The anterior thalamus provides a subcortical circuit supporting memory and spatial navigation

Abstract

The anterior thalamic nuclei (ATN), a central component of Papez' circuit, are generally assumed to be key constituents of the neural circuits responsible for certain categories of learning and memory. Supporting evidence for this contention is that damage to either of two brain regions, the medial temporal lobe and the medial diencephalon, is most consistently associated with anterograde amnesia. Within these respective regions, the hippocampal formation and the ATN (anteromedial, anteroventral, and anterodorsal) are the particular structures of interest. The extensive direct and indirect hippocampal-anterior thalamic interconnections and the presence of theta-modulated cells in both sites further support the hypothesis that these structures constitute a neuronal network crucial for memory and cognition. The major tool in understanding how the brain processes information is the analysis of neuronal output at each hierarchical level along the pathway of signal propagation coupled with neuroanatomical studies. Here, we discuss the electrophysiological properties of cells in the ATN with an emphasis on their role in spatial navigation. In addition, we describe neuroanatomical and functional relationships between the ATN and hippocampal formation.

Do the anterior and lateral thalamic nuclei make distinct contributions to spatial representation and memory?

“…1, top), including three anterior subnuclei (anterodorsal, anteroventral, anteromedial) and two lateral subnuclei (laterodorsal and lateroposterior). Neuroanatomical studies have suggested that subcortical inputs to the thalamus differentiate anterior and lateral subregions (for review see Mizumori et al, 2005 andJankowski et al, 2013; Fig. 1, bottom).…”

Dissociable effects of anterior and mediodorsal thalamic lesions on spatial goal-directed behavior

“…All the aforementioned brain areas share abundant connections with limbic thalamic nuclei (Gabbott et al 2005;Groenewegen 1988;Hoover and Vertes 2007) such as the anterior thalamic nuclei (ATN) and mediodorsal (MD) nuclei. While the ATN is known to support spatial navigation (Jankowski et al 2013;van Groen and Kadish 2002;Warburton et al 1999Warburton et al , 2001Wilton et al 2001;Wolff et al 2008a, b), the role of MD in goaldirected behavior has been the focus of recent studies in essentially non-spatial, instrumental settings (Mitchell et al 2007;Ostlund and Balleine 2008;Pickens 2008). Still few studies have directly compared the differential impact of lesion to either the ATN or the MD on goal-directed behavior and none of them involved processing of spatial information .…”

Thalamic functional connectivity and its association with behavioral performance in older age

“…Declining memory performance is perhaps the cognitive deficit most commonly associated with advancing age (see Craik & Rose, 2012 and Khan, Martin‐Montanez, Navarro‐Lobato, & Muly, 2014 for reviews). While the hippocampus clearly plays a vital role in explicit (Riedel et al., 1999; Schacter, Alpert, Savage, Rauch, & Albert, 1996; Squire, 1992) and implicit (Duss et al., 2014) memory, the connectivity between the hippocampus and other brain regions, including the anterior thalamus, has also been implicated in supporting memory function (Aggleton & Brown, 1999; Aggleton et al., 2010; Child & Benarroch, 2013; Jankowski et al., 2013). Evidence from patients with thalamic infarcts supports the view that disrupted thalamo‐cortical structural connectivity is associated with memory problems (Serra et al., 2014), while functional connectivity (FC) strength between the dorsomedial nucleus of the thalamus and parts of the striatum has also been negatively associated with episodic memory functioning in 49‐ to 80‐year‐olds (Ystad, Eichele, Lundervold, & Lundervold, 2010).…”