Brodmann Areas
Brodmann Areas
Here, we will learn the cortical areas of the cerebrum.
Lateral Cerebral Hemisphere
- To begin, draw a lateral face of the cerebral hemisphere.
Central Structures
- Include the precentral, central, and postcentral sulci.
- Between the central and precentral sulci, within the precentral gyrus, label the primary motor area.
- Between the postcentral and central sulci, within the postcentral gyrus, label the primary sensory area.
Premotor area
- In front of the primary motor area, label the premotor area.
Frontal eye fields
- Next, in front of the premotor area, label the frontal eye fields.
Broca's area
- Now along the anterior Sylvian fissure, in the inferior frontal gyrus, label Broca's area: the speech output area.
Primary auditory cortex
- Peel back the superior temporal gyrus and within the transverse temporal gyri (Heschl's gyri), label the primary auditory cortex.
Wernicke's area
- Next, within the posterior superior temporal gyrus label Wernicke's area, the language reception area.
Primary visual area
- Now, in the posterior occiput, draw the primary visual area.
- The primary visual cortex lies on the banks of the calcarine sulcus.
Superior parietal lobe ("Where" Pathway)
- Next, within the superior parietal lobe, label the "where" visual pathway, which provides visuo-spatial localization processing.
Inferior temporal lobe ("What" Pathway)
- Within the inferior temporal lobe, label the "what" visual pathway, which provides object recognition processing.
Broad Classification System
- Now, let's group these modalities into a broad classification system that, albeit an oversimplification, has great utility at the bedside.
Primary motor/sensory areas
- First group the precentral gyrus and postcentral gyrus as the primary motor/sensory areas.
Language region
- Next, group Broca's and Wernicke's areas as the language region.
Auditory processing area
- Now, group the primary auditory area and Wernicke's area as the auditory processing area.
Vision
- Then, group the primary visual area along with the Where & What Pathways under vision.
Motor planning area
- Now, group the premotor area, frontal eye fields, and Broca's area as the motor planning area.
Sensory planning region
- Then, encircle the superior parietal lobule as the sensory planning region.
learning and memory
#Now, let's start a diagram to address the major cognitive/behavioral areas and the areas for learning and memory.
Draw a lateral face of the hemisphere.
- In the dorsolateral prefrontal cortex, label executive function; task sequencing relies on this area.
- Injury here results in organizational deficits.
- Then, show that the orbitofrontal cortex governs social behavior. (See: Orbital gyri & Gyrus rectus)
- Injury here results in impulsivity.
- Now, in the center draw the medial-lying limbic lobe and corpus callosum.
- Show that motivation stems from the antero-superior limbic lobe: the anterior cingulate gyrus, in what is referred to as anterior cingulate (or medial frontal) cortex.
- Injury here results in a lack of attention and motivation (abulia).
- Next, show that learning is affiliated with the postero-superior limbic lobe: the posterior cingulate gyrus.
- Then, show that memory processing occurs most notably in the hippocampus and parahippocampal gyrus, in the inferior aspect of the limbic lobe.
Anterior cingulate cortex
- Although we learn about the anterior cingulate cortex along with the other prefrontal cortices, it is helpful to place it in the following context, as well: the posterior cingulate cortex affiliates with the hippocampus and is part of the posterior cingulate network of learning and memory; whereas, the anterior cingulate cortex affiliates with the amygdala and is part of the anterior cingulate network of motivation, attention, and behavior.
Brodmann areas
We will draw select, fundamental Brodmann areas and learn the specific functional anatomy of the cerebral cortex.
Include the header: area, anatomy, and function.
Lateral Cerebral Hemisphere
- Next, draw lateral surface of the cerebrum
- And then the medial surface of the cerebrum (include the corpus callosum for reference).
Cerebral Sulci
- On the lateral face, draw the precentral, central, and postcentral sulci, and then the Sylvian fissure with its anterior horizontal and anterior ascending rami, and also include the lateral parietotemporal line.
- On the medial face, draw the paracentral, central, parietooccipital, and calcarine sulci, and then draw pars marginalis and the cingulate sulcus and demarcate a line just above it.
BA 3, 1, 2
- Now, label Brodmann areas 3, 1, 2 within the postcentral and posterior paracentral gyri, from anterior to posterior; they constitute the primary sensory area.
BA 4
- Then, label area 4 within the precentral and anterior paracentral gyri. Indicate that it is the primary motor area.
Homunculus
- Within the primary motor and sensory areas, cortical representation of the face and body is somatotopically arranged in what is referred to as the homunculus.
BA 6
- Now, label area 6 in front of area 4 in the posterior frontal lobe.
- Indicate that it lies in the posterior frontal lobe and that it comprises the following motor areas: on the lateral hemisphere, area 6 is called the premotor area (it lies in the anterior precentral gyrus and posterior superior and middle frontal gyri) and on the medial hemisphere, area 6 is called the supplementary motor area (it lies in the medial aspect of the superior frontal gyrus). The premotor and supplementary motor areas help assemble complex motor programs.
BA 8
- Next, label area 8 in front of area 6 in the anterior frontal lobe.
- Indicate that it lies in the anterior frontal lobe and that the most notable feature of area 8 is that on its lateral surface it contains the human homologue to the rhesus monkey frontal eye fields; the animal model for human eye movements.
- In humans, however, volitional control of eye movements is derived from the anterior wall of the precentral sulcus and portions of many additional disparate Brodmann areas, including areas 4, 6, 8, and 9.
BA 44, 45
- Now, label area 44 in the pars opercularis and area 45 in the pars triangularis of the inferior frontal gyrus.
BA 41, 42
- Next, demarcate the superior temporal gyrus and then peel it back and label areas 41 and 42 in the transverse temporal (Heschl's) gyri; these gyri form the primary auditory cortex.
BA 22
- Then, label area 22 in the superior temporal gyrus.
- Indicate that in the posterior region of area 22 (and area 39 (the angular gyrus) lies Wernicke's area, the language reception area.
BA 17
- Now, within the occipital lobe, on the medial surface, indicate that area 17 lies on the banks of the calcarine sulcus and on the lateral surface, show that it lies at the occipital pole. Indicate that area 17 is the primary visual cortex.
BA 18, 19
- Now, on the medial face, show that area 18 lies above and below area 17.
- Then, show that area 19 lies above and below area 18.
- Indicate that area 18 lies in the occipital lobe and is the secondary visual cortex.
- Next, indicate that area 19 lies in the occipital lobe and is the tertiary visual cortex.
- Then, on the lateral face, show that area 18 lies anterior to area 17, and that area 19 lies anterior to area 18.
BA 9, 10, and 11
- Next, antero-inferior to area 8, along the surface of the lateral and medial faces of the cerebrum, from superior to inferior, label areas 9, 10, and 11.
BA 46
- Then, in between area 45 and area 10, label area 46.
BA 47
- Then, beneath area 46, label area 47.
BA 24
- Finally, in the anterior cingulate gyrus, label area 24.
These areas form the prefrontal cortex, which is subdivided into dorsolateral prefrontal, orbitofrontal, and anterior cingulate (medial frontal) cortices; each subdivision governs a discrete cognitive domain. Although the exact anatomy of these divisions is inconsistently defined, there is consensus regarding their functions.
Dorsolateral prefrontal cortex
- Indicate that, together, areas 9, 46, and a portion of area 10 form the dorsolateral prefrontal cortex.
Orbitofrontal cortex
- Together, areas 11, 47, and a portion of area 10 form the orbitofrontal cortex.
Anterior cingulate cortex
- And that area 24 comprises the anterior cingulate cortex.
Dorsolateral prefrontal cortex
- Indicate that (as noted previously) dorsolateral prefrontal cortex mediates executive function/task sequencing; injury here results in organizational deficits.
Orbitofrontal cortex
- Orbitofrontal cortex governs social behavior; damage here results in impulsivity.
Anterior cingulate cortex
- Anterior cingulate (medial frontal) cortex mediates motivation; injury here results in a lack of motivation (abulia).