Page 295 - MEGIN Book Of Abstracts - 2023

obtained an accuracy of 96.2 % using two features, the larger LH V1 activity was associated with larger halluci-
left superior frontal region and the left inferior tempo- nation subscale scores on the Scale for the Assessment
ral region. of Positive Symptoms. Early-stage visual processing def-
icits localized to V1 are present at disease onset in the
COMPARISON WITH EXISTING METHOD At source schizophrenia spectrum. This impairment appears to
level, we obtained a higher accuracy than traditional be restricted to the LH, consistent with previous reports
method using only FDR criterion (accuracy = 88.5 %). detailing a predominantly LH disease process in early
We used only the P300 m amplitude (not latency) on psychosis, and activity within this region was associ-
a single channel and two brain regions at a fairly high ated with an increased experience of hallucinations.
rate. These findings detail the cortical responses contribut-
ing to visual processing impairments and their relation-
Keywords: Diagnosis, Feature optimization, Machine ship with symptoms at disease onset, advancing our
learning, Magnetoencephalography, Schizophrenia understanding of their developmental trajectory over
the course of psychotic illness.
Journal of neuroscience methods (2020), Vol. 338
(32201352) (3 citations) Keywords: first-break, lateralization, schizophrenia spec-
trum, sensory impairment

Localization of Early-Stage Visual Processing Schizophrenia bulletin (2020), Vol. 46, No. 4 (32052843) (9
Deficits at Schizophrenia Spectrum Illness Onset citations)
Using Magnetoencephalography (2020)

Sklar, Alfredo L; Coffman, Brian A; Salisbury, Dean F Language-Related Neurophysiological Deficits in
Schizophrenia (2020)
UPMC Western Psychiatric Hospital, Department of Psychia-
try, University of Pittsburgh School of Medicine, Pittsburgh, PA Hirano, Shogo; Spencer, Kevin M; Onitsuka, Toshiaki;
Hirano, Yoji
ABSTRACT Impairments in early-stage visual process-
ing are observed in chronic psychosis. However, their Neural Dynamics Laboratory, Research Service, VA Boston
presence, localization within the brain, and contribu- Healthcare System, and Department of Psychiatry, Harvard
tion to cognitive symptoms remain less well estab- Medical School, Boston, MA, USA; Department of Neuro-
lished early in disease course. The present study utilized psychiatry, Graduate School of Medical Sciences, Kyushu
magnetoencephalography (MEG) to examine sensory University, Higashiku, Fukuoka, Japan
responses within primary visual cortex (V1). MEG was
recorded from 38 individuals diagnosed with a schizo- ABSTRACT Schizophrenia is a severe psychiatric dis-
phrenia spectrum illness at first psychotic episode order that affects all aspects of one's life with several
(FESz) and 38 matched healthy controls (HC) during cognitive and social dysfunctions. However, there is
visual search tasks. The inverse solution for cortical still no objective and universal index for diagnosis and
activity contributing to the M100 visual evoked field treatment of this disease. Many researchers have stud-
was derived. Task performance and V1 activation were ied language processing in schizophrenia since most of
compared between groups. FESz exhibited a reduced the patients show symptoms related to language pro-
V1 response relative to HC. This group deficit, however, cessing, such as thought disorder, auditory verbal hallu-
was selective for the left hemisphere (LH). A similar cinations, or delusions. Electroencephalography (EEG)
interaction was observed for response time with FESz and magnetoencephalography (MEG) with millisecond
exhibiting slower responses to right visual field targets, order high temporal resolution, have been applied
a difference not observed among HC. Among FESz, to reveal the abnormalities in language processing in

 ontents  Index 274
C