Steven J. Ellman

Relation between REM Sleep and Intracranial Self-Stimulation

Depriving rats of rapid eye movement (REM) sleep was shown to lower their thresholds and raise their response rates for rewarding brain stimulation. Conversely, allowing rats to self-stimulate while they were being deprived of this sleep form reduced the amount of REM rebound during recovery from deprivation. These results demonstrate a reciprocal relation between rewarding brain stimulation and REM sleep.

Escape from rewarding brain stimulation of dorsal brainstem and hypothalamus

Abstract Each of 9 albino rats had two bipolar electrodes aimed at lateral hypothalamic and either of two dorsal brainstem (dorsal raphe or locus coeruleus) sites. Every rat bar-pressed for stimulation at each electrode. Then, each animal learned to treadle-press to escape from passive electrical stimulation at each elctrode site. All animals learned to escape from first dorsal brainstem and then lateral hypothalamic stimulation at current intensities which also supported self-stimulation behavior. Animals appeared hyperactive under lateral hypothalamic stimulation (active or passive), but not under dorsal brainstem stimulation.

Relationship between dorsal brainstem sleep sites and intracranial self-stimulation

Based upon our previous findings that a reciprocal relationship exists between intracranial self-stimulation (ICSS) and rapid eye movement (REM) sleep, we hypothesized that the ICSS neural network is a part of the REM sleep system and fires during REM sleep. A series of experiments was designed to test a corollary to this hypothesis, that some sites involved in triggering REM sleep are also ICSS sites. We explored five locations: the locus coeruleus (LC), the medial longitudinal fasciculus (MLF) (both posterior midbrain and pontine level), the dorsal longitudinal fasciculus (DLF) (midbrain), and the ventral raphe (pontine level). We obtained rate-intensity functions from each animal that displayed ICSS. High to very high (15,000 per hour) rates of ICSS were obtained at several dorsal brain sites. These sites included the LC, pontine aspects of the MLF, and posterior midbrain aspects of the MLF and DLF. ICSS from the LC is interpreted as evidence that noradrenergic ICSS sites are part of the REM sleep neural network.

An Examination of Some Recent Criticisms of Psychoanalytic “Metapsychology”

Some of the recent criticisms of psychoanalytic metapsychology are discussed, particularly the contributions of Schafer and Rubinstein. An examination of the logic underlying these criticisms indicates that many of them are either I) extratheoretical and say nothing about the scientific status of the theory or formulation under scrutiny; 2) rely on certain a priori philosophical assumptions which, if adopted, would severely limit the scope of psychoanalytic theorizing. Several suggestions are offered which would allow for more fruitful discussion of substantive logical and empirical question.

Intracranial self-stimulation: Temporal interactions among mesencephalic and diencephalic sites

The monophasic pulse pair technique has been employed to ascertain whether pairs of intracranial self-stimulation (ICSS) sites interact with each other. The present study investigated the interactive properties of ICSS placements in the substantia nigra (SN) and mid-ventral periaqueductal gray (MV) with those hypothalamic ICSS placements within (MFB) or outside of (non MFB) the medial forebrain bundle. ICSS response rates when pulses of each pulse pair were split between two ICSS sites were significantly higher than the sum of rates when each site was stimulated singly with single-pulse trains. Moreover, all interaction conditions yielded higher rates than pulse pairs delivered to the mesencephalic site at an optimal interval, yet similar rates to pulse pair stimulation delivered to the diencephalic site. The symmetry of the interactions depended upon electrode loci: MV/MFB and SN/non MFB interactions were significantly higher when the mesencephalic site received the first pulse of each pair, effects which accounted for 49 and 58% of the variance respectively. Conversely, MV/non MFB and SN/MFB interactions were significantly higher when the mesencephalic site received the second pulse of each pair, effects which accounted for 5 and 14% of the variance respectively. These behavioral ICSS interactions are discussed in terms of interrelated heterogeneous subsystems subserving ICSS behavior.

The effect of hindbrain lesions on a variety of measures of feeding behavior in rats

Hyperphagia following hypothalamic (HYP) lesions appears to be due to the disruption of neural fibers ascending from more posterior structures. Direct connections exist between the locus coeruleus (LC) and subcoeruleus (SC), and several HYP nuclei. These experiments examined the effects of LC and SC lesions on food intake, taste responsivity, meal patterns, and the circadian aspects of feeding. Experiment 1 examined the effects of bilateral LC lesions on feeding in rats maintained on a sweetened milk diet. One week after the lesions, the rats became hyperphagic. Histological analyses revealed that the critical area involved in the hyperphagia was ventral to the LC. Experiment 2 examined the effects of SC lesions in rats maintained on a solid food diet. These rats became hyperphagic, but not hyperdipsic. Histological and neurochemical analyses indicate that SC, rather than LC, destruction is responsible for the hyperphagia.