The effects of developmental alcohol exposure on the neurobiology of spatial processing.

The consumption of alcohol during gestation is detrimental to the developing central nervous system. One functional outcome of this exposure is impaired spatial processing, defined as sensing and integrating information pertaining to spatial navigation and spatial memory. The hippocampus, entorhinal cortex, and anterior thalamus are brain regions implicated in spatial processing and are highly susceptible to the effects of developmental alcohol exposure. Some of the observed effects of alcohol on spatial processing may be attributed to changes at the synaptic to circuit level. In this review, we first describe the impact of developmental alcohol exposure on spatial behavior followed by a summary of the development of brain areas involved in spatial processing. We then provide an examination of the consequences of prenatal and early postnatal alcohol exposure in rodents on hippocampal, anterior thalamus, and entorhinal cortex-dependent spatial processing from the cellular to behavioral level. We conclude by highlighting several unanswered questions which may provide a framework for future investigation.

Human place learning in a virtual Morris water task: some important constraints on the flexibility of place navigation.

We investigated human place learning in a computerized version of the Morris water task (VMWT) under comparable conditions to those employed by Sutherland et al. (Sutherland et al. Psychobiology, 1987;15:48-57) with rats. Participants viewed a computer-generated environment and were trained to locate a hidden goal in one half of a circular pool (region 1). The opportunity to navigate in and view cues from region 2 was systematically varied during training. Participants were then started from region 2 to assess transfer. Accurate transfer performance was dependent upon prior experience viewing distal cues from region 2 while on a trajectory to the goal, a finding we interpret as inconsistent with the automatic formation and modification of a cognitive map (O'Keefe J, Nadel L. The Hippocampus as a cognitive map. Oxford, UK: Clarendon Press, 1978). Additionally, the transfer data reported here closely match the data obtained by Sutherland et al. with rats suggesting some generality in the principles involved in place learning.