Thinking About Brodmann Areas for Neurofeedback: Dyslexia
- John Davis
- Feb 28
- 23 min read
Updated: Mar 1
Why Brodmann Areas Still Matter—and How Their Role Has Evolved
Brodmann areas (BAs) continue to hold value for neuroscience and neurofeedback (NFB), but their clinical utility has evolved substantially with advances in our understanding of the brain’s functional networks.
When Korbinian Brodmann published his cortical map in 1909, the implicit promise was that each area—with its unique cellular microstructure—would map onto a distinct processing function.
Modern neuroscience, however, has revised that expectation in important ways, and these revisions suggest new strategies for planning NFB protocols.
From Phrenology to Dynamic Networks: A Brief Intellectual History
The functions that the brain supports are now understood to emerge from the coordinated activity of numerous cortical-subcortical networks composed of hubs and their directional excitatory and inhibitory connections. This perspective represents the further evolution of neurologic connectionist models—for example, models of language that developed in the late 19th century from the earlier phrenological frameworks of Gall and Spurzheim.
Today, neuroscientists view single BAs as participating in multiple networks depending on the task at hand.
The brain’s diverse functions involve overlapping networks of cell assemblies, often investigated as BAs or regions of interest (ROIs), whose constituents are dynamically reconfigured as task demands change.
Consider a telling example: BA 46, located in the dorsolateral prefrontal cortex, serves as a component of three major brain networks—the frontoparietal control network, the salience network, and the default mode network.
Each network supports a different portfolio of functions, yet all share this one Brodmann area.
This highlights not only the brain’s complexity and flexibility, but also an encouraging implication for clinical practice: neuroplasticity can proceed through reconfiguration of network function by recruiting new hubs, modules, or axonal pathways when a network becomes dysfunctional or damaged.
Probabilistic Borders and Microstructural Gradients
Studies of neuroanatomy—including histological analyses of brain tissue composition and investigations of individual variation in cortical coordinates—have led scientists to view BAs as lacking distinct borders. Instead, the territory of each BA is defined probabilistically. The three-dimensional coordinates specified in brain atlases indicate locations that contain specific BA histological characteristics only with a degree of likelihood, not with categorical certainty.
Furthermore, some BAs contain subfields defined by distinct connectivity patterns. For example, different subregions of BA 45 maintain different connections to other BAs.
A given BA is therefore more accurately described as having a gradient of microstructural organization rather than a homogeneous cytoarchitecture with uniform connections to other cortical or subcortical structures.
Reframing the Core Question: From “What Does a BA Do?” to “When and How Does It Communicate?”
This network-oriented perspective transforms the question “What does a BA do?” into the more nuanced inquiry, “When does a BA communicate with other BAs, and for what purpose?”
Answering this question requires understanding how a BA is embedded in multiple networks, the nature of connections within those networks, and how switching between networks occurs. Depending on its connectivity profile, a BA may serve as a hub with multiple influential links to other network sites, or a less critical satellite with fewer connections.
If a BA functions as a network hub, it may offer a gateway to modification of one or more networks and their function.
Rather than thinking about a BA as the site to train because a function is located there (reminiscent of phrenology), it is more appropriate to conceptualize it as a candidate gateway for training the network of which it is a part, thereby influencing brain-based function by altering the operation of the network that function depends on.
It should also be noted that while the atlas of BAs remains widely used for connectivity analysis, other atlases employ gross anatomical landmarks (e.g., the temporo-parietal junction), parcellation-based connectome analyses, or white matter connection mapping.
A Systematic Approach to BA-Informed Neurofeedback Planning
Below is a structured approach to using BAs for neurofeedback protocol development, adapted from the Test-Operate-Test-Exit (TOTE) problem-solving method of Miller, Galanter, and Pribram (1960):
1. Conduct a detailed assessment of the presenting concern using interview, questionnaire, cognitive, and psychophysiological (EEG) measures.
2. Integrate assessment findings into a plausible formulation that accounts for the presenting concern.
3. Correlate the formulation with findings from basic science and clinical research.
4. Identify the brain network(s) associated with the formulation that also correlate with research findings.
5. Identify the significant hub(s) in the network that are amenable to NFB.
6. Educate the client about the reasoning process and the level of certainty associated with the resulting NFB option. Request informed consent. This step is particularly important because the product of the preceding steps may be innovative and not yet reliably supported by a body of research.
7. Conduct NFB.
8. Expect change in network EEG activity, though not necessarily at the site of the hub where training occurs.
9. Measure change in EEG signal from the hub(s) and/or network, and additionally through interview and cognitive test data.
10. Update the NFB protocol if necessary.
11. Conclude NFB when the goal has been satisfied.
Dyslexia: A Network Perspective
Where and How Brain Activity Differs in Dyslexic Readers
Turker et al. (2023) investigated where and how brain activity in dyslexia differs from that in typical adult readers by examining four types of measures: functional activation, functional connectivity, effective connectivity (i.e., what area influences what other area), and the correlation between reading performance and the first three measures. Their study provides a richly detailed picture of the dyslexic brain that extends well beyond classical models of regional hypoactivation.
Three Core Left-Hemisphere Regions and Their Hypoactivation
Turker et al. (2023) summarize models of dyslexia and report that reading relies on three core left-hemisphere regions, all of which show hypoactivation in dyslexia:
• Left inferior frontal gyrus (IFG) – supports phonological output, attention, and working memory (node B in the figure below)
• Left temporo-parietal cortex (TPC, also known as the supramarginal gyrus or SMG) – mediates grapheme-phoneme decoding (node J)
• Left ventral occipito-temporal cortex (vOTC) – handles visual word form processing (node R)
What Happens When Word Difficulty Increases
The research of Turker et al. (2023) poses a critical question: is dyslexia related solely to hypoactivation in these three areas, or does it additionally involve anomalies in network communication? Testing typical readers and dyslexic readers with words and pseudowords of varying complexity, the authors found a revealing divergence. Typical readers showed graded increases in activation of the three core structures as word difficulty increased, whereas dyslexic readers did not.
Functional Connectivity Disruptions: A Globally Weaker Reading Network
In dyslexic subjects, the most prominent functional connectivity abnormalities involved the right cerebellum.
It showed reduced coupling with bilateral superior frontal, postcentral, and superior parietal cortices, orbito-temporal cortex, and bilateral supplementary motor area.
The right vOTC exhibited decreased connectivity with areas in the left pre- and post-central gyrus, bilateral vOTC-adjacent regions, left precuneus, and right supplementary motor area. However, increased connectivity was observed between the right vOTC and visual and motor areas (right cuneus and supracalcarine cortex).
The left vOTC demonstrated weaker functional connectivity with a region extending from the occipital poles to the superior lateral occipital cortices and precuneus. The left SMG (supramarginal gyrus) was connected more weakly than normal to the left vOTC and bilateral cerebellum. Taken together, dyslexic readers showed globally weaker connectivity throughout reading networks.
Effective Connectivity: How Regions Influence Each Other
Turker et al. (2023) examined effective connectivity among the three classic regions associated with dyslexia: left IFG, left TPC, and left vOTC. In typical readers, the TPC exerted excitatory effective connectivity on both the IFG and the vOTC, while the vOTC exerted inhibitory effective connectivity on the TPC and IFG. This arrangement suggests an efficient, selective modulation system in which stimulus type determines network dynamics.
In dyslexic readers, a strikingly different pattern emerged.
The TPC still exerted an excitatory influence on the vOTC and IFG but was itself inhibited by both sites.
Additionally, the IFG and vOTC inhibited each other. This bidirectional inhibition suggests a less efficient, more effortful processing configuration.
Comparing Typical and Dyslexic Readers: Divergent Network Architectures
When typical and dyslexic subjects were directly compared, several key differences in effective connectivity emerged. Dyslexic subjects showed weaker connectivity between the left TPC and IFG, stronger self-inhibition of the TPC, and reduced inhibition of the vOTC on the TPC during word reading.
In typical readers, words primarily engaged ventral lexical pathways, pseudowords recruited the dorsal decoding route (TPC-mediated), and the network showed selective, efficient modulation depending on stimulus type.
In dyslexia, both words and pseudowords relied heavily on the dorsal decoding route, interactions were more distributed and less efficient, cerebellar involvement was stronger, and intrinsic connectivity was weaker but more diffusely distributed.
These patterns suggest that dyslexic readers process words using effortful decoding strategies rather than automated recognition.
Brain-Behavior Relationships: Connectivity Matters for Reading Performance
Turker et al. (2023) demonstrated that connectivity was in fact important to the problem of dyslexia, not merely regional activation.
Better reading was associated with stronger connectivity between the right cerebellum and left IFG within the dorsal cerebellar-frontal reading pathway.
Greater activation of the left SMG, left vOTC, right vOTC, right cerebellum, and bilateral lingual gyri also correlated with better reading.
Better reading was further correlated with stronger functional connectivity between the left SMG and left vOTC, between the left SMG and right cerebellum, and between the left vOTC and right cerebellum. Effective connectivity results depended on whether subjects had dyslexia, as shown in the figure below.
The Paradox of Over-Recruitment: When More Connectivity Means Worse Reading
A counterintuitive finding emerged from the data: in dyslexia, higher connectivity often correlated with worse reading performance. This paradox suggests inefficient or compensatory over-recruitment of network resources.
Rather than reflecting a well-coordinated system, the increased connectivity in dyslexic readers appears to represent effortful, poorly targeted engagement of reading circuits.
Extending Classical Models: From Cortical Hypoactivation to Cortical-Subcortical Networks
These findings extend classical cortical hypoactivation models of dyslexia by introducing cortical-subcortical network dynamics. The classical regions remain associated with dyslexic reading, but understanding their connections adds a new dimension to our understanding of the disorder. This network perspective aligns with the idea that dyslexia involves reduced automaticity of processing in reading circuits.
In particular, dyslexic subjects over-engage the dorsal reading stream (left vOTC to left SMG to left ventral IFG), and connectivity of the right cerebellum is impaired, which compromises the dynamics of inhibitory control in the brain.
Turker et al. (2023) suggest that a treatment approach may involve neuromodulation to activate the left SMG (located in the temporo-parietal cortex classically associated with dyslexia) and areas of the right cerebellum in order to influence their reading-related connectivity. They propose in particular that task-related connectivity of the right cerebellum may be a neural marker for dyslexia.
Neurofeedback for Dyslexia: Integrating Network Science with Clinical Practice
Building on Prior Evidence
In an earlier BioSource post, we reviewed how NFB has been used for dyslexia. The key take-away from that review was as follows: neurofeedback can probably be helpful when it is based on careful baseline EEG assessment and combined with reading training; left hemisphere coherence training and inhibition of frontotemporal theta should be considered as training parameters.
How can the network perspective described by Turker et al. (2023) be integrated with those earlier findings and applied to the clinical challenge of dyslexia?
Theta Inhibition and Network Hypoactivation
NFB inhibition of left hemisphere theta is consistent with addressing the hypoactivation of network nodes described by Turker et al. (2023).
By reducing excessive theta activity, which is often associated with cortical underactivation, clinicians may facilitate increased engagement of the reading network nodes that are characteristically sluggish in dyslexia.
Coherence Training and Network Connectivity
NFB coherence training of the left hemisphere is also consistent with the findings of Turker et al. (2023). An illustrative example is the research of Coben et al. (2015), where the left occipito-parietal region adjacent to the SMG was shown to be of particular importance.
This approach directly targets the connectivity deficits that Turker and colleagues identified as central to the dyslexic reading pattern.
The Missing Piece: Right Cerebellar Involvement
What is notably absent from existing NFB research on dyslexia is the inclusion of right hemisphere cerebellar regions that Turker et al. (2023) found to be critically important in reading networks.
This represents a significant gap between current research evidence and clinical practice, and it points toward an important frontier for future investigation and protocol development.
Practical Training Targets: The Supramarginal Gyrus as a Network Gateway
In the absence of widely accessible NFB methods to train the cerebellum—other than 19-channel swLORETA neurofeedback—NFB providers may focus on training to increase activation of the left supramarginal gyrus (SMG, BA 40) and its connections to other nodes in the dyslexia network.
Two particularly important areas that the SMG connects with are the left inferior frontal gyrus (IFG, BAs 44, 45, 47) and the left occipito-temporal cortex (vOTC, BA 37).
Training at BA 40 (shown below) would be expected to affect connected nodes of the dyslexia network, including the right cerebellum. Graphic © Big8/Shutterstock.com.
A practical challenge is that the SMG is situated at the intersection of a line between Cz and P3, and between Pz and C3 in the 10-20 EEG system.
For practitioners with access to qEEG and NeuroGuide methods, however, it is possible to train both left BA 40 and the right cerebellum—along with the relevant connectivity metrics—directly via swLORETA.
Summary: Key Regions, Key Connections
In dyslexia, hypoactivation of several left hemisphere areas plays an important role: BA 40 (supramarginal gyrus), BA 37 (occipito-temporal cortex), BAs 44, 45, and 47 (inferior frontal gyrus), as well as the right cerebellum.
Critically, it is not simply the activation of these areas that matters, but also their functional and effective connectivity—both with each other and with the cerebellum.
Equipment Considerations and Training Options
A NFB provider with a 2-channel system has several options. BA 40 can be trained at the electrode position between Cz-P3 and between Pz-C3. BA 37 is located approximately at P9 in the 10-10 EEG system (below T5 in the 10-20 system). BAs 44, 45, and 47 can be targeted at F7. Coherence between these sites can also be trained with a 2-channel system.
More advanced NFB configurations may offer additional benefits by training effective connectivity between these sites, directly targeting the right cerebellum, and addressing the associated connectivity abnormalities that network research has identified as central to the reading difficulties in dyslexia.
Five Key Takeaways
Brodmann areas are best understood not as fixed functional units but as nodes participating in multiple, dynamically reconfigured brain networks, making them candidate gateways for neurofeedback rather than isolated training targets.
Dyslexia involves more than hypoactivation of three core left-hemisphere regions (IFG, SMG, vOTC); it also involves disrupted functional and effective connectivity across a broader cortical-subcortical reading network that includes the right cerebellum.
Dyslexic readers show a paradox of over-recruitment: increased connectivity correlates with worse reading performance, suggesting compensatory but inefficient engagement of reading circuits rather than well-coordinated processing.
Existing NFB approaches for dyslexia (left hemisphere theta inhibition and coherence training) align with network-level findings, but no current NFB protocols address the right cerebellar connectivity deficits that research has identified as critically important.
Practical NFB planning should target the left supramarginal gyrus (BA 40) as a network gateway, with advanced practitioners using swLORETA to additionally train right cerebellar connectivity and effective connectivity metrics across the reading network.
Glossary
10-10 EEG system: an extended electrode placement system that increases the number of scalp sites beyond the standard 10-20 system, providing finer spatial resolution for EEG recording. Relevant sites for dyslexia neurofeedback include P9, which approximates BA 37.
10-20 EEG system: the international standard system for electrode placement on the scalp during electroencephalography, using proportional measurements based on skull landmarks. Key sites referenced in dyslexia neurofeedback include Cz, C3, P3, Pz, T5, and F7.
anterior cingulate cortex: a medial cortical structure involved in error monitoring, attention allocation, and cognitive control. Bilateral differences in this region between dyslexic and typical readers were identified through multivariate analyses.
axonal pathways: bundles of nerve fibers (axons) that transmit electrochemical signals between brain regions and form the structural basis of network connectivity. Reconfiguration of these pathways is one mechanism through which neuroplasticity can occur.
BA 7 (superior parietal lobule/inferior parietal lobule): a Brodmann area in the parietal lobe involved in visuospatial processing and sensory integration. It was identified as one of the nodes showing maximal group differences in connectivity between typical and dyslexic readers. BA 37 (occipito-temporal cortex/fusiform gyrus): a Brodmann area at the junction of the occipital and temporal lobes that contains the visual word form area, critical for recognizing written words. It corresponds to the left ventral occipito-temporal cortex (vOTC) in reading models and shows hypoactivation in dyslexia. Approximate EEG electrode location: P9 in the 10-10 system (below T5 in the 10-20 system).
BA 40 (supramarginal gyrus): a Brodmann area in the inferior parietal lobule that supports grapheme-phoneme conversion and phonological processing. It is a key hub in the dorsal reading stream and shows hypoactivation and increased self-inhibition in dyslexia. Approximate EEG electrode location: at the intersection of lines between Cz and P3, and between Pz and C3.
BA 44 (pars opercularis): a Brodmann area forming part of the left inferior frontal gyrus, classically associated with speech production (Broca's area). It participates in articulatory planning and phonological output and is one of several IFG subregions showing hypoactivation in dyslexia. Approximate EEG electrode location: F7.
BA 45 (pars triangularis): a Brodmann area within the left inferior frontal gyrus involved in semantic processing and controlled language retrieval. It contains subfields with distinct patterns of connectivity to other Brodmann areas. Approximate EEG electrode location: F7.
BA 46 (dorsolateral prefrontal cortex): a Brodmann area in the middle frontal gyrus involved in executive function, working memory, and cognitive control. It illustrates the principle that a single BA can participate in multiple networks, serving as a component of the frontoparietal control network, salience network, and default mode network.
BA 47 (pars orbitalis): a Brodmann area in the ventral portion of the left inferior frontal gyrus involved in semantic processing and syntactic comprehension. Along with BAs 44 and 45, it forms part of the IFG complex that shows hypoactivation in dyslexia. Approximate EEG electrode location: F7.
Brodmann areas (BAs): a system of cortical regions originally mapped by Korbinian Brodmann in 1909 based on cytoarchitectural differences in cellular microstructure. Modern neuroscience views BAs as probabilistically defined regions that participate in multiple overlapping networks rather than serving singular functions.
cell assemblies: groups of interconnected neurons that fire together in coordinated patterns to support specific cognitive or behavioral functions. The brain's overlapping networks are composed of dynamically reconfigured cell assemblies.
cerebellum: a hindbrain structure traditionally associated with motor coordination and balance, now recognized as playing important roles in language, reading, and cognitive processing. In dyslexia, the right cerebellum shows impaired connectivity with cortical reading network nodes, and its task-related connectivity may serve as a neural marker for the disorder.
coherence training: a neurofeedback technique that targets the statistical relationship between EEG signals recorded at two or more electrode sites, aiming to normalize the degree of synchronization between brain regions. Left hemisphere coherence training is a recommended parameter for NFB treatment of dyslexia.
connectionist models: theoretical frameworks in neuroscience that explain brain function through the interactions and connections among distributed neural processing units rather than through the activity of isolated regions. Modern network-based models of reading represent the evolution of 19th-century connectionist theories of language.
cuneus: a wedge-shaped region of the occipital lobe involved in basic visual processing. In dyslexia, the right cuneus showed increased connectivity with the right vOTC, possibly reflecting compensatory visual processing.
cytoarchitecture: the cellular composition and layered structural organization of brain tissue that distinguishes one cortical region from another. Brodmann's original classification system was based on differences in cytoarchitecture across the cortex.
default mode network: a large-scale brain network active during rest, self-referential thought, and internally directed cognition. It includes BA 46 (dorsolateral prefrontal cortex) among its components, illustrating how single Brodmann areas participate in multiple functional networks.
dorsal reading stream: a neural pathway involved in grapheme-phoneme decoding that runs from the left ventral occipito-temporal cortex through the left supramarginal gyrus to the left inferior frontal gyrus. In dyslexia, both words and pseudowords over-rely on this route, reflecting effortful decoding rather than automated word recognition.
dynamic causal modeling (DCM): a statistical method used in neuroimaging to estimate the directed (effective) connectivity between brain regions and to determine how experimental conditions modulate those connections. Turker et al. (2023) used DCM to compare effective connectivity patterns between typical and dyslexic readers.
dyslexia: a neurodevelopmental reading disorder characterized by difficulties with accurate and fluent word recognition, poor decoding, and spelling difficulties. At the neural level, it involves hypoactivation of left hemisphere reading regions, globally weaker connectivity in reading networks, and impaired cerebellar-cortical interactions.
effective connectivity: the directed causal influence that one brain region exerts on another, including both excitatory and inhibitory effects. In typical readers, the left TPC exerts excitatory effective connectivity on the IFG and vOTC, while dyslexic readers show a pattern of mutual inhibition among these regions.
electroencephalography (EEG): a neurophysiological method that records the brain's electrical activity from electrodes placed on the scalp. EEG provides the signal used in neurofeedback and serves as a key assessment tool for identifying network abnormalities in dyslexia.
excitatory connectivity: a type of neural influence in which one brain region increases the activation or firing rate of another region. In typical readers, the left temporo-parietal cortex exerts excitatory influence on both the inferior frontal gyrus and the ventral occipito-temporal cortex during reading.
frontoparietal control network: a large-scale brain network that supports goal-directed behavior, cognitive flexibility, and task switching. BA 46 (dorsolateral prefrontal cortex) is one of its components.
functional connectivity: the statistical correlation or temporal synchrony between the activity of spatially distant brain regions, measured without inferring directional influence. Dyslexic readers show globally weaker functional connectivity throughout reading networks compared to typical readers.
grapheme-phoneme decoding: the cognitive process of converting written letter patterns (graphemes) into their corresponding speech sounds (phonemes). This function is primarily mediated by the left temporo-parietal cortex and is a core deficit in dyslexia.
histology: the microscopic study of the structure and composition of biological tissues. Histological analysis of brain tissue is the basis for defining Brodmann areas and their probabilistic borders.
hub: a brain region within a network that maintains multiple influential connections to other regions and plays a disproportionately important role in network function. Hubs may serve as gateways for neurofeedback training aimed at modifying network activity.
hypoactivation: reduced neural activation in a brain region relative to a normative or control comparison. In dyslexia, the left inferior frontal gyrus, left temporo-parietal cortex, left ventral occipito-temporal cortex, and right cerebellum all show hypoactivation during reading tasks.
inferior frontal gyrus (IFG): a frontal lobe structure comprising BAs 44, 45, and 47 that supports phonological output, attention, working memory, semantic retrieval, and articulatory planning. The left IFG is one of three core regions showing hypoactivation in dyslexia. Approximate EEG electrode location: F7.
inhibitory connectivity: a type of neural influence in which one brain region decreases the activation or firing rate of another region. In dyslexic readers, the IFG and vOTC mutually inhibit each other, and the TPC shows increased self-inhibition compared to typical readers.
insula: a cortical region located deep within the lateral sulcus, involved in interoception, emotional processing, and multimodal sensory integration. The left insula was identified through multivariate analyses as showing recruitment differences between dyslexic and typical readers.
lingual gyrus: a medial occipital lobe structure involved in visual processing, particularly the encoding of letters and words. Bilateral lingual gyri activation correlates with better reading performance.
multivariate analysis: a statistical approach that simultaneously examines patterns across multiple variables or brain regions, capable of detecting distributed differences in neural recruitment that univariate methods may miss. In Turker et al. (2023), multivariate analyses revealed group differences in the left insula, bilateral anterior cingulate, right precuneus, and left cerebellum.
NeuroGuide: a commercial software platform for quantitative EEG analysis and neurofeedback that provides normative databases, source localization capabilities, and connectivity metrics. It enables swLORETA-based training of deep structures such as the cerebellum.
neuromodulation: the use of targeted techniques to alter neural activity in specific brain regions or networks. Turker et al. (2023) suggest neuromodulation of the left SMG and right cerebellum as a potential approach to treating dyslexia.
neurofeedback (NFB): a form of biofeedback that uses real-time displays of brain electrical activity (typically EEG) to enable individuals to learn to self-regulate neural function. In dyslexia treatment, NFB approaches include theta inhibition, coherence training, and swLORETA-based connectivity training.
neuroplasticity: the brain's capacity to reorganize its structure and function in response to experience, learning, injury, or targeted intervention. Network reconfiguration through new hubs, modules, or axonal pathways is one mechanism by which neuroplasticity can address dysfunctional networks.
occipital poles: the posterior tips of the occipital lobes, which contain primary visual cortex. The left vOTC showed weaker functional connectivity with a region extending from the occipital poles to the superior lateral occipital cortices in dyslexic readers.
parcellation-based connectome analyses: methods that divide the brain into discrete parcels (regions) based on structural or functional criteria and then map the complete pattern of connections among those parcels. These analyses offer an alternative to Brodmann area-based approaches for characterizing brain network organization.
phrenology: a discredited 19th-century theory that mental faculties could be determined by the shape of the skull and that specific brain regions each housed a single, distinct psychological function. The network-based conceptualization of BA function represents a departure from phrenological thinking about localized brain function.
postcentral gyrus: the cortical region immediately posterior to the central sulcus that serves as the primary somatosensory cortex. In dyslexia, the right cerebellum showed reduced coupling with the bilateral postcentral cortices.
precentral gyrus: the cortical region immediately anterior to the central sulcus that serves as the primary motor cortex. The right vOTC in dyslexia showed decreased connectivity with the left precentral gyrus.
precuneus: a medial parietal lobe structure involved in visuospatial processing, episodic memory retrieval, and self-referential thought. The right precuneus showed recruitment differences between dyslexic and typical readers, and the left precuneus showed decreased connectivity with the right vOTC in dyslexia.
pseudowords: pronounceable letter strings that follow the orthographic rules of a language but have no meaning (e.g., "bloop" or "tramble"). In reading research, pseudowords are used to assess phonological decoding ability because they cannot be recognized through stored lexical representations.
quantitative EEG (qEEG): a method of analyzing EEG data by comparing an individual's brain electrical activity to normative databases using statistical measures. QEEG assessment is used to identify network abnormalities that can guide neurofeedback protocol development for dyslexia.
regions of interest (ROIs): predefined brain areas selected for focused analysis in neuroimaging research, often corresponding to Brodmann areas or anatomical landmarks. ROIs are used to investigate the role of specific cortical and subcortical structures within larger functional networks.
salience network: a large-scale brain network that detects and filters behaviorally relevant stimuli and coordinates switching between other networks. BA 46 (dorsolateral prefrontal cortex) is among its components.
self-inhibition: a neural process in which a brain region suppresses its own activity through local inhibitory mechanisms. In dyslexia, the left temporo-parietal cortex shows stronger self-inhibition than in typical readers, potentially contributing to reduced engagement during reading.
standardized weighted low-resolution electromagnetic tomography (swLORETA): an EEG source localization method that estimates the three-dimensional distribution of electrical activity within the brain from scalp recordings. When implemented with 19-channel EEG systems, swLORETA neurofeedback enables training of deep structures such as the cerebellum and direct targeting of connectivity metrics between specified brain regions.
supracalcarine cortex: a region of the occipital lobe located above the calcarine sulcus, involved in visual processing. In dyslexia, the right vOTC showed increased connectivity with the right supracalcarine cortex.
superior frontal cortex: a region in the dorsal and medial portions of the frontal lobe involved in executive function and higher-order motor planning. The right cerebellum showed reduced coupling with the bilateral superior frontal cortices in dyslexic readers.
superior lateral occipital cortex: a region of the lateral occipital lobe involved in higher-order visual processing and object recognition. The left vOTC showed weaker functional connectivity with a region extending from the occipital poles to this area in dyslexia.
superior parietal cortex: the upper portion of the parietal lobe involved in visuospatial attention and sensory integration. The right cerebellum showed reduced coupling with the bilateral superior parietal cortices in dyslexic readers.
supplementary motor area (SMA): a medial frontal cortical region involved in motor planning, sequencing, and the coordination of bilateral movements. In dyslexia, the right cerebellum and right vOTC both showed decreased connectivity with the SMA.
supramarginal gyrus (SMG): a structure in the inferior parietal lobule corresponding to BA 40 that plays a central role in phonological processing and grapheme-phoneme conversion. It is part of the left temporo-parietal cortex and shows hypoactivation and weakened connectivity in dyslexia. See also BA 40.
temporo-parietal cortex (TPC): a cortical region at the junction of the temporal and parietal lobes, encompassing the supramarginal gyrus, that is critical for grapheme-phoneme decoding. The left TPC is one of three core regions hypoactivated in dyslexia and shows altered excitatory and inhibitory connectivity patterns in dyslexic readers.
Test-Operate-Test-Exit (TOTE): a cybernetic model of problem-solving and behavioral regulation introduced by Miller, Galanter, and Pribram (1960). It describes a feedback loop in which a current state is tested against a goal, an operation is performed if a discrepancy exists, the result is tested again, and the process exits when the goal is achieved. This model is adapted in the document as a framework for systematic neurofeedback protocol development.
theta activity: EEG oscillations in the 4-8 Hz frequency band, often associated with drowsiness, inattention, or cortical underactivation when excessive. Inhibition of frontotemporal theta through neurofeedback is a recommended training parameter for addressing hypoactivation in dyslexia.
ventral lexical pathway: a neural route involved in rapid, whole-word recognition that connects the visual word form area in the ventral occipito-temporal cortex to frontal language regions. In typical readers, words primarily engage this pathway, whereas dyslexic readers under-recruit it and instead over-rely on the dorsal decoding route.
ventral occipito-temporal cortex (vOTC): a cortical region at the ventral surface of the occipito-temporal junction, encompassing BA 37 and the visual word form area, that is essential for visual word recognition. The left vOTC shows hypoactivation in dyslexia, and both left and right vOTC exhibit disrupted connectivity patterns. See also BA 37.
visual word form area (VWFA): a functionally defined region within the left ventral occipito-temporal cortex (BA 37/fusiform gyrus) that is specialized for the rapid visual recognition of written words and letter strings. Hypoactivation of the VWFA is a hallmark neural finding in dyslexia.
white matter connections: myelinated axonal tracts that link cortical and subcortical brain regions and provide the structural basis for network communication. White matter connection mapping offers an alternative to Brodmann area-based atlases for characterizing brain connectivity.
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About the Author
Dr. John "Dusty" Raymond Davis is an adjunct lecturer in the Department of Psychiatry and Behavioural Neurosciences at McMaster University's Faculty of Health Sciences. His scholarly contributions include research on EEG changes in major depression and case studies on neurological conditions.
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