Auditory Recognition Memory Research Articles

ID 88 – Anterior thalamus in cognition: An intracerebral recording study

Objective To study the involvement of the anterior thalamic nuclei (ANT) in the cognitive processes. Methods We recorded the event-related potentials (ERPs) by visual and auditory memory encoding-recognition tasks by intracerebral recordings in patients with pharmacoresistent epilepsy who underwent the deep brain stimulation (DBS) surgery of the anterior thalamic nuclei with depth electrodes implanted bilaterally in the ANT. We compared the results with epilepsy-surgery candidates with depth electrodes implanted bilaterally in the hippocampus. Results In the ANT we recorded ERPs during the visual encoding and visual and auditory recognition tasks. No significant ERPs were recorded during the encoding phase by auditory stimuli in ANT. In hippocampus ERPs were recorded by visual and auditory memory encoding and recognition tasks. In the recognition tasks (visual and auditory) the ERPs in ANT preceded the ERPs in hippocampus. Conclusions ERPs are elicited by visual memory encoding and recognition, as well as by auditory recognition memory processes, but not by encoding auditory memory processing in the ANT. The ANT precedes the hippocampus in the memory recognition pathway. Key message ANT has a specific role in the memory processes, especially the memory recognition.

Impact of Fetal-Neonatal Iron Deficiency on Recognition Memory at 2 Months of Age

To assess the effects of fetal-neonatal iron deficiency on recognition memory in early infancy. Perinatal iron deficiency delays or disrupts hippocampal development in animal models and thus may impair related neural functions in human infants, such as recognition memory. Event-related potentials were used in an auditory recognition memory task to compare 2-month-old Chinese infants with iron sufficiency or deficiency at birth. Fetal-neonatal iron deficiency was defined 2 ways: high zinc protoporphyrin/heme ratio (ZPP/H > 118 μmol/mol) or low serum ferritin (<75 μg/L) in cord blood. Late slow wave was used to measure infant recognition of mother's voice. Event related potentials patterns differed significantly for fetal-neonatal iron deficiency as defined by high cord ZPP/H but not low ferritin. Comparing 35 infants with iron deficiency (ZPP/H > 118 μmol/mol) to 92 with lower ZPP/H (iron-sufficient), only infants with iron sufficiency showed larger late slow wave amplitude for stranger's voice than mother's voice in frontal-central and parietal-occipital locations, indicating the recognition of mother's voice. Infants with iron sufficiency showed electrophysiological evidence of recognizing their mother's voice, whereas infants with fetal-neonatal iron deficiency did not. Their poorer auditory recognition memory at 2 months of age is consistent with effects of fetal-neonatal iron deficiency on the developing hippocampus.

Is cortisol the driving force behind acute stress effects on the PRSE and PRP effect?

Being centrally obeseorpossessing ahighwaist-hip ratio (WHR) is often associated with elevated cortisol, which may increase vulnerability to stress (Epel et al., 2000). A high WHR combined with stress exposure can also lead to cognitive impairment (Lasikiewicz et al., 2013). These observations are predominantly derived from Western populations. It is unclear whether the same holds true for Southeast Asians based on noted differences in body shape. The current study explored differences in WHR, salivary cortisol and cognitive performance in 49 Chinese Singaporeans (mean age 51±6.43 years). Cognitive performance was assessed before and after exposure to the Trier Social Stress Test (TSST; Kirschbaum et al., 1993) versus no-stress control. The TSST was effective in inducing a psychological and physiological stress response. Further, high WHR females exposed to stress secreted more cortisol across the experimental session compared to no-stress or lowWHR females. When considered in terms of responders versus nonresponders based on cortisol change, highWHR female responders exhibited poorer performance on the Auditory Verbal Learning (delayed recall) and Spatial Recognition Memory tasks. However, the samewas not true formales. The findings offer some continued support for the suggestion that subtle interactions exist between stress and central obesity, which may influence stress responsivity and cognition but only in females. More research is needed to elucidate the mechanisms which give rise to these effects, particularly in Asian samples, with due consideration of the adequacy of markers of central obesity in this population.

Anatomical pathways for auditory memory II: information from rostral superior temporal gyrus to dorsolateral temporal pole and medial temporal cortex

Auditory recognition memory in non-human primates differs from recognition memory in other sensory systems. Monkeys learn the rule for visual and tactile delayed matching-to-sample within a few sessions, and then show one-trial recognition memory lasting 10–20 min. In contrast, monkeys require hundreds of sessions to master the rule for auditory recognition, and then show retention lasting no longer than 30–40 s. Moreover, unlike the severe effects of rhinal lesions on visual memory, such lesions have no effect on the monkeys' auditory memory performance. The anatomical pathways for auditory memory may differ from those in vision. Long-term visual recognition memory requires anatomical connections from the visual association area TE with areas 35 and 36 of the perirhinal cortex (PRC). We examined whether there is a similar anatomical route for auditory processing, or that poor auditory recognition memory may reflect the lack of such a pathway. Our hypothesis is that an auditory pathway for recognition memory originates in the higher order processing areas of the rostral superior temporal gyrus (rSTG), and then connects via the dorsolateral temporal pole to access the rhinal cortex of the medial temporal lobe. To test this, we placed retrograde (3% FB and 2% DY) and anterograde (10% BDA 10,000 mW) tracer injections in rSTG and the dorsolateral area 38DL of the temporal pole. Results showed that area 38DL receives dense projections from auditory association areas Ts1, TAa, TPO of the rSTG, from the rostral parabelt and, to a lesser extent, from areas Ts2-3 and PGa. In turn, area 38DL projects densely to area 35 of PRC, entorhinal cortex (EC), and to areas TH/TF of the posterior parahippocampal cortex. Significantly, this projection avoids most of area 36r/c of PRC. This anatomical arrangement may contribute to our understanding of the poor auditory memory of rhesus monkeys.

The positivity effect and auditory recognition memory for musical excerpts in young, middle-aged, and older adults.

The term was coined to describe older adults' preferential processing of positive information over negative information in visual memory recognition studies (Reed & Carstensen, 2012). The socioemotional selectivity theory (Carstensen, 1995) postulates that, as a result of changes in motivation toward future goals, emotional priorities change over the life span. Young adults and those who perceive no limitation of time are motivated to expand their horizons in terms of acquiring information and broadening their number of social contacts. Older adults and those who perceive limitations in their time remaining are motivated to focus on the present and narrow their social contacts to meaningful relationships with family and close friends (Carstensen, 2006). The shift in goals contributes to differences in how information is processed. Socioemotional selectivity theory predicts that because of this shift over time, older adults will prefer processing positive information rather than negative information in contrast to the preferences of younger adults (Reed, Chan, & Mikels, 2014).The positivity effect has been widely demonstrated in memory recognition studies using visual stimuli (Charles, Mather, & Carstensen, 2003; Mather & Carstensen, 2003; Mickley, Steinmetz, Muscatell, & Kensinger, 2010; Mikels, Larken, ReuterLorenz, & Carstensen, 2005; Spaniol, Voss & Grady, 2008). The positivity effect in terms of emotion perception by older adults has also been found in studies using auditory stimuli, specifically music. Laukka and Juslin (2007) examined age-related differences in emotion recognition as expressed in speech and music. Older adults were less accurate in their recognition of negative emotion expression than positive for speech and music stimuli. Lima and Castro (2011) further examined age-related changes in emotion recognition expressed by music. Participants ranging in age from 17- 84 years were asked to listen to musical excerpts portraying happiness, sadness, scariness, and peacefulness. They were then asked to rank how much each excerpt represented each emotional quality. An age-related difference was noted, with older adults not as responsive to sad and scary music as young adults. No agerelated difference was noted for happy and peaceful music. Vieillard, Didierjean, and Maquestiaux (2012) examined age-related differences in determining complexity in the perception of valence and arousal while listening to excerpts of film music. Older adults did not rate peaceful and threatening excerpts as significantly different. The older adults may not have found the threatening music to be stimulating and may have paid less attention to negatively arousing stimuli as a way of controlling their emotional responses to the music (Vieillard et al., 2012). In sum, the results of studies using visual as well as auditory stimuli provide support for the positivity effect because older adults were more responsive to stimuli representing positive emotions than they were to stimuli representing negative emotions. The goal of the present study was to examine the presence of the positivity effect in recognition memory for music.There were three objectives for the current study. The first objective was to investigate age-related differences in the interaction between emotion and cognition based on recognition of emotionally valenced musical stimuli. The precise goal of the study was to examine if the positivity effect based on the socioemotional selectivity theory (Carstensen, 1992) would be generalized to recognition memory in an auditory domain, specifically music. Young, middle-aged, and older adults listened to carefully chosen musical excerpts for later recognition memory, in addition to completing cognitive tests and measures of affect. We hypothesized that if older adults in the sample demonstrated the positivity effect for recognition memory of musical excerpts, they would recognize proportionally more of the pleasant excerpts than they would the unpleasant. …

Low-Level Prenatal Lead Exposure Alters Auditory Recognition Memory in 2-Month-Old Infants: An Event-Related Potentials (ERPs) Study

This study used event-related potentials (ERPs) to assess effects of low-level prenatal lead exposure on auditory recognition memory in 2-month-old infants. Infants were divided into four groups according to cord-blood lead concentration: (1) <2.00 μg/dL, (2) 2.00–2.99 μg/dL, (3) 3.0–3.7 μg/dL, and (4) ≥3.7 μg/dL. The first group showed the normally expected differences in P2, P750, and late slow wave (LSW) amplitudes elicited by mothers’ and strangers’ voices. These differences were not observed for one or more ERP components in the other groups. Thus, there was electrophysiological evidence of poorer auditory recognition memory at 2 months with cord-blood lead ≥2.00 μg/dL.

Neural correlates of auditory recognition memory in the primate dorsal temporal pole

Temporal pole (TP) cortex is associated with higher-order sensory perception and/or recognition memory, as human patients with damage in this region show impaired performance during some tasks requiring recognition memory (Olson et al. 2007). The underlying mechanisms of TP processing are largely based on examination of the visual nervous system in humans and monkeys, while little is known about neuronal activity patterns in the auditory portion of this region, dorsal TP (dTP; Poremba et al. 2003). The present study examines single-unit activity of dTP in rhesus monkeys performing a delayed matching-to-sample task utilizing auditory stimuli, wherein two sounds are determined to be the same or different. Neurons of dTP encode several task-relevant events during the delayed matching-to-sample task, and encoding of auditory cues in this region is associated with accurate recognition performance. Population activity in dTP shows a match suppression mechanism to identical, repeated sound stimuli similar to that observed in the visual object identification pathway located ventral to dTP (Desimone 1996; Nakamura and Kubota 1996). However, in contrast to sustained visual delay-related activity in nearby analogous regions, auditory delay-related activity in dTP is transient and limited. Neurons in dTP respond selectively to different sound stimuli and often change their sound response preferences between experimental contexts. Current findings suggest a significant role for dTP in auditory recognition memory similar in many respects to the visual nervous system, while delay memory firing patterns are not prominent, which may relate to monkeys' shorter forgetting thresholds for auditory vs. visual objects.

Neural correlates of auditory recognition memory in primate lateral prefrontal cortex

The neural underpinnings of working and recognition memory have traditionally been studied in the visual domain and these studies pinpoint the lateral prefrontal cortex (lPFC) as a primary region for visual memory processing (Miller et al., 1996; Ranganath et al., 2004; Kennerley and Wallis, 2009). Herein, we utilize single-unit recordings for the same region in monkeys (Macaca mulatta) but investigate a second modality examining auditory working and recognition memory during delayed matching-to-sample (DMS) performance. A large portion of neurons in the dorsal and ventral banks of the principal sulcus (area 46, 46/9) show DMS event-related activity to one or more of the following task events: auditory cues, memory delay, decision wait time, response, and/or reward portions. Approximately 50% of the neurons show evidence of auditory-evoked activity during the task and population activity demonstrated encoding of recognition memory in the form of match enhancement. However, neither robust nor sustained delay activity was observed. The neuronal responses during the auditory DMS task are similar in many respects to those found within the visual working memory domain, which supports the hypothesis that the lPFC, particularly area 46, functionally represents key pieces of information for recognition memory inclusive of decision-making, but regardless of modality.

Auditory Recognition Memory in 2-Month-Old Infants as Assessed by Event-Related Potentials

Previous studies of auditory recognition memory in sleeping newborns reported 2 event-related potential (ERP) components, P2 and negative slow wave (NSW), reflecting voice discrimination and detection of novelty, respectively. In the present study, using high-density recording arrays, ERPs were acquired from 26 2-month-old awake infants as they were presented with a familiar and unfamiliar voice (i.e., mother and stranger) with equal probability. In addition to P2 and NSW, we observed a positive slow wave (PSW) over the right temporo-parietal scalp, indicating memory updating. Our study suggests that infants appear to have the capacity to encode novel stimuli as early as 2 months of age.

Auditory and visual memory in musicians and nonmusicians.

Numerous studies have shown that musicians outperform nonmusicians on a variety of tasks. Here we provide the first evidence that musicians have superior auditory recognition memory for both musical and nonmusical stimuli, compared to nonmusicians. However, this advantage did not generalize to the visual domain. Previously, we showed that auditory recognition memory is inferior to visual recognition memory. Would this be true even for trained musicians? We compared auditory and visual memory in musicians and nonmusicians using familiar music, spoken English, and visual objects. For both groups, memory for the auditory stimuli was inferior to memory for the visual objects. Thus, although considerable musical training is associated with better musical and nonmusical auditory memory, it does not increase the ability to remember sounds to the levels found with visual stimuli. This suggests a fundamental capacity difference between auditory and visual recognition memory, with a persistent advantage for the visual domain.

Auditory recognition memory is inferior to visual recognition memory

Visual memory for scenes is surprisingly robust. We wished to examine whether an analogous ability exists in the auditory domain. Participants listened to a variety of sound clips and were tested on their ability to distinguish old from new clips. Stimuli ranged from complex auditory scenes (e.g., talking in a pool hall) to isolated auditory objects (e.g., a dog barking) to music. In some conditions, additional information was provided to help participants with encoding. In every situation, however, auditory memory proved to be systematically inferior to visual memory. This suggests that there exists either a fundamental difference between auditory and visual stimuli, or, more plausibly, an asymmetry between auditory and visual processing.

Primate auditory recognition memory performance varies with sound type

Neural correlates of auditory processing, including for species-specific vocalizations that convey biological and ethological significance (e.g., social status, kinship, environment), have been identified in a wide variety of areas including the temporal and frontal cortices. However, few studies elucidate how non-human primates interact with these vocalization signals when they are challenged by tasks requiring auditory discrimination, recognition and/or memory. The present study employs a delayed matching-to-sample task with auditory stimuli to examine auditory memory performance of rhesus macaques ( Macaca mulatta), wherein two sounds are determined to be the same or different. Rhesus macaques seem to have relatively poor short-term memory with auditory stimuli, and we examine if particular sound types are more favorable for memory performance. Experiment 1 suggests memory performance with vocalization sound types (particularly monkey), are significantly better than when using non-vocalization sound types, and male monkeys outperform female monkeys overall. Experiment 2, controlling for number of sound exemplars and presentation pairings across types, replicates Experiment 1, demonstrating better performance or decreased response latencies, depending on trial type, to species-specific monkey vocalizations. The findings cannot be explained by acoustic differences between monkey vocalizations and the other sound types, suggesting the biological, and/or ethological meaning of these sounds are more effective for auditory memory.

Auditory recognition memory is inferior to visual recognition memory

Visual memory for scenes is surprisingly robust. We wished to examine whether an analogous ability exists in the auditory domain. Participants listened to a variety of sound clips and were tested on their ability to distinguish old from new clips. Stimuli ranged from complex auditory scenes (e.g., talking in a pool hall) to isolated auditory objects (e.g., a dog barking) to music. In some conditions, additional information was provided to help participants with encoding. In every situation, however, auditory memory proved to be systematically inferior to visual memory. This suggests that there exists either a fundamental difference between auditory and visual stimuli, or, more plausibly, an asymmetry between auditory and visual processing.

Stimulus- and response-locked neuronal generator patterns of auditory and visual word recognition memory in schizophrenia

Examining visual word recognition memory (WRM) with nose-referenced EEGs, we reported a preserved ERP ‘old-new effect’ (enhanced parietal positivity 300–800 ms to correctly-recognized repeated items) in schizophrenia ([Kayser, J., Bruder, G.E., Friedman, D., Tenke, C.E., Amador, X.F., Clark, S.C., Malaspina, D., Gorman, J.M., 1999. Brain event-related potentials (ERPs) in schizophrenia during a word recognition memory task. Int. J. Psychophysiol. 34(3), 249–265.]). However, patients showed reduced early negative potentials (N1, N2) and poorer WRM. Because group differences in neuronal generator patterns (i.e., sink-source orientation) may be masked by choice of EEG recording reference, the current study combined surface Laplacians and principal components analysis (PCA) to clarify ERP component topography and polarity and to disentangle stimulus- and response-related contributions. To investigate the impact of stimulus modality, 31-channel ERPs were recorded from 20 schizophrenic patients (15 male) and 20 age-, gender-, and handedness-matched healthy adults during parallel visual and auditory continuous WRM tasks. Stimulus- and response-locked reference-free current source densities (spherical splines) were submitted to unrestricted Varimax-PCA to identify and measure neuronal generator patterns underlying ERPs. Poorer (78.2±18.7% vs. 87.8±11.3% correct) and slower (958±226 vs. 773±206 ms) performance in patients was accompanied by reduced stimulus-related left-parietal P3 sources (150 ms pre-response) and vertex N2 sinks (both overall and old/new effects) but modality-specific N1 sinks were not significantly reduced. A distinct mid-frontal sink 50-ms post-response was markedly attenuated in patients. Reductions were more robust for auditory stimuli. However, patients showed increased lateral-frontotemporal sinks (T7 maximum) concurrent with auditory P3 sources. Electrophysiologic correlates of WRM deficits in schizophrenia suggest functional impairments of posterior cortex (stimulus representation) and anterior cingulate (stimulus categorization, response monitoring), primarily affecting memory for spoken words.

Reference‐independent ERP old/new effects of auditory and visual word recognition memory: Joint extraction of stimulus‐ and response‐locked neuronal generator patterns

To clarify polarity, topography, and time course of recognition memory ERP old/new effects during matched visual and auditory continuous word recognition tasks, unrestricted temporal PCA jointly analyzed stimulus- and response-locked, reference-free current source densities (31-channel, N=40). Randomization tests provided unbiased statistics for complete factor topographies. Old/new left parietal source effects were complemented by lateral frontocentral sink effects in both modalities, overlapping modality-specific P3 sources 160 ms preresponse. A mid-frontal sink 45 ms postresponse terminated the frontoparietal generator pattern, showed old/new effects consistent with bilateral activation of anterior cingulate and SMA, and preceded similar activity extending posteriorly along the longitudinal fissure. These methods separated old/new stimulus source (preresponse) and response sink (postresponse) effects from motor and modality-specific ERPs.

Using Event-Related Potentials to Study Perinatal Nutrition and Brain Development in Infants of Diabetic Mothers

Proper prenatal and postnatal nutrition is essential for optimal brain development and function. The early use of event-related potentials enables neuroscientists to study the development of cognitive function from birth and to evaluate the role of specific nutrients in development. Perinatal iron deficiency occurs in severely affected infants of diabetic mothers. In animal models, severe perinatal iron deficiency targets the explicit memory system of the brain. Cross-sectional ERP studies have shown that infants of diabetic mothers have impairments in recognition memory from birth through 8 months of age. The purpose of this study was to evaluate longitudinal development of recognition memory using ERPs in infants of diabetic mothers compared with control infants. Infants of diabetic mothers were divided into high and low risk status based upon their birth weights and iron status and compared with healthy control infants. Infants were tested in the newborn period for auditory recognition memory, at 6 months for visual recognition memory and at 8 months for cross modal memory. ERPs were evaluated for developmental changes in the slow waves that are thought to reflect memory and the Nc component that is thought to reflect attention. The results of the study showed differences in development between the IDMs and control infants in the development of the slow waves over the left anterior temporal leads and age-related patterns of development in the NC component. These results are consistent with animal models showing that perinatal iron deficiency affects the development of the memory networks of the brain. This study highlights the value of using ERPs to translate basic science information obtained from animal models to the development of the human infant.

Birdsong Memory: A Neural Dissociation between Song Recognition and Production

Songbirds learn their song from an adult conspecific tutor when they are young, much like the acquisition of speech in human infants. When an adult zebra finch is re-exposed to its tutor's song, there is increased neuronal activation in the caudomedial nidopallium (NCM), the songbird equivalent of the auditory association cortex. This neuronal activation is related to the fidelity of song imitation, suggesting that the NCM may contain the neural representation of song memory. We found that bilateral neurotoxic lesions to the NCM of adult male zebra finches impaired tutor-song recognition but did not affect the males' song production or their ability to discriminate calls. These findings demonstrate that the NCM performs an essential role in the representation of tutor-song memory. In addition, our results show that tutor-song memory and a motor program for the bird's own song have separate neural representations in the songbird brain. Thus, in both humans and songbirds, the cognitive systems of vocal production and auditory recognition memory are subserved by distinct brain regions.

Different effects of lesions to auditory core and belt cortex on auditory recognition in dogs

Auditory recognition memory, in contrast to memory in other modalities, is not affected by damage to the perihinal cortex, and its neural basis remains unknown. In an attempt to elucidate this problem, we investigated the role of canine auditory core and belt areas in auditory recognition. Either core or posterior belt areas were surgically removed. The core and belt regions were defined on the basis of response properties and thalamocortical connectivity established in previous studies. The animals were tested on auditory delayed matching to sample (DMS, a recognition memory task) using complex, trial-unique auditory stimuli. Both core and belt lesions impaired auditory recognition, however, the underlying deficit was different. Lesions to the core areas impaired auditory localization abilities. Lesions to the posterior belt areas did not affect this component of the recognition task, but affected auditory quality discrimination and/or recognition. The deficit following the posterior belt lesion did not increase with retention delay, suggesting that auditory belt areas do not constitute a substrate for auditory recognition memory. Their main function appears to be processing of complex sound patterns, including immediate recognition.

DEVELOPMENT OF MATERNAL AND PATERNAL VOICE RECOGNITION MEMORY IN NEWBORN INFANTS.

Objective Further understanding of memory development in newborn infants is important because brain structures critical for memory are vulnerable to perinatal injury. Although newborns can recognize their mothers9 voices, there is a high degree of prenatal and postnatal experience, and it is not clear whether lesser degrees of experience will result in memory formation. Our purpose was to further evaluate the role of experience in neonatal auditory recognition memory by comparing how newborns respond to the mother9s voice (high degree of experience) or the father9s voice (less experience) versus a stranger9s voice using event-related potentials (ERPs), a technique commonly used in cognitive neuroscience. Methods Subjects (N = 30) were healthy, term newborns ≤ 4 days of age. ERPs were recorded from 16 standard scalp electrodes during active sleep while listening to recordings of the word “baby” in the mother9s voice alternating with a female stranger9s voice or father9s voice alternating with a male stranger9s voice. Results Of the 15 mothers, 80% spoke specifically to the fetus in utero on a daily basis and all spoke frequently to the infant after birth. Of the 15 fathers, 66% reported talking specifically to the fetus daily (33%) or weekly (33%). Postnatally, 73% of the fathers spent 12 to 24 hours per day rooming-in and 93% spoke frequently to the baby. Infants9 ERPs demonstrated recognition of both mothers9 and fathers9 voices, evidenced by increased negativity to the stranger9s voice from 400 to 1200 msec over the midline frontal electrode (Fz) (mean amplitude for parent9s voice: 2.2 ± 1.8 μv; stranger9s voice: −2.0 ± 1.3 μv; p = .0216), with similar amplitudes for fathers9 and mothers9 voices. There was a significant difference between male and female voices over the right hemisphere, most notable over the posterior right temporal area (T6) from 1,200 to 2,000 msec, with amplitudes for male voices (father and stranger, 1.4 ± 1.4 μv) significantly greater than those elicited by female voices (mother and stranger, −2.0 ± 1.1 μv; p = .045). Conclusion Although pre- and postnatal exposure to the fathers9 voices was less than to the mothers9 voices, the exposures to the fathers9 voices reported in this study were sufficient to elicit ERP patterns associated with recognition memory. Differences in responses between male and female voices over the right hemisphere may indicate the development of specialization within the auditory cortex. Further investigation to quantify the amount of experience required for auditory encoding will be useful in developing assessments for infants at risk of perinatal brain injury.

Interleukin-6 Covaries Inversely With Cognitive Performance Among Middle-Aged Community Volunteers

Recent evidence suggests that higher peripheral levels of interleukin 6 (IL-6) are associated with poorer cognitive function and predict future cognitive decline among the elderly. The current investigation extends the study of relationships between plasma IL-6 and cognitive performance to healthy middle-aged adults and to an examination of more specific cognitive domains. Five hundred relatively healthy community volunteers aged 30 to 54 had blood drawn for the determination of plasma IL-6 levels and completed a battery of neuropsychological tests evaluating memory and executive function. After controlling for age, gender, race, and education, hierarchical regression analyses revealed an inverse relationship between circulating levels of IL-6 and performance on clusters of tests assessing auditory recognition memory, attention/working memory, and executive function. In contrast, there was no association between IL-6 and performance on tests of general memory. Secondary analyses demonstrated that relationships between IL-6 and auditory recognition and working memory and executive function were independent of a number of health factors, including body mass index, smoking, and hypertension. These findings contribute to a growing body of evidence linking chronic inflammation to poorer cognitive functioning and extend these findings to a midlife community sample, raising the possibility that IL-6 may represent a biomarker for risk of future cognitive decline.