Executive control, willed actions, and nonconscious processing.

The prefrontal cortex is differentially involved in implicit and explicit facial emotion processing: An fNIRS study

Imaging of Eating Disorders: Multiple Techniques to Demonstrate the Dynamic Brain

Inefficient executive cognitive control in schizophrenia is preceded by altered functional activation during information encoding: An fMRI study

Differential Neural Activation for Updating Rule versus Stimulus Information in Working Memory

Dissociable contributions of the prefrontal cortex to hippocampus- and caudate nucleus-dependent virtual navigation strategies

Influence of attention mechanisms on cerebellar and basal ganglia activity during vocal emotion decoding.

To compare the glutamate dehydrogenase (GDH) activity and amounts of GDHI, GDHII, and GDHIII immunoreactive forms in prefrontal, anterior and posterior cingulate cortex and cerebellar cortex of patients with schizophrenia and control subjects. GDH enzymatic activity was measured and levels of GDH immunoreactive forms were determined in extracts of autopsied samples of prefrontal, anterior and posterior cingulate cortex (areas 10, 24, and 23 by Brodmann), and cerebellar cortex of patients with schizophrenia (n=8) and controls (n=9). GDH enzymatic activity was significantly increased in the prefrontal cortex (area 10) (p<0.004), the posterior cingulate cortex (area 23) (p<0.05) and the cerebellar cortex (p<0.002) and was unchanged in the anterior cingulate cortex (area 24) in patients with schizophrenia compared to controls. The levels of immunoreactive GDH I, GDH II and GDH III were significantly higher in the prefrontal cortex of patients with schizophrenia than in controls (p<0.008, p<0.003, and p<0.0001, respectively). Levels of all three immunoreactive GDH forms were unchanged in the anterior cingulate cortex (area 24), but they were increased in the posterior cingulate cortex (area 23) (p<0.004, p<0.001 and p<0.02, respectively). The levels of immunoreactive GDH II and GDH III, but not GDH I, were significantly increased in the cerebellar cortex of patients with schizophrenia compared with the control group (p<0.02 and p<0.001, respectively). The alteration in the levels of GDH immunoreactive forms in the brain of patients with schizophrenia is one of the causes of impaired brain glutamate metabolism and an important aspect of schizophrenia pathogenesis.

Patients with schizophrenia exhibit impairments in working memory that often appear in attenuated form in persons at high risk for the illness. The authors hypothesized that deviations in task-related brain activation and deactivation would occur in persons with an at-risk mental state performing a working memory task that entailed the maintenance and manipulation of letters. Participants at ultra high risk for developing psychosis (N=60), identified using the Comprehensive Assessment of At-Risk Mental States, and healthy comparison subjects (N=38) 14 to 29 years of age underwent functional MRI while performing a verbal working memory task. Group differences in brain activation were identified using analysis of covariance. The two groups did not show significant differences in speed or accuracy of performance, even after accounting for differences in education. Irrespective of task condition, at-risk participants exhibited significantly less activation than healthy comparison subjects in the left anterior insula. During letter manipulation, at-risk persons exhibited greater task-related deactivation within the default-mode network than comparison subjects. Region-of-interest analysis in the at-risk group revealed significantly greater right dorsolateral prefrontal cortex activation during manipulation of letters. Despite comparable behavioral performance, at-risk participants performing a verbal working memory task exhibited altered brain activation compared with healthy subjects. These findings demonstrate an altered pattern of brain activation in at-risk persons that contains elements of reduced function as well as compensation.

Functional imaging has proved an important tool in the study of depression with studies consistently reporting abnormalities. In this chapter we consider the converging findings from a number of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) studies that critically implicate regions of the medial prefrontal cortex in depression. The medial region of prefrontal cortex is extensively interconnected with other cortical and subcortical structures. More specifically, many of the connections of this region are to structures within the classically defined limbic system, a set of structures with a fundamental role in emotional aspects of processing. The medial prefrontal cortex also projects extensively to more lateral areas of cortex involved in the control of willed action and behavior. It thus provides a plausible substrate for mediating emotional determinants of cognition and behavior that may be dysfunctional in depression. Results from lesion studies, in both animals and humans, are consistent with this proposition. Damage to the medial portion of prefrontal cortex produces a spectrum of deficits, many of which have an emotional component. Specifically, the deficits associated with medial prefrontal damage suggest that this region performs an interpretative role in response to emotional stimuli. Thus it is involved less in the experience of emotion per se and more in the incorporation of emotional factors in decision making and behavioral response. Functional imaging of normal emotional processing, including transiently induced mood changes, would also suggest that medial prefrontal regions are involved in a number of aspects of mood and emotional processing. In this chapter we will briefly review this literature before considering data from recent neuroimaging studies of depression supporting a theory that medial prefrontal cortex dysfunction is the fundamental cortical manifestation of clinical depression. The evidence suggests that medial prefrontal function is abnormal in the resting state and that this abnormality can be related to clinical features of the disorder. Further, cognitive activation studies have demonstrated that depressed patients fail to show normal activation of this region in response to cognitive challenges. Finally, we discuss evidence suggesting that medial prefrontal abnormality can be related to response to various treatments in depressed patients and, indeed, that this region may be important in predicting treatment outcomes.

Event Abstract Back to Event Functional and anatomical organization of lateral prefrontal cortex for memory Michael Petrides1, 2* 1 Montreal Neurological Institute, Cognitive Neuroscience Unit, Canada 2 McGill University, Department of Psychology, Canada The lateral prefrontal cortex consists of many areas that differ in terms of their architectonic structure and their inputs from and outputs to other cortical and subcortical brain regions. There is considerable evidence that the mid-dorsolateral prefrontal cortex (areas 46 and 9/46) is part of a wider fronto-parietal network critical for working memory processing. In the past, evidence was provided for the critical role of the mid-dorsolateral prefrontal cortex in the monitoring of information in working memory, but the role of the posterior parietal cortex has proven elusive. Recent research with functional magnetic resonance imaging has now provided evidence that the posterior parietal cortex plays a critical role in the manipulation of information during working memory processing. In contrast to the mid-dorsolateral prefrontal cortex, the mid-ventrolateral prefrontal cortex (areas 45 and 47/12) plays a critical role in controlled memory retrieval. The evidence has been obtained primarily from functional neuroimaging studies with normal human subjects that provide information about engagement of a cortical area in a cognitive process but no information on the neural computations performed. We have therefore examined the activity of single neurons in macaque monkeys during the performance of a controlled retrieval task identical to a task used in functional neuroimaging studies with humans. This task required the retrieval of a particular dimension from a recent multimodal memory experience. This research demonstrated the existence of neurons in this part of the prefrontal cortex that appear to code the isolation of specific information from an event in memory: their firing is a function of current information in memory and retrieval instruction. Thus, the mid-dorsolateral prefrontal cortex (areas 46 and 9/46) is specialized in the tracking of events that occupy working memory and works in concert with posterior parietal cortex for the manipulation of information in working memory, while the mid-ventrolateral prefrontal region (areas 45 and 47/12) is selectively involved in the active controlled retrieval of information memory. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Oral Presentation Topic: Plenary lectures Citation: Petrides M (2009). Functional and anatomical organization of lateral prefrontal cortex for memory. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Jun 2009; Published Online: 04 Jun 2009. * Correspondence: Michael Petrides, Montreal Neurological Institute, Cognitive Neuroscience Unit, Montréal, Canada, michael.petrides@mcgill.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Michael Petrides Google Michael Petrides Google Scholar Michael Petrides PubMed Michael Petrides Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Implicit and explicit processing of emotional facial expressions in Parkinson’s disease

This article proposes a unified framework for understanding creative problem solving, namely, the explicit-implicit interaction theory. This new theory of creative problem solving constitutes an attempt at providing a more unified explanation of relevant phenomena (in part by reinterpreting/integrating various fragmentary existing theories of incubation and insight). The explicit-implicit interaction theory relies mainly on 5 basic principles, namely, (a) the coexistence of and the difference between explicit and implicit knowledge, (b) the simultaneous involvement of implicit and explicit processes in most tasks, (c) the redundant representation of explicit and implicit knowledge, (d) the integration of the results of explicit and implicit processing, and (e) the iterative (and possibly bidirectional) processing. A computational implementation of the theory is developed based on the CLARION cognitive architecture and applied to the simulation of relevant human data. This work represents an initial step in the development of process-based theories of creativity encompassing incubation, insight, and various other related phenomena.

Solving the Credit Assignment Problem: The interaction of Explicit and Implicit learning with Internal and External State Information Wai-Tat Fu (wfu@cmu.edu) Human Factors Division and Beckman Institute University of Illinois at Urbana-Champaign 1 Airport Road, Savoy, IL 61874, USA John R. Anderson (ja+@cmu.edu) Department of Psychology Carnegie Mellon University 5000 Forbes Avenue Pittsburgh, PA 15213 USA recognition of external state information (signs on the walls). Indeed, many have argued that real-world skills often involve the interplay between cognition (internal), perception, and action (external) that the understanding of these interactive skills requires careful study of how internal (memory) and external information (cues in the environment) are processed in the learning processes (Ballard, 1997; Fu & Gray, 2000; 2004; Gray & Fu, 2004; Larkin, 1989; Gray, Sims, Fu, & Schoelles, in press). The navigation problem above is an example of one of the most difficult situations in skill learning: when the learner has to perform a sequence of actions but only gets feedback on their success at the end of the sequence (e.g., when the destination is reached). This creates a credit-assignment problem, in which the learner has to assign credits to earlier actions that are responsible for eventual success. When actions are interdependent, either memory of previous actions or recognition of the correct problem state in the external environment is required to properly assign credits to the appropriate actions. In this article, we present results from an experiment in which we study how people learn to solve the credit-assignment problem in a simple but challenging example of such a situation. Our focus is on the recent proposal that humans exhibit two distinct learning processes and we apply it to learning of action sequences with delayed feedback: an explicit process (with awareness) that requires memory for actions and outcomes, and an implicit process (without awareness) that does not require such memory. We will first review research in some related areas that informed the design of our experiment. Abstract In most problem-solving activities, feedback is received at the end of an action sequence. This creates a credit-assignment problem where the learner must associate the feedback with earlier actions, and the interdependencies of actions require the learner to either remember past choices of actions (internal state information) or rely on external cues in the environment (external state information) to select the right actions. We investigated the nature of explicit and implicit learning processes in the credit-assignment problem using a probabilistic sequential choice task with and without external state information. We found that when explicit memory encoding was dominant, subjects were faster to select the better option in their first choices than in the last choices; when implicit reinforcement learning was dominant subjects were faster to select the better option in their last choices than in their first choices. However, implicit reinforcement learning was only successful when distinct external state information was available. The results suggest the nature of learning in credit assignment: an explicit memory encoding process that keeps track of internal state information and a reinforcement-learning process that uses state information to propagate reinforcement backwards to previous choices. However, the implicit reinforcement learning process is effective only when the valences can be attributed to the appropriate states in the system – either internally generated states in the cognitive system or externally presented stimuli in the environment. Introduction Consider a person navigating in a large office building. The person has to decide when to turn left or right at various hallway intersections. The sequence of decisions is interdependent – e.g., turning left at a particular hallway intersection will affect the decisions at the next intersections. The person may therefore need to keep track of previous actions to inform what actions to take in the future. In reality, memory of previous actions (internal state information) may not be necessary as people can explicitly seek information in the environment (external state information) to know where one is located or which direction to go to reach a destination (Fu & Gray, 2006). Learning to navigate is therefore likely to involve both the retention of internal state information (memory) and the Explicit and Implicit Learning Probability Learning and Classification There have been numerous studies on the learning of the probabilistic relationship between choices and their consequences. The simplest situation is the probability- learning experiment in which subjects guess which of the alternatives occurs and then receives feedback on their guesses (e.g., Estes, 1964). One robust finding is that subjects often “probability match”; that is, they will choose a particular alternative with the same probability that it is reinforced (e.g., Friedman et al., 1964). This leads many to propose that probability matching is the result of an implicit

Explicit and implicit emotional processing in peripheral vision: A saccadic choice paradigm

Previous studies have shown that neutral observers are able to identify kinship in strangers by matching photographs of children with their parents. We asked whether this ability depended on implicit and/or explicit cognitive processes. Fifty unrelated male observers viewed triads of photographs (one woman in her early 20's and two older women) and had to select which of the two older women was the mother, and rate their confidence in their decision. Observers identified 62.5% of mother-daughter pairs correctly (p &lt; .001). Signal detection analyses showed that confidence was related to accuracy (d' = .28) and observers could report the cues they utilized. However, those who failed to show a relationship between confidence and accuracy (d' ≤ 0) still performed significantly above chance, and both confidence and d' decreased over trials whereas accuracy did not. Results show that neutral observers spontaneously used both explicit and implicit cognitive processes in the task. Recognition of kinship by neutral observers may be a task which allows the interplay between explicit and implicit cognition for a system relevant to ancestral social environments to be observed in the laboratory.