Impaired error awareness is related to poorer outcome following a traumatic brain injury (TBI). D... more Impaired error awareness is related to poorer outcome following a traumatic brain injury (TBI). Deficits in error awareness are also found in major depressive disorder (MDD). However, neural measures of impairments in error awareness have not been examined in the MDD that commonly follows a TBI (TBI-MDD). These measures may be a marker for the development of TBI-MDD. The current study assessed neural activity related to error awareness in TBI-MDD. Four groups completed a response inhibition task while EEG was recorded - healthy controls (N=15), MDD-only (N=15), TBI-only (N=16), and TBI-MDD (N=12). Error related EEG activity was compared using powerful randomisation statistics that included all electrodes and time points. Participants with TBI-MDD displayed a significantly less frontally distributed neural activity, suggesting reduced contribution from frontal generating brain sources in TBI-MDD. Neural activity during this time window has been suggested by previous research to refle...
The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky d... more The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky decision-making tasks for examining decision-making deficits in clinical populations. Several cognitive models, including the expectancy-valence learning (EVL) model and the prospect valence learning (PVL) model, have been developed to disentangle the motivational, cognitive, and response processes underlying the explicit choices in these tasks. The purpose of the current study was to develop an improved model that can fit empirical data better than the EVL and PVL models and, in addition, produce more consistent parameter estimates across the IGT and SGT. Twenty-six opiate users (mean age 34.23; SD 8.79) and 27 control participants (mean age 35; SD 10.44) completed both tasks. Eighteen cognitive models varying in evaluation, updating, and choice rules were fit to individual data and their performances were compared to that of a statistical baseline model to find a best fitting model. The...
Several studies have found that response inhibition in the stop signal task is associated with a ... more Several studies have found that response inhibition in the stop signal task is associated with a delay in subsequent response speed, which may result from the automatic retrieval of a conflicting stimulus-goal association. This study investigated the neurophysiological correlates of this sequence effect using event related potentials (ERPs). ERPs were recorded in 17 healthy people while they performed the stop signal task. We found reduced P3b amplitude for responses following successful inhibition, but only when the stimulus was repeated from the previous trial (repetition-after-effects). For responses following failed inhibition, P3b amplitude was reduced regardless of stimulus repetition status. We also found a general increase in frontal N2 amplitude on response trials following inhibition, regardless of stimulus repetition or behavioural slowing. The complex pattern of ERP findings, dependent on stimulus repetition and success of inhibition, suggests multiple sources of behavioural slowing in the present data. ERP findings suggest that a memory retrieval processes underlies the repetition component of inhibition after effects. These findings are considered within the broader context of ERP findings in the negative priming literature.
Stop task after-effects are behavioral consequences of response inhibition (i.e., slowed response... more Stop task after-effects are behavioral consequences of response inhibition (i.e., slowed response time), and may index both behavioral control adjustments and repetition priming. Patients with schizophrenia and healthy controls completed a stop task, and responses to the go signal were analyzed according to characteristics of the immediately preceding trial. Schizophrenia was associated with reduced slowing following unsuccessful response inhibition, however there was no evidence of impairments in repetition priming. These results support neurocognitive models of schizophrenia that suggest an absence or reduction of behavioral adjustments (perhaps reflecting impaired error detection), but are inconsistent with current retrieval-based repetition priming accounts.
Impaired error awareness is related to poorer outcome following a traumatic brain injury (TBI). D... more Impaired error awareness is related to poorer outcome following a traumatic brain injury (TBI). Deficits in error awareness are also found in major depressive disorder (MDD). However, neural measures of impairments in error awareness have not been examined in the MDD that commonly follows a TBI (TBI-MDD). These measures may be a marker for the development of TBI-MDD. The current study assessed neural activity related to error awareness in TBI-MDD. Four groups completed a response inhibition task while EEG was recorded - healthy controls (N=15), MDD-only (N=15), TBI-only (N=16), and TBI-MDD (N=12). Error related EEG activity was compared using powerful randomisation statistics that included all electrodes and time points. Participants with TBI-MDD displayed a significantly less frontally distributed neural activity, suggesting reduced contribution from frontal generating brain sources in TBI-MDD. Neural activity during this time window has been suggested by previous research to refle...
The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky d... more The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky decision-making tasks for examining decision-making deficits in clinical populations. Several cognitive models, including the expectancy-valence learning (EVL) model and the prospect valence learning (PVL) model, have been developed to disentangle the motivational, cognitive, and response processes underlying the explicit choices in these tasks. The purpose of the current study was to develop an improved model that can fit empirical data better than the EVL and PVL models and, in addition, produce more consistent parameter estimates across the IGT and SGT. Twenty-six opiate users (mean age 34.23; SD 8.79) and 27 control participants (mean age 35; SD 10.44) completed both tasks. Eighteen cognitive models varying in evaluation, updating, and choice rules were fit to individual data and their performances were compared to that of a statistical baseline model to find a best fitting model. The...
Several studies have found that response inhibition in the stop signal task is associated with a ... more Several studies have found that response inhibition in the stop signal task is associated with a delay in subsequent response speed, which may result from the automatic retrieval of a conflicting stimulus-goal association. This study investigated the neurophysiological correlates of this sequence effect using event related potentials (ERPs). ERPs were recorded in 17 healthy people while they performed the stop signal task. We found reduced P3b amplitude for responses following successful inhibition, but only when the stimulus was repeated from the previous trial (repetition-after-effects). For responses following failed inhibition, P3b amplitude was reduced regardless of stimulus repetition status. We also found a general increase in frontal N2 amplitude on response trials following inhibition, regardless of stimulus repetition or behavioural slowing. The complex pattern of ERP findings, dependent on stimulus repetition and success of inhibition, suggests multiple sources of behavioural slowing in the present data. ERP findings suggest that a memory retrieval processes underlies the repetition component of inhibition after effects. These findings are considered within the broader context of ERP findings in the negative priming literature.
Stop task after-effects are behavioral consequences of response inhibition (i.e., slowed response... more Stop task after-effects are behavioral consequences of response inhibition (i.e., slowed response time), and may index both behavioral control adjustments and repetition priming. Patients with schizophrenia and healthy controls completed a stop task, and responses to the go signal were analyzed according to characteristics of the immediately preceding trial. Schizophrenia was associated with reduced slowing following unsuccessful response inhibition, however there was no evidence of impairments in repetition priming. These results support neurocognitive models of schizophrenia that suggest an absence or reduction of behavioral adjustments (perhaps reflecting impaired error detection), but are inconsistent with current retrieval-based repetition priming accounts.
Uploads
Papers by Daniel Upton