fMRI Investigation Research Articles

T58. SARCASM COMPREHENSION AS A SOCIAL COGNITION MEASURE IN SCHIZOPHRENIA – A SYSTEMATIC LITERATURE SEARCH AND META-ANALYSIS ON THE USE OF THE TASIT

BackgroundSocial cognition tasks with higher ecologically validity could be helpful both as an outcome measure for training and for social cognition impairment in schizophrenia. The comprehension of sarcasm and irony is a candidate for a valid, replicable task.MethodsTests and paradigms as well as studies in schizophrenia are available in English, Dutch, German, Italian, Greek, Japanese and other languages. The Awareness of Social Inference Test (TASIT) (McDonald et al.,J head trauma rehabil 2003,) is currently the by far most applied paradigm. Here, we present a systematic literature research and meta-analysis on application of these paradigms in patients with schizophrenia.Results25 studies with data from n=2185 patients with schizophrenia and n=1474 controls used the TASIT. This exceeds the numbers for other irony comprehension paradigms. Separate meta-analyses were calculated for the “sarcasm-enriched” and “sarcasm-minimal” subtests with data from 5 different English language studies. In both subtests, patients with schizophrenia showed significant impairment. Non-English translations of the TASIT show a comparable picture. Longitudinal data are available from 4 studies. Studies in high risk populations showed mixed results, however the TASIT is included in longitudinal cohort studies such as NAPLS-2.DiscussionWe discuss differences with other task such as paradigms without prosodic or face information or the available fMRI investigations.

Investigating visual effects of a disgust nocebo with fMRI.

There is growing evidence that placebos are able to influence visual perception. A previous functional magnetic resonance imaging study on the processing of disgust images demonstrated that a ''disgust placebo'' (inert pill administered with the verbal suggestion of an anti-nausea medication) reduced visual cortex activity and connectivity. In the present functional magnetic resonance imaging investigation, visual effects corresponding to a ''disgust nocebo'' (an odorless substance introduced as an aversive smell that enhances disgust feelings) were examined. Data from 29 females were reanalyzed. They viewed disgusting, fear-eliciting, and neutral images once with and once without the nocebo. In the nocebo condition with disgusting images disgust experienced that significantly increased fusiform gyrus activation, which also showed enhanced coupling with the amygdala and several (extra)striate cortex regions. The nocebo changed the affective value and motivational relevance of the stimuli as well the perception of basic visual features. These findings demonstrate that nocebo-related expectations can have a strong influence on the experience of sensory input.

Haptic aesthetics in the blind: A behavioral and fMRI investigation.

Understanding perception and aesthetic appeal of arts and environmental objects, what is appreciated, liked, or preferred, and why, is of prime importance for improving the functional capacity of the blind and visually impaired and the ergonomic design for their environment, which however so far, has been examined only in sighted individuals. This paper provides a general overview of the first experimental study of tactile aesthetics as a function of visual experience and level of visual deprivation, using both behavioral and brain imaging techniques. We investigated how blind people perceive 3D tactile objects, how they characterize them, and whether the tactile perception, and tactile shape preference (liking or disliking) and tactile aesthetic appreciation (judging tactile qualities of an object, such as pleasantness, comfortableness etc.) of 3D tactile objects can be affected by the level of visual experience. The study employed innovative behavioral measures, such as new forms of aesthetic preference-appreciation and perceptual discrimination questionnaires, in combination with advanced functional Magnetic Resonance Imaging (fMRI) techniques, and compared congenitally blind, late-onset blind and blindfolded (sighted) participants. Behavioral results demonstrated that both blind and blindfolded-sighted participants assessed curved or rounded 3D tactile objects as significantly more pleasing than sharp 3D tactile objects, and symmetric 3D tactile objects as significantly more pleasing than asymmetric 3D tactile objects. However, as compared to the sighted, blind people showed better skills in tactile discrimination as demonstrated by accuracy and speed of discrimination. Functional MRI results demonstrated that there was a large overlap and characteristic differences in the aesthetic appreciation brain networks in the blind and the sighted. As demonstrated both populations commonly recruited the somatosensory and motor areas of the brain, but with stronger activations in the blind as compared to the sighted. Secondly, sighted people recruited more frontal regions whereas blind people, in particular, the congenitally blind, paradoxically recruited more 'visual' areas of the brain. These differences were more pronounced between the sighted and the congenitally blind rather than between the sighted and the late-onset blind, indicating the key influence of the onset time of visual deprivation. Understanding of the underlying brain mechanisms should have a wide range of important implications for a generalized cross-sensory theory and practice in the rapidly evolving field of neuroaesthetics, as well as for 'cutting-edge' rehabilitation technologies for the blind and the visually impaired.

The rewarding nature of provocation-focused rumination in women with borderline personality disorder: a preliminary fMRI investigation

The rewarding nature of provocation-focused rumination in women with borderline personality disorder: a preliminary fMRI investigation

The rewarding nature of provocation-focused rumination in women with borderline personality disorder: a preliminary fMRI investigation

BackgroundUnderstanding why individuals with borderline personality disorder (BPD) ruminate on prior provocations, despite its negative outcomes, is crucial to improving interventions. Provocation-focused rumination may be rewarding in the short term by amplifying anger and producing feelings of justification, validation, and increased energy, while reducing self-directed negative affect. If provocation-focused rumination is utilized regularly as a rewarding emotion regulation strategy, it could result in increased activation in reward-related neural regions. The present pilot study examined neural correlates of provocation-focused rumination, relative to other forms of thought, in BPD.MethodFunctional magnetic resonance imaging (fMRI) was utilized to examine this theory in a pilot study of women diagnosed with BPD (n = 13) and healthy controls (n = 16). All participants received highly critical feedback on a previously written essay in the scanner, followed by prompts to engage in provocation-focused, self-focused, and neutral thought.ResultsWhole-brain analyses showed that in response to the provocation, participants with BPD (compared to controls) demonstrated increased activation in the ventrolateral prefrontal cortex (PFC). BPD participants also showed greater activation in the dorsomedial PFC during provocation-focused rumination (relative to neutral-focus). Subsequent ROI analyses revealed that provocation-focused rumination (compared to neutral-focus) increased activation in the nucleus accumbens for the BPD group only.ConclusionsThese findings, while preliminary due to the small sample size and limitations of the protocol, provide initial data consistent with the proposed neurobiological mechanism promoting provocation-focused rumination in BPD. Directions for further research are discussed.

Early life social stress and resting state functional connectivity in postpartum rat anterior cingulate circuits

IntroductionContinued development and refinement of resting state functional connectivity (RSFC) fMRI techniques in both animal and clinical studies has enhanced our comprehension of the adverse effects of stress on psychiatric health. The objective of the current study was to assess both maternal behavior and resting state functional connectivity (RSFC) changes in these animals when they were dams caring for their own young. It was hypothesized that ECSS exposed dams would express depressed maternal care and exhibit similar (same networks), yet different specific changes in RSFC (different individual nuclei) than reported when they were adult females. MethodsWe have developed an ethologically relevant transgenerational model of the role of chronic social stress (CSS) in the etiology of postpartum depression and anxiety. Initial fMRI investigation of the CSS model indicates that early life exposure to CSS (ECSS) induces long term changes in functional connectivity in adult nulliparous female F1 offspring. ResultsECSS in F1 dams resulted in depressed maternal care specifically during early lactation, consistent with previous CSS studies, and induced changes in functional connectivity in regions associated with sensory processing, maternal and emotional responsiveness, memory, and the reward pathway, with robust changes in anterior cingulate circuits. LimitationsThe sample sizes for the fMRI groups were low, limiting statistical power. ConclusionThis behavioral and functional neuroanatomical foundation can now be used to enhance our understanding of the neural etiology of early life stress associated disorders and test preventative measures and treatments for stress related disorders.

An fMRI investigation of the neural correlates underlying the autonomous sensory meridian response (ASMR).

Introduction: The "autonomous sensory meridian response" (ASMR) is a neologism used to describe an internal sensation of deep relaxation and pleasant head tingling which is often stimulated by gentle sounds, light touch, and personal attention. Methods: An fMRI-based methodology was employed to examine the brain activation of subjects prescreened for ASMR-receptivity (n=10) as they watched ASMR videos and identified specific moments of relaxation and tingling. Results: Subjects who experienced ASMR showed significant activation in regions associated with both reward (NAcc) and emotional arousal (dACC and Insula/IFG). Brain activation during ASMR showed similarities to patterns previously observed in musical frisson as well as affiliative behaviors. Conclusion: This is the first study to measure the activation of various brain regions during ASMR and these results may help to reveal the mechanistic underpinnings of this sensation.

An fMRI investigation of empathic processing in boys with conduct problems and varying levels of callous-unemotional traits.

The ability to empathise relies in part on using one's own affective experience to simulate the affective experience of others. This process is supported by a number of brain areas including the anterior insula (AI), anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC), and the amygdala. Children with conduct problems (CP), and in particular those with high levels of callous-unemotional traits (CP/HCU) present with less empathy than their peers. They also show reduced neural response in areas supporting empathic processing when viewing other people in distress. The current study focused on identifying brain areas co-activated during affective introspection of: i) One's own emotions (‘Own emotion’); ii) Others' emotions (‘Other emotion’); and iii) One's feelings about others' emotions (‘Feel for other’) during fearful vs neutral scenarios in typically developing boys (TD; n = 31), boys with CP/HCU (n = 31), and boys with CP and low levels of CU (CP/LCU; n = 33). The conjunction analysis across conditions within the TD group revealed significant clusters of activation in the AI, ACC/mPFC, and occipital cortex. Conjunction analyses across conditions in the CP/HCU and CP/LCU groups did not identify these areas as significantly activated. However, follow-up analyses were not able to confirm statistically significant differences between groups across the whole network, and Bayes-factor analyses did not provide substantial support for either the null or alternate hypotheses. Post-hoc comparisons indicated that the lack of conjunction effects in the CP/HCU group may reflect reduced affective introspection in the ‘Other emotion’ and ‘Feel for other’ conditions, and by reduced affective introspection in the ‘Own emotion’ condition in the CP/LCU group. These findings provide limited and ultimately equivocal evidence for altered affective introspection regarding others in CP/HCU, and altered affective introspection for own emotions in CP/LCU, and highlight the need for further research to systematically investigate the precise nature of empathy deficits in children with CP.

Analysis of the Brain-activation Areas During the Visual Stimulations of 2D and 3D Imagery using Functional Magnetic Resonance Imaging

The aim of this study is an functional magnetic resonance imaging (fMRI) investigation of the activity of the Brodmann brain areas during the viewing of 2D and 3D images. By using the 3.0 Tesla MRI system, an 8-channel SENSE Head Coil, and the ESys fMRI system in 5 adult males, 3D T1-weighted images were obtained from anatomic images. A gradient-EPI sequence was used for the acquisition of the brain functional images. The monitor was installed so that the images could be seen through a mirror located in the coil. The 3D appearance of the triangular, cubic, and hexagonal shapes were visually stimulated by the 2D and 3D images, and a pair of red–blue cardboard glasses was worn during the viewing of the 3D images. The display object is composed of 4 stimulus projections every 60 s and 4 resting periods of 20 s every 20 s. The acquired data were analyzed using the SPM-8 program. For the 2D imagery, the activation area of the brain is larger than that of the 3D imagery (p < .05). In the visual-cortex activation area, the number of clusters is larger for the 3D imagery (p < .05). It is expected that the basic data of this study will be used to analyze the effects of 3D-image contents on the areas of the human brain.

Reduced empathic responses for sexually objectified women: An fMRI investigation

Sexual objectification is a widespread phenomenon characterized by a focus on the individual's physical appearance over his/her mental state. This has been associated with negative social consequences, as objectified individuals are judged to be less human, competent, and moral. Moreover, behavioral responses toward the person change as a function of the degree of the perceived sexual objectification. In the present study, we investigated how behavioral and neural representations of other social pain are modulated by the degree of sexual objectification of the target. Using a within-subject fMRI design, we found reduced empathic feelings for positive (but not negative) emotions toward sexually objectified women as compared to non-objectified (personalized) women when witnessing their participation to a ball-tossing game. At the brain level, empathy for social exclusion of personalized women recruited areas coding the affective component of pain (i.e., anterior insula and cingulate cortex), the somatosensory components of pain (i.e., posterior insula and secondary somatosensory cortex) together with the mentalizing network (i.e., middle frontal cortex) to a greater extent than for the sexually objectified women. This diminished empathy is discussed in light of the gender-based violence that is afflicting the modern society.

FMRI Investigation on Gradual Change of Awareness States in Implicit Sequence Learning

Awareness of implicit knowledge is a changing process. Previous studies have examined brain activation patterns corresponding to the start and end stages of implicit learning, but failed to reveal the gradual changing course of awareness in implicit learning. The present study explored brain activation changes corresponding to different awareness states elicited by two different stimulus onset asynchrony (SOA, 850 ms and 1350 ms) over the whole course of implicit sequence learning (i.e., divided into three phases), by using a process dissociation procedure (PDP) paradigm and the technique of functional magnetic resonance imaging (fMRI). In the results, it was found that the 850 ms SOA elicited primarily an awareness state of unconsciousness, under which the frontal lobe was significantly activated during the early phase of implicit sequence learning, with its activation levels correlated positively to consciousness levels. In contrast, the 1350 ms SOA triggered predominantly an awareness state of consciousness, under which the activation levels of the inferior parietal lobule correlated positively to consciousness levels during the middle phase, and positively to consciousness levels as well as negatively to unconsciousness levels during the late phase of implicit sequence learning. Overall, the frontal lobe and inferior parietal lobule were found to play critical roles in mediating awareness states over the course of implicit sequence learning.

GABA concentrations in the anterior temporal lobe predict human semantic processing

There is now considerable convergent evidence from multiple methodologies and clinical studies that the human anterior temporal lobe (ATL) is a semantic representational hub. However, the neurochemical nature of the ATL in the semantic processing remains unclear. The current study investigated the neurochemical mechanism underlying semantic processing in the ATL. We combined functional magnetic resonance imaging (fMRI) with resting-state magnetic resonance spectroscopy (MRS) to measure task-related blood-oxygen level-dependent (BOLD) signal changes during sematic processing and resting-state GABA concentrations in the ATL. Our combined fMRI and MRS investigation showed that the stronger ATL BOLD response induced by the semantic task, the lower GABA concentration in the same region. Moreover, individuals with higher GABA concentration in the ATL showed better semantic performance and stronger BOLD-related fluctuations in the semantic network. Our data demonstrated that the resting-state GABA concentration predicts neural changes in the human ATL and task performance during semantic processing. Our findings indicate that individuals with higher GABA may have a more efficient semantic processing leading to better task performance and imply that GABAergic neurochemical processes are potentially crucial to the neurobiological contribution of the ATL to semantic cognition.

BOLD Activity During Correct-Answer Feedback in Cued Recall Predicts Subsequent Retrieval Performance: An fMRI Investigation Using a Partial Trial Design.

Receiving correct answer feedback following a retrieval attempt has proven to be a highly effective means of learning new information, yet the mechanisms behind its efficacy remain poorly understood. Here, fMRI was used to examine how BOLD activity measured during a period of feedback could predict subsequent memory (SM) performance on a final test. Twenty-five human subjects studied pairs of associated words, and were then asked to covertly recall target words in response to provided cues. Correct answer feedback was provided immediately after covert retrieval attempts. A partial trial design enabled separate modeling of activity related to retrieval and to feedback processing. During initial study, typical SM effects were observed across the whole brain. During feedback following a failed recall attempt, activity in only a subset of these regions predicted final test performance. These regions fell within the default mode network (DMN) and demonstrated negative SM effects, such that greater deactivation was associated with successful recall. No "task-positive" regions demonstrated SM effects in this contrast. The obtained results are consistent with a growing literature that associates DMN deactivation with successful learning in multiple task contexts, likely reflecting differences in the allocation of attentional resources during encoding.

Expectancy modulates pupil size during endogenous orienting of spatial attention

fMRI investigations in healthy humans have documented phasic changes in the level of activation of the right temporal-parietal junction (TPJ) during cued voluntary orienting of spatial attention. Cues that correctly predict the position of upcoming targets in the majority of trials, i.e., predictive cues, produce higher deactivation of the right TPJ as compared with non-predictive cues. Since the right TPJ is the recipient of noradrenergic (NE) innervation, it has been hypothesised that changes in the level of TPJ activity are matched with changes in the level of NE activity. Based on aforementioned fMRI findings, this might imply that orienting with predictive cues is matched with different levels of NE activity as compared with non-predictive cues. To test this hypothesis, we measured changes in pupil dilation, an indirect index of NE activity, during voluntary orienting of attention with highly predictive (80% validity) or non-predictive (50% validity) cues. In agreement with current interpretations of the tonic/phasic activity of the Locus Coeruleus-Norepinephrinic system (LC-NE), we found that the steady level of cue predictiveness that characterised both the predictive and non-predictive conditions caused, across consecutive blocks of trials, a progressive decrement in pupil dilation during the baseline-fixation period that anticipated the cue period. With predictive cues we observed increased pupil dilation as compared with non-predictive cues. In addition, the relative reduction in pupil size observed with non-predictive cues increased as a function of cue-duration. These results show that changes in the predictiveness of cues that guide voluntary orienting of spatial attention are matched with changes in pupil dilation and, putatively, with corresponding changes in LC-NE activity.

Neural Correlates of Direct Access Trading in a Real Stock Market: An fMRI Investigation.

Background: While financial decision making has been barely explored, no study has previously investigated the neural correlates of individual decisions made by professional traders involved in real stock market negotiations, using their own financial resources.Aim: We sought to detect how different brain areas are modulated by factors like age, expertise, psychological profile (speculative risk seeking or aversion) and, eventually, size and type (Buy/Sell) of stock negotiations, made through Direct Access Trading (DAT) platforms.Subjects and methods: Twenty male traders underwent fMRI while negotiating in the Italian stock market using their own preferred trading platform.Results: At least 20 decision events were collected during each fMRI session. Risk averse traders performed a lower number of financial transactions with respect to risk seekers, with a lower average economic value, but with a higher rate of filled proposals. Activations were observed in cortical and subcortical areas traditionally involved in decision processes, including the ventrolateral and dorsolateral prefrontal cortex (vlPFC, dlPFC), the posterior parietal cortex (PPC), the nucleus accumbens (NAcc), and dorsal striatum. Regression analysis indicated an important role of age in modulating activation of left NAcc, while traders' expertise was negatively related to activation of vlPFC. High value transactions were associated with a stronger activation of the right PPC when subjects' buy rather than sell. The success of the trading activity, based on a large number of filled transactions, was related with higher activation of vlPFC and dlPFC. Independent of chronological and professional age, traders differed in their attitude to DAT, with distinct brain activity profiles being detectable during fMRI sessions. Those subjects who described themselves as very self-confident, showed a lower or absent activation of both the caudate nucleus and the dlPFC, while more reflexive traders showed greater activation of areas involved in strategic decision making.Discussion: The neural correlates in DAT are similar to those observed in other decision making contexts. Trading is handled as a well-learned automatic behavior by expert traders; for those who mostly rely on heuristics, cognitive effort decreases, and transaction speed increases, but decision efficiency lowers following a poor involvement of the dlPFC.

Sleep-amount differentially affects fear-processing neural circuitry in pediatric anxiety: A preliminary fMRI investigation

Insufficient sleep, as well as the incidence of anxiety disorders, both peak during adolescence. While both conditions present perturbations in fear-processing-related neurocircuitry, it is unknown whether these neurofunctional alterations directly link anxiety and compromised sleep in adolescents. Fourteen anxious adolescents (AAs) and 19 healthy adolescents (HAs) were compared on a measure of sleep amount and neural responses to negatively valenced faces during fMRI. Group differences in neural response to negative faces emerged in the dorsal anterior cingulate cortex (dACC) and the hippocampus. In both regions, correlation of sleep amount with BOLD activation was positive in AAs, but negative in HAs. Follow-up psychophysiological interaction (PPI) analyses indicated positive connectivity between dACC and dorsomedial prefrontal cortex, and between hippocampus and insula. This connectivity was correlated negatively with sleep amount in AAs, but positively in HAs. In conclusion, the presence of clinical anxiety modulated the effects of sleep-amount on neural reactivity to negative faces differently among this group of adolescents, which may contribute to different clinical significance and outcomes of sleep disturbances in healthy adolescents and patients with anxiety disorders.

ICN_Atlas: Automated description and quantification of functional MRI activation patterns in the framework of intrinsic connectivity networks

Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectivity networks (ICNs) appear to link patterns of resting state and task-related state connectivity. These networks provide an opportunity of functionally-derived description and interpretation of fMRI maps, that may be especially important in cases where the maps are predominantly task-unrelated, such as studies of spontaneous brain activity e.g. in the case of seizure-related fMRI maps in epilepsy patients or sleep states. Here we present a new toolbox (ICN_Atlas) aimed at facilitating the interpretation of fMRI data in the context of ICN. More specifically, the new methodology was designed to describe fMRI maps in function-oriented, objective and quantitative way using a set of 15 metrics conceived to quantify the degree of ‘engagement’ of ICNs for any given fMRI-derived statistical map of interest. We demonstrate that the proposed framework provides a highly reliable quantification of fMRI activation maps using a publicly available longitudinal (test-retest) resting-state fMRI dataset. The utility of the ICN_Atlas is also illustrated on a parametric task-modulation fMRI dataset, and on a dataset of a patient who had repeated seizures during resting-state fMRI, confirmed on simultaneously recorded EEG. The proposed ICN_Atlas toolbox is freely available for download at http://icnatlas.com and at http://www.nitrc.org for researchers to use in their fMRI investigations.

S147 Imaging biomarkers of primary headache disorders

The primary headache disorders, such as migraine and cluster headache are not directly life threatening, but both confer considerable disability, robs quality of life and bears enormous socio-economic burden. Repeated pain attacks and activation of the pain matrix finally may lead to the chronification of the disease, a mechanism of which was proposed to be central sensitisation. While headache disorders were thought to be functional in nature, imaging studies revealed several structural alterations next to the functional deficit. In a series of investigations we showed that the size of the subcortical structures are altered. Microstructure of the white matter was found affected in migraine as well as in cluster headache. Interestingly, the degree of white matter diffusion alterations were different between patients having aura symptoms and those not experiencing aura. Furthermore, in two resting state fMRI investigations we showed that the amplitude of the resting BOLD fluctuation is higher in certain frequencies in cluster headache as well as in migraine. In migraine patients that was primarily true for patients with aura symptoms. We hypothesized that two competing processes exist in the brain of headache patients. The increased excitability might result in degenerative changes on one hand. On the other hand the repetitive painful episodes may cause maladaptive plasticity. The imaging marker of these two processes might be different. Our results provide important clues about the pathomechanism of headache disorders and the imaging measures might serve as useful biomarkers.

Interactions of the Salience Network and Its Subsystems with the Default-Mode and the Central-Executive Networks in Normal Aging and Mild Cognitive Impairment.

Previous functional magnetic resonance imaging (fMRI) investigations suggest that the intrinsically organized large-scale networks and the interaction between them might be crucial for cognitive activities. A triple network model, which consists of the default-mode network, salience network, and central-executive network, has been recently used to understand the connectivity patterns of the cognitively normal brains versus the brains with disorders. This model suggests that the salience network dynamically controls the default-mode and central-executive networks in healthy young individuals. However, the patterns of interactions have remained largely unknown in healthy aging or those with cognitive decline. In this study, we assess the patterns of interactions between the three networks using dynamical causal modeling in resting state fMRI data and compare them between subjects with normal cognition and mild cognitive impairment (MCI). In healthy elderly subjects, our analysis showed that the salience network, especially its dorsal subnetwork, modulates the interaction between the default-mode network and the central-executive network (Mann-Whitney U test; p < 0.05), which was consistent with the pattern of interaction reported in young adults. In contrast, this pattern of modulation by salience network was disrupted in MCI (p < 0.05). Furthermore, the degree of disruption in salience network control correlated significantly with lower overall cognitive performance measured by Montreal Cognitive Assessment (r = 0.295; p < 0.05). This study suggests that a disruption of the salience network control, especially the dorsal salience network, over other networks provides a neuronal basis for cognitive decline and may be a candidate neuroimaging biomarker of cognitive impairment.

Modulation of Oscillatory Power and Connectivity in the Human Posterior Cingulate Cortex Supports the Encoding and Retrieval of Episodic Memories.

Existing data from noninvasive studies have led researchers to posit that the posterior cingulate cortex (PCC) supports mnemonic processes: It exhibits degeneration in memory disorders, and fMRI investigations have demonstrated memory-related activation principally during the retrieval of memory items. Despite these data, the role of the PCC in episodic memory has received only limited treatment using the spatial and temporal precision of intracranial EEG, with previous analyses focused on item retrieval. Using data gathered from 21 human participants who underwent stereo-EEG for seizure localization, we characterized oscillatory patterns in the PCC during the encoding and retrieval of episodic memories. We identified a subsequent memory effect during item encoding characterized by increased gamma band oscillatory power and a low-frequency power desynchronization. Fourteen participants had stereotactic electrodes located simultaneously in the hippocampus and PCC, and with these unique data, we describe connectivity changes between these structures that predict successful item encoding and that precede item retrieval. Oscillatory power during retrieval matched the pattern we observed during encoding, with low-frequency (below 15 Hz) desynchronization and a gamma band (especially high gamma, 70-180 Hz) power increase. Encoding is characterized by synchrony between the hippocampus and PCC, centered at 3 Hz, consistent with other observations of properties of this oscillation akin to those for rodent theta activity. We discuss our findings in light of existing theories of episodic memory processing, including the information via desynchronization hypothesis and retrieved context theory, and examine how our data fit with existing theories for the functional role of the PCC. These include a postulated role for the PCC in modulating internally directed attention and for representing or integrating contextual information for memory items.