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QUOTE from Morris, R. G. M. (2001). Episodic-like memory in animals: psychological criteria, neural mechanisms and the value of episodic-like tasks to investigate animal models of neurodegenerative disease. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 356(1413), 1453-1465.
“the view taken here is that the hippocampus is a system for the automatic recording of attended experience that enables the encoding, storage and private recollection of experience in a form that would be advantageous to an animal but cannot yet be communicated to another.” (p. 1463)
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Clayton, NS, Dickinson, A (1999) Memory for the content of caches by scrub jays (Aphelocoma coerulescens). Journal of Experimental Psychology-Animal Behavior Processes, Vol.25, No.1, Pp.82-91.
To test whether scrub jays (Aphelocoma coerulescens) remember the contents of food caches, in Experiment 1 birds cached peanuts and kibbles in two distinct caching trays and recovered them 4 or 172 hr later. The relative incentive value of the foods was manipulated by prefeeding one of the foods immediately before cache recovery. Birds preferentially searched for non-prefed food caches even when the caches had been pilfered prior to the recovery test. In Experiment 2, birds cached both foods in different sites within each tray, recovering peanuts from one tray and kibbles from the other tray 3 hr later. After prefeeding with one food, birds preferentially searched tray sites in which they had cached but not retrieved the non-prefed food. Thus jays remember the specific foods they cache and recover by a mnemonic process that cannot be explained in terms of simple associations between the foods and their cache locations.
Fortin, N. J., Agster, K. L., & Eichenbaum, H. B. (2002). Critical role of the hippocampus in memory for sequences of events. Nature Neuroscience, 5(5), 458-462.
Recent models of hippocampal function emphasize the potential role of this brain structure in encoding and retrieving sequences of events that compose episodic memories. Here we show that hippocampal lesions produce a severe and selective impairment in the capacity of rats to remember the sequential ordering of a series of odors, despite an intact capacity to recognize odors that recently occurred. These findings support the hypothesis that hippocampal networks mediate associations between sequential events that constitute elements of an episodic memory.
Healy, S. D., de Kort, S. R., & Clayton, N. S. (2005). The hippocampus, spatial memory and food hoarding: a puzzle revisited. Trends in Ecology & Evolution, 20(1), 17-22.
Behavioural ecology assumes that cognitive traits and their underlying neural substrates are shaped by natural selection in much the same way as morphological traits are, resulting in adaptation to the natural environment of the species concerned. Recently, however, the 'neuroecology' approach of attempting to gain insight into brain structure and function by testing predictions about variation in brain structure based on knowledge of the lifestyle of the animal has been criticized on the grounds that such an adaptationist view cannot provide insight into the underlying mechanisms. Furthermore, the criticism has focussed on attempts to use variation in demand for spatial memory and in hippocampal size as a basis for predicting variation in cognitive abilities. Here, we revisit this critique against the field of so- called 'neuroecology' and argue that using knowledge of the natural history of animals has lead to a better understanding of the interspecific variation in spatial abilities and hippocampal size, and to the generation of novel hypotheses and predictions.
Kandel, E. R. (2001). Neuroscience - The molecular biology of memory storage: A dialogue between genes and synapses. Science, 294(5544), 1030-1038.
One of the most remarkable aspects of an animal's behavior is the ability to modify that behavior by learning, an ability that reaches its highest form in human beings. For me, learning and memory have proven to be endlessly fascinating mental processes because they address one of the fundamental features of human activity: our ability to acquire new ideas from experience and to retain these ideas over time in memory. Moreover, unlike other mental processes such as thought, language, and consciousness, learning seemed from the outset to be readily accessible to cellular and molecular analysis. I, therefore, have been curious to know: What changes in the brain when we learn? And, once something is learned, how is that information retained in the brain? I have tried to address these questions through a reductionist approach that would allow me to investigate elementary forms of learning and memory at a cellular molecular level-as specific molecular activities within identified nerve cells.
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McKenna, P., & Gerhand, S. (2002). Preserved semantic learning in an amnesic patient. Cortex, 38(1), 37- 58.
A case study is reported of an amnesic patient (KN), who displayed an ability to learn a substantial body of new visual and verbal semantic concepts, despite having a severe deficit in episodic memory. In two experiments, using an errorless learning paradigm, he was able to perform at a level close to that of his wife, who served as a control subject. When recall of material was retested after a delay of several months, during which time there were no further learning sessions, his retention was at least as good as, if not better, than that of his wife. This is taken as further evidence for the dissociation of semantic and episodic processes in amnesia. It also provides further evidence for the role of "errorless learning" in efficient acquisition of new facts in amnesia.
Examples of new learning —
i. name pictures e.g. purple hairstreak=butterfly, oak woodland, light grey underside;
ii. word definitions: carmagnole=dance; dayan=senior rabbi; hebetic, virement, eland, cadera=crater
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Morimura, N., & Matsuzawa, T. (2001). Memory of movies by chimpanzees (Pan troglodytes). Journal of Comparative Psychology, 115(2), 152-158.
How do animals remember what they see in daily life? The processes involved in remembering such visual information may be similar to those used in interpreting moving images on a monitor. In Experiment 1, 4 adult chimpanzees (Pan troglodytes) were required to discriminate between movies using a movie-to- movie matching-to-sample task. All chimpanzees demonstrated the ability to discriminate movies from the very 1st session onward. In Experiment 2, the ability to retain a movie was investigated through a matching-to-sample task using movie stills. To test which characteristics of movies are relevant to memory, the authors compared 2 conditions. In the continuous condition, the scenes comprising the movie progressed gradually, whereas in the discrete condition, the authors introduced a sudden change from one scene to another. Chimpanzees showed a recency effect only in the discrete condition, suggesting that composition and temporal order of scenes were used to remember the movies.
Ekstrom, A. D., Kahana, M. J., Caplan, J. B., Fields, T. A., Isham, E. A., Newman, E. L., & Fried, I. (2003). Cellular networks underlying human spatial navigation. Nature, 425(6954), 184-187.
Place cells of the rodent hippocampus constitute one of the most
striking examples of a correlation between neuronal activity and
complex behaviour in mammals. These cells increase their
firing rates when the animal traverses specific regions of its
surroundings, providing a context-dependent map of the
environment. Neuroimaging studies implicate the hippocampus
and the parahippocampal region in human navigation. However,
these regions also respond selectively to visual stimuli.
It thus remains unclear whether rodent place coding has a
homologue in humans or whether human navigation is driven by a
different, visually based neural mechanism. We directly recorded
from 317 neurons in the human medial temporal and frontal lobes
while subjects explored and navigated a virtual town. Here we
present evidence for a neural code of human spatial navigation
based on cells that respond at specific spatial locations and
cells that respond to views of landmarks. The former are present
primarily in the hippocampus, and the latter in the
parahippocampal region. Cells throughout the frontal and temporal
lobes responded to the subjects' navigational goals and to
conjunctions of place, goal and view.
Shors, T. J., Miesegaes, G., Beylin, A., Zhao, M. R., Rydel, T., & Gould, E. (2001). Neurogenesis in the adult is involved in the formation of trace memories. Nature, 410(6826), 372-376.
The vertebrate brain continues to produce new neurons throughout life(1-12). In the rat hippocampus, several thousand are produced each day, many of which die within weeks(13). Associative learning can enhance their survival(13,14); however, until now it was unknown whether new neurons are involved in memory formation. Here we show that a substantial reduction in the number of newly generated neurons in the adult rat impairs hippocampal-dependent trace conditioning, a task in which an animal must associate stimuli that are separated in time(15). A similar reduction did not affect learning when the same stimuli are not separated in time, a task that is hippocampal-independent(16,17). The reduction in neurogenesis did not induce death of mature hippocampal neurons or permanently alter neurophysiological properties of the CA1 region, such as long-term potentiation. Moreover, recovery of cell production was associated with the ability to acquire trace memories. These results indicate that newly generated neurons in the adult are not only affected by the formation of a hippocampal-dependent memory(13), but also participate in it.