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apicaldendrite

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Figure 1. Regions of the brain which contain Von Economo neurons. (A) Lateral view of the brain, with fronto-insular cortex (FI) shown in red. (B) Medial view of the brain, with anterior cingulate cortex (ACC) shown in red. Adapted from Von Economo and Koskinas (1925). FI and the spindle cell containing region of ACC are indicated on coronal sections through (C) a human brain (from a 50 year old female) and (D) a common chimpanzee brain. The sections are shown such that the right hemisphere of the brain is on the right side of the figure. Sections are from the Yakovlev Brain Collection at the National Museum of Health and Medicine. Note that FI is much larger in the human than in the chimpanzee. (E) A Von Economo neuron and a pyramidal neuron in layer 5 of FI. Note that the VEN has only a single apical and a single basal dendrite, while the pyramidal neuron has a single apical dendrite, but multiple basal dendrites. Photomi-crograph is from a section of the 50 year old human female shown in part (C) of this figure.

Figure 2. Stereological counts for the total number of VENs in area FI in both hemispheres in 5 adult humans and 11 apes (4 chimpanzees, 2 bonobos, 3 orangutan and 2 gorillas). Each circle represents a single data point; the bars indicate the means for apes and for humans. The counts were done by John Allman, Jason Kaufman, and Nicole Tetreault using brains in the Yakovlev collection at the National Museum of Health and Medicine, the Semendeferi collection at UCSD, and the Allman collection at Caltech.

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Figure 3. The long slender morphology of a VEN (left) compared with a neighboring pyramidal neuron in human area FI based on a Golgi reconstruction done by Karli Watson, Tiffany Jones and John Allman (2006). These examples are representative of a large population of VENs and neighboring pyramidal neurons reconstructed from FI and ACC in a young adult male subject.

Figure 4. The antibody to the gene product for MET strongly stains the soma and dendrites of VENs and a subset of pyramidal neurons in layer 5 of FI. Fixed human frontoinsular cortex (FI) obtained from NICHD Brain and Tissue Bank was sectioned at 50 μm on a vibratome (Vibratome Series 1000). The immunohistochemical method used was adapted from Loup et al. (1998). The protocol was modified slightly to include an additional incubation in sodium citrate for 30 minutes to allow better primary antibody detection (Chemicon, CA), an incubation of the primary antibody (rabbit anti c-met, Santa Cruz, cat. No. 161) with 2% normal goat serum and 0.1% triton X-100 in PBS for 48 hours at 4°C, and an incubation with the corresponding bioti-nylated secondary antibody, goat anti-rabbit IgG (1/200, Vector laboratories, CA) at 4°C over-night. The avidin-biotin complex method was used to detect the secondary antibody (ABC elite kit, Vector laboratories, CA) and the reaction product was visualized by 3,3’-diaminobenzidine tetrachloride (DAB) and nickel (Sigma, CA). Control sections were incubated with no primary antibody.

25 μM

Figure 5. Stereological counts of the number of VENs in right FI in a developmental series of human brains. Each circle represents a single data point; the bars indicate the mean of all points in a given age category. The counts were done by John Allman, Jason Kaufman, and Nicole Tetreault using brains in the Yakovlev collection at the National Museum of Health and Medicine and the Allman collection at Caltech. Note the rapid growth of the VEN population from birth to 8 months postnatal and the apparent reduction of number later in life.

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Figure 6. The ratio of the number of VENs in right hemisphere FI to left hemisphere FI in great apes and humans. In human neonates 38 to 40 weeks postconception, there are about the same number of VENs on each side, but in older individuals there are more on the right side in every individual we have counted. Note that the right hemisphere VEN population grows more rapidly than the left, and the right-to-left ratio greatly overshoots the adult ratio at 7 and 8 months. Note also that the VEN population is consistently about 30% larger in FI on the right side in apes, which suggests that a hemispheric specialization related to social emotion/cognition emerged in apes before the advent of language. This graph is based on stereological counts done by John Allman, Jason Kaufman and Nicole Tetreault on brains in the Yakovlev, Semendeferi, and Allman collections.

2.22.01.81.61.41.21.00.80.6

Adult Human (5)

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Figure 7. Severe, selective, disease-specific, and early loss of VENs in frontotemporal dementia (FTD). (A) VENs per section were reduced by 74% in FTD compared with nonneurological control subjects (NNC) (p<0.005, Tukey’s test after F-test for 3- group ANOVA). (B) Layer 5 neighboring neurons (NNs), in contrast, did not show a statistically significant reduction in FTD. (C) VENs per 10,000 NNs estimates indicated selective VEN depletion in FTD compared with NNC subjects and patients with AD (p < 0.05, Tukey’s tests after F-test for 3 group ANOVA). (D) Even mild stages of FTD-related atrophy were accompanied by marked VEN dropout. From: Seeley et al., 2006.

Figure 8. VEN swelling and dysmorphism in frontotemporal dementia (FTD). VENs in nonneu-rological control subjects (NNC) and Alzheimer’s disease (AD) patients showed prominent clustering, smooth contours, and slender, tapering somata. In FTD (Pick’s and FTLD-U), the surviving VENs were often solitary and swollen, and showed twisting and kinking of proximal dendrites. Pick’s disease is related to an isoform of Tau; FTLD-U is related to abnormal ubiqui-tination. Cresyl violet stain. Scale bar is 20 μm in length. From: Seeley et al., 2006.

NNC FTLD-UPick’sAD

Figure 9. Left: view of the medial aspect of the right hemisphere of a human brain. The corpus callosum is shaded in red; the septum in green. Right: medial aspect of a brain with partial agenesis of the corpus callosum. The specimen is of a 71 year old female (MU112-66 from the Yakovlev collection at the National Museum of Health and Medicine). Although the patient lived in the late 19th and early 20th centuries before modern neuropsychiatric diagnostic criteria had been established, her clinical history suggests that her social behavior was very abnormal. In childhood, she was described as “extremely sensitive, shy and retiring,” and in adulthood as “reserved and prudish.” She was admitted to a state hospital at age 45 after developing violent crying episodes at work. Although there were no other physical or neurological abnormalities detected, she was assessed as having a mental age of 12 and an IQ of 77 and remained institu-tionalized. From Kaufman et al., in submission.

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Figure 10. Stereological counts of VENs in frontoinsular cortex (FI) and anterior cingulate cortex (ACC) in an individual with complete (BCH57-49) and an individual with partial agenesis of the corpus callosum (MU112-66) compared wth 4 normal adults. Each circle represents a single data point; the bars indicate the mean for each category. Only the left hemisphere was available for the complete agenesis case. The complete agenesis case was a 48 year old male who died of coronary thrombosis; unfortunately no other clinical history is available. The partial agensis case was a 71 year old female who died of respiratory and renal infection. She is described in the legend for Fig. 9. The normals are a 50 year old female (V42-57), who died of myocarditis, a 50 year old male (MU88-65), who died of myocardial infarction, a 58 year old male (MU169-87), who died of cardiac arrest, and an 86 year old male (MU75-64), who died of myocardial infarction. None of the normals had any history of neurological disorders. All of the brains are in the Yakovlev collection at the National Museum of Health and Medicine.

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Figure 11. The distribution of the VENs in FI in a normal 50 year old female (left) compared with the partial agenesis case, a 71 year old female (right). All of the VENs in the ventral cortex of a section through the frontal lobe were plotted at a magnification of 600x using the program Neurolucida (MBF Bioscience, Williston, VT). The VENs in ACC were not plotted.

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Figure 12. The distribution of MET expression in mouse brain coronal section #346 from the Allen Brain Atlas (http://www.brainatlas.org/aba/). On the left (top) is an image of the entire Nissl stained section, and below is a higher magnification image of the same section centered on the septum. LS indicates the lateral septum. On the right are the maps of MET gene expression for the entire section and at higher magnification. The dense aggregation of MET positive cells is in the lateral septum; elsewhere the expression is very sparse. Note also the similarity to the pattern of gene expression for AVPR1a (see Figure 13).

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Figure 13. The distribution of AVPR1a expression in mouse brain coronal section #341 from the Allen Brain Atlas (http://www.brainatlas.org/aba/). On the left (top) is an image of the entire Nissl stained section, and below is a higher magnification image of the same section centered on the septum. LS indicates the lateral septum. On the right are the maps of AVPR1a gene expres-sion for the entire section and at higher magnification. Note the dense aggregation of AVPR1a positive cells in the lateral septum and the very sparse expression elsewhere. Note also the similarity to the pattern of gene expression for Met (see Figure 12).

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Figure 14. Cingulate-septal circuit loop for self-monitoring of social error. The lateral septum (LS) accesses social memory (the identity of individuals in a social context). The neurons in the diagonal band of Broca (DBB) serve as pacemakers and coordinate a recurrent cycle of activity in the loop. Neurons (including possibly the VENs) in the anterior cingulate cortex (ACC) monitor the outcome of social interactions and register social error. The social error signal is relayed to the LS for updating of social memory. Vasopressin injected into the LS facilitates social memory, and blocking vasopressin in the LS reduces social memory (Dantzer et al, 1988). Knocking out the gene AVPR1a produces a specific deficit in social memory formation with no effect on non-social memory (Bielsky et al, 2004). The neurons expressing MET and AVPR1a probably participate in the ACC-LS-DBB circuit, and the abnormal autistic alleles of these genes may cause this circuit to malfunction. Neurons in the diagonal band of Broca participate in the timing of the hippocampal theta rhythm (Sotty et al, 2003) and may similarly be involved in the regulation of the cingulate theta rhythm and the mechanism of social error recognition (Allman et al, 2001; Mundy, 2003; Henderson et al, 2006). Individual variance in autistic patients in blood flow in anterior cingulate cortex is strongly correlated (r = 0.928) with a measure of their tendency to treat people as interchangeable, i.e. lacking individual identity (Ohnishi et al, 2000). Thus, defects in this circuit may be responsible for some of the social and cognitive deficits in autism.

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Figure 15. Methodical details of the quantitative cytoarchitectural approach applied in the proposed project. A,B,C, embedding human brain hemispheres in celloidin (A), cutting them on a microtome (B) and storing sections before staining (C). D,E, representative photomicrographs of 200-μm-thick sections through area 17 in postmortem brains from a 4-year-old normal control (D) and a 4-year-old autistic patient (E) stained with gallocyanin (a Nissl stain). The rectangles indicate the positions at which the high-power photomicrographs were taken. Note that the cell minicolumns in the brain of the autistic patient appear to be more numerous, smaller, and less compact in their cellular configuration than in the brain of the normal control. F,G, representative photomicrographs of 200-μm-thick sections through layer V of the temporal fusiform gyrus in postmortem brains from a 7-year-old normal control (F) and a 11-year-old autistic patient (G) stained with gallocyanin. Note the reduced neuron density and perikaryal size in the brain of the autistic patient compared with the normal control. H,I,K, representative photomicrographs of 50-μm-thick sections through the anterior cingulate cortex in the postmortem brain from a 60-year-old normal control (re-cut from a 500-μm-thick section as shown in C), immunopro-cessed for the detection of SMI311 to visualize VENs (H), calretinin (I) and calbindin (K). Note the characteristic morphology of the VENs, i.e. their very elongate, gradually tapering, large sized cell soma with a single large apical and basal dendrite, and poor radial arborization. L, immunohistochemical visualization of capillaries in a 200-μm-thick section through the amyg-dala in the postmortem brain from a 51-year-old normal control using an antibody against colla-gen IV. The rectangle indicates the position at which the high-power photomicrograph was taken. Note that the use of thick sections allows one to identify nuclei within the amygdala (LNA, lateral nucleus of the amygdala; BNA, basal nucleus of the amygdala; ABNA, accessory basal nucleus of the amygdala) as well as to estimate capillary length densities and capillary lengths with the Space Ball method (for details see Kreczmanski et al., 2005). Scale bar = 1 mm in D,E, 300 μm in the high-power photomicrographs in D,E, 50 μm in F,G, 25 μm in H,I,K, 3 mm in L and 1 mm in the high-power photomicrograph in L.

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Locus ConservationMap (17 species)

25 BP sequencereads crossing RNAsplice junctions

RNA Mapping by Ultra High Throughput Sequencing

25 BP sequencereads

IL2 receptor locus

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RefSeq known RNA

89122000 89122500

Locus ConservationMap (17 species)

25 BP sequencereads crossing RNAsplice junctions

RNA Mapping by Ultra High Throughput Sequencing

25 BP sequencereads

SPP1 locus

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RefSeq known RNA