The understanding of the functions of a certain portion of the cortex ultimately is dependent on a knowledge of the connections or interrelationships of that particular cortex. Consequently, the visual cortex and the auditory area are better understood because of the works of Poliak (1932), Talbot (1942), Talbot, Woolsey and Thompson (1946), and of Walker (1937a,1937b), of Ades and Felder (1942, 1945), Ades (1943), Woolsey and Walzl (1942), Walzl and Woolsey (1943), Tunturi (1944, 1945), Rose (1949), and Rose and Woolsey (1949).

In recent years, increasing numbers of conflicting reports (to be commented on in the section devoted to a review of the literature) have appeared in the world literature regarding the effect of chlorpromazine on epilepsy and on the seizure activity seen in the electroencephalographic tracings of epileptic patients. These have ranged, with regard to epilepsy, from one extreme position in which the drug is advocated as a therapeutically efficacious method of treatment, to the other extreme in which it is held accountable for having precipitated epileptic seizures in patients with no previous history of similar distrubance who are undergoing treatment for an unrelated illness.

Among the various focal epileptic seizure patterns commonly encountered one of the most interesting and least understood is that of ictal epileptic automatism. The most characteristic feature of ictal epileptic automatism is the association of a profound impairment of higher mental functions such as memory and conscious understanding with a rather strikingly contrasting retention of motor control, of the capacity for reception of sensory stimuli and of the possibility to integrate motor and sensory activities into complex and correctly performed motor actions (Penfield and Jasper, 1954). [...]

The need for continued investigation into the mechanism of motor function has been emphasized recently by Bucy (1957) in a critical review entitled, "ls there a pyramidal tract?" and by Lassek, Woolsey, Walker, and Boshes (1957) in a symposium of inquiry into the state of our knowledge of the pyramidal tract presented before the eighth annual meeting of the American Academy of Neurology. [...]

The integration of a circulatory system into any tissue or organ utilizing oxygen permits a faster workrate and, more efficiency in terms of general body economy. Such integration, however, carries the accompanying threat of the consequence of sudden interruption in the local or general circulation. Organs that have acquired "specialization", at the cost of powers of regeneration, pay for such interruption, if prolonged, with permanent loss of function. Certain gross structural changes, in addition to the permanent functional loss, take place in the offended tissue.

The following work was undertaken because of the increasing body of evidence indicating that a high dietary fat intake is related to certain diseases, among which is multiple sclerosis with which we were particularly concerned. Recent nutritional surveys have suggested that geographic variations in the incidence of multiple sclerosis are due at least in part to the amount of fat consumed. Dr. Swank (Swank, 1950; Swank, Lerstad, Strom and Backer, 1952) made a survey of Holland, Denmark, Norway and Switzerland and compared figures of the dietary habits and the incidence of multiple sclerosis before, during, and after World War II when there were wide fluctuations in the dietary habits.

Thesis (BHSc--Health Science) -- Auckland University of Technology, 2004. / Also held in print (91 leaves, 30 cm.) in Akoranga Theses Collection (T 618.9280475 BIR)

Thesis (Ph.D.)--Syracuse University, 2007. / "Publication number: AAT 3295530."

Concurrent alternating stimulation of two limbic sites culminates in typical kindling of generalized seizures from one site (dominant), whereas the other site (suppressed) supports only nongeneralized seizures for as long as stimulation of the dominant site continues (kindling antagonism). Burchfiel and Applegate (1989; 1990) claimed that antagonism reflects a frank arrest of kindling from the suppressed site at an intermediate stage. They argued, moreover, that the eventual generalization of seizures provoked from the suppressed site after the termination of stimulation of the dominant site reflects a resumption of kindling from its previous state of arrest. Burchfiel and Applegate also claimed that the behaviorally stereotyped arrest of kindling from the suppressed site reveals critical transitions between sequentially expressed mechanisms that govern both antagonism and kindling. They therefore viewed kindling as a stepwise process that is mediated by qualitatively and temporally distinct mechanisms. This position hinges on the assumption that antagonism reflects a true arrest of kindling from the suppressed site rather than a transient inhibition of seizures. I conducted the following experiments to determine whether the assumption is justified, In Experiment 1, I replicated and extended the observations of Burchfiel and Applegate concerning the expression of antagonism during alternating stimulation of limbic as well as nonlimbic sites. The results of Experiment 1 thus indicate that antagonism is indeed a robust phenomenon and therefore worthy of further study. In Experiment 2, the imposition of a prolonged stimulation-free period (30 d) after the termination of stimulation of the dominant site (amygdala) did not significantly reduce the number of stimulations of the suppressed site (septal area) required to elicit a generalized seizure. Also, epileptiform after discharge provoked from the septal area increased during alternating stimulation, and the septal area supported generalized seizures after fewer stimulations in rats previously expressing antagonism as compared to control rats previously kindled from the amygdala. Collectively, these data are consistent with the view of Burchfiel and Applegate that kindling from the suppressed site progresses to an intermediate stage during alternating stimulation and resumes after the termination of stimulation of the dominant site. The results of Experiment 2 also suggest the possibility that the development of seizures from the suppressed site after the termination of stimulation of the dominant site is dictated by the additive expression of: first, the well-documented facilitation of kindling from one site that reliably follows kindling from another (i.e., transfer between the amygdala, which supported generalized seizures, and the septal area); second, (partial) kindling from the septal area, which previously supported nonconvulsive or partial seizures, during the Initial Phase. The results of Experiment 3 revealed that the facilitation of seizure development from the septal area observed in rats previously exposed to alternating stimulation, which perhaps is attributable to partial kindling from the suppressed site, was site specific. Rats subjected to alternating stimulation of the left amygdala and right septal area and control rats previously stimulated only in the left amygdala subsequently demonstrated generalized seizures following similar numbers of stimulations of the previously unstimulated right amygdala. Another plausible view is that antagonism reflects a long-lasting (> 30 d) form of inhibition that is perhaps uniquely invoked by alternating stimulation, While the results of Experiments 1 - 3 do not rule out this possibility, the results of Experiment 4 clearly indicate that the persistence of any such effects of alternating stimulation is not mediated by continuing influences of the dominant site: After the establishment of antagonism, radio-frequency lesions of the dominant site (amygdala) failed to alter the development of seizures provoked by stimulation of the suppressed site (septal area). / Graduate

The function of a neural network is dependent on more than the static patterns of connections between neurons. For example, in response to time-varying stimuli in the environment, sensory neurons are activated in specific temporal patterns. Thus, to extract relevant information the neurons of a neural network must have the appropriate temporal properties. We have studied the dynamic properties of the synapses and of action potential generation in the cricket cercal system, a system that detects low-frequency air disturbances. First, we show that the electrotonic properties of the interneurons in the cricket cercal sensory system are preserved during postembyronic development, thereby maintaining their frequency filtering properties. Also, we found that the frequency of the spikes in the interneurons is linearly related to the level of injected current and that the interneurons show very little spike adaptation. Last, we combine a biophysical model of the spiking mechanism of an interneuron with the known temporal dynamics of the synaptic input in a computer simulation. We found that the rate of synaptic depression, a function of the fractional release rate of the sensory neuron synapses, is the most important factor in determining the temporal response of the interneurons to sound stimuli. In contrast, synaptic facilitation had a relatively weak effect on the temporal properties of the interneurons.