BrainBlog

Making memories: How one protein does it The JHU Gazette 12 March 2012 [snip] "Studying tiny bits of genetic material that control protein formation in the brain, Johns Hopkins scientists say that they have new clues to how memories are made and how drugs might someday be used to stop disruptions in the process that lead to mental illness and brain-wasting diseases. "In a report published in the March 2 issue of Cell, the researchers say that certain microRNAs—genetic elements that control which proteins get made in cells—are the key to controlling the actions of so-called brain-derived neurotrophic factor, or BDNF , long linked to brain cell survival, normal learning and memory boosting." [snip] Read the full article

Impaired Cognitive Function and Hippocampal Neurogenesis Following Cancer Chemotherapy Clin Cancer Res . 2012 Feb 14; Christie LA, Acharya MM, Parihar VK, Nguyen A, Martirosian V, Limoli CL Abstract PURPOSE: A substantial proportion of breast cancer survivors report significant, long-lasting impairments in cognitive function, often referred to as "chemobrain." Advances in detection and treatment mean that many more patients are surviving long-term following diagnosis of invasive breast cancer. Thus, it is important to define the types, extent and persistence of cognitive impairments following treatment with cytotoxic cancer drugs. EXPERIMENTAL DESIGN: We examined the effects of chronic treatment with two agents commonly used in breast cancer patients, cyclophosphamide and doxorubicin (Adriamycin). Athymic nude rats were given 50mg/kg cyclophosphamide, 2mg/kg doxorubicin or saline injections once per week for 4 weeks. A novel place recognition task and contextual and cued fear...

Intraneuronally Injected Amyloid Beta Inhibits Long-Term Potentiation In Rat Hippocampal Slices J Neurophysiol. 2012 Feb 15; Nomura I, Takechi H, Kato N Abstract Extracellular accumulation of amyloid beta (Aβ) is a hallmark of Alzheimer's disease (AD). It has been reported that extracellular perfusion of Aβ inhibits long-term potentiation (LTP), which is strongly related to memory in animal models. However, it has recently been proposed that intracellular Aβ may be the first pathological change to occur in AD. Here, we have investigated the effect on LTP of intracellular injection of Aβ (Aβ(1-40), Aβ(1-42)) into hippocampal pyramidal cells using patch clamp technique. We found that injection of 1 nM Aβ(1-42) completely blocked LTP and extracellular perfusion of a p38 MAPK inhibitor or a metabotropic glutamate receptor blocker reversed these blocking effects on LTP. Furthermore, we have examined the effects of different concentrations of Aβ(1-40) and Aβ(1-42) on LTP and showed that...

Hippocampal hyperactivation associated with cortical thinning in Alzheimer's disease signature regions in non-demented elderly adults Journal of Neuroscience. 2011 Nov 30; 31(48): 17680-17688 Putcha D, Brickhouse M, O'Keefe K, Sullivan C, Rentz D, Marshall G, Dickerson B, Sperling R Abstract Alzheimer's disease (AD) is associated with functional and structural alterations in a distributed network of brain regions supporting memory and other cognitive domains. Functional abnormalities are present in mild cognitive impairment (MCI) with evidence of early hyperactivity in medial temporal lobe regions, followed by failure of hippocampal activation as dementia develops. Atrophy in a consistent set of cortical regions, the "cortical signature of AD," has been reported at the stage of dementia, MCI, and even in clinically normal (CN) older individuals predicted to develop AD. Despite multiple lines of evidence for each of these findings, the relationship between this st...

Hippocampal Subregions are Differentially Affected in the Progression to Alzheimer's Disease Anat Rec (Hoboken). 2011 Nov 18; Greene SJ, Killiany RJ, Abstract Atrophy within the hippocampus (HP) as measured by magnetic resonance imaging (MRI) is a promising biomarker for the progression to Alzheimer's disease (AD). Subregions of the HP along the longitudinal axis have been found to demonstrate unique function, as well as undergo differential changes in the progression to AD. Little is known of relationships between such HP subregions and other potential biomarkers, such as neuropsychological (NP), genetic, and cerebral spinal fluid (CSF) beta amyloid and tau measures. The purpose of this study was to subdivide the hippocampus to determine how the head, body, and tail were affected in normal control, mild cognitively impaired, and AD subjects, and investigate relationships with HP subregions and other potential biomarkers. MRI scans of 120 participants of the Alzheimer's Di...

From the Brain Observatory website at the end of last night's work: "We have reached the corpus callosum. The team is resting for the night. The brain will be safe surrounded by our chillers until tomorrow morning. The cutting will resume again at 8AM PST. "Tomorrow will be a big day - We will try to cover the medial temporal lobes and the area surrounding the hippocampus." The Brain Observatory Today at 0800 PST, 1100 EST, 1600 GMT. === Today's New York Times article by Benedict Carey about the brain sectioning: Dissection Begins on Famous Brain Read here

A press release rom the NIH: Genetic Tags Reveal Secrets of Memories’ Staying Power in Mice A better understanding of how memory works is emerging from a newfound ability to link a learning experience in a mouse to consequent changes in the inner workings of its neurons. Researchers, supported in part by the National Institutes of Health's National Institute of Mental Health (NIMH), have developed a way to pinpoint the specific cellular components that sustain a specific memory in genetically-engineered mice. "Remarkably, this research demonstrates a way to untangle precisely which cells and connections are activated by a particular memory," said NIMH Director Thomas Insel, M.D. "We are actually learning the molecular basis of learning and memory." For a memory to last long-term, the neural connections holding it need to be strengthened by incorporating new proteins triggered by the learning. Yet, it's been a mystery how these new proteins — born deep inside...

The excellent neuroblog, Mind Hacks , has a post today that includes discussion about a program of research examining the hippocampal structures of professional navigators (e.g., taxi drivers) - research with fascinating neuropsychological results. The Mind Hacks post can be read at: post . A link to a .pdf of one of these publications can be found at: London Taxi Drivers and Bus Drivers: A Structural MRI and Neuropsychological Analysis . I am off to read this paper right now, which was published in 2006 in the journal Hippocampus .