Brain stimulation and elicited memories

Abstract

Background Since the late 1930s, electric brain stimulation (EBS) in awake patients has been known to occasionally elicit patient descriptions of a form of memory flashbacks, known as experiential phenomena. One understanding of these sensations are as caused by an augmentation of the capacity for memory retrieval. However, an alternative hypothesis holds that memory flashbacks during EBS are “synthetic constructions” in the form of mental events, falsely interpreted as memories. Methods A critical narrative review is used to discuss the false memory hypothesis in relation to the current empirical literature and source attribution theory. Results EBS as well as situational demands in the form of interaction between patient and neurosurgeon may both lead to the creation of mental events and influence their interpretation in a way that may create false memories. The false memory hypothesis provides a potential explanation for several apparent inconsistencies in the current literature such as (a) the fragmented nature of experiential reports, (b) the ability of EBS to induce memory retrieval errors in controlled studies, (c) that Penfield’s elicitations of experiential phenomena are so rarely replicated in the modern era, and (d) the limited utility of techniques that elicit experiential phenomena in the treatment of memory disorders. Conclusions The hypothesis that experiential phenomena may largely be “synthetic constructions” deserves serious consideration by neurosurgeons.

Evoking artificial speech perception through invasive brain stimulation for brain-computer interfaces: current challenges and future perspectives

“…Hallucinations are vivid perceptions created in one's mind that can be evoked during brain stimulation in the absence of other external stimuli. Penfield distinguished illusions and hallucinations, which are both categorized as experiential phenomena or vivid subjective experiences evoke by cortical stimulation that is usually related to one's past (Mullan and Penfield, 1959;Penfield and Perot, 1963;Gloor, 1990;Sjöberg, 2023). Illusions are distortions of real perceptions or sensory stimuli, such as echoes or distortions of external objects, whereas hallucinations can be defined as vivid percepts that are experienced in the environment, such as hearing noises or seeing faces (Braun et al, 2003;Elliott et al, 2009;Jaroszynski et al, 2022).…”