Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657194
Title: Development of the thalamocortical system
Author: Magowan, G.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1996
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Abstract:
Three different culture techniques are exploited in this thesis to investigate thalamocortical development: (i) co-cultures of organotypic explants on a collagen substrate (organotypic cultures have the advantage of maintaining in vivo connectivity in culture). (ii) Isolated cultures of embryonic thalamus on a collagen substrate (enables the independent growth and survival of the thalamus to be monitored). (iii) Dissociated cultures of thalamus combined with time-lapse microscopy (enables the growth of individual thalamic neurones to be monitored). These experiments yielded the following results. (i) Neurotransmitters may be involved in regulating thalamic outgrowth and survival but do not appear to play a crucial role in target selection. A wide range of neurotransmitter antagonists failed to block the ability of E15 thalamic axons to recognise their target cells in cortical layer 4, although several of these antagonists inhibited thalamic outgrowth. (ii) An optimal level of activity appears crucial for generating appropriate signals for thalamic ingrowth and termination within layer 4. (iii) The survival and growth of the late embryonic thalamus can occur without external influences, and this intrinsic control may use an autocrine mechanism that becomes increasingly reliant on neural activity for its maintenance as it ages. After birth this intrinsic control becomes ineffective. (iii) Glutamate can increase survival of the embryonic thalamus in a dose dependent manner although by E19 it has no effect. (iv) Both the NMDA and Kainate/AMPA receptor subtypes appear to be involved in mediating glutamate induced cell survival. (v) Nitric Oxide (NO), a novel neurotransmitter, is present in both the developing thalamus and cortex in vivo and is also expressed within the thalamocortical tracts which connect these two structures. (vi) Growth cones of dissociated embryonic thalamic neurones are also responsive to added NO in vitro providing strong evidence that NO is involved in regulating thalamocortical development.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.657194  DOI: Not available
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