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Cynthia A. Erickson

Bio: Cynthia A. Erickson is an academic researcher from Metropolitan State University of Denver. The author has contributed to research in topics: Stimulus (physiology) & Perirhinal cortex. The author has an hindex of 13, co-authored 22 publications receiving 2924 citations. Previous affiliations of Cynthia A. Erickson include Colorado State University & University of California, Davis.

Papers
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Journal ArticleDOI
TL;DR: It is suggested that PF cortex plays a primary role in working memory tasks and may be a source of feedback inputs to IT cortex, biasing activity in favor of behaviorally relevant stimuli.
Abstract: Prefrontal (PF) cells were studied in monkeys performing a delayed matching to sample task, which requires working memory. The stimuli were complex visual patterns and to solve the task, the monkeys had to discriminate among the stimuli, maintain a memory of the sample stimulus during the delay periods, and evaluate whether a test stimulus matched the sample presented earlier in the trial. PF cells have properties consistent with a role in all three of these operations. Approximately 25% of the cells responded selectively to different visual stimuli. Half of the cells showed heightened activity during the delay after the sample and, for many of these cells, the magnitude of delay activity was selective for different samples. Finally, more than half of the cells responded differently to the test stimuli depending on whether they matched the sample. Because inferior temporal (IT) cortex also is important for working memory, we compared PF cells with IT cells studied in the same task. Compared with IT cortex, PF responses were less often stimulus-selective but conveyed more information about whether a given test stimulus was a match to the sample. Furthermore, sample-selective delay activity in PF cortex was maintained throughout the trial even when other test stimuli intervened during the delay, whereas delay activity in IT cortex was disrupted by intervening stimuli. The results suggest that PF cortex plays a primary role in working memory tasks and may be a source of feedback inputs to IT cortex, biasing activity in favor of behaviorally relevant stimuli.

1,438 citations

Journal ArticleDOI
TL;DR: In this article, a chronic in vivo recording technique was used to monitor mRNA responses of several transcription factor genes to two different patterns of LTE-inducing electrical stimulation of entorhinal cortical afferents to hippocampus.
Abstract: Recent studies suggest a role for rapid induction of transcription factors in stimulus-induced neuronal plasticity in the mammalian brain. Synaptic activation of transcription factors has been analyzed in the hippocampus using the long-term potentiation or enhancement (LTP/LTE) paradigm. Using this approach, several studies have identified transcription factors that are induced in hippocampal granule cells by NMDA receptor-dependent mechanisms; however, the link between long-term plasticity and activation of these genes has been called into question by reports suggesting that the thresholds for LTE and gene activation differ. To address this issue, we have used a chronic in vivo recording technique to monitor mRNA responses of several transcription factor genes to two different patterns of LTE-inducing electrical stimulation of entorhinal cortical afferents to hippocampus. One pattern consisted of 10 repetitions of a 20 or 25 msec train of pulses at 400 Hz (80 or 100 pulses total). This "10-train" pattern has been used in previous studies of LTE and produces robust synaptic enhancement lasting at least 3 d (Barnes, 1979). The other stimulation pattern consisted of 50 repetitions of a 20 msec train delivered at 400 Hz (400 pulses total), which is similar to parameters used in other studies reporting induction of c-fos in association with LTE (Dragunow et al., 1989; Jeffery et al., 1990; Abraham et al., 1992). Our results indicate that expression of zif268, monitored by in situ hybridization and immunostaining, is strongly induced by the 10-train stimulus pattern to levels similar to those induced by seizure activity. JunB mRNA levels are also modestly increased by the 10-train stimulus pattern; however, increases in JunB immunostaining were not detected. Neither c-fos nor c-jun mRNA were detectably induced by this stimulus. In contrast, the 50-train stimulus pattern resulted in a robust induction of c-fos and c-jun mRNA, in addition to zif268 and junB. Transcription factor responses to either stimulus pattern were blocked by the noncompetitive NMDA receptor antagonist MK-801. Identical transcription factor responses were observed in adult (6-12-month-old) and aged (23-26-month-old) rats, suggesting that synaptic mechanisms involved in these responses are preserved in aged animals. Analysis of LTE following either the 10- or 50-train stimulus patterns revealed identical magnitudes of initial induction and decay kinetics (approximately 3 d) and indicates that the 10-train stimulus pattern is sufficient to produce maximal synaptic enhancement.(ABSTRACT TRUNCATED AT 400 WORDS)

336 citations

Journal ArticleDOI
TL;DR: For instance, this article found that the majority of these neurons (64%) responded both to identity and facial expression, suggesting that these parameters are processed jointly in the amygdala, while large fractions of neurons showed pure identity-selective or expression-selectively responses.
Abstract: The amygdala is purported to play an important role in face processing, yet the specificity of its activation to face stimuli and the relative contribution of identity and expression to its activation are unknown. In the current study, neural activity in the amygdala was recorded as monkeys passively viewed images of monkey faces, human faces, and objects on a computer monitor. Comparable proportions of neurons responded selectively to images from each category. Neural responses to monkey faces were further examined to determine whether face identity or facial expression drove the face-selective responses. The majority of these neurons (64%) responded both to identity and facial expression, suggesting that these parameters are processed jointly in the amygdala. Large fractions of neurons, however, showed pure identity-selective or expression-selective responses. Neurons were selective for a particular facial expression by either increasing or decreasing their firing rate compared with the firing rates elicited by the other expressions. Responses to appeasing faces were often marked by significant decreases of firing rates, whereas responses to threatening faces were strongly associated with increased firing rate. Thus global activation in the amygdala might be larger to threatening faces than to neutral or appeasing faces.

307 citations

Journal ArticleDOI
TL;DR: It is proposed that the link between rodent and human work can be made much stronger by combining neurophysiological and behavioral investigation of normal aging in the non-human primate.

263 citations

Journal ArticleDOI
TL;DR: With long-term training, perirhinal neurons tend to link the representations of temporally associated stimuli with stimulus pairs that had been associated on at least 2 d of training.
Abstract: Recent lesion studies have implicated the perirhinal cortex in learning that two objects are associated, i.e., visual association learning. In this experiment we tested whether neuronal responses to associated stimuli in perirhinal cortex are altered over the course of learning. Neurons were recorded from monkeys during performance of a visual discrimination task in which a predictor stimulus was followed, after a delay, by a GO or NO-GO choice stimulus. Association learning had two major influences on neuronal responses. First, responses to frequently paired predictor-choice stimuli were more similar to one another than was the case with infrequently paired stimuli. Second, the magnitude of activity during the delay was correlated with the magnitude of responses to both the predictor and choice stimuli. Both of these learning effects were found only for stimulus pairs that had been associated on at least 2 d of training. Early in training, the delay activity was correlated only with the response to the predictor stimuli. Thus, with long-term training, perirhinal neurons tend to link the representations of temporally associated stimuli.

229 citations


Cited by
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Journal ArticleDOI
TL;DR: It is proposed that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them, which provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task.
Abstract: ▪ Abstract The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed

10,943 citations

Book ChapterDOI
TL;DR: This chapter demonstrates the functional importance of dopamine to working memory function in several ways and demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.
Abstract: Publisher Summary This chapter focuses on the modern notion of short-term memory, called working memory. Working memory refers to the temporary maintenance of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behavior. Working memory is a system that is critically important in cognition and seems necessary in the course of performing many other cognitive functions, such as reasoning, language comprehension, planning, and spatial processing. This chapter demonstrates the functional importance of dopamine to working memory function in several ways. Elucidation of the cognitive and neural mechanisms underlying human working memory is an important focus of cognitive neuroscience and neurology for much of the past decade. One conclusion that arises from research is that working memory, a faculty that enables temporary storage and manipulation of information in the service of behavioral goals, can be viewed as neither a unitary, nor a dedicated system. Data from numerous neuropsychological and neurophysiological studies in animals and humans demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.

10,081 citations

Journal ArticleDOI
20 Nov 1997-Nature
TL;DR: It is demonstrated that it is possible to retain information about only four colours or orientations in visual working memory at one time, but it is also possible to retaining both the colour and the orientation of four objects, indicating that visual workingMemory stores integrated objects rather than individual features.
Abstract: Short-term memory storage can be divided into separate subsystems for verbal information and visual information, and recent studies have begun to delineate the neural substrates of these working-memory systems. Although the verbal storage system has been well characterized, the storage capacity of visual working memory has not yet been established for simple, suprathreshold features or for conjunctions of features. Here we demonstrate that it is possible to retain information about only four colours or orientations in visual working memory at one time. However, it is also possible to retain both the colour and the orientation of four objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing sixteen individual features to be retained when distributed across four objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features, which places significant constraints on cognitive and neurobiological models of the temporary storage of visual information.

3,608 citations

Journal ArticleDOI
TL;DR: Although the dorsolateral PFC is but one critical structure in a network of anterior and posterior “attention control” areas, it does have a unique executiveattention role in actively maintaining access to stimulus representations and goals in interference-rich contexts.
Abstract: We provide an “executive-attention” framework for organizing the cognitive neuroscience research on the constructs of working-memory capacity (WMC), general fluid intelligence, and prefrontal cortex (PFC) function. Rather than provide a novel theory of PFC function, we synthesize a wealth of singlecell, brain-imaging, and neuropsychological research through the lens of our theory of normal individual differences in WMC and attention control (Engle, Kane, & Tuholski, 1999; Engle, Tuholski, Laughlin, & Conway, 1999). Our critical review confirms the prevalent view that dorsolateral PFC circuitry is critical to executive-attention functions. Moreover, although the dorsolateral PFC is but one critical structure in a network of anterior and posterior “attention control” areas, it does have a unique executiveattention role in actively maintaining access to stimulus representations and goals in interference-rich contexts. Our review suggests the utility of an executive-attention framework for guiding future research on both PFC function and cognitive control.

2,075 citations

Journal ArticleDOI
TL;DR: Much remains unknown about how normal ageing affects the neural basis of cognition, but recent research on individual differences in the trajectory of ageing effects is helping to distinguish normal from pathological origins of age-related cognitive changes.
Abstract: As we grow older, we may grow wiser, but we can also experience memory loss and cognitive slowing that can interfere with our daily routines. The cognitive neuroscience of human ageing, which relies largely on neuroimaging techniques, relates these cognitive changes to their neural substrates, including structural and functional changes in the prefrontal cortex, medial temporal lobe regions and white matter tracts. Much remains unknown about how normal ageing affects the neural basis of cognition, but recent research on individual differences in the trajectory of ageing effects is helping to distinguish normal from pathological origins of age-related cognitive changes.

2,010 citations