Lobes, brain

Temporal lobe brain structures, in particular the hippocampal formation, appear to play a pivotal yet transient role in the formation of new explicit memories. This chapter focuses on possible neurochemical mechanisms underlying the encoding of new information in the hippocampus and the modulation of memory function by different neurotransmitter systems in the brain. 

Jacobsen, L.K., Giedd, J.N., Kreek, M.J., Gottschalk, C., and Kosten, T.R (2001 b) Quantitative medial temporal lobe brain morphology and hypothalamic-pituitary-adrenal axis function in cocaine dependence a preliminary report. Drug Alcohol Depend 62 49-56. 

Hutsler JJ. 2003. The specialized structure of human language cortex Pyramidal cell size asymmetries within auditory and language-associated regions of the temporal lobes. Brain Lang 86(2) 226-242. 

In contrast to the orthopterans, PDH-IR cells are distributed widely in the optic lobes, brain, and subesophageal ganglion of Manduca sexta (59). This differential distribution may reflect a diversity of functions which remains to be explored. 

Courville J, Diakew N (1976) Cerebellar corticonuclear projection in the cat. The vermis of the anterior and posterior lobes. Brain Res., 110, 1-20. 

Ekerot C-F, Earson B (1973) Correlation between sagittal projection zones of climbing and mossy fibre paths in cat cerebellar anterior lobe. Brain Res., 64, 446-450. 

Haines DE (1969) The cerebellum of Galago and Tupaia. I. Corpus cerebelli and flocculonodular lobe. Brain Behav. Evol, 2, 377-414. 

Whitworth RH Jr, Haines DE (1986b) The inferior olive of Saimir sciurus olivocerebellar projections to the anterior lobe. Brain Res., 372, 55-72. 

Wiklund L, Bjorklund A, Sjolund B (1977) The indolaminergic innervation of the inferior olive. 1. Convergence with the direct, pinal afferents in the areas projecting to the cerebellar anterior lobe. Brain Res., 131, 1-21. 

The POMC gene is expressed in the anterior and intermediate lobes of the pituitary. The most conserved sequences between species are within the amino terminal fragment, the ACTH region, and the (3-endorphin region. POMC or related products are found in several other vertebrate tissues, including the brain, placenta, gastrointestinal tract, reproductive tract, lung, and lymphocytes. 

If one is patient, the blood flow will start. However, where no flow occurs, then one needs to resort to the bottom of the lobe of the ear, because while the blood flow may be restricted to the extremities in certain severe conditions, the flow to the head and the brain is not, and one can usually get an adequate amount of capillary blood from the ear. Once the blood... 

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. 

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. 

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. 

Mesocortical A neural pathway that connects the ventral tegmentum to the cortex, particularly the frontal lobes. It is one of the major dopamine pathways in the brain. 

Figure 3. Sketch of DDC-expressing neurons in the Drosophila larval CNS. The CNS consists of brain lobes and a segmented ventral ganglion. Filled circles represent dopamine cells open circles represent serotonin cells grayed circles represent DDC cells that contain no detectable tyrosine hydroxylase or serotonin immunoreactivity, indicating that these cells may produce neither transmitter (Lundell and Hirsh, 1994). M, medial dopamine neurons VL, ventrolateral serotonin neurons DL, dorsolateral dopamine neurons. The hatched rectangle shows the region of the ventral ganglion that is shown in Figures 4 and 6.

The majority of DDC-expressing cells in the brain lobes are dopamine cells. Most of these dopamine cells have axons that project into a common axonal fiber extending anteriomedially within the brain lobe and then separating into finer fibers that cross between the lobes. The dopamine cells occur in small clusters of two to six cells, which suggests that these cells might share common lineages. The serotonin cells within the lobes are also found in pairs, and each pair projects axons into closely associated tracts. The pathways of the serotonin tracts often parallel those of the dopamine cells but are distinct (Lundell and Hirsh, 1994). 

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. 

The pituitary gland, or hypophysis, is located at the base of the brain just below the hypothalamus. It is composed of two functionally and anatomically distinct lobes (see Figure 10.2) ... 

Textbooks on neuroscience often describe the location and function of hundreds of individual brain regions (see references above). However, for current purposes these will be kept to a minimum (Figure 2.1). Anatomically, the brain can be subdivided into the forebrain containing the telencephalon and diencephalon, the midbrain or mesencephalon and the hindbrain (metencephalon and myelencephalon). The telencephalon includes the left and right cerebral hemispheres encompassed by the cerebral cortex (neocortex). Cortex is a translation of the word bark and is so-called because its surface, made up of numerous sulci (grooves or invaginations) and gyri (raised areas), is on the outer surface of the brain like the bark of a tree. Each hemisphere is divided into four lobes, named from the front (rostral) to back (caudal) of the brain frontal, temporal, parietal and occipital. 

H. M. was the first human case in which specific amnesia could be linked to selective regions of the brain. Since then, many patients have been identified as having selective lesions to the temporal lobe system, especially within the hippocampus. They have exhibited amnesias similar to H. M. s. For example, amnesic patient, R. B, who had a specific lesion in the CA1 region of hippocampus, showed profound loss of ability to form new memories of people, places, and events [5]. R. B. also lost memories regarding public and personal events that he had experienced two... 

FIGURE 53-1 Illustrative drawing of the temporal lobe system in the human brain. (A) Anatomical sites, marked by black dots, within the temporal lobe where electrical stimulation evoked experiential responses in Penfield s patients. (B) The location of the hippocampus and amygdala inside the temporal lobe. 

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