Biomedical subjects

Daniel Tranel

Publications and source records attributed to Daniel Tranel.

At least 19 recordsLinked to original sources

PubMed2007

Age of seizure onset, functional reorganization, and neuropsychological outcome in temporal lobectomy.

Patients with early onset seizure disorder tend to have less cognitive decline following surgical resection than patients with late onset seizure disorder. Differential opportunity for presurgical cerebral functional reorganization has been proposed to account for this "age of onset" effect. However, the relationships between age of seizure onset, functional organization, and neuropsychological outcome remain incompletely understood. To shed additional light on these issues, we investigated 66 patients with anterior temporal lobectomies (37 left; 29 right), all of whom completed comprehensive neuropsychological assessment prior to and following surgical resection. The sample was divided into two groups: 34 patients with early onset (EO) epilepsy and 32 patients with late onset (LO) epilepsy. We found the typical age of onset effect: post-surgically, EO patients demonstrated relatively better outcome in multiple neuropsychological domains, especially verbal memory, compared to LO patients. Based on presurgical Wada testing, 23 patients were classified as having traditional cerebral functional organization (TFO) and 35 were classified as having nontraditional cerebral functional organization (NTFO). The NTFO group had an earlier age of seizure onset than the TFO group, and NTFO was more frequent in EO patients (70%) than LO patients (50%). NTFO patients demonstrated relatively better post-surgical outcome in several neuropsychological domains, compared to TFO patients. Our findings are consistent with the notion that functional reorganization may be an explanatory factor for the better neuropsychological outcome of EO epilepsy patients following anterior temporal lobectomy.

Adult↗

PubMed2006

The long and the short of it: relational memory impairments in amnesia, even at short lags.

Classic studies of amnesia led to characterizations of hippocampal function emphasizing involvement in long-term memory rather than short-term (or working) memory. In two experiments, we show that when memory for relations among co-occurring items is tested, hippocampal amnesia results in a deficit even at very short lags. Hence, we find evidence for hippocampal involvement in relational memory, even at short lags normally considered the province of working memory.

Amnesia↗

PubMed2006

Cardiovascular and respiratory responses during musical mood induction.

Music is used to induce moods in experimental settings as well as for therapeutic purposes. Prior studies suggest that subjects listening to certain types of music experience strong moods and show physiological responses associated with the induced emotions. We hypothesized that cardiovascular and respiratory patterns could discriminate moods induced via music. 18 healthy subjects listened to 12 music clips, four each to induce happiness, sadness, and fear, while cardiovascular and respiratory responses were recorded using an electrocardiogram and chest strain-gauge belt. After each clip subjects completed a questionnaire. Subjects consistently reported experiencing the targeted mood, suggesting successful mood induction. Cardiovascular activity was measured by calculating time domain measures and heart rate changes during each clip. Respiratory activity was measured by total, inspiration, and expiration lengths as well as changes in mean respiration rate during each clip. Evaluation of individuals' patterns and mixed-model analyses were performed. Contrary to expectations, the time domain measures of subjects' cardiovascular responses did not vary significantly between the induced moods, although a heart rate deceleration was found during the sadness inductions and acceleration during the fear inductions. The time domain respiratory measures varied with clip type: the mean breath length was longest for the sad induction, intermediate during fear, and shortest during the happiness induction. However, analysis using normalized least mean squares adaptive filters to measure time correlation indicated that much of this difference may be attributable to entrainment of respiration to characteristics of the music which varied between the stimuli. Our findings point to the difficulty in detecting psychophysiological correlates of mood induction, and further suggest that part of this difficulty may arise from failure to differentiate it from tempo-related contributions when music is used as the inducer.

Adult↗

PubMed2006

Psychophysiological anticipation of positive outcomes promotes advantageous decision-making in normal older persons.

Previous studies have demonstrated that aging has an adverse effect on laboratory decision-making in some older adults, and such findings have important implications for real-world reasoning and judgment. Emotion, and its accompanying somatic responses, is thought to contribute significantly to decision-making. In the present study, we had two objectives: 1) to investigate decision-making in a new sample of elderly participants, using the Iowa Gambling Task (IGT); and 2) to investigate psychophysiological correlates of decision-making, focusing on anticipatory skin conductance responses (SCRs) that participants produce immediately prior to their behavioral response. We hypothesized that the previous behavioral findings would be replicated, and further, that the older adult participants with IGT impairments would show a lack of discriminatory anticipatory SCRs during the IGT. The results supported both predictions. First, a subgroup of the new elderly sample demonstrated impaired decision-making on the IGT, replicating our previous findings. Second, the participants with impaired IGT performance failed to demonstrate discriminatory anticipatory SCRs for advantageous versus disadvantageous choices, whereas participants with normal IGT performance did demonstrate such discrimination; in the latter case, however, SCR magnitude was higher for advantageous decisions (unlike the pattern in young normal adults). Our data lead to the suggestion that strong decision-making abilities among older adults may be a function of positive somatic markers, whereas poor decision-making abilities may arise from an abnormal somatic response generated in anticipation of a future event.

Aged↗

PubMed2006

The influence of autonomic arousal and semantic relatedness on memory for emotional words.

Increased memory for emotional stimuli is a well-documented phenomenon. Emotional arousal during the encoding of a stimulus is one mediator of this memory enhancement. Other variables such as semantic relatedness also play a role in the enhanced memory for emotional stimuli, especially for verbal stimuli. Research has not addressed the contributions of emotional arousal, indexed by self-report and autonomic measures, and semantic relatedness on memory performance. Twenty young adults (10 women) were presented neutral-unrelated words, school-related words, moderately arousing emotional words, and highly arousing taboo words while heart rate and skin conductance were measured. Memory was tested with free recall and recognition tests. Results showed that taboo words, which were both semantically related and high arousal were remembered best. School-related words, which were high on semantic relatedness but low on arousal, were remembered better than the moderately arousing emotional words and semantically unrelated neutral words. Psychophysiological responses showed that within the moderately arousing emotional and neutral word groups, those words eliciting greater autonomic activity were better remembered than words that did not elicit such activity. These results demonstrate additive effects of semantic relatedness and emotional arousal on memory. Relatedness confers an advantage to memory (as in the school-words), but the combination of relatedness and arousal (as in the taboo words) results in the best memory performance.

Adolescent↗

PubMed2006

Preface: psychophysiology and cognitive neuroscience.

The intersection of psychophysiology and cognitive neuroscience has proved to be fertile ground for advancing our understanding of the neurobiological basis of behavior. The eight original empirical articles in this special issue contribute a variety of new evidence for how various bodily processes interrelate with brain processes, especially in the service of emotions and feelings. The findings are rich in their own right, and they also underscore the value of psychophysiological approaches in the investigation of brain-behavior relationships. This type of work is helping to shape a new field of "affective neuroscience."

Brain↗

PubMed2006

Effects of intraoperative hypothermia on neuropsychological outcomes after intracranial aneurysm surgery.

OBJECTIVE: Subarachnoid hemorrhage and surgical obliteration of ruptured intracranial aneurysms are frequently associated with neurological and neuropsychological abnormalities. We reported that intraoperative cooling did not improve neurological outcome in good-grade surgical subarachnoid hemorrhage patients, as assessed by the Glasgow Outcome Scale score or other neurological and functional measures (National Institutes of Health Stroke Scale, Rankin Disability Scale, Barthel Activities of Daily Living). We now report the results of neuropsychological testing in these patients. METHODS: A total of 1,001 patients who bled < or = 14 days before surgery were randomly assigned to intraoperative hypothermia (t = 33 degrees C) or normothermia (37 degrees C). Outcome was assessed approximately 3 months after surgery. Patients underwent the Benton Visual Retention, Controlled Oral Word Association, Rey-Osterrieth Complex Figure, Grooved Pegboard, and the Trail Making tests. T-scores for each test were calculated from normative data. T-scores were averaged to calculate a Composite Score. A test result (or the Composite Score) was considered "impaired" if the T-score was two or more standard deviations below the norm. A Mini-Mental State Examination was also performed. RESULTS: Neurological outcome data were available in 1,000 patients. Sixty-one patients died. Of the 939 survivors, 873 completed 3 or more tests (exclusive of the Mini-Mental State Examination). Patients with poor neurological outcomes were less likely to complete testing; only 3.9% of Good Outcome (Glasgow Outcome Scale score = 1) patients were untested, compared with 38.6% of patients with Glasgow Outcome Scale scores of 3 and 4. There were no prerandomization demographic differences between the two treatment groups. For hypothermic patients, 16.8% were impaired from their Composite Score versus 20.0% of patients in the normothermic group (p = 0.317). For patients in the hypothermic group, 54.5% were impaired on at least one test, compared with 55.5% of patients in the normothermic group (p = 0.865). Similar results were seen in patients with baseline WFNS scores = I. Mini-Mental State Examination scores in the hypothermic and normothermic groups were 27.4 +/- 3.8 and 26.8 +/- 4.5, respectively. INTERPRETATION: This is the largest prospective evaluation of neuropsychological function after subarachnoid hemorrhage to date. Testing was completed in a high fraction of patients, demonstrating the feasibility of such testing in a large trial. However, the frequent inability to complete testing in poor-outcome patients suggests that testing may be best used to refine outcome assessments in good-grade patients. Many patients showed impairment on at least one test, with global impairment present in 17 to 20% of patients (18-21% of survivors). This was true even among the patients with the best preoperative condition (WFNS = 1). There was no difference in the incidence of impairment between hypothermic and normothermic groups.

Aged↗

PubMed2006

Specific reading and phonological processing deficits are associated with damage to the left frontal operculum.

Functional neuroimaging studies in normal subjects indicate that a region in the left frontal operculum (FO) is more active when subjects read pronounceable nonwords as compared to most word types. Here, we report convergent evidence on this finding using the lesion method. We tested the prediction that subjects with left FO damage would have impaired reading of pronounceable nonwords, but relatively intact reading of most word types. Eleven target subjects with circumscribed left FO lesions, and two comparison groups of either brain-damaged or normal subjects matched to the target subjects for age, sex, handedness, and education, were studied using reading tasks derived from previous neuroimaging work. As predicted, the FO group was significantly less accurate than the comparison groups at reading nonwords. By contrast, the FO subjects showed relatively intact word reading, a pattern consistent with the syndrome of "phonological dyslexia". The FO subjects, however, did exhibit particular difficulty reading low frequency words with inconsistent grapheme-to-phoneme correspondences (e.g., PINT), which parallels the finding from functional imaging studies that reading such items produces more activation in left FO than reading high frequency words and low frequency words with consistent grapheme-to-phoneme correspondences (e.g., JADE) (Fiez et al., 1999). In several follow-up experiments, we found that the FO subjects were also impaired on other phonological tasks that have been associated with left frontal opercular activation in functional neuroimaging studies. The findings converge nicely with extant functional imaging work, and provide further evidence that regions within the left FO are part of a system that makes specific and critical contributions to some of the phonological processes that support reading.

Adult↗

PubMed2006

Impairments of emotion and real-world complex behavior following childhood- or adult-onset damage to ventromedial prefrontal cortex.

The behavioral syndrome resulting from damage to the ventromedial prefrontal (VM) region presents major challenges for clinical assessment and management, stemming from the absence of reliable neurologic or psychometric markers, coupled with often debilitating impairments of decision-making and behavior regulation. Damage to this region disrupts neural circuitry critical for emotion, which in turn may contribute to impairments in real-world competencies. Here we present findings from patients with focal lesions in the VM region acquired either in childhood or adulthood, and show that there is a relationship between emotional dysfunction and impairments in real-world behavioral competencies. Emotion was rated by participants' relatives on dimensions including frustration tolerance, lability, anxiety, and blunted affect. Real-world competencies were rated by the relatives on dimensions including judgment, planning, and initiation, and were evaluated by clinician ratings in areas including social, financial, and occupational function. VM damage resulted in severe disruption of emotion, and this emotional dysfunction accounted for a significant portion of impaired real-world competencies. The long-term impairments associated with childhood-onset lesions were at least as severe as those resulting from adult-onset damage. Greater focus on the contribution of emotional dysfunction to the real-world competencies of patients with damage in the VM region may sharpen their neuropsychological assessment and facilitate rehabilitation efforts.

Adult↗

PubMed2006

Impaired naming of unique landmarks is associated with left temporal polar damage.

Previous studies have shown that the left temporal polar (TP) region is important for the retrieval of proper names for persons. It has been proposed that the key specialization of left TP is for proper nouns (rather than names for persons, per se), which predicts that left TP should support other categories whose members are denoted by proper names (e.g., landmarks). A lesion study tested the hypothesis that impaired naming of famous unique landmarks would be associated with damage to left TP. A Landmark Recognition and Naming Test was administered to participants with lesions to left TP, right TP, or regions outside TP. The results provided strong support for the hypothesis: Landmark naming was significantly inferior in the left group, supporting the hypothesis. The findings converge with previous lesion and functional imaging data to support the idea that the left TP region is important for the retrieval of names for unique entities. This fits the proposal that left TP contains convergence regions that operate as intermediaries between conceptual knowledge retrieval and lexical retrieval for classes of unique stimuli (H. Damasio, D. Tranel, T. J. Grabowski, R. Adolphs, & A. R. Damasio, 2004).

Adult↗

PubMed2006

Knowing "what" and knowing "when".

The ability to situate autobiographical memories accurately in the "time-line" of one's own life is a particular aspect of retrograde memory that has received little attention in well-controlled, systematic studies. Here, we addressed this issue by testing the hypothesis that patients with basal forebrain damage would be impaired in their ability to place various autobiographical memories accurately on a 'time-line' of their life. Seven such subjects were contrasted with 11 medial temporal lobe subjects, 8 brain-damaged comparison subjects, and 18 normal comparison subjects, using a procedure in which subjects placed autobiographical events on a time-line of their life. The basal forebrain group was very impaired in this task, relative to the other groups, and on average, misplaced events by more than five years. Although the basal forebrain group was also impaired in retrieving the contents of autobiographical memory, they did not differ statistically from the medial temporal lobe group in this regard (and the medial temporal lobe group did not have impaired time placement of memories). The results indicate an intriguing dissociation between "knowing what" and "knowing when," and suggest that the basal forebrain contains structures that are especially important for "knowing when." Our findings are compatible with the view that the basal forebrain participates critically in retrieval strategies important for memory chronology, which contrasts with the medial temporal lobe's critical role in relational memory per se.

Adult↗

PubMed2006

Correlations between regional brain volumes and memory performance in anoxia.

This study was aimed at investigating the quantitative relationship between regional brain volumes (hippocampus, amygdala, as well as cerebrum, frontal lobe, parietal lobe, temporal lobe) and performance on anterograde and retrograde memory tests in anoxic patients. We used high-resolution MRI to measure brain volumes in 13 anoxic patients. Neuropsychological testing was conducted contemporaneously with MRI. To control for age and sex, neuroanatomical volume residuals were calculated using regression equations derived from a group of 87 healthy comparison participants. We found that anoxic patients with severe amnesia had hippocampal volumes that were 36% smaller than normal, whereas patients with mild or no amnesia had normal hippocampal volumes. Regional gray matter volumes in severe amnesic anoxics were substantially smaller than expected. Performances on anterograde memory tests were significantly correlated with hippocampal and regional gray matter volume residuals. There was a significant correlation between white matter volume (but not hippocampal volume) and performance on the Visual Retention Test, a multi-dimensional test of cognitive function. There were no significant correlations between neuroanatomical measures and performance on a retrograde memory test. Our results indicate a strong quantitative relationship between performance on anterograde memory tests and hippocampal and regional gray matter volume residuals. Correlations between white matter volume residuals and performance on the VRT were found to be independent of hippocampal volume. Given the strong correlation between hippocampal volume and total gray matter volume residuals, a quantitative, normalized measure of total gray matter volume may provide a good indication of clinical outcome in anoxia.

Adult↗

PubMed2005

Development of shared information in communication despite hippocampal amnesia.

This study investigated the ability of individuals with amnesia to acquire referential labels across a series of collaborative, dynamic interactions with a communication partner. Despite their inability to learn arbitrary relations in paired-associate learning, the amnesic patients showed remarkably robust collaborative learning across trials, at a rate equal to that of normal comparison subjects. The amnesic participants' learning resulted in their arriving at labels for a set of abstract shapes (tangrams), thus facilitating rapid and efficient communication. The labels generated and used by the amnesics during interactions with their partners became simpler across trials, with most labels stabilizing long before the end of training and then being used consistently throughout; moreover, they endured long after the task had ended. These findings have important implications for understanding the memory systems involved in semantic learning and in acquiring shared knowledge ('common ground') among communication partners, and the nature of hippocampal-dependent versus hippocampal-independent learning.

Adult↗

PubMed2005

Neural systems responding to degrees of uncertainty in human decision-making.

Much is known about how people make decisions under varying levels of probability (risk). Less is known about the neural basis of decision-making when probabilities are uncertain because of missing information (ambiguity). In decision theory, ambiguity about probabilities should not affect choices. Using functional brain imaging, we show that the level of ambiguity in choices correlates positively with activation in the amygdala and orbitofrontal cortex, and negatively with a striatal system. Moreover, striatal activity correlates positively with expected reward. Neurological subjects with orbitofrontal lesions were insensitive to the level of ambiguity and risk in behavioral choices. These data suggest a general neural circuit responding to degrees of uncertainty, contrary to decision theory.

Adult↗

PubMed2005

Memories for emotional autobiographical events following unilateral damage to medial temporal lobe.

Abnormalities of both memory and emotion have been reported in patients with unilateral damage to the anteromedial temporal lobe, probably reflecting the functions of the amygdala and hippocampus in these processes. Emotion and memory are also known to interact: emotional experiences often leave remarkably durable autobiographical memories. To explore this interaction, and to extend prior studies to the domain of autobiographical memory, we investigated the recollection of real-life emotional events in patients with unilateral damage to the anteromedial temporal lobe. Twenty-three patients who had undergone unilateral temporal lobectomy for the treatment of epilepsy (12 left, 11 right) and 20 healthy comparison participants completed an emotional autobiographical memory test. Participants were asked to recollect their five most emotional memories from any time in their lives and then they completed a word-cued autobiographical memory task. Participants dated each memory and gave ratings on scales of pleasantness, intensity, significance, novelty, vividness and frequency of rehearsal. Left temporal lobectomy (LTL) and healthy comparison groups generated similar numbers of pleasant and unpleasant memories, whereas the right temporal lobectomy (RTL) group produced significantly fewer memories of unpleasant events (P < 0.01). When memories were further categorized according to pleasantness and intensity, the RTL group produced significantly fewer unpleasant/high intensity memories than the other groups (P < 0.01). All groups reported more memories from between the ages of 10 and 30 (the so-called autobiographical memory 'bump'). The results demonstrate a positive bias in the recollection of autobiographical memory following right-sided anteromedial temporal damage. This finding is consistent with the notion that the right, but not the left, anteromedial temporal lobe is involved in the retrieval of negatively valenced, high-intensity memories.

Adult↗

PubMed2005

Does gender play a role in functional asymmetry of ventromedial prefrontal cortex?

We found previously in a lesion study that the right-sided sector of the ventromedial prefrontal cortices (VMPCs) was critical for social/emotional functioning and decision-making, whereas the left side appeared to be less important. It so happened that all but one of the subjects in that study were men, and the one woman did not fit the pattern very well. This prompted a follow-up investigation, in which we explored the following question: Does gender play a role in the development of defects in social conduct, emotional functioning and decision-making, following unilateral VMPC damage? We culled from our Patient Registry same-sex pairs of men or women patients who had comparable unilateral VMPC damage in either the left or right hemisphere. Two male pairs and one female pair were formed, and we included two additional women with unilateral right VMPC damage (8 patients in all). The domains of measurement covered social conduct, emotional processing and personality, and decision-making. We found a systematic effect of gender on the pattern of left-right asymmetry in VMPC. In men, there were severe defects following unilateral right VMPC damage, but not following left-sided damage. In women, there were defects following unilateral left VMPC damage; following right-sided damage, however, defects were mild or absent. The findings suggest that men and women may use different strategies to solve similar problems--e.g. men may use a more holistic, gestalt-type strategy, and women may use a more analytic, verbally-mediated strategy. Such differences could reflect asymmetric, gender-related differences in the neurobiology of left and right VMPC sectors.

Adult↗

PubMed2005

Emotional autobiographical memories in amnesic patients with medial temporal lobe damage.

The recollection of emotional autobiographical memories has received little attention in patients with memory disorders. Here, we addressed this topic in amnesic patients with damage to the hippocampus (HC group; n = 8) or the hippocampus, amygdala, and surrounding cortices (HC+ group; n = 2). These patients were asked to recollect emotional events from their lives. HC patients produced recollections that were strikingly similar to those of brain-damaged (n = 10) and healthy (n = 25) comparison participants, in terms of both quantity and quality. In contrast, HC+ patients produced a lower proportion of unpleasant memories compared with the other participants. Specifically, the ratings and words used to describe recollections in the HC+ patients were more affectively positive. All groups produced more memories from between 10 and 30 years of age (the so-called autobiographical memory "bump") compared with other time periods in their lives. These results suggest that structures surrounding the hippocampus, but not the hippocampus itself, may be necessary for the recollection of highly emotional, unpleasant autobiographical memories. The amygdala and surrounding cortices of the medial temporal lobe may be a necessary component in the neural circuitry necessary for vivid recollection of unpleasant emotional events.

Adult↗

PubMed2005

Amygdala damage impairs emotional memory for gist but not details of complex stimuli.

Neurobiological studies demonstrate the amygdala's role in emotional memory, and psychological studies suggest a particular pattern: enhanced memory for the gist but not the details of complex stimuli. We hypothesized that these two findings are related. Whereas normal (n = 52) and brain-damaged (n = 22) controls showed the expected enhancement of gist memory when the encoding context was emotional, persons with unilateral damage to the medial temporal lobe including the amygdala (n = 16) did not show this pattern. Furthermore, amygdala volume showed a significant positive correlation with gist memory but not with overall memory. A further study in four subjects with selective medial temporal damage sparing the amygdala, and one with selective damage confined to the amygdala, confirmed the specificity of this effect to the amygdala. The data support a model whereby the amygdala focuses processing resources on gist, possibly accounting for features of traumatic memories and eyewitness testimony in real life.

Adult↗