The temporoparietal junction (TPJ) is a crucial region of the brain located at the junction of the temporal and parietal lobes. It is a complex and multifunctional area with various subregions that play significant roles in a wide range of cognitive and sensory processes.
Multisensory Integration: The TPJ plays a vital role in integrating information from multiple sensory modalities. It helps merge sensory input from the auditory, visual, and somatosensory systems, facilitating the perception of the environment and one's own body.
Theory of Mind (ToM): The TPJ is particularly known for its involvement in the theory of mind processes. Theory of mind refers to the ability to understand and attribute mental states, beliefs, desires, and intentions to oneself and others. The TPJ is crucial for processing social and emotional cues and inferring the mental states of others, which is essential for empathy and social interactions.
Self-Other Distinction: It also plays a role in distinguishing between self and other. This is important for recognizing one's own actions, thoughts, and sensations as distinct from those of others.
Spatial Awareness and Navigation: The TPJ is involved in spatial awareness and navigation. It helps with understanding one's position in space, processing landmarks, and orienting oneself in the environment.
Attention: The TPJ is associated with attentional processes, particularly in reorienting attention. It helps redirect attention to unexpected or salient stimuli in the environment.
Memory: Some parts of the TPJ are involved in memory functions, particularly working memory and episodic memory, which are important for tasks like remembering instructions or past experiences.
Language Processing: In the left hemisphere, the TPJ is involved in language processing and comprehension, particularly for understanding complex syntax and semantics.
Disorders and Impairments: Dysfunctions or lesions in the TPJ have been associated with various cognitive and neurological disorders, such as autism spectrum disorder, schizophrenia, and neglect syndrome. Damage to the TPJ can lead to impairments in theory of mind, spatial awareness, and attentional processes.
Neuroimaging Studies: Neuroimaging studies, including functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), have provided insights into the TPJ's activation patterns during various tasks, helping researchers better understand its functions.
The TPJ is a highly interconnected region, with strong connections to other brain areas, such as the prefrontal cortex, the superior temporal gyrus, and the inferior parietal lobule. Its role in a wide array of cognitive functions makes it a subject of ongoing research and exploration, and it plays a central role in our understanding of social cognition and perception.
Glioblastomas involving the right white matter of the temporoparietal junction are more likely to result in poor postoperative KPS scores and prognoses. Impairments of several kinds of brain functions caused by tumor invasion to the WM-TPJ may be associated with lower KPS scores 1).
The few studies tackling the outcome and neurological burdens of surgical operations addressing TPJ document the presence of language disturbances and visual field damages, with the latter hardly recovered in time. This observation advocates for identifying and functionally monitoring the optic radiation (OR) bundles that cross the white matter below the temporoparietal junction. In a study, Michele et al. adopted a multimodal approach to address the anatomic-functional correlates of the OR's dorsal loop. In particular, they combined cadavers' dissection with tractography and electrophysiological data collected in drug-resistant epileptic patients explored by stereoelectroencephalography (SEEG). Cadaveric dissection allowed them to appreciate the course and topography of the dorsal loop. More surprisingly, both tractography and electrophysiological observations converged on a unitary picture highly coherent with the data obtained by neuroanatomical observation. The combination of diverse and multimodal observations allows overcoming the limitations intrinsic to single methodologies, defining a unitary picture that makes it possible to investigate the dorsal loop both pre-surgically and at the individual patient level, ultimately contributing to limiting the postsurgical damages. Notwithstanding, such a combined approach could serve as a model of investigation for future neuroanatomical inquiries tackling white matter fiber's anatomy and function through SEEG-derived neurophysiological data 2) 3).