[Abstract Title]. - Society for Neuroscience

cholinergic input to neocortex in cortical plasticity and remodelling, rather than a specific role in
certain brain functions such as episodic memory.
Disclosures: P.L. Croxson , None; P.G.F. Browning, None; D. Gaffan, None; M.G. Baxter,
None.
Poster
292. Acetylcholine, Neurotrophins, and Cognition
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 292.8/SS21
Topic: F.02.d. Cognitive learning and memory systems
Support: Medical Research Council UK
Christopher Welch Trust
Title: A novel method for infrared eyetracking of macaque monkeys without head fixation is
behaviourally confirmed by demonstrating degraded transfer of memories between the visual
hemifields in normal macaques
Authors: *C. R. WILSON, M. J. BUCKLEY, D. GAFFAN;
Exptl. Psychology, Univ. of Oxford, Oxford, United Kingdom
Abstract: Investigations of the effects of unilateral lesions in the human brain often show
lateralized effects in the contra-lesional hemifield (e.g. Hornak et al., 1997; Vuilleumier et al.,
2007). To understand the mechanisms involved experiments in macaque monkeys may be used
to test specific hypotheses, because circumscribed and experimentally produced lesions can be
made in monkeys. However, existing methods for measuring the direction of gaze in the monkey
require the surgical implantation of a head post for head restraint, and often the implantation of
scleral search coils. The presence of a head post, however, impedes surgical access to the brain,
and ideally, in a lesion experiment with monkeys, one should measure the pre-operative ability
of each animal in the task of interest before making any lesion. Here we present a novel method
for measuring gaze direction which allows us to present visual stimuli at known positions in the
visual field in normal monkeys with no head post or other surgical preparation. The method
provides online measurements in real time, thus allowing stimuli to be presented in known
positions in the visual field.
In order to provide a behavioural validation of this method, we replicated in monkeys a recent
finding in normal human subjects (Hornak et al., 2002). Normal human subjects show degraded
recognition memory for visual objects when the objects are presented for memorization in one