RT info:eu-repo/semantics/doctoralThesis
T1 Exploration of self-integrity in psychotic disorders through electroencephalographic activity analysis during a speech production and perception task
A1 Beño Ruiz De la Sierra, Rosa María
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Psiquiatría
K1 Corollary discharge
K1 Descarga corolaria
K1 Ipseity
K1 Ipseidad
K1 Anomalous self-experiences
K1 Experiencias anómalas del yo
K1 Schizophrenia
K1 Esquizofrenia
K1 32 Ciencias Médicas
AB Schizophrenia has been proposed as a self-disorder, with Anomalous Self-Experiences (ASEs) consistently identified in people with psychosis, even in at-risk states and early stages, remaining stable within this syndrome. These experiences reflect disruptions in preconscious identification of mental contents as our own, encompassing both cognitive and somatic aspects. ASEs can potentially impair the experience of ipseity, i.e., the automatic and preconscious sense of personal identity. The ipseity disturbance model suggests that diverse symptoms, including positive, negative, cognitive, and disorganized ones, may all share forms of disturbed ipseity. Given the preconscious nature of ASEs, some neural alteration likely underlies them, though current studies reveal little about the possible mechanisms involved.Accurately identifying self-generated actions and thoughts is fundamental for developing and maintaining an intact sense of self. Corollary discharge is a neural mechanism that attenuates sensory consequences of self-initiated acts, contributing to self-identification, and appears altered in schizophrenia. A potential link between ASEs and corollary discharge dysfunction has been proposed, suggesting that early dysfunction could hinder the pre-reflective coordination between sensorimotor actions and environment, diminishing self-agency and leading to self-disorders. However, this hypothesis has not yet been tested.The present doctoral thesis explored the corollary discharge mechanism as a potential biological substrate of ASEs in psychotic disorders. To this end, the auditory N1 Event-Related Potential (ERP) during Electroencephalographic (EEG) recordings was studied as an index of corollary discharge-mediated auditory cortical suppression. First, in a sample of healthy controls, N1 and P2 components were elicited by three conditions: i) real-time listening to self-pronounced vowels while speaking (talk condition), ii) passive listening to recorded self-uttered vowels (listen-self condition), and iii) passive listening to vowels recorded with an external voice (listen-other condition). Then, the talk and listen-self conditions were studied in people with schizophrenia. ASEs were scored alongside positive and negative symptoms using the 'Inventory of Psychotic-Like Anomalous Self-Experiences' (IPASE), the ‘Positive and Negative Syndrome Scale for Schizophrenia’ (PANSS), and the ‘Brief Negative Symptom Scale’ (BNSS). Finally, the specificity of corollary discharge alteration and its relationship with ASEs was explored by comparing the results found in schizophrenia with a group of people with bipolar disorder.N1 ERP amplitude was lower in the talk condition compared to the listen-self and listen-other conditions in healthy controls. There were no differences between the two listening conditions, nor in the amplitude of P2 across task-conditions. The lower N1 amplitude in the talk condition was found in both patient groups. However, N1 suppression was significantly reduced in schizophrenia and inversely correlated with ASEs and positive and negative symptoms severity, with the same results found when first-episode and chronic patients were studied separately. People with bipolar disorder showed intermediate attenuation between both groups, not significantly different from either controls or schizophrenia, but N1 suppression was not related to the severity of ASEs in this group.These findings replicate previous studies, confirming N1 auditory ERP suppression as an index of the correct functioning of the corollary discharge mechanism during vocalization. When speaking, we do not recognize our own voice based on the physical characteristics of that specific auditory stimulus. Instead, sensory identification of our own voice occurs at a pre-stimulus level, before the perception of the emitted sound, where corollary discharge takes place. Additionally, these results support previous data linking auditory N1 ERP amplitude with altered corollary discharge mechanisms in schizophrenia and suggest that corollary discharge dysfunction may underlie ASEs in this illness, which are also related to positive and negative symptoms. However, the intermediate suppression values observed in bipolar patients might suggest that a cortical inhibitory deficit is present in a smaller subset of individuals with bipolar disorder compared to those with schizophrenia.
YR 2024
FD 2024
LK https://uvadoc.uva.es/handle/10324/72377
UL https://uvadoc.uva.es/handle/10324/72377
LA eng
NO Escuela de Doctorado
DS UVaDOC
RD 24-dic-2024