The pharmacological disruption of memory by various
protein synthesis inhibitory drugs (PSIs) has implicated
protein synthesis as a requirement for long term learning
but not for short. However, evidence derived from PSI
research remains equivocal, with the apparent amnesic
effects of PSIs being attributed to drug side-effects and
general behavioural debilitations.
Research reported in this thesis investigates the
behavioural effects on short and long term habituation of
the dorsal antennae withdrawal reflex in the snail (Helix
aspersa) of three antibiotic drugs known to reversibly
inhibit protein synthesis; anisomycin, actinomycin D, and
puromycin. Initially, habituation was established as true
learning in the snail and was demonstrated to be capable of
retention for over 24 hours from one training session and
over 6 months from a series of training sessions. The
parametric characteristics of both short and long term
habituation in the snail was established and found to be
identical to those demonstrated in vertebrate habituation.
Such characteristics were found to be different for short
and long term habituation. Injection of PSIs showed no
effect on short term habituation but disrupted long term
habituation if PSI was active within a 'critical time
window' during or for approximately 40 minutes after
training. Later injections had no amnesic effect, and
neither did injections 2 hours prior to training. The
amnesic effects were demonstrated not to be attributable to
drug side-effects by the development and application of a
'behavioural test battery' to screen general snail behaviour
for drug induced debilitations at a variety of doses.
Dose/amnesic effect relationships are also reported.
Potentially confounding effects, such as, state dependent
learning, and drug performance effects, were controlled out.
The effects of the PSIs on short and long term habituation
are then reported in terms of their effects on the
established short and long term parametric characteristics
of the learning. Drug injected snails showed normal short
term parametric characteristics in training. However, in a
long term retest drug treated snails also showed the
parametric characteristics of short term habituation which
demonstrated the degree of induced amnesia.
The results are discussed in terms of a gene expression
model of long term habituation and suggest that short and
long term habituation are mediated by different processes.
Short term habituation is protein synthesis independent and
long term habituation is protein synthesis dependent.
Date of Award | 1988 |
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Original language | English |
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Awarding Institution | |
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PROTEIN SYNTHESIS INHIBITION AND SHORT AND LONG TERM HABITUATION OF THE DORSAL ANTENNAE WITHDRAWAL RESPONSE IN HELIX ASPERSA
RAY, S. (Author). 1988
Student thesis: PhD