Anterior thalamic lesions alter both hippocampal-dependent behavior and hippocampal acetylcholine release in the rat

Abstract

The anterior thalamic nuclei (ATN) are important for learning and memory as damage to this region produces a persistent amnestic syndrome. Dense connections between the ATN and the hippocampus exist, and importantly, damage to the ATN can impair hippocampal functioning. Acetylcholine (ACh) is a key neurotransmitter in the hippocampus, and in vivo measures of ACh are correlated to learning and memory performance. In the present study, complete lesions of the ATN impaired performance on two measures of hippocampal-dependent learning and memory (spontaneous alternation and delayed alternation) and severely disrupted behaviorally evoked ACh efflux within the hippocampus of adult male rats. In contrast, incomplete ATN lesions did not impair spontaneous alternation performance but did impair delayed alternation performance while blunting hippocampal ACh efflux. Interestingly, ATN lesions of any size did not affect basal concentrations of ACh in the hippocampus. These results demonstrate that the ATN have the capacity to modulate behaviorally relevant neuronal transmission within the hippocampus.

Analyzing Nootropic Effect of <i>Phyllanthus reticulatus</i> Poir. on Cognitive Functions, Brain Antioxidant Enzymes and Acetylcholinesterase Activity against Aluminium-Induced Alzheimer’s Model in Rats: Applicable for Controlling the Risk Factors of Alzheimer’s Disease

“…* P < 0.05, ** P < 0.01 significant difference from the disease control group. the arms entry [72]. In RA test the measured parameters were WR and CR.…”

The neurobiology of thalamic amnesia: Contributions of medial thalamus and prefrontal cortex to delayed conditional discrimination

“…It is well established that AT lesions in rats affect T-maze, plus-maze, and radial arm maze measures of allocentric spatial memory that depend on hippocampal function (Aggleton et al, 1996;Aggleton and Nelson, 2014;Dumont and Aggleton, 2013;Mair et al, 2003;Savage et al, 2011;Sziklas and Petrides, 2007). Indeed, Dalyrmple-Alford (2005, 2006) have provided direct evidence that AT lesions have greater effects than IL lesions on radial maze spatial memory tasks (but see Mair et al, 1998).…”

The reuniens and rhomboid nuclei: Neuroanatomy, electrophysiological characteristics and behavioral implications

“…The anterior, midline, intralaminar and mediodorsal nuclei are primary candidates for this association (Carlesimo et al, 2011; De Witte et al, 2011; Van Der Werf et al, 2003a). In rats, lesions of anterior thalamic nuclei produce deficits on a variety of learning and memory tasks, all of which are also affected by hippocampal lesions (Aggleton and Brown, 1999; Aggleton et al, 2010; Bailey and Mair, 2005; Gibb et al, 2006; Gold and Squire, 2006; Mair et al, 2003; Mitchell and Dalrymple-Alford, 2005, 2006; Moreau et al, 2013; Savage et al, 2011; Warburton et al, 2001; Wolff et al, 2006, 2008). For example, Lopez et al (2009) recently demonstrated that fiber-sparing excitotoxic lesions of the intralaminar nuclei in rats influence the consolidation/retrieval of remote (at 25 days), but not recent (at 5 days), spatial memory.…”