Robert J. Marcus

Effects of caudate nuclei or frontal cortex ablations in cats. II. Sleep-wakefulness, EEG, and motor activity ☆

Abstract The effects of caudate nuclei ablation or frontal cortex removal on the percentages of wakefulness and sleep stages, spontaneous motor activity, and the EEG were studied in cats by means of 24-hr polygraphic recordings for a 6-month period. A significant, permanent, reduction of sleep (particularly REM sleep) and an increase in motor activity were observed in cats with removal of most of the frontal tissue in front of the A22 stereotaxic plane. A similar decrease in sleep was also observed in animals with bilateral, almost total, removal of the caudate nuclei, but this reduction almost fully recovered after the second postlesion month. Motor hyperactivity was more marked in cats with caudate ablations than in cats with frontal ablations and persisted indefinitely. No marked or lasting effects on the EEG were observed. Sham-operated cats and those with unilateral caudate removal behaved like intact cats. It is concluded that both the frontal cortex and the caudate nuclei are parts of a postulated, complex, forebrain system modularing brain stem activating-deactivating central nervous system mechanisms.

Effects of caudate nuclei or frontal cortex ablations in cats. IV. Bar pressing, maze learning, and performance.

Abstract Bar pressing, maze learning, and passive avoidance acquisition were examined, before and/or after surgery, in cats with extensive unilateral or bilateral ablations of the caudate nuclei or frontal cortices and in sham-operated cats. The caudate ablations were by aspiration using a midline transcallosal approach. In a two-bar lever-pressing situation the acaudate animals showed specific defects consisting of difficulties in shaping the use of the paws, tendency to persist at the response producing the last reward, inability to execute two concurrent motor acts, and peculiar postural adjustments. These changes contributed to slow rates of responding, markedly impaired ability to alternate, and interfered with all phases of acquisition and performance. Frontal cats, conversely, exhibited markedly irregular behavior, inability to sustain performance, and slow rates of bar pressing without the other response peculiarities of acaudate cats. The unilaterally ablated animals exhibited only fragments of these defects. In a standard T-maze, on spatial alternation and black-white discrimination tasks, acaudate cats showed errors of perseveration while frontal cats produced mainly randomly distributed errors. Such defects were not seen in unilaterally lesioned animals. The above deficits did not manifest any marked recovery even in cats studied for up to 16 months. Passive avoidance was normal in all animals except the cat with the largest caudate removal. Sham-operated cats behave like intact animals. In conclusion: (i) Stable, chronic cats with caudate removal and absence of dorsofrontal cortical damage are capable of learning, retention, and performance far beyond previous suggestions; (ii) The discrete behavioral deficits resulting from extensive caudate or frontal lesions are different, suggesting that these structures play different functional roles. The deficits resulting from caudate destruction are discussed in terms of interference with high level sensory motor processess; their similarities with some clinical manifestations of human basal ganglia pathology are noted.

Transbrachial arteriography: techniques and complications

A study of 72 patients angiographically examined by the percutaneous transbrachial technique with 4–5F catheters is reported. Even though the patients were preselected to reduce the risk of the technique, an unacceptably high incidence (7%) of major complications, including 3 patients requiring surgery for brachial thrombosis, was encountered. Although transbrachial catheterization with single 4F catheter midstream injections as reported in the literature may be safe, this technique is unwarranted when selective studies are planned and the alternative transfemoral approach is available.

Effects of caudate nuclei or frontal cortex ablations in cats: III. Recovery of limb placing reactions, including observations in hemispherectomized animals.

This is a long-term study of the time course of impairments of the limb placing reactions in cats following bilateral removal of the frontal cortical areas (n = 9), bilateral (n = 11), or unilateral (n = 10), ablation of the caudate nuclei or removal of one cerebral hemisphere (n = 5). In addition the effects of d-amphetamine and of removal of the remaining frontal cortex on the placing reactions of the limbs contralateral to the hemispherectomy were assessed. The main results were: (i) a substantial recovery of the contact placing reactions was observed in frontal cats; the recovery started very late (third or fourth month) and was considered as complete within 6 to 9 months in four cats. (ii) A variable degree of impairment of the contact placing reactions occurred in caudatectomized cats; both the magnitude of the impairments and the length of the recovery period (up to 4 months) were proportional to the extent of the ablation. (iii) No recovery of the contact placing reactions was observed in limbs contralateral to the hemispherectomy either spontaneously, under the action of d-amphetamine (producing a transient enhancement of proprioceptive components and a pseudocontact placing reaction), or following removal of the remaining frontal cortex. The meaning of the above findings in the context of pertinent literature, the mechanisms of compensation following frontal ablation, and the possible participation of the caudate in the physiological control of the contact placing reactions are discussed.

Blocking of Experimental Spike and Wave by a Localized Forebrain Lesion

In 10 out of 16 cats, the 3/sec spike and wave electrocortical pattern was produced by electrical stimulation of the midline thalamus. In these animals, a unilateral lesion in the area of the inferior thalamic peduncle (ITP) markedly decreased the homolateral spike and wave complexes and the spontaneous EEG spindle bursts; the blockade was bilateral in two cases with bilateral ITP lesions.

Thiazide diuretics do not potentiate cAMP response to parathyroid hormone.

We evaluated the hypothesis that thiazide-induced hypercalcemia reflects potentiation of the cAMP response to parathyroid hormone (PTH) consequent to inhibition of phosphodiesterase in bone and kidney. A panel of thiazide diuretics did inhibit low-Km phosphodiesterase activity from bone homogenates. However, furosemide, a nonthiazide diuretic that does not promote calcium retention, was more potent a phosphodiesterase inhibitor than either chloro- or hydrochlorothiazide (CTZ, HCTZ). Thiazides did not influence basal or PTH-stimulated cAMP levels in incubated calvaria or renal cortical slices. Administration of CTZ or HCTZ to rats for 4 days did not affect basal cAMP, nor did such treatment potentiate the cAMP response in Calvaria to infusion of parathyroid extract in vivo. CTZ, HCTZ, and furosemide increased basal adenylate cyclase from renal cortex but did not affect PTH-stimulated activity. Adenylate cyclase from bone was not affected by thiazides but was inhibited by furosemide. Thiazide treatment potentiated the calcemic response to parathyroid extract in vivo but did not affect the calcemic response to dibutyryl cAMP. We conclude that potentiation of the cAMP response to PTH does not underlie the unique effects of thiazides on calcium metabolism.

Bilateral aortoiliac pressure measurements from a single puncture site

Bilateral aortoiliac pressure measurements were obtained at the time of aortography by performing contralateral iliac artery catheterization in 102 patients with peripheral vascular disease. Patients studied had mild-to-moderate aortoiliac disease and in their cases the additional information was believed to be important in therapeutic decision making. Patients with severe ulcerative disease, peripheral thromboembolism, and significant aortic aneurysms were excluded. Pressure gradients out of proportion to the degree of stenosis as measured on the arteriograms were frequently found, particularly during high flow states with intraarterial injections of a vasodilator. There were two failures of catheterization and three minor complications, none embolic. We conclude that contralateral iliac artery catheterization in selected patients is both safe and generally easily performed by experienced angiographers.