Effects of dorsal hippocampal damage on conditioning and conditioned‐response timing: A pooled analysis

Abstract

Charlotte (2015) Effects of dorsal hippocampal damage on conditioning and conditioned-response timing: a pooled analysis. Hippocampus, 25 (4 A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractBehavioral findings suggest that the dorsal hippocampus (DHPC) plays a role in timing of appetitive conditioned responding. The present article explored the relationship between the extent of DHPC damage and timing ability, in a pooled analysis of three published studies from our laboratory. Initial analyses of variance confirmed our previous reports that DHPC damage reduced peak times (a measure of timing accuracy). However, the spread (a measure of timing precision) was unchanged, such that the coefficient of variation (spread / peak time) was significantly larger in DHPC-lesioned animals. This implies that, in addition to the wellestablished effect of DHPC lesions on timing accuracy, DHPC damage also produced a deficit in precision of timing. To complement this analysis, different generalized linear mixed-effects models (GLMMs) were performed on the combined dataset, to examine which combinations of the different behavioral measures of timing were the best predictors of the degree of hippocampal damage. The results from the GLMM analysis suggested that the greater the DHPC damage, the greater the absolute difference between the observed peak time and reinforced duration. Nevertheless, this systematic relationship between damage and performance was not specific to the temporal domain: paradoxically the greater the damage the greater the magnitude of peak responding. We discuss these lesion effects in terms of scalar timing theory.3

Ventral hippocampal neurons inhibit postprandial energy intake

“…Inactivation of dHC and vHC neurons could also increase intake through additional mechanisms that are not necessarily mutually exclusive. For instance, inactivation of dHC neurons could also influence meal timing by interfering with the ability to track the amount of time that has elapsed since the last meal (Itskov et al, ; MacDonald et al, ; Tam and Bonardi, , b; Tam et al, ). dHC and vHC inactivation could also interfere with satiety signaling.…”

“…could also influence meal timing by interfering with the ability to track the amount of time that has elapsed since the last meal (Itskov et al, 2011;MacDonald et al, 2011;Bonardi, 2012a, 2012b;Tam et al, 2015). dHC and vHC inactivation could also interfere with satiety signaling.…”

Episodic future thinking: mechanisms and functions

“…These observations have been supported by some evidence from patients with hippocampal damage (77) or atrophy following Alzheimer’s disease (76) showing that temporal discounting is not attenuated by situations requiring episodic future thinking in these populations (see also [78] for similar findings in healthy older adults). However, another study of amnesic patients (79) provided seemingly contradictory results, i.e., patients showed attentuation of temporal discounting in a situation also thought to induce episodic future thinking. This outcome may have occurred because in the latter study (79), amnesics could have benefited from mere semantic (rather than episodic) future thinking (see also 80).…”

“…However, another study of amnesic patients (79) provided seemingly contradictory results, i.e., patients showed attentuation of temporal discounting in a situation also thought to induce episodic future thinking. This outcome may have occurred because in the latter study (79), amnesics could have benefited from mere semantic (rather than episodic) future thinking (see also 80). Consistent with this interpretation, recent fMRI evidence indicates that the role of the hippocampus may be less pronounced when people imagine familiar personal scenarios, i.e., in cases where they can draw on prior semantic knowledge (81).…”

Procedural Performance Benefits after Excitotoxic Hippocampal Lesions in the Rat Sequential Reaction Time Task

“…While the dorsal hippocampus has been associated preferentially with spatial and relational learning (Fanselow and Dong 2010), as well as timing processes (Tam et al 2015), the ventral hippocampal connections to amygdala, prefrontal cortex, and nucleus accumbens (Kelley and Domesick 1982;Verwer et al 1997;Pitkänen et al 2000) are probably responsible for influencing and facilitating sensorimotor processes (Bast and Feldon 2003), as well as fear conditioning Zhang et al 2001). It can therefore be assumed that inactivation of the dorsal hippocampus may primarily change behaviour that relies strongly on sensory input and procedures that are part of the processing of contextual information in a given learning task, as well as behaviour that is sensitive to temporal aspects of learning and performance (e.g.…”