Faculty Bibliography

The role of interpositus nuclei (IN) in timing in the sub-second range is well supported in eyeblink conditioning studies. Timing impairments shown in the seconds range in patients with intermediate cerebellar lesion, and known intermediate cerebellar cortex projection to IN raise the question of a possible involvement of IN in timing in the supra-second range as well. To address this question, we tested rats (Sprague-Dawley) given bilateral lesions of IN with Colchicine in a 2- vs. 8-s temporal discrimination task, followed by three daily sessions of a temporal bisection tests with five added intermediate non-reinforced durations. IN lesioned rats showed normal acquisition of the temporal discrimination, but a transient impairment of temporal sensitivity during the bisection tests. In addition, their response latencies suggested a different behavioral strategy from that of control animals. Our results indicate that the IN of the cerebellum may not be critically involved in temporal processing in the 2-8 s range, but may play a role in the cognitive processes that access temporal information in the mediation of choice behavior.

Objective To evaluate gastrointestinal (GI) problems in a large, well-characterized sample of children with pervasive developmental disorders (PDDs). Methods One hundred seventy two children entering one of two trials conducted by the Research Units on Pediatric Psychopharmacology (RUPP) Autism Network were assessed comprehensively prior to starting treatment and classified with regard to GI symptoms. Results Thirty nine (22.7%) were positive for GI problems, primarily constipation and diarrhea. Those with GI problems were no different from subjects without GI problems in demographic characteristics, measures of adaptive functioning, or autism symptom severity. Compared to children without GI problems, those with GI problems showed greater symptom severity on measures of irritability, anxiety, and social withdrawal. Those with GI problems were also less likely to respond to treatment

Chronic treatment with selective serotonin reuptake inhibitors (SSRIs) alleviates both anxiety symptoms and associated physiologic disturbances in anxious patients. However, limited research considers the degree to which chronic SSRI treatment influences anxiety in healthy individuals. This study examined the effect of 2-week citalopram treatment on two threat responses: short- and long-duration-potentiated startle. Prior work suggests that these two responses provide neurally and functionally distinct models of fear and anxiety, respectively, in rodents. Healthy volunteers (n=53) received either placebo or citalopram (20 mg per day) for 2 weeks under double-blind conditions. They were each tested twice, before and after treatment. Participants were exposed to three conditions, including one in which predictable aversive shocks were signaled by a cue, a second in which unpredictable shocks were anticipated, and a third in which no shocks were administered. Aversive states were indexed by acoustic startle. Phasic fear-potentiated startle to the threat cue, as well as sustained startle potentiation to the experimental context in the predictable and unpredictable conditions, were investigated. Citalopram affected neither baseline startle nor short-duration fear-potentiated startle to discrete threat cues. However, citalopram reduced long-duration startle potentiation in the predictable conditions. These results are consistent with the hypothesis that short- and long-duration aversive states are mediated by distinct neural systems. They suggest that citalopram alleviates symptoms of anticipatory anxiety, not fear, by acting on mechanisms underlying long-duration aversive states.

INTRODUCTION: Numerous studies point to an association between childhood trauma and the later development of psychotic illness. However, little is known about the prevalence of childhood trauma and its relationship to attenuated positive and other symptoms in individuals at heightened clinical risk for psychosis. METHOD: Thirty clinical high-risk patients (83% male, 43% Caucasian, and with a mean age of 19) were ascertained from the New York metropolitan area and evaluated for prodromal and affective symptoms, and queried regarding experiences of childhood trauma and abuse. RESULTS: Ninety-seven percent endorsed at least one general trauma experience, 83% reported physical abuse, 67% emotional abuse, and 27% sexual abuse. As hypothesized, total trauma exposure was positively associated with severity of attenuated positive symptoms (in particular grandiosity), an effect primarily accounted for by ethnic minority participants, who reported greater exposure to trauma. Trauma exposure was related to affective symptoms only in the Caucasian subgroup. CONCLUSIONS: Childhood trauma was commonly self-reported, especially among clinical high-risk patients from ethnic minorities, for whom trauma was related to positive symptoms. Future areas of research include an evaluation of potential mechanisms for this relationship, including neuroendocrine and subcortical dopaminergic function

Although the clarity of many memories fades with time, some memories may maintain their original precision. Here we used a context discrimination procedure to evaluate whether the hippocampus is important in maintaining precision as memories mature. Spared discrimination in hippocampal-lesioned mice indicated that precise, remote context memories may be supported by extra-hippocampal brain regions.

Mood, attention and motivation co-vary with activity in the neuromodulatory systems of the brain to influence behaviour. These psychological states, mediated by neuromodulators, have a profound influence on the cognitive processes of attention, perception and, particularly, our ability to retrieve memories from the past and make new ones. Moreover, many psychiatric and neurodegenerative disorders are related to dysfunction of these neuromodulatory systems. Neurons of the brainstem nucleus locus coeruleus are the sole source of noradrenaline, a neuromodulator that has a key role in all of these forebrain activities. Elucidating the factors that control the activity of these neurons and the effect of noradrenaline in target regions is key to understanding how the brain allocates attention and apprehends the environment to select, store and retrieve information for generating adaptive behaviour

PURPOSE: To examine perceived need for care for mental health problems as a possible contributor to ethnic disparities in receiving care among low-income depressed women. METHODS: The role of ethnicity, somatization, and stigma as they relate to perceived need for care is examined. Participants were 1577 low-income women who met criteria for depression. RESULTS: Compared with U.S.-born depressed white women, most depressed ethnic minority women were less likely to perceive a need for mental health care (black immigrants: OR 0.30, p < 0.001; U.S.-born blacks: OR 0.43, p < 0.001; immigrant Latinas: OR 0.52, p < 0.01). Stigma-related concerns decreased the likelihood of perceiving a need for mental health care (OR 0.80, p < 0.05). Having multiple somatic symptoms (OR 1.57, p < 0.001) increased the likelihood of endorsing perceived need. CONCLUSIONS: Findings suggest that there are ethnic differences in perceived need for mental healthcare that may partially account for the low rates of care for depression among low-income and minority women. The relations among stigma, somatization, and perceived need were strikingly similar across ethnic groups.