this paper is to present such a reformulation. The cell assembly provides the cognitive system with flexibility far beyond the simple activation of concepts. Instead of viewing the assembly as simply active or latent we see the activation of the assembly as coming in a series of phases. Each phase of activity serves a different purpose, giving the theory the power and flexibility to handle a wide range of psychological data.

In recall tasks, increased levels of arousal soon after presentation time leads to short-term performance that is contradictory to standard memory models. Despite the fact that long-term recall is excellent in such situations, short-term recall is poor, worse than in the long-term case. This article presents a model, based upon Hebb's cell assembly construct, to account for this puzzling data.

Prof. Dr. Josef KesslerTo AnnaBecause memory and sensations are so uncertain, so biased, we always rely on a certain reality – call it alternate reality – to prove the reality of events. To what extent facts we recognize as such really are as they seem, and to what extent these are facts merely because we label them as such, is an impossible distinction to draw. Therefore, in order to pin down reality as reality, we need another reality to relativize the first. Yet that other reality requires a third reality to serve as its grounding. An endless chain is created within our consciousness, and it is the maintenance of this chain which produces the sensation that we are actually here, that we ourselves exist. But something can happen to sever that chain and we are at a loss. What is real? Is reality on this side of the break in the chain? Or over there, on the other side? Haruki Murakami: South of the Border, West of the Sun translated by Philip Gabriel (Vintage, London) Acknowledgements I wish to express my sincere gratitude to the confiding and unhesitant cooperation of the participating patients and their relatives and friends. This work would have failed without their loyal collaboration during and far beyond the test sessions, and neuroscientific patient work

Abstract. A typical human brain consists of roughly 100 billion neurons, and one key aim of Biological Cybernetics is to simulate neural systems. A good model of a neuron accurately represents the behaviour of biological neurons, typically the spiking behaviour. For cybernetic systems that aim to function in real time with thousands, millions, or even billions of simulated neurons, it is also important that the model is computationally efficient. One Fatiguing Leaky Integrate and Fire neuron is a model that has four free parameters per neuron. This model has been used in cybernetic agents, but there have been few links to actual biological behaviour. A model of a rat neocortical neuron is developed with four specific parameter settings. This model is tuned to a particular input regime. When compared to a biological neuron it gets 90 % of spikes roughly correct. Further modifications of the fatigue model enables the FLIF neuron to account for spontaneous neural firing, a known neural property, that is not present in the data. These modifications provide other FLIF models with a similar fit to the biological data. The best of these models correctly predicts over 94 % of the spikes.

An emotional memory advantage has been found across the life span where recall is better for emotional (as opposed to neutral) stimuli. Our goal was to design emotionally valent word lists for easy use by practitioners and to test whether demented and healthy elderly participants showed an emotional memory advantage with these lists. Three new word lists (a positive, a negative, and a neutral list) were constructed. Thirty-eight controls, 37 with mild cognitive impairment and 20 Alzheimer’s dementia participants ’ free recall was tested. Unsurprisingly, controls had better recall overall. Emotionally valent words were recalled better in comparison to neutral words in all 3 groups. No recall advantage for positive versus negative words emerged. Learning differed among the groups with the Alzheimer’s dementia participants showing flatter learning curves. The results tentatively suggest that emotional memory may stay intact longer but that learning of such lists becomes more difficult as dementia progresses.