Temporal lobes

Two major subdivisions of the temporal lobe were investigated PHR and the temporal neocortex (including IT and STG). 

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The hippocampus, which got its name from the Greek word for seahorse, due to its form, is a nucleus in the depth of the temporal lobe. The hippocampus is important for the integration of sensory information, for spatial orientation and for memory formation. The hippocampal formation contains the CA (cornu ammonis) regions, the dentate gyms and the subiculum. 

The temporal lobe is the inferior middle portion of the cerebral cortex of both hemispheres. The temporal lobes are involved in the analysis of visual and acoustic information and in memory formation. The hippocampus is part of the inner, medial side of the temporal lobes. 

Lee TS, Eid T, Mane S, Kim JH, Spencer DD, Ottersen OP, et al. Aquaporin-4 is increased in the sclerotic hippocampns in hnman temporal lobe epilepsy. Acta Neuropathol (Berl) 2004 108 493-502. 

Locatelli ER, Varghese JP, Shuaih A, Potohcchio SJ. Cardiac asystole and bradycardia as a manifestation of left temporal lobe complex partial seizure. Ann Intern Med... 

Complex partial seizures manifest themselves as bizarre behaviours which are also known as psychomotor or temporal lobe epilepsy, since a lesion (focus) is often found in that brain area. Repetitive and apparently purposeful movements vary from simple hand clenching or rubbing to more bizarre hand movements and walking. These can last a few minutes, often disrupt other ongoing activity or speech and the patient has no subsequent memory of them. Complex seizures may develop from simple ones. 

Many seizures are associated with distinctive EEG patterns (Fig. 16.1). Perhaps the most striking is the 3 per second spike wave activity seen in most leads (cortical areas) in absence seizures, which can be invoked by hyperventilation. Otherwise distinctive EEG patterns are usually only found during an actual seizure, with burst spiking seen alongside clonus in TCS and abnormal discharges with the behavioural patterns of partial epilepsy and in particular that originating in the temporal lobe. 

There have been a number of observations which show increased excitation and/or reduced inhibition in slices prepared from human epileptic brain tissue. Thus burst discharges can be evoked with stimuli that would not do so in normal animal tissue and these can be blocked by NMD A receptor antagonists. The inhibitory postsynaptic currents (IPSCs) in hippocampal dentate granule cells in slices prepared from temporal lobe epileptic tissue are in fact reduced by stimulation that activates NMDA currents (Isokawa 1996), which are more prolonged than usual and show changes in slope conductance. 

Isokawa, M, Levesque, MF, Babb, TL and Engel Jr, J (1993) Single mossy fibre axonal systems of human dentate granule cells studied in hippo-campal slices from patients with temporal lobe epilepsy. J. Neurosci. 13 1511-1522. 

Isokawa, M, Levesque, M, Fried, I and Engel, J Jr (1997) Glutamate currents in morphologically identified human dentate granule cells in temporal lobe epilepsy. J. Neurophysiol. 77 3355-3369. 

Kerwin, R (1992) A history of frontal and temporal lobe aspects of the neuropharmacology of schizophrenia. J. Psychopharm. 6 230-240. 

Compared to the Category Test, SSP and SRT results show a relatively mixed performance profile. This profile is indicative of temporal lobe impairment and may explain the idiosyncratic character of PCP-induced brain dysfunction. Other HRB subtest data suggest that parietal lobe-mediated functions are less influenced by PCP abuse, since approximately 30 percent of this sample had error-free performances on a test sensitive to finger agnosia. 

Mesial temporal lobe epilepsy (MTLE) A type of epilepsy that consists of partial seizures arising from the mesial temporal lobe of the brain. Often this type of epilepsy is associated with an anatomic change described as hippocampal sclerosis. Patients with this type of epilepsy often have excellent outcomes with surgery for epilepsy. 

His MRI is normal, and focal epileptiform activity originating from his left temporal lobe is observed on the EEC. 

Named for the bones of the cranium under which they lie, the lobes are conspicuously defined by prominent sulci of the cortex, which have a relatively constant position in human brains. Each lobe is specialized for different activities (see Figure 6.3). Located in the anterior portions of the hemispheres, the frontal lobes are responsible for voluntary motor activity, speaking ability, and higher intellectual activities. The parietal lobes, which are posterior to the frontal lobes, process and integrate sensory information. The occipital lobes, located in the posterior-most aspects of the cerebrum, process visual information, and the temporal lobes, located laterally, process auditory information. 

Occipital lobe One of four, together with the frontal, parietal and temporal, lobes of the cerebral hemispheres. 

Buhl, E. H., Otis, T. S. and Mody, I. Zinc-induced collapse of augmented inhibition by GABA in a temporal lobe epilepsy model. Science 271 369-373,1996. 

Frontotemporal dementias occur as familial forms and, more commonly, as sporadic diseases. They are characterized by a remarkably circumscribed atrophy of the frontal and temporal lobes of the cerebral cortex, often with additional, subcortical changes. In 1994, an autosomal-dominantly inherited form of frontotemporal dementia with parkinsonism was linked to chromosome 17q21.2. Subsequently, other forms of frontotemporal dementia were linked to this region, resulting in the denomination frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) for this class of disease. All cases of FTDP-17 have so far shown a filamentous pathology made of hyperphosphorylated tau protein (Fig. 45-7). In 1998, mutations in tau were reported in FTDP-17 patients [29-31]. Since then, more than 30 different mutations have been described in over 80 families with FTDP-17 (Fig. 45-6). 

Amnesia patients showed the role of the temporal lobe in memory 860... 

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