The ultrastructural organization of the patch matrix compartments in the human striatum

DARPP-32 cells and neuropil define striosomal system and isolated matrix cells in human striatum

The dorsal striatum forms a central node of the basal ganglia interconnecting the neocortex and thalamus with circuits modulating mood and movement. Striatal projection neurons (SPNs) include relatively intermixed populations expressing D1-type or D2-type dopamine receptors (dSPNs and iSPNs) that give rise to the direct (D1) and indirect (D2) output systems of the basal ganglia. Overlaid on this organization is a compartmental organization, in which a labyrinthine system of striosomes made up of sequestered SPNs is embedded within the larger striatal matrix. Striosomal SPNs also include D1-SPNs and D2-SPNs, but they can be distinguished from matrix SPNs by many neurochemical markers. In the rodent striatum the key signaling molecule, DARPP-32, is a exception to these compartmental expression patterns, thought to befit its functions through opposite actions in both D1- and D2-expressing SPNs. We demonstrate here, however, that in the dorsal human striatum, DARPP-32 is concentrated in the neuropil and SPNs of striosomes, especially in the caudate nucleus and dorsomedial putamen, relative to the matrix neuropil in these regions. The generally DARPP-32-poor matrix contains scattered DARPP-32-positive cells. DARPP-32 cell bodies in both compartments proved negative for conventional intraneuronal markers. These findings raise the potential for specialized DARPP-32 expression in the human striosomal system and in a set of DARPP-32-positive neurons in the matrix. If DARPP-32 immunohistochemical positivity predicts differential functional DARPP-32 activity, then the distributions demonstrated here could render striosomes and dispersed matrix cells susceptible to differential signaling through cAMP and other signaling systems in health and disease. DARPP-32 is highly concentrated in cells and neuropil of striosomes in post-mortem human brain tissue, particularly in the dorsal caudate nucleus. Scattered DARPP-32-positive cells are found in the human striatal matrix. Calbindin and DARPP-32 do not colocalize within every spiny projection neuron in the dorsal human caudate nucleus.

Transient compartmentalization and accelerated volume growth coincide with the expected development of cortical afferents in the human neostriatum

The neostriatum plays a central role in cortico-subcortical circuitry underlying goal-directed behavior. The adult mammalian neostriatum shows chemical and cytoarchitectonic compartmentalization in line with the connectivity. However, it is poorly understood how and when fetal compartmentalization (AChE-rich islands, nonreactive matrix) switches to adult (AChE-poor striosomes, reactive matrix) and how this relates to the ingrowth of corticostriatal afferents. Here, we analyze neostriatal compartments on postmortem human brains from 9 postconceptional week (PCW) to 18 postnatal months (PM), using Nissl staining, histochemical techniques (AChE, PAS-Alcian), immunohistochemistry, stereology, and comparing data with volume-growth of in vivo and in vitro MRI. We find that compartmentalization (C) follows a two-compartment (2-C) pattern around 10PCW and is transformed into a midgestational labyrinth-like 3-C pattern (patches, AChE-nonreactive perimeters, matrix), peaking between 22 and 28PCW during accelerated volume-growth. Finally, compartmentalization resolves perinatally, by the decrease in transient "AChE-clumping," disappearance of AChE-nonreactive, ECM-rich perimeters, and an increase in matrix reactivity. The initial "mature" pattern appears around 9 PM. Therefore, transient, a 3-C pattern and accelerated neostriatal growth coincide with the expected timing of the nonhomogeneous distribution of corticostriatal afferents. The decrease in growth-related AChE activity and transfiguration of corticostriatal terminals are putative mechanisms underlying fetal compartments reorganization. Our findings serve as normative for studying neurodevelopmental disorders.

Ultrastructural evidence for glutamatergic dysregulation in schizophrenia

The aim of this paper is to summarize ultrastructural evidence for glutamatergic dysregulation in several linked regions in postmortem schizophrenia brain. Following a brief summary of glutamate circuitry and how synapses are identified at the electron microscopic (EM) level, we will review EM pathology in the cortex and basal ganglia. We will include the effects of antipsychotic drugs and the relation of treatment response. We will discuss how these findings support or confirm other postmortem findings as well as imaging results. Briefly, synaptic and mitochondrial density in anterior cingulate cortex was decreased in schizophrenia, versus normal controls (NCs), in a selective layer specific pattern. In dorsal striatum, increases in excitatory synaptic density were detected in caudate matrix, a compartment associated with cognitive and motor function, and in the putamen patches, a region associated with limbic function and in the core of the nucleus accumbens. Patients who were treatment resistant or untreated had significantly elevated numbers of excitatory synapses in limbic striatal areas in comparison to NCs and responders. Protein levels of vGLUT2, found in subcortical glutamatergic neurons, were increased in the nucleus accumbens in schizophrenia. At the EM level, schizophrenia subjects had an increase in density of excitatory synapses in several areas of the basal ganglia. In the substantia nigra, the protein levels of vGLUT2 were elevated in untreated patients compared to NCs. The density of inhibitory synapses was decreased in schizophrenia versus NCs. In schizophrenia, glutamatergic synapses are differentially affected depending on the brain region, treatment status, and treatment response.

Morphological Properties of the Two Types of Caudate Interneurons: Kohonen Self-Organizing Maps and Correlation-Comparison Analysis

Our previous study found that caudate and putaminal interneurons are morphologically very different, and that accordingly they could be divided in two separate clusters. In addition, it also demonstrated, as a collateral result, that the caudate cluster itself consists of two clusters of morphologically different interneurons. Hence, the objective of this study is a morphological description and subtle differing of morphologies of these two types of caudate interneurons, i.e., an investigation of those morphological traits which characterize them uniquely, and which would distinguish them. Binary two-dimensional images of caudate interneurons, taken from deceased adult human subjects, were analyzed by using 46 parameters, describing the morphology of interneurons. The parameters can be divided in the following classes: size (surface) of a neuron, neuronal shape, length of neuronal morphological compartments, dendritic branching, morphological organization, and complexity. The morphological determination of caudate interneurons was performed in a step-wise manner. The first step was the assignment of each individual neuron to an adequate cluster where it belonged according to morphological criteria. This was done by using the trained artificial neural network, Kohonen self-organizing map. After the clusters were formed, the analysis is further continued by the precise, feature-wise determination of morphological differences found between clusters of caudate interneurons and then finished by defining correlation-based, mutual, inter-parametric relations for each of the clusters. The first was performed by using single-factor analysis, and the second by correlation-comparison analysis. Single-factor analysis showed significance for 34 parameters (morphological features) that distinguish between the clusters. Correlation-comparison analysis extended the results of single-factor analysis by demonstrating significance for 198 inter-parametric correlation pairs that represent 19.13% of mismatched correlations of the first kind among the total number of correlations. This represents a significant inter-cluster separation zone. In addition, the analysis extracted one correlation of the second kind, namely, the DO-MDCBO, very highly significant (p<0.001), positive (r=0.45) in the cluster I, while negative (r=-0.13), also significant (p<0.05) in the cluster II. The two clusters of caudate interneurons were found to be significantly morphologically different. These differences, albeit not strong as the caudate-putaminal differences, are more numerous with respect to significant morphological properties defining them. They probably underlie, influence, and modulate different neurofunctional behavior of the two types of interneurons, which need to be further investigated by future studies.

Microstructural organizational patterns in the human corticostriatal system

The axons that project into the striatum are known to segregate according to macroscopic cortical systems; however, the within-region organization of these fibers has yet to be described in humans. We used in vivo fiber tractography, in neurologically healthy adults, to map white matter bundles that originate in different neocortical areas, navigate complex fiber crossings, and project into the striatum. As expected, these fibers were generally segregated according to cortical origin. Within a subset of pathways, a patched pattern of inputs was observed, consistent with previous ex vivo histological studies. In projections from the prefrontal cortex, we detected a topography in which fibers from rostral prefrontal areas projected mostly to rostral parts of the striatum and vice versa for inputs originating in caudal cortical areas. Importantly, within this prefrontal system there was also an asymmetry in the subset of divergent projections, with more fibers projecting in a posterior direction than anterior. This asymmetry of information projecting into the basal ganglia was predicted by previous network-level computational models. A rostral-caudal topography was also present at the local level in otherwise somatotopically organized fibers projecting from the motor cortex. This provides clear evidence that the longitudinal organization of input fields, observed at the macroscopic level across cortical systems, is also found at the microstructural scale at which information is segregated as it enters the human basal ganglia.

Immunohistochemical localization of enkephalin in the human striatum: a postmortem ultrastructural study

Within the basal ganglia, the functionally defined region referred to as the striatum contains a subset of GABAergic medium spiny neurons expressing the neuropeptide enkephalin. Although the major features of ultrastructural enkephalin localization in striatum have been characterized among various species, its ultrastructural organization has never been studied in the human brain. Human striatal tissue was obtained from the Maryland and Alabama Brain Collections from eight normal controls. The brains were received and fixed within 8 h of death allowing for excellent preservation suitable for electron microscopy. Tissue from the dorsal striatum was processed for enkephalin immunoreactivity and prepared for electron microscopy. General morphology of the dorsal striatum was consistent with light microscopy in human. The majority of neurons labeled with enkephalin was medium-sized and had a large nonindented nucleus with a moderate amount of cytoplasm, characteristic of medium spiny neurons. Of the spines receiving synapses in dorsal striatum, 39% were labeled for enkephalin and were of varied morphologies. Small percentages (2%) of synapses were formed by labeled axon terminals. Most (82%) labeled terminals formed symmetric synapses. Enkephalin-labeled terminals showed no preference toward spines or dendrites for postsynaptic targets, whereas in rat and monkey, the vast majority of synapses in the neuropil are formed with dendritic shafts. Thus, there is an increase in the prevalence of axospinous synapses formed by enkephalin-labeled axon terminals in human compared with other species. Quantitative differences in synaptic features were also seen between the caudate nucleus and the putamen in the human tissue.

Striatal mitochondria in subjects with chronic undifferentiated vs. chronic paranoid schizophrenia

Schizophrenia (SZ) is a heterogeneous disease with a spectrum of symptoms, risk factors, and etiology. Abnormalities in mitochondria, the energy-producing organelles of the cell, have been observed in mixed cohorts of subjects with SZ. The purpose of the present study was to determine if striatal mitochondria were differentially affected in two different DSM-IV subgroups of SZ. Postmortem striatal tissue was examined from normal controls (NC), chronic paranoid SZs (SZP), and chronic undifferentiated SZs (SZU). Tissue was processed for calbindin immunohistochemistry to identify striosomal compartments, prepared for electron microscopy and analyzed using stereological methods. In both caudate and putamen, the density of mitochondria in the neuropil was decreased in SZP compared to both NCs and SZU. In the putamen, both the SZP and the SZU subgroups had fewer mitochondria per synapse than did NCs. When examining patch matrix compartments, striatal compartments associated with different circuitry and function, only the matrix exhibited changes. In the caudate matrix, the SZP subgroup had fewer mitochondria in the neuropil than did the SZU and NCs. In the putamen matrix, the SZP had fewer mitochondria in the neuropil as compared to NCs, but not the SZU. The numbers of mitochondria per synapse in both the SZP and the SZU groups were similar to each other and fewer than that of NCs. A decrease in mitochondrial density in the neuropil distinguishes the SZP from the SZU subgroup, which could be associated with the symptoms of paranoia and/or could represent a protective mechanism against some of the symptoms that are less pronounced in this subtype than in the SZU subgroup such as cognitive and emotional deficits.

Basal ganglia pathology in schizophrenia: dopamine connections and anomalies

Schizophrenia is a severe mental illness that affects 1% of the world population. The disease usually manifests itself in early adulthood with hallucinations, delusions, cognitive and emotional disturbances and disorganized thought and behavior. Dopamine was the first neurotransmitter to be implicated in the disease, and though no longer the only suspect in schizophrenia pathophysiology, it obviously plays an important role. The basal ganglia are the site of most of the dopamine neurons in the brain and the target of anti-psychotic drugs. In this review, we will start with an overview of basal ganglia anatomy emphasizing dopamine circuitry. Then, we will review the major deficits in dopamine function in schizophrenia, emphasizing the role of excessive dopamine in the basal ganglia and the link to psychosis.

Dopaminergic synapses in the caudate of subjects with schizophrenia: relationship to treatment response

The typical symptoms of schizophrenia (SZ) are psychotic symptoms (hallucinations, delusions, disorders of thought or speech, grossly disorganized behavior) as well as cognitive impairments and negative symptoms. Not all patients respond to treatment and in those who do, only psychotic symptoms are usually improved. Imaging studies have shown that SZ subjects with high striatal dopamine release are far more responsive to antipsychotic drugs than those patients who have dopamine levels lower than or comparable to that of normal controls. In the present study we hypothesized that there was a link between psychosis and the number of dopaminergic synapses in the caudate nucleus in SZ. We examined dopaminergic synapses at the electron microscopic level in postmortem caudate from cases obtained from the Maryland Brain Collection. SZs were subdivided based on treatment response or resistance. The tissue was processed for the immunocytochemical localization of tyrosine hydroxylase (TH), the synthesizing enzyme for dopamine, and prepared for electron microscopy. The density of all TH labeled synapses was 43% greater in treatment responders than in controls and 62% greater in than in treatment resistant SZ. Axodendritic, but not axospinous, TH-labeled synapses showed this increase. TH-labeled axodendritic synapses in treatment responders were elevated in density (1.95 +/- 0.093/10 microm(3)) compared to treatment resistant SZ (0.04 +/- 0.017/10 microm(3)) and controls (0.11 +/- 0.044/10 microm(3)). The results of the present study suggest that one anatomical underpinning of good treatment response may be a higher density of dopaminergic synapses and support a biological basis to treatment response and resistance. Moreover, these data have important implications for linking specific neuropathology with particular symptoms.

Differential synaptic changes in the striatum of subjects with undifferentiated versus paranoid schizophrenia

Subjects with schizophrenia (SZ) have an increased density of synapses characteristic of corticostriatal or thalamostriatal glutamatergic inputs in the caudate matrix and putamen patches. SZ is a heterogeneous disease in many aspects including symptoms. The purpose of the present study was to determine if the synaptic organization in two different DSM-i.v. subgroups of SZ was differentially affected. Postmortem striatal tissue was obtained from the Maryland Brain Collection from normal controls (NC), chronic paranoid SZs (SZP), and chronic undifferentiated SZs (SZU). Tissue was prepared for calbindin immunocytochemistry to identify patch matrix compartments, prepared for electron microscopy and analyzed using stereological methods. The synaptic density of asymmetric synapses, characteristic of glutamatergic inputs, was elevated equivalently in striatal patches in the SZP and SZU versus NC. The SZU also had an increased density of asymmetric synapses in the striatal matrix compared to NC. Moreover, symmetric axospinous synapses, characteristic of intrinsic inhibitory inputs and dopaminergic afferents, showed a dichotomy in synaptic density between the SZU and SZP in the striatal and caudate matrix. These data show discreet differences in synaptic organization between SZU and SZP and/or NCs. The results suggest that abnormal corticostriatal and/or corticothalamic inputs to striatal patches may be related to limbic dysfunction, which is perturbed in both subtypes of SZ. The selective increase in axospinous synapses in the matrix of the SZU subgroup compared to the SZP may be related to more severe cognitive problems in that subset of SZ compared to SZP.

Chemical architecture of the posterior striatum in the human brain

The neurochemical organization of the posterior caudate nucleus (CN) (body, gyrus and tail) and putamen (Put) was analyzed in the human brain using adjacent sections stained for acetylcholinesterase (AChE), limbic system-associated membrane protein (LAMP), enkephalin (ENK), parvalbumin (PV), calbindin (CB) and tyrosine hydroxylase (TH). Striosomes were visualized in all striatal regions but the anterior two thirds of the CN tail. They were highly immunoreactive (-ir) for ENK and LAMP, devoid of PV and AChE staining, and surrounded by a ring of tissue with pale TH- and CB-ir neuropil. In the Put, other rings of tissue completely free of ENK labeling surrounded certain striosomes (clear septa). In the CN body, gyrus and tail some markers revealed gradients and heterogeneities along the dorsoventral and mediolateral axes. A rim of striatal tissue densely stained for ENK and LAMP and poorly labeled for PV was noticeable along the lateral edge of the Put and the dorsolateral sector of the CN body. Our results illustrate a chemical architecture in the posterior striatum that is heterogeneous and slightly different from that found in the more anterior striatum.

Striatal vs extrastriatal dopamine D2 receptors in antipsychotic response--a double-blind PET study in schizophrenia

Blockade of dopamine D2 receptors remains a common feature of all antipsychotics. It has been hypothesized that the extrastriatal (cortical, thalamic) dopamine D2 receptors may be more critical to antipsychotic response than the striatal dopamine D2 receptors. This is the first double-blind controlled study to examine the relationship between striatal and extrastriatal D2 occupancy and clinical effects. Fourteen patients with recent onset psychosis were assigned to low or high doses of risperidone (1 mg vs 4 mg/day) or olanzapine (2.5 mg vs 15 mg/day) in order to achieve a broad range of D2 occupancy levels across subjects. Clinical response, side effects, striatal ([11C]-raclopride-positron emission tomography (PET)), and extrastriatal ([11C]-FLB 457-PET) D2 receptors were evaluated after treatment. The measured D2 occupancies ranged from 50 to 92% in striatal and 4 to 95% in the different extrastriatal (frontal, temporal, thalamic) regions. Striatal and extrastriatal occupancies were correlated with dose, drug plasma levels, and with each other. Striatal D2 occupancy predicted response in positive psychotic symptoms (r=0.62, p=0.01), but not for negative symptoms (r=0.2, p=0.5). Extrastriatal D2 occupancy did not predict response in positive or negative symptoms. The two subjects who experienced motor side effects had the highest striatal occupancies in the cohort. Striatal D2 blockade predicted antipsychotic response better than frontal, temporal, and thalamic occupancy. These results, when combined with the preclinical data implicating the mesolimbic striatum in antipsychotic response, suggest that dopamine D2 blockade within specific regions of the striatum may be most critical for ameliorating psychosis in schizophrenia.

Synaptic differences in the patch matrix compartments of subjects with schizophrenia: a postmortem ultrastructural study of the striatum

The striatum processes motor, cognitive, and limbic circuitry. Striatal patch and matrix compartments are organized differently in many aspects including connectivity. Abnormalities in either compartment could have different functional consequences. The present study compares the synaptic organization in the patches and matrix in subjects with schizophrenia (SZ, n = 14) versus normal controls (NC, n = 8). Postmortem striatal tissue was processed for calbindin immunocytochemistry to identify the patch versus matrix compartments, prepared for electron microscopy, and analyzed using stereology. Several synaptic changes were observed in the SZ subjects vs. NCs including a higher density of cortical-type synapses in the putamen patch (44% higher) and in the caudate matrix (36% higher) in SZ cases on typical antipsychotic drugs. These changes appeared to be normalized rather than caused by treatment. The abnormal connectivity may represent a failure of normal synaptic pruning and may play a role in limbic or cognitive dysfunction in schizophrenia.

DISC1 immunoreactivity at the light and ultrastructural level in the human neocortex

Disrupted-In-Schizophrenia 1 (DISC1) is one of two genes that straddle the chromosome 1 breakpoint of a translocation associated with an increased risk of schizophrenia. DISC1 has been identified in the brain of various mammalian species, but no previous immunocytochemical studies have been conducted in human neocortex. We examined DISC1 immunoreactivity in frontal and parietal cortex (BA 4, 9, 39, and 46) in normal human brain. At the light microscopic level, immunolabeling was prominent in the neuropil, in multiple populations of cells, and in the white matter. At the ultrastructural level, staining was prominent in structures associated with synaptic function. Immunolabeled axon terminals comprised 8% of all terminals and formed both asymmetric and symmetric synapses. Labeled axon terminals formed synapses with labeled spines and dendrites; in some, only the postsynaptic density (PSD) of the postsynaptic structure was labeled. The most common configuration, however, was an unlabeled axon terminal forming an asymmetric synapse with a spine that had immunoreactivity deposited on the PSD and throughout the spine. The presence of DISC1 in multiple types of synapses suggests the involvement of DISC1 in corticocortical as well as thalamocortical connections. Staining was also present in ribosomes, parts of the chromatin, in dendritic shafts, and on some microtubules. Labeling was absent from the Golgi apparatus and multivesicular bodies, which are associated with protein excretion. These anatomical localization data suggest that DISC1 participates in synaptic activity and microtubule function, and are consistent with the limited data on its adult function.

Synaptic differences in the postmortem striatum of subjects with schizophrenia: a stereological ultrastructural analysis

The striatum processes motor, cognitive, and limbic function, all of which are perturbed in schizophrenia. The present study examined the synaptic organization of the caudate and putamen in schizophrenia. Postmortem striatum was obtained from 10 normal controls (NC) and 17 subjects with schizophrenia (SZ), prepared for electron microscopy, and analyzed using stereological principles. The densities of total synapses, asymmetric synapses (characteristic of excitatory inputs), and asymmetric axospinous synapses (characteristic of cortical input) were higher in the caudate of the SZs vs. NCs. These changes were most profound in the off-drug SZ cases and were also elevated in subjects on antipsychotic drugs (APDs). In comparison to NCs, there were no significant differences in the putamen of the SZ cohort as a whole group; however, there were more asymmetric axospinous synapses in the off-drug subgroup. The increase in density of synapses in the SZs does not appear to be caused by antipsychotic medication and may represent failure of normal synaptic pruning or abnormal sprouting. Higher density of cortical-type synapses in SZs vs. NCs may reflect adaptation of corticostriatal circuitry or hyperstimulation of striatal projection neurons. The abnormal synaptic organization could have several important and different downstream effects depending on the precise circuitry involved and may be related to limbic or cognitive dysfunction in schizophrenia.

The immunocytochemical localization of substance P in the human striatum: A postmortem ultrastructural study

The striatum is a basal ganglia structure that is involved in motor, cognitive, and behavioral functions. In the striatum, the neuroactive peptide, substance P, is colocalized with GABA in the subset of medium spiny neurons that projects to the substantia nigra. Normal human striata (n = 5) obtained from the Maryland Brain Collection were processed for substance P immunoreactivity, prepared for electron microscopy, and analyzed using both stereology and simple profile counts. Most substance P-labeled neurons had a nonindented nucleus and a moderate amount of cytoplasm, typical of medium spiny projection neurons in other species. A small percentage (8%) of labeled neurons had indented nuclei, but otherwise had similar morphology. Synapses formed on labeled cell bodies were rare. Synapses formed by substance P-labeled axon terminals constituted 4.4% of the total synapses in the neuropil. Labeled terminals (1) formed synapses with both spines and dendrites with approximately equal frequency, (2) formed mostly symmetric synapses (76-85%), and (3) formed synapses predominantly with unlabeled (78%) profiles. Substance P-labeled spines varied in shape and comprised 37-42% of all spines forming synapses. In the caudate, the proportion of synapses with perforated postsynaptic densities was 55% on unlabeled vs. 45% on labeled spines, but in the putamen, this type of synapse was much more frequently present on unlabeled (73%) vs. labeled (27%) spines. These data describe substance P in the normal human striatum, which serve as comparative data to that of other species as well as normative data for further studies of brain disease that may involve striatal substance P neurons.

Neuropathological alterations in alcoholic brains. Studies arising from the New South Wales Tissue Resource Centre

Alcohol dependence and abuse are among the most costly health problems in the world from both social and economic points of view. Patterns of drinking appear to be changing throughout the world with more women and young people drinking heavily. Excessive drinking can lead to impairment of cognitive function and structural brain changes--some permanent, some reversible. Patterns of damage appear to relate to lifetime alcohol consumption but, more importantly, to associated medical complications. The most significant of these is the alcohol-related vitamin deficient state, the Wernicke-Korsakoff syndrome (WKS), which is caused by thiamin deficiency but is seen most commonly in alcoholics. Careful selection and classification of alcoholic cases into those with and without these complications, together with detailed quantitative neuropathological analyses has provided data that gives clues to the most vulnerable regions and cells in the brain. Brain shrinkage is largely accounted for by loss of white matter. Some of this damage appears to be reversible. Alcohol-related neuronal loss has been documented in specific regions of the cerebral cortex (superior frontal association cortex), hypothalamus and cerebellum. No change is found in basal ganglia, nucleus basalis, or serotonergic raphe nuclei. Many of these regions which are normal in uncomplicated alcoholics are damaged in those with the WKS. Dendritic and synaptic changes have been documented in alcoholics and these, together with receptor and transmitter changes, may explain functional changes and cognitive deficits, which precede more severe structural neuronal changes. A resource to provide human brain tissues for these types of studies has been developed at the University of Sydney--the New South Wales Tissue Resource Centre. The aim of this facility is to provide research groups throughout the world with fresh and/or frozen tissues from well-characterized cases of alcohol-related brain damage and matched controls. The development of new technologies in pathology and molecular biology means that many more questions can be addressed using appropriately stored human brain tissues. Examples of the application of some of these techniques, involving neurochemical, neuropharmacological, neuroimaging and gene expression studies are included in this paper. Important public health outcomes have arisen from some of these studies including the enrichment of bread flour with thiamin for the whole of Australia. Researchers with an interest in alcohol studies can access tissues from this brain bank.