Attention, configuration, and hippocampal function

Selective hippocampal lesions disrupt a novel cue effect but fail to eliminate blocking in rabbit eyeblink conditioning

“…This f inding fits with theories that propose that the hippocampus is involved in the detection of novel cues during training (Gluck & Myers, 1993;Vinogradova, 2001). This finding does not support the predictions of others (e.g., Buhusi & Schmajuk, 1996) who have proposed that novelty was not a hippocampal-dependent task but was dependent on the nucleus accumbens.…”

“…This matching of stimuli to stored representations and the subsequent encoding of complex stimulus fits with the role of the hippocampus in classical conditioning as hypothesized in models and theories of the hippocampus (Bunsey & Eichenbaum, 1993;Gluck & Myers, 1993;Vinogradova, 2001). An alternate theory is that novelty detection does not take place in the hippocampus but takes place in the nucleus accumbens (Buhusi & Schmajuk, 1996).…”

Segregated Populations of Hippocampal Principal CA1 Neurons Mediating Conditioning and Extinction of Contextual Fear

“…Accordingly, mice acquired conditioned fear normally but showed resistance to extinction. These findings provide strong molecular and cellular support for the comparator theory (Buhusi and Schmajuk, 1996; Gray and McNaughton, 2000; Vinogradova, 2001) proposing that the hippocampal responses to mismatch between anticipated and delivered reinforcement provided by septal and cortical inputs, respectively, is critical for extinction of conditioned responses. Interestingly, the septal cholinergic input facilitates somatic but depresses dendritic field potentials of hippocampal pyramidal neurons (Rovira et al, 1982).…”

“…Two key inputs from the entorhinal cortex and medial septum (Wheal and Miller, 1980) are thought to provide the hippocampus with signals on actual and predicted events, respectively (Buhusi and Schmajuk, 1996; Gray and Mc-Naughton, 2000; Vinogradova, 2001). Because the latter signals have been selectively implicated in extinction of conditioned responses (Gray and McNaughton, 2000), we hypothesized that elimination of hippocampal cholinergic input from the medial septum would be critical for pErk upregulation and fear extinction.…”

A Heteroassociative Learning Model Robust to Interference

“…When an association is learned between a high dimensional data space and a smaller space representing labels (valences in the present case), one central problem is about the association of close patterns with different labels or of different combinations of patterns with different labels. This classical problem has been termed configural learning (Buhusi and Schmajuk, 1996). Based on biological data and also benefiting from the separation between exteroceptive and interoceptive data, we have proposed in the present model a mechanism able to automatically detect such interference at the heteroassociative level and to trigger new learning accordingly.…”