Bilateral lesions in the temporal lobe can lead to Klüver-Bucy syndrome. This condition is characterized by visual agnosia, which is the inability to recognize the meaning of objects based on visual cues. Individuals with this syndrome tend to orally examine all objects, including dangerous ones, and show attention to irrelevant stimuli. They may also experience hypersexuality, changes in dietary habits, and decreased emotionality.

Recent studies have emphasized the significance of the amygdala in the development of this syndrome. The amygdala is responsible for conditioning the association of fear with painful stimuli and can trigger emotional or avoidance responses through its connections to the medial frontal cortex and anterior cingulate gyrus. Additionally, the amygdala projects to the nucleus accumbens, known as a "reward center" within the basal ganglia. The nucleus accumbens receives dopaminergic input from the ventral tegmental area, signaling pleasurable events. It is also the most common site for the plaques and tangles associated with Alzheimer's disease.

Different lobes of the cerebral cortex have been studied to understand their functions. Lesions caused by disease or surgical interventions in humans, as well as experiments on animals, have helped define these functions. Another approach involves correlating the physical manifestations of epileptic seizures with the specific brain locations that give rise to them, known as epileptic seizure foci. For example, epileptic foci in the motor cortex result in movements on the contralateral side, with the nature of these movements depending on the somatotopic location of the seizure focus. Seizures originating in the somatosensory cortex cause a touch sensation during an epileptic aura. Similarly, seizures starting in the visual cortex cause visual auras, such as scintillations or colors, while those in the auditory cortex cause auditory auras, such as humming or buzzing sounds. Vestibular cortex involvement leads to a sensation of spinning. Complex behaviors can arise from seizures originating in the association areas of the temporal lobe, and if the olfactory cortex is involved, a malodorous aura may be perceived (known as uncinate fit).

The electrical activity of the cortex is also an important aspect to consider.
Fig. 10.4 ). In addition, the hippocampus and amygdala are connected to the prefrontal cortex, the basal forebrain, and the anterior cingulate cortex.
Bilateral temporal lobe lesions can produce Klüver-Bucy syndrome, which is characterized by loss of the ability to recognize the meaning of objects from visual cues (visual agnosia); a tendency to examine all objects, even dangerous ones, orally; attention to irrelevant stimuli; hypersexuality; a change in dietary habits; and decreased emotionality.
Although this syndrome was originally described as following large lesions of most or all of the temporal lobe, more recent studies have highlighted the role of the amygdala. The amygdala conditions the association of fear with painful stimuli and may trigger, via connections to the medial frontal cortex and anterior cingulate gyrus, emotional or avoidance responses when these stimuli recur. In addition, the amygdala projects to the nucleus accumbens, a region of the basal ganglia which has been called a “reward center.” The nucleus accumbens signals pleasurable events in response to dopaminergic input from the ventral tegmental area of the brainstem and is also the most common site of the plaques and tangles associated with Alzheimer’s disease.
Thefunctionsofthedifferentlobesofthecerebralcortexhavebeendefinedaccordingtoboththeeffectsoflesionsproducedbydiseaseorthoseofsurgicalinterventionstotreatdiseaseinhumansandfromexperimentsonanimals.Inanotherapproach,thephysicalmanifestationsofepileptic seizures havebeencorrelatedwiththebrainlocationsthatgiverisetoseizures(epileptic seizure foci). Forexample,epilepticfociinthemotorcortexcausemovementsonthecontralateralside;theexactmovementsrelatetothesomatotopiclocationoftheseizurefocus.Seizuresthatoriginateinthesomatosensorycortexcauseanepileptic aura inwhichatouchsensationisperceived.Similarly,seizuresthatstartinthevisualcortexcauseavisualaura(scintillations,colors),thoseintheauditorycortexcauseanauditoryaura(humming,buzzing,ringing),andthoseinthevestibularcortexcauseasensationofspinning.Complexbehaviorresultsfromseizuresthatoriginateintheassociationareasofthetemporallobe;inaddition,amalodorousauramaybeperceivediftheolfactorycortexisinvolved (uncinate fit).
The Electrical Activity of the Cortex