The role of the hippocampus in approach-avoidance conflict decision-making: Evidence from rodent and human studies

Ito, Rutsuko; Lee, Andy

doi:10.1016/j.bbr.2016.07.039

Cited by 136 publications

(112 citation statements)

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“…Interestingly, in our dataset, hippocampal responses are only seen when a token appeared to create behavioral conflict, but not at the trial start when all features of the situation were already signaled. This may indicate that the hippocampus is specifically involved in monitoring behavioral conflict, including a retrieval of threat memory (Oehrn et al, 2015; Ito and Lee, 2016). …”

Section: Discussionmentioning

confidence: 99%

“…However, as a limitation to this distinction, a role of the anterior cingulate rather than hippocampus has also been highlighted in an approach–avoidance task with naturalistic continuous responses (Gonen et al, 2016). Reconciling spatial, mnemonic, conflict processing, and behavioral control functions of the hippocampus may therefore require more elaborated experimental scenarios (Ito and Lee, 2016). …”

Section: Discussionmentioning

confidence: 99%

“…Using rodent approach–avoidance conflict tests, such as the elevated plus maze (EPM) or open-field test (OFT), a plethora of lesion and drug infusion studies have implicated the ventral hippocampus and medial prefrontal cortex (mPFC) in the control of such behaviors (Gray and McNaughton, 2000; Kjelstrup et al, 2002; Trent and Menard, 2010; Weeden et al, 2015; Ito and Lee, 2016). In line with these findings, a recent lesion study suggested a similar role of the human homolog, the anterior hippocampus, in anxiety-like behavior (Bach et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Dissecting the Function of Hippocampal Oscillations in a Human Anxiety Model

et al. 2017

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Neural oscillations in hippocampus and medial prefrontal cortex (mPFC) are a hallmark of rodent anxiety models that build on conflict between approach and avoidance. Yet, the function of these oscillations, and their expression in humans, remain elusive. Here, we used magnetoencephalography (MEG) to investigate neural oscillations in a task that simulated approach–avoidance conflict, wherein 23 male and female human participants collected monetary tokens under a threat of virtual predation. Probability of threat was signaled by color and learned beforehand by direct experience. Magnitude of threat corresponded to a possible monetary loss, signaled as a quantity. We focused our analyses on an a priori defined region-of-interest, the bilateral hippocampus. Oscillatory power under conflict was linearly predicted by threat probability in a location consistent with right mid-hippocampus. This pattern was specific to the hippocampus, most pronounced in the gamma band, and not explained by spatial movement or anxiety-like behavior. Gamma power was modulated by slower theta rhythms, and this theta modulation increased with threat probability. Furthermore, theta oscillations in the same location showed greater synchrony with mPFC theta with increased threat probability. Strikingly, these findings were not seen in relation to an increase in threat magnitude, which was explicitly signaled as a quantity and induced similar behavioral responses as learned threat probability. Thus, our findings suggest that the expression of hippocampal and mPFC oscillatory activity in the context of anxiety is specifically linked to threat memory. These findings resonate with neurocomputational accounts of the role played by hippocampal oscillations in memory.SIGNIFICANCE STATEMENT We use a biologically relevant approach–avoidance conflict test in humans while recording neural oscillations with magnetoencephalography to investigate the expression and function of hippocampal oscillations in human anxiety. Extending nonhuman studies, we can assign a possible function to hippocampal oscillations in this task, namely threat memory communication. This blends into recent attempts to elucidate the role of brain synchronization in defensive responses to threat.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dissecting the Function of Hippocampal Oscillations in a Human Anxiety Model

et al. 2017

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“…The authors suggest that a challenge is to understand how conflict processing relates to the functions of spatial navigation and memory and how all of these functions need not be mutually exclusive. [66] Physiology The hippocampus shows two major "modes" of activity, each associated with a distinct pattern of neural population activity and waves of electrical activity as measured by an electroencephalogram (EEG). These modes are named after the EEG patterns associated with them: theta and large irregular activity (LIA).…”

Section: Role In Approach-avoidance Conflict Processingmentioning

confidence: 99%

“…It is suggested that the memory, spatial cognition, and conflict processing functions may be seen as working together and not mutually exclusive. [47] …”

Section: Theories Of Hippocampal Functionsmentioning

confidence: 99%

The Hippocampus

Wright¹

2017

Wiki J Med

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The hippocampus (named after its resemblance to the seahorse, from the Greek ἱππόκαμπος, "seahorse" from ἵππος hippos, "horse" and κάμπος kampos, "sea monster") is a major component of the brains of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial memory that enables navigation. The hippocampus is located under the cerebral cortex; (allocortical) [1][2] [3] and in primates it is located in the medial temporal lobe, underneath the cortical surface. It contains two main interlocking parts: the hippocampus proper (also called Ammon's horn) [4] and the dentate gyrus.In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of the brain to suffer damage; short-term memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia (the inability to form and retain new memories).In rodents as model organisms, the hippocampus has been studied extensively as part of a brain system responsible for spatial memory and navigation. Many neurons in the rat and mouse hippocampus respond as place cells: that is, they fire bursts of action potentials when the animal passes through a specific part of its environment. Hippocampal place cells interact extensively with head direction cells, whose activity acts as an inertial compass, and conjecturally with grid cells in the neighboring entorhinal cortex.Since different neuronal cell types are neatly organized into layers in the hippocampus, it has frequently been used as a model system for studying neurophysiology. The form of neural plasticity known as long-term potentiation (LTP) was first discovered to occur in the hippocampus and has often been studied in this structure. LTP is widely believed to be one of the main neural mechanisms by which memories are stored in the brain.

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Ventral, but not dorsal, hippocampus inactivation impairs reward memory expression and retrieval in contexts defined by proximal cues

et al. 2017

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The hippocampus (HPC) has been widely implicated in the contextual control of appetitive and aversive conditioning. However, whole hippocampal lesions do not invariably impair all forms of contextual processing, as in the case of complex biconditional context discrimination, leading to contention over the exact nature of the contribution of the HPC in contextual processing. Moreover, the increasingly well-established functional dissociation between the dorsal (dHPC) and ventral (vHPC) subregions of the HPC has been largely overlooked in the existing literature on hippocampal-based contextual memory processing in appetitively motivated tasks. Thus, the present study sought to investigate the individual roles of the dHPC and the vHPC in contextual biconditional discrimination (CBD) performance and memory retrieval. To this end, we examined the effects of transient post-acquisition pharmacological inactivation (using a combination of GABA and GABA receptor agonists muscimol and baclofen) of functionally distinct subregions of the HPC (CA1/CA3 subfields of the dHPC and vHPC) on CBD memory retrieval. Additional behavioral assays including novelty preference, light-dark box and locomotor activity test were also performed to confirm that the respective sites of inactivation were functionally silent. We observed robust deficits in CBD performance and memory retrieval following inactivation of the vHPC, but not the dHPC. Our data provides novel insight into the differential roles of the ventral and dorsal HPC in reward contextual processing, under conditions in which the context is defined by proximal cues.

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The role of the hippocampus in approach-avoidance conflict decision-making: Evidence from rodent and human studies

Cited by 136 publications

References 136 publications

Dissecting the Function of Hippocampal Oscillations in a Human Anxiety Model

Dissecting the Function of Hippocampal Oscillations in a Human Anxiety Model

The Hippocampus

Ventral, but not dorsal, hippocampus inactivation impairs reward memory expression and retrieval in contexts defined by proximal cues

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