Book of abstracts - British Neuroscience Association

56.06
Dissecting exploratory behaviour: Cue-based searching
strategies during Morris water maze acquisition.
Harvey D, Commins S
Department of Psychology,, National University of Ireland,, Maynooth,,
Co. Kildare,, Ireland.
The Morris water maze (MWM) was described over 25 years ago as a
simple and effective paradigm for examining spatial learning and
memory in laboratory animals. Since then, many elaborate studies
spanning several areas of neuroscience have employed this
straightforward task, showing its wide versatility and ease of
adaptation to many protocols. However, despite innumerable findings
since its introduction, the precise intricacies on how rodents acquire
information regarding the hidden platforms location remain
ambiguous. Often, overarching navigational strategies are reported
when documenting rodent performance in the pool. These include
those termed egocentric (defining the relation of an object, goal, or
location relative to the subject) or allocentric (defining the relation of
an object, goal, or location relative to another location, where this
object is independent of the subject). Indeed previous research has
strongly publicised the use of allocentric processes in solving the
MWM; particularly through the use of visual distal cues in forming
spatial relations with the platforms location. The current study
demonstrates how animals interact with these external visual cues
during acquisition of the task. It is shown that the use of several
identified swimming strategies, strongly associated with the cues, in
combination with initial view-matching and egocentric guidance,
ultimately allows animals infer the hidden platforms’ location (via
allocentric extrapolation) with training. Furthermore, hippocampal
BDNF expression is also shown to closely correlate with this
acquisition, elucidating its role in learning.
56.07
Neural correlates of source memory in young and old humans are
revealed by a high-density erps array.
Scanlon P, Commins S, Roche R
National University of Ireland, Maynooth, Maynooth, Co. Kildare, Ireland.
Failures of source memory (the ability to recall the specific context in which
events took place) have been associated with cognitive decline in the
elderly. Source memory deficits appear to be more indicative of age-related
memory impairment than disruption of item memory. An Opposition
Procedure developed by Jacoby and colleagues (Jennings and Jacoby,
1997) tests this source memory capacity by drawing on repetition errors in
a word recall task in which novel words are presented repeatedly at 3
differing lags (0, 4 and 16 trials). This task is sensitive to source memory
dysfunction, with older adults being found to produce significantly more
errors in repetition than healthy younger adults. In this study we recorded
128-channel EEG from normal healthy participants (N=10) (age 20-30) and
healthy older adults (N=10) (aged 60-70) while they executed the
Opposition Task. Behavioural results showed that accuracy decreased
significantly (p