Tag: Brain Science

Dr. Stephen Smith’s team at the Stanford University School of Medicine developed a new technique to visualize the detailed anatomy, indeed the micro-circuitry, of brain tissue. The new technique is called array tomography and is based on

• automated ultra-thin sectioning of brain tissue
• putting arrays of these ultra-thin sections of brain tissue in order on optical coverslips
• staining and imaging the two-dimensional arrays of ultra-thin sectioned brain tissue
• computational reconstruction of the brain tissue into three dimensions

The following video is a considerable achievement. Smith’s team has reconstructed a section of the cerebral cortex in the mouse’s whisker (technically vibrissae) system. Whisker’s in rodents have functional similarities with our hands and are extremely important for active touch in rodents.

Mouse cortex associated with whiskers is known as barrel cortex. The following video takes you on a tour of a small sliver of this barrel cortex inside a single barrel associated with one whisker on the mouse’s snout.

The upper left area of the video shows the full slice of barrel cortex that you’re journeying through. At top is the surface of the brain and at bottom is the white matter (the communication lines of the brain). In between is the grey matter that contains six layers of brain cells (neurons) and their processes. The red box encompasses the area that you’re currently focused on.

Green – A subset of pyramidal cells express a green fluorescent protein marker (including axons and dendrites).

Blue – Some of the larger dendrites and axons are delineated by blue microtubule immunolabeling.

Red – Synapses are marked by red synapsin I immunofluorescence.

Other connectome related blog posts:

Mapping the Brain’s Connections: the Connectome

The Connectome: Automated Submicron Reconstruction of Brain Circuitry

Other whisker related blog posts:

Wiggling Whiskers for a Living?

Wiggling Whiskers: Directional Tuning

Whisker Related Brain Anatomy Data for Building Simulations

Wiggling Whiskers: Neurons in the Barrel Cortex and Object Localization

Adult Brain is Continually Modified by Experience: Demonstration in the Whisker System

Methods for drug screening efforts during drug discovery are mostly inadequate to address the complexity of interactions within the intact body. These limits become even more apparent when the drugs are meant to target behavior and psychology. A paper published earlier this year (“Zebrafish Behavioral Profiling Links Drugs to Biological Targets and Rest/Wake Regulation” January 15, 2010 in Science) presents a promising technique to address these limits.

The team developed a whole organism, high-throughput screen for drugs. They placed individual zebrafish larva into wells with the drug that they wanted to test. Each plate had 80 zebrafish larva moving around in their own wells. Behavior was automatically measured using video recording techniques and automated tracking software. The results went through cluster analysis.

Behavioral profiling results showed:

• relationships between the drugs tested and their targets
• a conserved vertebrate neuropharmacology
• identified regulators of the target behavior

Individual drugs with unknown targets were clustered with drugs with known neuropharmacological properties. The well-known drugs could predict the targets for the drugs without characterized targets that were clustered with them. In addition, behavioral profiling identified previously unidentified pathways involved in the target behavior. I recommend this article to anyone wondering how to get a handle on the huge number of variables that need to be addressed in drug discovery, systems biology, and neuroscience.

Information acquired through touch seems to exert broad influence over thought. Shoppers more readily understand and are confident about products they touch. Impressions formed by touching one thing can influence perceptions about another thing. For example, water seems to taste better from a firm bottle than from a flimsy bottle. The recent paper “Incidental Haptic Sensations Influence Social Judgments and Decisions” published June 25, 2010 in Science presents these examples to emphasize the under appreciated importance of touch.

The research team tested how the experience of weight, texture, and hardness through active touch influenced judgments and decisions about unrelated events, situations, and objects.

The researchers point out the weight is metaphorically associated with concepts of seriousness and importance. “That’s heavy!” In one study individuals were asked to evaluate a job candidate by reviewing resumes on either light or heavy clipboards. Evaluations using heavy clipboards rated the job candidates as better overall and as displaying more serious interest in the position. The individuals evaluating the candidates using heavy clipboards also evaluated their own accuracy on the task as more important than did those using the light clipboards.

In another study, individuals were asked whether particular public issues should receive more or less government funding. Men allocated more money to social issues when the clipboard was heavy than when it was light. Women chose to fund social issues at close to the maximum amount irrespective of clipboard weight.

Next, the research addressed texture’s effects on an individual’s perceptions of social interactions. They point out that metaphorically roughness and smoothness are associated with concepts of difficulty and harshness. “I’m having a rough day.” Participants who interacted with rough textures rated observed social interactions as more difficult and harsh than did participants who interacted with smooth surfaces.

Finally, the experience of hardness in active touch and its effect on thought was investigated. Hardness is metaphorically associated with the concepts of stability, rigidity, and strictness. Individuals who felt a hard block judged employees to be more rigid or strict than participants who felt a soft blanket.

The research then went a step further and tested passive touch’s influences on thought. Participants were primed by the seat of their pants. They either sat on a hard wooden chair or a soft cushioned chair. Participants sitting on hard chairs judged employees to be more stable and less emotional than did participants in soft chairs.