Abstract
Temporal lobes are one of the four major lobes of the cerebral cortex and perform a complex array of interrelated functions. They play an important role in various day-to-day functioning. The common pathologies leading to isolated temporal lobe dysfunction are infarction (of the middle cerebral artery), hemorrhage, seizures, tumors, encephalitis, and traumatic brain injury. Temporal lobe syndromes include a wide array of various neurological (Kluver-Bucy syndrome, Geschwind Gastaut syndrome, etc.), elementary (e.g., vertiginous syndromes, hallucinations, etc.), neuropsychiatric (e.g., anxiety, agitation, aggression, etc.), and cognitive (e.g., Korsakoff amnesia, cortical deafness, etc.) disorders. The presentation depends on a multitude of factors including involvement of dominant or non-dominant lobe. Left temporal lobe involvement usually leads to various forms of aphasia while right side involvement leads to more covert and varied syndromes. In this chapter, the authors discuss the anatomy of the temporal lobe, its functional aspects, and various syndromes of temporal lobe dysfunction.
TopChapter Outline
- 1.
Introduction
- 2.
Anatomy of temporal lobe
- 3.
Functional anatomy of temporal lobe
- 4.
Connections of the temporal lobe
- 5.
Temporal lobe syndromes
- 6.
Neuropsychology of the temporal lobe: Assessment and its implications
- 7.
Conclusion
TopAnatomy Of Temporal Lobe
The temporal lobe is the second-largest lobe and accounts for more than 20% of the total neocortex volume. The lobe extends to the Sylvian fissure superiorly and to an imaginary line posteriorly. The lateral parietal-temporal line separates the temporal lobe from the parietal lobe superiorly and occipital lobe inferiorly. Its anterior and inferior boundaries are formed by the middle cranial fossa. The temporal lobe is divided into two sections: neocortex and mesial temporal lobe. The mesial/medial temporal lobe contains areas such as the hippocampus, parahippocampal gyrus, amygdala, etc. and is called the limbic lobe as well. The temporal lobe is divided by four sulci into five gyri. The five gyri are superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, fusiform gyrus, and parahippocampal gyrus. The temporal lobe receives blood supply from both the internal carotid artery (anterior choroidal artery which supplies the anterior part of the parahippocampal gyrus, the amygdala and the uncus and middle cerebral artery which supplies the superior and inferior temporal gyri) and the vertebrobasilar artery (supplies the inferior surface). The temporal lobes are tied to other lobes intimately through various association tracts. The largest of these association tracts include the occipitotemporal and uncinate fasciculus.
Key Terms in this Chapter
Temporal Lobe: The temporal lobe is the region where sound is processed and, not surprisingly, it is also a region where auditory language and speech comprehension systems are located. The auditory cortex is located on the upper banks of the temporal lobe and within the Sylvian fissure.
Temporal Lobe Syndromes: The common pathologies which affect the temporal lobes in insolation include infarction (of middle cerebral artery inferior division), epilepsy, tumors, traumatic brain injury, intracerebral hemorrhage, and encephalitis.
Kluver-Bucy Syndrome: Is a rare behavioral impairment characterized by inappropriate sexual behaviors and mouthing of objects. Other signs and symptoms, include a diminished ability to visually recognize objects, loss of normal fear and anger responses, memory loss, distractibility, seizures, and dementia.