Cognitive Activation by Central Thalamic Stimulation: The Yerkes-Dodson Law Revisited

Abstract

ᮀ Central thalamus regulates forebrain arousal, influencing activity in distributed neural networks that give rise to organized actions during alert, wakeful states. Central thalamus has been implicated in working memory by the effects of lesions and microinjected drugs in this part of the brain. Lesions and drugs that inhibit neural activity have been found to impair working memory. Drugs that increase activity have been found to enhance and impair memory depending on the dose tested. Electrical deep brain stimulation (DBS) similarly enhances working memory at low stimulating currents and impairs it at higher currents. These effects are time dependent. They were observed when DBS was applied during the memory delay (retention) or choice response (retrieval) but not earlier in trials during the sample (acquisition) phase. The effects of microinjected drugs and DBS are consistent with the Yerkes-Dodson law, which describes an inverted-U relationship between arousal and behavioral performance. Alternatively these results may reflect desensitization associated with higher levels of stimulation, spread of drugs or current to adjacent structures, or activation of less sensitive neurons or receptors at higher DBS currents or drug doses.

Midline thalamic reuniens lesions improve executive behaviors

“…There were no observed changes in tasks involving either spatial memory or value-based decision making. These data complement ongoing efforts to understand the role of midline thalamic structures in human cognition, including the development of thalamic stimulation as a therapeutic strategy for acquired cognitive disabilities (Schiff, 2008; Mair et al, 2011), and point to the NRe as a potential target for clinical intervention. …”

“…This prospect gives the NRe a potentially unique role in thalamocortical control over executive behavior by adjusting the arousal level of the prefrontal cortex (Groenewegen and Berendse, 1994; Schiff, 2008; Mair et al, 2011). …”

Anterior thalamic nuclei lesions and recovery of function: Relevance to cognitive thalamus

“…One question, for example, is whether MD function is enhanced by enrichment in the presence of an ATN lesion. Other work has shown that low levels of thalamic stimulation can enhance conditional discrimination, which may provide additional tools for cognitive neuro-rehabilitation (Mair and Hembrook, 2008;Mair et al, 2011;Shah and Schiff, 2012). Savage and her colleagues have already produced novel evidence of recovery of function in PTD model of the Wernicke-Korsakoff syndrome.…”

Cognitive control of movement via the cerebellar-recipient thalamus

“…For instance, central thalamus is known to contribute to working memory via its action on forebrain arousal (Mair et al, 2011). This action has often been related to the ascending reticular activation system, which notably provides intralaminar nuclei with profuse cholinergic inputs (Groenewegen and Berendse, 1994).…”