Lee X. Blonder

Neural substrates of facial emotion processing using fMRI

We identified human brain regions involved in the perception of sad, frightened, happy, angry, and neutral facial expressions using functional magnetic resonance imaging (fMRI). Twenty-one healthy right-handed adult volunteers (11 men, 10 women; aged 18-45; mean age 21.6 years) participated in four separate runs, one for each of the four emotions. Participants viewed blocks of emotionally expressive faces alternating with blocks of neutral faces and scrambled images. In comparison with scrambled images, neutral faces activated the fusiform gyri, the right lateral occipital gyrus, the right superior temporal sulcus, the inferior frontal gyri, and the amygdala/entorhinal cortex. In comparisons of emotional and neutral faces, we found that (1) emotional faces elicit increased activation in a subset of cortical regions involved in neutral face processing and in areas not activated by neutral faces; (2) differences in activation as a function of emotion category were most evident in the frontal lobes; (3) men showed a differential neural response depending upon the emotion expressed but women did not.

Altered brain activation in cognitively intact individuals at high risk for Alzheimer’s disease

OBJECTIVE To determine whether brain function is altered in cognitively normal individuals at high risk for AD several years before the typical age at onset for this illness. BACKGROUND Neuropathologic alterations in AD precede cognitive impairment by several years. It is unknown whether functional alterations in neural circuitry accompany these neuropathologic changes, and if so, whether they may be detectable before onset of symptoms. METHODS We used functional MRI to compare cortical activation between two groups of cognitively normal women differing only in their risk for developing AD. Visual naming and letter fluency tasks were used to activate brain areas subserving object and face recognition, previously described sites of hypometabolism and neuropathologic alteration in AD. The risk groups differed in family history of AD and apolipoprotein E allele status, but were matched in age, education, and measures of cognitive performance. Average age of the study participants was 52 years. RESULTS The regional patterns of brain activation were similar between groups. However, the high risk group showed areas of significantly reduced activation in the mid- and posterior inferotemporal regions bilaterally during both tasks despite identical naming and letter fluency performance. CONCLUSIONS Cognitively normal individuals at high risk for AD demonstrate decreased brain activation in key areas engaged during naming and fluency tasks. Decreased activation in the high risk group may be a consequence of the presence of subclinical neuropathology in the inferotemporal region or in the inputs to that region. If so, these findings provide evidence of a window of opportunity for disease-modifying treatment before the onset of symptomatic AD.

Women at risk for AD show increased parietal activation during a fluency task

Background Imaging studies have shown disparities in resting metabolism and in functional activation between cognitively normal individuals at high and low risk for AD. A recent study has shown increased parietal activation in high-risk subjects during a paired associates recall task, which the authors postulated might overlap activation typically observed in verbal fluency. Objective To determine whether parietal activation is altered in a letter fluency task in cognitively normal individuals at high risk for AD. MethodsfMRI was used to compare cortical activation between two groups of cognitively normal women differing in their risk for developing AD. A letter fluency task was used, which activates left frontal and parietal regions. The risk groups differed in family history of AD and APOE allele status but were matched in age, education, and measures of cognitive performance. Average age of the study participants was 53 years. Results The regional patterns of brain activation were similar between groups and similar to patterns observed by other investigators. However, the high-risk group showed significantly increased activation in the left parietal region despite identical letter fluency performance between risk groups. Conclusions Cognitively normal individuals at high risk for AD show increased brain activation in the left parietal region with letter fluency, a region adjacent to that observed by others using a recall task. This convergence of results indicates disruption of functional circuits involving the left parietal lobe in asymptomatic individuals at increased risk for AD.

Emotional dysfunction in Parkinson's disease

In addition to motor symptomatology, idiopathic Parkinson’s disease is characterized by emotional dysfunction. Depression affects some 30 to 40 percent of Parkinson patients and other psychiatric co-morbidities include anxiety and apathy. Neuropsychological and neuroimaging studies of emotional dysfunction in Parkinson patients suggest abnormalities involving mesolimbic and mesocortical dopaminergic pathways. There is also evidence suggesting that the interaction between serotonin and dopamine systems is important in the understanding and treatment of mood disorders in Parkinson’s disease. In this review we discuss the neuropsychiatric abnormalities that accompany Parkinsons disease and describe their neuropsychological, neuropharmacologic, and neuroimaging concomitants.

Semantic-phonologic treatment for noun and verb retrieval impairments in aphasia

Nouns and verbs differ in their neural and psycholinguistic attributes. It is not known whether these differences lead to distinct patterns of response to treatment for individuals with word retrieval impairments associated with aphasia. Eight participants with naming disorders induced by left hemisphere strokes were treated with a semantic-phonologic treatment protocol for nouns and verbs using a single participant multiple baseline design. We measured treatment gains in a picture naming measure and other secondary language and communication measures. Treatment led to improved picture naming for trained nouns and verbs in five of eight patients, with no difference evident between nouns and verbs. Improvements for untrained words were minimal. Improvement in verb retrieval was associated with increases on a functional measure of communicative effectiveness. Improvement for nouns and verbs was associated with severity of word retrieval impairment at onset. Although distinct in neural and psycholinguistic attributes, nouns and verbs were affected by treatment in a similar pattern in this group of individuals. Training-specific effects suggest the need for careful selection of training words to have potential for functional benefit in daily communication.

Prosodic characteristics of speech pre- and post-right hemisphere stroke.

Case-control studies have shown right hemisphere specialization in the production of intonation in speech. We examined spontaneous prosody in audiotapes of interviews with a 77-year-old right-handed woman recorded 6 months before and 6 weeks after she suffered a stroke affecting the right frontotemporo-parietal regions and the right basal ganglia. Post-stroke, the patient had a normal Mini-Mental Status Examination Score of 29, hemispatial neglect, and impairments in the comprehension of facial expression and prosody. Self-rated mood was within normal limits. We compared beginning, peak, and ending fundamental frequencies (fo) in breath groups, the timing of these fo changes, rate of speech, pause duration, and breath-group duration. We found that post-stroke, the patient had a more restricted fo contour, no changes in the timing of peak fo, an increased rate of speech, less variability in pause duration, and no changes in breath-group duration.

Differences in Functional Magnetic Resonance Imaging Activation by Category in a Visual Confrontation Naming Task

Objective. Cortical processing involved in seemingly similar tasks may differ in important ways. The authors mapped cortical regions engaged in a commonly performed picture naming task, seeking differences by semantic category. Functional magnetic resonance imaging was used during presentation of standardized line drawings in 18 healthy right‐handed female participants, comparing living versus nonliving entities. During visual naming, across categories there was strong activation of left frontal (BA45/47), bilateral temporo‐occipital junction (BA19), and inferior temporal regions (BA36/37). Activation of right inferior temporal cortex (BA19 & 37) was greater during naming of living versus nonliving category items. No category differences in activation strength in the left temporal lobe were observed. The authors conclude that visual semantic operations may involve visual association cortex in the right temporal lobe in women.

Emotional expression and emotional recognition in breast cancer survivors: A controlled comparison

The role of emotional expression (EE) in the onset and progression of cancer remains equivocal. The purpose of this study was to compare breast cancer patients (n = 25) and matched healthy controls (n = 25) on self-report and behavioral measures of EE and emotional recognition. Based upon Pennebakers paradigm, participants completed a verbal positive or negative EE behavioral task. Transcripts of participants’ responses were analyzed using the Linguistic Inquiry and Word Count and were coded for emotional valence and intensity by trained raters blind to experimental condition. Breast cancer patients and healthy controls did not differ on self-report, dispositional measures of EE nor on a behavioral measure of emotional recognition. During the behavioral EE task, patients used significantly less inhibition words than controls and were rated as expressing more intense emotion. Results provide some support for the view that cancer diagnosis and treatment can alter emotionally expressive behavior.

Affective facial and lexical expression in aprosodic versus aphasic stroke patients.

Past research has shown that lesions in the left cerebral hemisphere often result in aphasia, while lesions in the right hemisphere frequently impair the production of emotional prosody and facial expression. At least 3 processing deficits might account for these affective symptoms: (1) failure to understand the conditions that evoke emotional response; (2) inability to experience emotions; (3) disruption in the capacity to encode non-verbal signals. To better understand these disorders and their underlying mechanisms, we investigated spontaneous affective communication in right hemisphere damaged (RHD) stroke patients with aprosody and left hemisphere damaged (LHD) stroke patients with aphasia. Nine aprosodic RHD patients and 14 aphasic LHD patients participated in a videotaped interview within a larger treatment protocol. Two naïve raters viewed segments of videotape and rated facial expressivity. Verbal affect production was tabulated using specialized software. Results indicated that RHD patients smiled and laughed significantly less than LHD patients. In contrast, RHD patients produced a greater percentage of emotion words relative to total words than did LHD patients. These findings suggest that impairments in emotional prosodic production and facial expressivity associated with RHD are not induced by affective-conceptual deficits or an inability to experience emotions. Rather, they likely represent channel-specific nonverbal encoding abnormalities.

Longitudinal functional alterations in asymptomatic women at risk for Alzheimer's disease.

Purpose. The authors sought to determine whether known alterations of brain function in normal individuals who are at high risk for Alzheimers disease (AD) worsen or stay the same after a significant interval of time. Methods. The authors used func tional magnetic resonance imaging (fMRI) to observe cortical activation during confrontation naming in 14 women with high AD risk and 10 with low risk, based on family history and apolipoprotein‐E4 allele status. They repeated the identical scan protocol in the same patients after 4 years. Results. fMRI activation in high‐AD‐risk participants was found to be further diverged from that of their low‐AD‐risk counterparts over this period. Conclusion. fMRI may report on the presence and pro gression of neuropathology in the ventral temporal cortex or in functionally connected regions in presymptomatic AD.