Thesis (Ph. D.)--University of Chicago, 1912. / Includes bibliographical references (p. [27]-29). Also available on the Internet. Also issued online.

Thesis (Ph. D.)--University of Chicago, 1919. / Descriptive letterpress on versos facing the plates. "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Author's abstract of this paper issued by the [Wistar institute] Bibliographic service, January 16." "Reprinted from the Journal of comparative neurology, Vol. 34, No. 1, February, 1922." "Literature cited": p. 58-60.

A larqe body of evidence supports the conclusion that mesolimbic dopaminerqic neurons, in particular those that innervate the nucleus accumbens (n.ACC), are important for the expression of d-amphetamine stimulated locomotor behavior (ASLB) . However, one recent study has contradicted this conclusion, reporting that bilateral lesions of the n.ACC fail to block ASLB. It appears that this study contains a methodoloqical flaw in that it employed a qeneral measure of activity which did not distinquish between locomotion and rcaring. In the present study, we used observer ratinqs of videotaped responses to determine the seperate effects of 2.0 mq/kq d-amphetamine on locomotion and rearinq in rats with either sham or radio-frequency lesions of the n.ACC. It was found that n.ACC lesiongs blocked the locomotor stimulation, but not the increased rearinq, which follows d-amphetamine administration. Additionally, the time spent engaging in stereotyped behaviors followinq administration of a hiqh dose of the donamine agonist apomorphine was not affected by the lesion. These results support the general conclusion that dooaminemic terminals in the n.ACC are important for the expression of ASLB, and further suggest that d-amnhetamine-stimulated locomotion and rearing are mediated throuoh different neural suibstrates.

Note:

Autor Markéta Popelová Název práce Software tool for modelling coding and processing of information in auditory cortex of mice Abstrakt Porozumění zpracovávání a kódování informací ve sluchové k·ře (AC) je stále ne- dostatečné. Z několika r·zných d·vod· by bylo užitečné mít výpočetní model AC, například z d·vodu vysvětlení, či ujasnění procesu kódování informací v AC. Prv- ním cílem této práce bylo vytvořit softwarový nástroj (simulátor SUSNOMAC), zaměřený na modelování AC. Druhým cílem bylo navrhnout výpočetní model AC s následujícími vlastnostmi: Izhikevich·v model neuronu, dlouhodobá plasticita ve formě Spike-timing-dependent plasticity (STDP), šestivrstvá architektura, pa- rametrizované typy neuron·, hustota neuron· a pravděpodobnost vzniku synapsí. Navržený model byl testován v desítkách experiment·, s r·znými sadami para- metr· a v r·zných velikostech (až 100 000 neuron· s takřka 21 milióny synapsí). Experimenty byly analyzovány a jejich výsledky srovnány s pozorováním skutečné AC. V práci popisujeme a analyzujeme několik zajímavých pozorování o aktivitě modelované sítě a vzniku tonotopického uspořádání AC. 1

Neurons are characterized by an electric potential which is established between their inside and outside media. They exhibit specific voltage fluctuations, in response to strong enough current impulses, called action potentials. In this work, a bang-bang controlled bilinear system (BLS) is derived to approximate the generation of a simple neuron's action potential. The shape of the response, as well as the timing seem to be useful for experimental planning and interpretation to neural physiologists. The BLS-model has the potential to aid the design and fabrication of commercial neural networks for communication, control and computing. In this manner, a variable-structure membrane impedance, such as exhibited by a stable focus and a saddle point in state space, and/or other modes, arises naturally. Added positive and negative stimuli, such as from other neurons, have the capability to alter the voltage across the inside and the outside media of the neuron and elicit an advanced or delayed response in the action potential. Such latency is significant as noted above, and is an active area of experimental research. The response shape and the timing with respect to some other event(latency} are related to experimental data. This simple model is compared to the complex and highly celebrated Hodgkin-Huxley model for the squid giant axon. The bang-bang feedback control is given a biological interpretation of sodium and potassium ion channels in this axon, that yields a variable-structure membrane impedance. / Graduation date: 2000

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Anatomy / Master / Master of Medical Sciences

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy