Involuntary Memory - Neurological Basis

Neurological Basis

Research studies regarding the neurological functions of involuntary memory have been few in number. Thus far, only two neuroimaging studies have been conducted comparing involuntary memories to voluntary memories using Positron Emission Tomography (PET).

The first study found that involuntary memory retrieval is mediated by the hippocampus, which is known to be associated with successful episodic memory retrieval. In addition, activity in areas such as the left inferior frontal gyrus, left superior temporal gyrus, left hippocampus, and right superior occipital cortex, have been implicated in involuntary memory when dealing with involuntary word recognition tasks. Areas implicated with executive control processes such as right dorsolateral prefrontal cortex, and bilateral medial/lateral parietal cortex were more active during voluntary word recognition tasks.

The second study found that the medial temporal lobe, the posterior cingulate gyrus, and the precunueus, are activated during retrieval success with or without executive control seen within right dorsolateral prefrontal cortex. This implies that involuntary memories are successfully retrieved using the same system as voluntary memory when retrieving perceptual information. Voluntary and involuntary recall were both associated with increased activations in the posterior cingulated gyrus, left precuneus, and right parahippocampal gyrus. In addition, right dorsolateral prefrontal cortex, and left precuneus were more active during voluntary recall, while left dorsolateral prefrontal cortex was more active during involuntary recall. It is suggested that the activation seen in left dorsolateral prefrontal cortex during involuntary memory recall reflects the attempt to prevent the recollected material from interfering with the semantic judgment task.