: 3326 --3339, 1997. HASSELMO,M.E.AND SCHNELL, E. Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: computational modeling and brain slice physiology. J. Neurosci. 14: 3898 --3914,  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... sequence prediction, priming or playback of the subsequent event according to the functional mode of the system (i.e. learning, recognition or reenactment of a sequence) The transition from a functional mode to the next is endogenously determined by the type of neuromodulation (ACh in particular; Hasselmo et al. 1994) and the biological rhythms. For the purpose of linking a specific behavior to a particular view of the environment, as in a PerAc (Perception Action) architecture (Gaussier Zrehen, 1995) linking of these transitional states to elementary motor actions has been found to better support the ....

....maintained in DG and reaching CA3 by the mossy fibers is matched with the present pattern of activation forwarded by the direct connections from EC to CA3 pyramides distal dendrites. Therefore, the learning process is modulated according to the degree of predictedness or novelty of the events. Hasselmo et al. 1994) has shown how ACh septal modulation of the Hs activity could provide for an automatic control of the learning process, as a function of novelty or familiarity of the events. One can suppose that a match inducing familiarity preempts the learning of a new transition and sequence. The resulting ....

Hasselmo, M.E., Scnell, E., (1994). Laminar Selectivity of the Cholinergic Suppression of Synaptic Transmission in Rat Hippocampal Region CA1: Computational Modeling and Brain Slice Physiology, The Journal of Neuroscience, 14(6), 3898-3914.

....information consists of allocentric direction and distance data for obstacles in the environment [4] Organisation is important as it ensures that any overlap between input vectors is meaningful. The neural network (described in more detail below) is similar to that described by Hasselmo et al. [11, 12]. An important additional feature of the presented model is a parameter which can a ect both robot behaviour and also information processing within the network [10] This parameter simulates na and is closely dependent upon a measure of anxiety. 2.1 The hippocampus network architecture The ....

....which squares in its representation the regions are in (shaded squares) and sets the corresponding values to 1. All other values remain set to 0. Translation of the representation into an input vector starts at the top left and ends bottom right. has been described in detail by Hasselmo et al. [11, 12] and will be brie y mentioned here. 2.2 Anxiety Generalised anxiety disorder (gad) has been de ned as abnormally high anxiety [2] and as dependent on hippocampal hyperactivity [16] To date, no computational mechanism has been proposed which accounts for gad. However, increased anxiety, increased ....

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M.E. Hasselmo and E. Schnell. Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region ca1: Computational modeling and brain slice physiology. J Neurosci, 14:3898{ 3914, 1994.

....transmission during learning to allow simultaneous self organization and association between two regions. Previous experiments show that the neuromodulator acetylcholine selectively suppresses synaptic transmission within the olfactory cortex (Hasselmo and Bower, 1992; 1993) and hippocampus (Hasselmo and Schnell, 1994). If the model is valid for neocortical structures, cholinergic suppression should be stronger for feedback but not feedforward synapses. Here we review experimental data (Hasselmo and Cekic, 1996) comparing cholinergic suppression of synaptic transmission in layers with predominantly feedforward ....

....transmission may allow combination of associative feedback and self organizing feedforward connections in the neocortex. Behav. Brain Res. in press. Hasselmo M.E. Anderson B.P. and Bower J.M. 1992) Cholinergic modulation of cortical associative memory function. J. Neurophysiol. 67: 1230 1246. Hasselmo M.E. and Schnell, E. 1994) Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: Computational modeling and brain slice physiology. J. Neurosci. 15: 3898 3914. Hecht Nielsen, R. 1987) Counterpropagation networks. Applied Optics 26: 4979 4984. Li, H. and Cauller, L.J. ....

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Hasselmo ME, Schnell E (1994) Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: Computational modeling and brain slice physiology. J. Neurosci. 14: 3898-3914.

.... McClelland, McNaughton, O Reilly, 1995) However, no models of hippocampal function in specific memory tasks exist; all published models of declarative memory demonstrate storage and retrieval of arbitrary binary vectors (Marr, 1971; Rolls, 1989; Gluck Myers, 1993; Alvarez Squire, 1994; Hasselmo Schnell, 1994; O Reilly McClelland, 1994; Levy, 1996; Rolls, 1996) Although these theories can address general principles involved in memory, they cannot address the role of the hippocampus in specific tasks. This makes it difficult to compare their results to real experiments or to generate testable ....

.... extensively in the recurrent connections in CA3 and in the Schaffer collaterals connecting CA3 to CA1 (see Landfield Deadwyler, 1988) Also supporting this theory are data showing the effect of ACh: while suppressing neuronal transmission in intrahippocampal synapses, ACh enhances LTP in them (Hasselmo Schnell, 1994). We make the simplifying assumption that ACh shuts off the CA3 recurrent connections completely. Experiments in hippocampal slices show that it diminishes synaptic efficacy across the Schaffer collaterals by approximately 90 percent, while diminishing the efficacy of the perforant path (inputs ....

[Article contains additional citation context not shown here]

Hasselmo, M. E., & Schnell, E. (1994). Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: Com- The Role of the Hippocampus 107 putational modeling and brain slice physiology. Journal of Neuroscience, 14(6), 3898--3914.

No context found.

: 3326 --3339, 1997. HASSELMO,M.E.AND SCHNELL, E. Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: computational modeling and brain slice physiology. J. Neurosci. 14: 3898 --3914,

No context found.

Hasselmo, M.E. and Schnell, E. (1994) Laminar selectivity of the cholinergic suppression of synaptic transmission in rat hippocampal region CA1: computational modeling and brain slice physiology J. Neurosci. 14, 3898--3914

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