 and 12 week old subjects, since the older kittens reached a running asymptote within the first few shock trials.

Postnatal development of respiratory and vocal responses during aversive classical conditioning in cats.

Respiratory rate, respiration amplitude, and vocal responses were recorded in cats of different ages during classic conditioning. Vocal responses to the conditional stimulus (CS) appeared first in 8-week-old kittens, and became prominent at older ages. An increase in respiration rate occurred after the onset of the CS in cats of all ages.

Postnatal development of heart rate patterns elicited by an aversive CS and US in cats.

Heart rate and motor responses were recorded in cats of different ages during classical conditioning. A deceleratory-acceleratory heart rate pattern observed during the CS-US interval in one- and four-week-old kittens is an alpha conditioned response, a potentiated original response to the CS. At eight weeks of age two new distinct patterns of pure acceleration or pure deceleration are acquired during conditioning and in the absence of motor learning.

Protection from extinction by a conditioned inhibitor.

The phenomenon of protection from extinction (PFE) of a conditioned stimulus (CS) by a conditioned inhibitor (CI) has not been yet unequivocally demonstrated for the CS-CI compound in which the CS precedes the onset of the CI. Preliminary data from a project addressed to this problem strongly indicate that PFE is a real and robust phenomenon. Moreover, the protection is demonstrated not only for the CS duration overlapping with the CI but also for the early part of the CS which is not prevented by the CI from eliciting a conditioned response.

The effect of conditioned stimuli signalling food upon the autochthonous instrumental responses in dogs.

Food CSs, presented (i) concomitantly with SD controlling bar pressing for food, or (ii) on the background of non-discriminated bar pressing (FR 1/15), suppress instrumental performance but elicit undiminished conditioned salivation. This result supports Soltysik-Konorski's model of CNS mechanism controlling food-oriented behavior which postulates drive inhibition by taste-consummatory neurons.

Single unit activity in basal ganglia of monkeys during performance of a delayed response task.

Single unit activity was recorded from the basal ganglia (caudate, putamen and globus pallidus) of monkeys during the performance of a delayed-response task. The task was divided into five epochs: stimulus onset, delay, pre-response, post-response and reqard. A high percentage of units recorded from the basal ganglia were found to show significant changes in activity during one or more epochs.

Post-consummatory arousal of drive as a mechanism of incentive motivation.

A review of experimental papers on the problem of incentive motivation reveals little or no support for the hypothesis that conditioned food signals facilitate autochthonous instrumental responses (i.e., responses motivated by the same drive and rewarded by the same unconditioned stimulus).

Transfer of the "same-different' differentiation task in dogs.

Four dogs, previously trained to perform on the "same-different" differentiation with tones transfered readily to the same task with new stimuli of the same (auditory) modality. The data are interpreted as an support for the "matching" hypothesis and a disproof of the notion of "conditioned switching".

A failure to train the "same-different" differentiation of photic stimuli in dogs.

Dogs were unable to learn "same-different" differentiation of pairs of photic stimuli when continuous light (CL) and pulsing light (PL) were presented in four combinations: CL-PL and PL-CL served as S(D) (positive instrumental conditioned stimulus), whereas CL-CL PL-PL were S delta (inhibitory stimulus). Also the dogs which have learned this task with tones were unable to transfer to photic stimuli. Differentiation of the single stimuli (CL and PL) as S(D) and S(delta) was quite easy and showed that the stimuli were readily discriminable.

A further study on the effect of medial prefrontal ablation upon classical defensive conditoned relfexes in dogs.

In 8 dogs with removed medial prefrontal cortex, the positive and differential classically conditioned leg flexion responses and accompanying heart rate reactions were not changed or slightly reduced. In some animals a transient increase in cardiac responses to shock was also observed.

The performance of goats in triple choice delayed response tasks.

Goats have been successfully trained in types of triple choice delayed response situations. Their levels of performance indicated that they are able to solve delayed response tasks very successfully and can make correct choices in a post-delay response reward design after delays of 30 min, which is considerably longer than has been previously reported for dogs and cats. Goats do not readily approach and investigate novel stimuli and require a complex compound stimulus in the delayed response situation.