apply several mouseover events to neighboring (connected) nodes

I have a network diagram (force-directed graph), a scatterplot, and a table that are all interconnected (see jsFiddle). I have the interconnections working the way I want them for mouseover events. I would like to modify my code so that when I mouseover a node in the network diagram, not only is the moused-over node highlighted (and its connections in the scatterplot and table), but its immediate neighbor nodes are also highlighted (as well as their connections in the scatterplot and table).

I looked at the information in Highlight selected node, its links, and its children in a D3 force directed graph for help. Somewhere along the way (not exactly sure where) I found an example of a function that helps define the connected nodes, isConnected().

function isConnected(a, b) {
    return linkedByIndex[a.index + "," + b.index] || linkedByIndex[b.index + "," + a.index] || a.index == b.index;
    }

I'd like to incorporate this function into my mouseover events, perhaps with an if() statement, so that I can do all of the "highlighting" that I want. But, I'm new to D3 and js and am not sure how to set it up.

Below is the snippet of code (from the jsFiddle) that I would like to modify. I would appreciate any suggestions or pointers to other examples.

var node = svg.selectAll(".node")
    .data(graph.nodes)
    .enter().append("g")
    .attr("class", function(d) { return "node " + d.name + " " + d.location; })
    .call(force.drag)
    .on("mouseover", function(d) { 
        // I would like to insert an if statement to do all of these things to the connected nodes
        // if(isConnected(d, o)) {
            d3.select(this).select("circle").style("stroke-width", 6);