Simultaneous Monitoring of Presynaptic Transmitter Release and Postsynaptic Receptor Trafficking Reveals an Enhancement of Presynaptic Activity in Metabotropic Glutamate Receptor-Mediated Long-Term Depression.

Simultaneous Monitoring of Presynaptic Transmitter Release and Postsynaptic Receptor Trafficking Reveals an Enhancement of Presynaptic Activity in Metabotropic Glutamate Receptor-Mediated Long-Term Depression.

J Neurosci. 2013 Mar 27; 33(13): 5867-5877
Xu W, Tse YC, Dobie FA, Baudry M, Craig AM, Wong TP, Wang YT

Although the contribution of postsynaptic mechanisms to long-term synaptic plasticity has been studied extensively, understanding the contribution of presynaptic modifications to this process lags behind, primarily because of a lack of techniques with which to directly and quantifiably measure neurotransmitter release from synaptic terminals. Here, we developed a method to measure presynaptic activity through the biotinylation of vesicular transporters in vesicles fused with presynaptic membranes during neurotransmitter release. This method allowed us for the first time to selectively quantify the spontaneous or evoked release of glutamate or GABA at their respective synapses. Using this method to investigate presynaptic changes during the expression of group I metabotropic glutamate receptor (mGluR1/5)-mediated long-term depression (LTD) in cultured rat hippocampal neurons, we discovered that this form of LTD was associated with increased presynaptic release of glutamate, despite reduced miniature EPSCs measured with whole-cell recording. Moreover, we found that specific blockade of AMPA receptor (AMPAR) endocytosis with a membrane-permeable GluR2-derived peptide not only prevented the expression of LTD but also eliminated LTD-associated increase in presynaptic release. Thus, our work not only demonstrates that mGluR1/5-mediated LTD is associated with increased endocytosis of postsynaptic AMPARs but also reveals an unexpected homeostatic/compensatory increase in presynaptic release. In addition, this study indicates that biotinylation of vesicular transporters in live cultured neurons is a valuable tool for studying presynaptic function. HubMed – depression


Alleviating psychosocial issues for individuals with communication impairments and their families following stroke: A case series of interdisciplinary assessment and intervention.

NeuroRehabilitation. 2013 Jan 1; 32(2): 351-358
Jones C, O’Keeffe K, Kingston C, Carroll A

INTRODUCTION: A high incidence of depression following a stroke has been reported. Many studies exclude those with communication impairments. However, there is an increased risk of psychosocial issues for individuals with communication difficulties. Psychosocial issues have a significant impact on the individual and their families. There is very limited research in this area. METHODS: A retrospective case review of the assessment and intervention with three individuals with significant communication difficulties following stroke was completed. Key interdisciplinary intervention factors were identified. RESULTS: Psychosocial issues were identified in all three cases. The assessment of cognitive difficulties, interdisciplinary intervention targeting communication between family members, facilitation of emotional expression and liaison with appropriate community services were identified as key interventions. These interventions targeted at psychosocial issues resulted in a positive outcome for the individuals and their family. DISCUSSION AND CONCLUSION: Psychosocial issues are prevalent in individuals and their families with significant communication impairments following stroke. Clinically, these issues may be overlooked. The complexity of working with individuals with cognitive and communication impairments also contributes to poor identification of psychosocial issues. This case series clearly highlights that intervening at the psychosocial level through interdisciplinary working can facilitate meaningful outcomes for the individual and their family. HubMed – depression


An exploration of clinical dementia phenotypes among individuals with and without traumatic brain injury.

NeuroRehabilitation. 2013 Jan 1; 32(2): 199-209
Dams-O’Connor K, Spielman L, Hammond FM, Sayed N, Culver C, Diaz-Arrastia R

OBJECTIVE: To characterize the clinical profiles of individuals with dementia who do and do not report a history of TBI. INTRODUCTION: Some evidence suggests that a history of traumatic brain injury (TBI) is associated with an increased risk of dementia later in life. The clinical features of dementia associated with TBI have not been well investigated. While there is some evidence that TBI is associated with increased risk of Alzheimer’s disease (AD), there are also indications that dementia associated with TBI has prominent behavioral, affective, and motor symptoms, making it distinct from AD. METHODS: The current study involves secondary analysis of baseline data from the National Alzheimer’s Coordinating Center (NACC) Uniform Data Set (UDS). RESULTS: Individuals with dementia who reported a history of TBI had higher fluency and verbal memory scores and later onset of decline, but they are on more medications, had worse cardiovascular and cerebrovascular health, were more likely to have received medical attention for depression, and were more likely to have a gait disorder, falls, and motor slowness. CONCLUSION: These findings suggest that dementia among individuals with a history of TBI may represent a unique clinical phenotype that is distinct from known dementia subtypes. HubMed – depression