Brodmann Area 46 | What It Does And Where It Sits

A lateral prefrontal patch tied to working memory, rule holding, and goal-directed control during demanding tasks.

Brodmann Area 46 is one of those brain labels you’ll see in papers, MRI atlases, and clinic notes, yet it can feel oddly vague until you pin down three things: where it sits, what makes it distinct under the microscope, and what kinds of tasks light it up in studies.

This article gives you that map. You’ll get a plain-language location guide, the naming traps that confuse readers, and a practical way to read “BA46” claims without overreading them. Along the way, you’ll see how modern atlases slice this region into smaller pieces, and why one study’s “46” can differ from another’s.

Where Brodmann Area 46 Sits In The Frontal Lobe

Brodmann’s map is based on cytoarchitecture: the layered look of cortex under a microscope. In the human brain, Area 46 is in the lateral prefrontal cortex, most often placed around the middle frontal gyrus region. Many writers pair it with the dorsolateral prefrontal cortex (DLPFC), since DLPFC studies often report activation around BA46 and nearby BA9.

That pairing is useful, yet it’s not a perfect one-to-one match. “DLPFC” is a functional label used in imaging and stimulation work, while “Area 46” is a histology label from tissue structure. When you read a claim like “DLPFC equals BA46,” treat it as shorthand, not a strict border claim.

If you want a quick, credible definition of the label itself, the BrainInfo entry for area 46 of Brodmann is a solid starting point and keeps the focus on the anatomical naming. It also helps when different labs swap between “46,” “BA46,” and “middle frontal area 46” in the same paragraph.

Why Location Descriptions Vary Across Sources

Even when two sources agree that Area 46 sits on lateral prefrontal cortex, they can still draw it a bit differently. Some reasons are boring but real: different reference brains, different sectioning planes, and different conventions for labeling sulci and gyri. Other reasons come from method: an MRI-based atlas can only estimate cytoarchitectural borders, while a histology atlas can trace them more directly on tissue.

Modern resources often blend both. The Allen Brain Map anatomy atlases show adult human reference material with Brodmann-style annotation. It’s a helpful visual anchor when you need to connect a paper’s coordinate table to a named region.

Neighbors That Get Mentioned Alongside 46

Area 46 rarely appears alone. You’ll often see it paired with BA9 (sometimes written as 9/46) in work on working memory and executive control. You’ll also see references to nearby lateral prefrontal areas like 45 and 10 depending on the task, the subject group, and how broadly the authors define their region of interest.

A clean way to read those neighbor lists is to ask: is the paper speaking in atlas terms (Brodmann numbers), functional terms (DLPFC), or both? When both appear, you’re reading a translation attempt between two labeling systems.

What “Area 46” Means Under The Microscope

Brodmann numbers come from how cortex looks in layers: thickness, cell density, and the look of granular layers. Lateral prefrontal cortex is often described as “granular” cortex because of a well-developed layer IV. That structural detail matters because Brodmann’s original boundaries follow these microscopic cues, not task activation maps.

So when a paper reports BA46 activation using fMRI, it’s mapping a functional signal onto an anatomical label. That can be done well, yet it always carries some uncertainty, since fMRI and cytoarchitecture are different measurement types.

Cytoarchitecture Versus Functional Labels

In practical reading, this is the split: “BA46” is meant to point to a tissue-defined patch, while “DLPFC” is meant to point to a functional zone often measured with imaging or stimulation. The overlap is large in many atlases, but the borders do not line up perfectly in every scheme.

When you see strong claims tied to “BA46,” check if the authors used an atlas-based labeling method, a subject-specific parcellation, or a broad region-of-interest mask. Those choices change what “46” actually captures.

Brodmann Area 46 In Dorsolateral Prefrontal Cortex Tasks

Area 46 shows up again and again in tasks that demand holding information online while doing something with it. That includes classic working memory tasks, rule maintenance tasks, and selection under competition. A well-known PubMed-indexed paper by Rowe and colleagues describes a role for dorsolateral prefrontal area 46 in attentional selection, including selection from within working memory (PubMed record).

Here’s the useful takeaway: BA46 is often most engaged when a task asks you to keep a goal or rule active, then apply it as distractions compete for attention. It’s not just “memory storage.” It’s more like a control desk that keeps the current rule from slipping when the task gets busy.

Working Memory: Holding, Updating, Selecting

Working memory is not a single thing. Many tasks mix at least three demands: holding a target, updating it, and choosing what to act on. In imaging reviews, dorsolateral prefrontal regions, often including BA46 and BA9, are linked with these control-heavy parts of working memory rather than simple sensory persistence.

One widely cited review on working memory in PubMed Central (NIH) notes that dorsolateral prefrontal regions are associated with processes often attributed to the “central executive,” while also warning against treating one region as the whole story. That framing fits how BA46 is best understood: it’s a frequent player, not a solo engine.

Rule Holding And Task Sets

Many experiments that recruit BA46 share a pattern: the subject must keep an abstract rule active across a delay, then use it to pick a response. If the rule changes mid-run, the task also tests shifting and updating. These demands are common in lab tasks because they cleanly separate “keep the rule online” from “press the button.”

So when you read “BA46 supports rule-guided behavior,” think of tasks where the rule is not visible on the screen the whole time. The subject must keep it in mind while other cues come and go.

Common Naming Traps That Cause Confusion

Area labels get slippery when authors mix atlases, species, and shorthand. Here are the recurring traps that trip up readers who are new to this region, plus ways to keep your footing.

BA46 Versus 9/46

Some atlases carve a transition zone that spans parts of BA9 and BA46. You’ll see “9/46” used to signal this border region. In imaging work, “9/46” can also show up when a cluster lands near the border and the atlas label is split across both. When a result is reported as “9/46,” treat it as “near the BA9–BA46 border,” not as a claim that the cluster uniquely belongs to both at once.

Human Versus Macaque Labels

Nonhuman primate work often uses “area 46” too, yet the exact borders and subdivisions differ across species and naming schemes. Many papers do careful cross-species mapping. Others use shorthand. If you’re comparing macaque electrophysiology to human fMRI, check what atlas or parcellation each paper used before you line up the claims.

Atlas Labels Versus MNI Coordinates

Imaging papers may report coordinates in a standard space (like MNI). Then they attach an atlas label to those coordinates. Two groups can use the same coordinates but attach different labels if they use different atlases. If a result feels inconsistent across papers, this is often why.

When you need a modern, connectivity-based view that subdivides the middle frontal gyrus and names an “area 46” region among related parcels, the Brainnetome Atlas paper in PubMed Central (NIH) is a strong reference point. It shows how one atlas breaks a familiar gyrus into multiple parcels, including area 46 and divisions of 9/46.

How Researchers Identify Area 46 In Practice

In day-to-day research writing, “BA46” can come from several pipelines. None is perfect, so it helps to know what each pipeline implies about precision.

Histology-based labeling on postmortem tissue is closest to the original Brodmann idea, since it uses the same kind of evidence. Imaging studies often rely on an atlas mapped to MRI space. Some use subject-specific parcellations that try to align borders to the person’s anatomy or connectivity.

When a paper says “BA46” with no method detail, scan the Methods section for the atlas name (or the toolbox used for labeling). That’s where the real meaning of “46” lives.

Table 1: Quick Map Of Labels You’ll See Around Area 46

This table helps you translate common labels into what they usually mean in papers and atlases, plus the practical reading note that keeps you from overreading a label.

Label In Papers	What It Usually Refers To	Practical Reading Note
BA46	Cytoarchitectural Area 46 in lateral prefrontal cortex	Ask which atlas or labeling method was used in imaging work
Area 46	Same as BA46, often in older writing or animal work	Check species and naming scheme before comparing across papers
Middle frontal area 46	A phrasing that ties 46 to middle frontal gyrus territory	Gyri-based phrasing can blur cytoarchitectural borders
DLPFC	Functional zone on lateral prefrontal cortex	Often overlaps BA46 and BA9, but it’s not a strict Brodmann label
BA9/46	A border or combined parcel spanning BA9 and BA46	Common in atlases that define a transition region
MFG (middle frontal gyrus)	A gyral anatomy label, not a Brodmann area	Useful for gross location, weaker for microstructural claims
ROI “46” mask	A study-defined region-of-interest linked to 46 in an atlas	ROI choices can shape results; look for mask source and thresholding
Connectivity-based “46”	A parcel named 46 based on connectivity patterns	Can split 46 into subparts; read parcel definitions before comparing

What Area 46 Findings Can And Can’t Tell You

It’s tempting to treat a Brodmann number like a “function sticker.” That move makes reading feel easy, then it causes confusion later. A better habit is to separate three levels: task demand, measurement type, and label precision.

A task demand like “rule holding” is a behavioral description. A measurement type like fMRI BOLD is one way of tracking activity. A label like “BA46” is an atlas-based tag applied after the signal is measured. Mixing those levels is where sloppy claims come from.

What You Can Say With Confidence

• BA46 frequently appears in studies where subjects keep a goal or rule active during a delay.
• BA46 is often reported with BA9 in dorsolateral prefrontal findings on working memory control.
• Atlas and parcellation choices change where “46” borders land in MRI space.

What Needs Caution In Reading

• “BA46 causes X” language, unless the method supports causal claims (like lesion evidence).
• Assuming one coordinate cluster equals the full area across individuals.
• Assuming “DLPFC” and “BA46” are interchangeable labels in all contexts.

How Lesion And Stimulation Work Relates To Area 46 Claims

Lesion work can strengthen causal language since tissue damage can change performance. Still, lesions often span multiple areas, so the mapping back to BA46 can be broad. Stimulation work (like TMS or tDCS) also adds causal leverage, yet stimulation fields can spread beyond one labeled area.

If you read a stimulation paper that says it targeted BA46, check whether it targeted a scalp location tied to a coordinate, a functional localizer, or an atlas-defined parcel. These choices change what “targeted” means in real tissue terms.

Table 2: Study Methods You’ll See For Area 46

This table sums up how common methods relate to what authors mean when they write “BA46,” plus what to check before you trust a claim.

Method	What It Measures	What To Check In The Paper
Task fMRI (BOLD)	Blood-oxygen signal linked with task demands	Atlas name, smoothing, subject alignment, label assignment method
Resting-state fMRI	Functional coupling patterns at rest	Parcellation choice and how parcels are named “46” across atlases
Diffusion MRI (tractography)	White-matter pathway estimates	Seed region definition for “46,” plus tracking parameters
Lesion mapping	Performance changes linked with damaged tissue	Lesion extent, overlap maps, and whether damage spans BA9 too
TMS / tDCS	Perturbation effects on behavior or signals	Targeting method, field spread estimates, coil montage details
Intracranial recordings	Local electrical activity with high time resolution	Electrode placement labeling and how “46” was assigned

A Practical Way To Read BA46 Mentions In Papers

When you see “BA46” in a paper, run a quick three-step check. It keeps you from accepting a label at face value while still letting you use the result.

1. Find the labeling method. Look for the atlas, toolbox, or histology reference used to assign “46.”
2. Spot the task demand. Write down what the subject had to hold, update, or select. That’s the demand the activation likely tracks.
3. Note the neighbors. If BA9, 45, or 10 show up in the same cluster or ROI, treat the result as dorsolateral lateral prefrontal control rather than a single tiny patch story.

This reading style is also handy when you see headlines that oversimplify. BA46 results are often real and consistent across labs. The overreach usually comes from pretending the label is a clean border in every brain and every atlas.

Takeaways You Can Use When Writing Or Studying

If you’re writing a report, building a study, or just trying to learn the brain map, here’s the cleanest mental picture to keep: Brodmann Area 46 is a cytoarchitectural label used often as shorthand for a dorsolateral lateral prefrontal control region that supports demanding goal and rule maintenance.

Stick with that level of claim unless your source goes deeper with methods that support deeper claims. Your writing will sound grounded, and your reading will get faster.