Sensitivity to Theta-Burst Timing Permits LTP in Dorsal Striatal Adult Brain Slice.
Sensitivity to theta-burst timing permits LTP in dorsal striatal adult brain slice.
J Neurophysiol. 2013 Aug 7;
Hawes SL, Gillani F, Evans RC, Benkert EA, Blackwell KT
Long term potentiation (LTP) of excitatory afferents to the dorsal striatum likely occurs with learning to encode new skills and habits, yet corticostriatal LTP is challenging to evoke reliably in brain slice under physiological conditions. Here we test the hypothesis that stimulating striatal afferents with theta-burst timing, similar to recently reported in vivo temporal patterns corresponding to learning, evokes LTP. Recording from adult mouse brain slice extracellularly in 1mM Mg2+, we find LTP in dorsomedial and dorsolateral striatum is preferentially evoked by certain theta-burst patterns. In particular, we demonstrate that greater LTP is produced using moderate intra-burst and high theta-range frequencies, and that pauses separating bursts of stimuli are critical for LTP induction. By altering temporal pattern alone, we illustrate the importance of burst-patterning for LTP induction, and demonstrate that corticostriatal long term depression is evoked in the same preparation. In accord with prior studies, LTP is greatest in dorsomedial striatum and relies on NMDA receptors. We also demonstrate a requirement for both Gq- and Gs/olf -coupled pathways, as well as several kinases associated with memory storage: PKC, PKA, and ERK. Our data builds on previous reports of activity-directed plasticity by identifying effective values for distinct temporal parameters in variants of theta-burst LTP induction paradigms. We conclude that those variants which best match reports of striatal activity during learning behavior are most successful in evoking dorsal striatal LTP in adult brain slice without altering ACSF. Future application of this approach will enable diverse investigations of plasticity serving striatal-based learning. HubMed – depression
Different factors influence self-reports and third-party reports of anger by adults with intellectual disabilities.
J Appl Res Intellect Disabil. 2013 Sep; 26(5): 410-9
Rose J, Willner P, Shead J, Jahoda A, Gillespie D, Townson J, Lammie C, Woodgate C, Stenfert Kroese B, Felce D, Macmahon P, Rose N, Stimpson A, Nuttall J, Hood K
Many people with intellectual disabilities display high levels of anger, and cognitive-behavioural anger management interventions are used routinely. However, for these methods to be used optimally, a better understanding is needed of different forms of anger assessment. The aim of this study was to investigate the relationship of a range of measures to self- and carer reports of anger expression, including instruments used to assess mental health and challenging behaviour.Adults with intellectual disabilities, who had been identified as having problems with anger control, their key-workers and home carers all rated the service users’ trait anger, using parallel versions of the same instrument (the Provocation Inventory). In addition, service users completed a battery of mental health assessments (the Glasgow Depression Scale, Glasgow Anxiety Scale and Rosenberg Self-Esteem Scale), and both groups of carers completed a battery of challenging behaviour measures (the Hyperactivity and Irritability domains of the Aberrant Behavior Checklist and the Modified Overt Anger Scale).Participants had high levels of mental health problems (depression: 34%; anxiety: 73%) and severe challenging behaviour (26%). Hierarchical linear regression analysis was used to explore the extent to which anger ratings by the three groups of respondents were predicted by demographic factors, mental health measures and challenging behaviour measures. Older service users rated themselves as less angry and were also rated as less angry by home carers, but not by key-workers. More intellectually able service users were rated as more angry by both sets of carers, but not by the service users themselves. Significantly, mental health status (but not challenging behaviour) predicted service users’ self-ratings of anger, whereas challenging behaviour (but not mental health status) predicted carers’ ratings of service users’ anger.Service users and their carers appear to use different information when rating the service users’ anger. Service users’ self-ratings reflect their internal emotional state and mental health, as reflected by their ratings of anxiety and depression, whereas staff rate service users’ anger on the basis of overt behaviours, as measured by challenging behaviour scales. HubMed – depression
Racial/Ethnic Differences in the Association Between Symptoms of Depression and Self-rated Mental Health Among Older Adults.
Community Ment Health J. 2013 Aug 8;
Jang Y, Park NS, Kang SY, Chiriboga DA
The study examined racial/ethnic differences in the association between symptoms of depression and self-rated mental health among older adults. Data came from the first wave of the National Social Life, Health, and Aging Project, a population-based study of non-institutionalized older adults aged 57 to 85. The sample consisted of non-Hispanic Whites (n = 2,110), Blacks (n = 509), and Hispanics (n = 304). The association between symptoms of depression and self-rated mental health was weaker among minority groups than that among non-Hispanic Whites. Tests of interaction effects showed that the predictability of depressive symptoms to self-rated mental health was substantially weakened among Blacks of advanced ages and Hispanics with multiple chronic conditions. The study explored potential sources of racial/ethnic differences in subjective reports of mental health and called attention to older minorities with advanced ages and cormorbid conditions in mental health services and interventions. HubMed – depression
Reward Signals, Attempted Suicide, and Impulsivity in Late-Life Depression.
JAMA Psychiatry. 2013 Aug 7;
Dombrovski AY, Szanto K, Clark L, Reynolds CF, Siegle GJ
IMPORTANCE Suicide can be viewed as an escape from unendurable punishment at the cost of any future rewards. Could faulty estimation of these outcomes predispose to suicidal behavior? In behavioral studies, many of those who have attempted suicide misestimate expected rewards on gambling and probabilistic learning tasks. OBJECTIVES To describe the neural circuit abnormalities that underlie disadvantageous choices in people at risk for suicide and to relate these abnormalities to impulsivity, which is one of the components of vulnerability to suicide. DESIGN Case-control functional magnetic resonance imaging study of reward learning using a reinforcement learning model. SETTING University hospital and outpatient clinic. PATIENTS Fifty-three participants 60 years or older, including 15 depressed patients who had attempted suicide, 18 depressed patients who had never attempted suicide (depressed control subjects), and 20 psychiatrically healthy controls. MAIN OUTCOMES AND MEASURES Components of the cortical blood oxygenation level-dependent response tracking expected and unpredicted rewards. RESULTS Depressed elderly participants displayed 2 distinct disruptions of control over reward-guided behavior. First, impulsivity and a history of suicide attempts (particularly poorly planned ones) were associated with a weakened expected reward signal in the paralimbic cortex, which in turn predicted the behavioral insensitivity to contingency change. Second, depression was associated with disrupted corticostriatothalamic encoding of unpredicted rewards, which in turn predicted the behavioral oversensitivity to punishment. These results were robust to the effects of possible brain damage from suicide attempts, depressive severity, co-occurring substance use and anxiety disorders, antidepressant and anticholinergic exposure, lifetime exposure to electroconvulsive therapy, vascular illness, and incipient dementia. CONCLUSIONS AND RELEVANCE Altered paralimbic reward signals and impulsivity and/or carelessness may facilitate unplanned suicidal acts. This pattern, also seen in gambling and cocaine use, may reflect a primary deficit in the paralimbic cortex or in its mesolimbic input. The overreactivity to punishment in depression may be caused in part by a disruption of appetitive learning in the corticostriatothalamic circuits. HubMed – depression