Underlying Brain Areas Research Articles

One-trial odour recognition learning and its underlying brain areas in the zebrafish

Distinguishing familiar from novel stimuli is critical in many animals’ activities, and procedures based on this ability are among the most exploited in translational research in rodents. However, recognition learning and the underlying brain substrates remain unclear outside a few mammalian species. Here, we investigated one-trial recognition learning for olfactory stimuli in a teleost fish using a behavioural and molecular approach. With our behavioural analysis, we found that zebrafish can learn to recognise a novel odour after a single encounter and then, discriminate between this odour and a different one provided that the molecular structure of the cues is relatively differentiated. Subsequently, by expression analysis of immediate early genes in the main brain areas, we found that the telencephalon was activated when zebrafish encountered a familiar odour, whereas the hypothalamus and the optic tectum were activated in response to the novel odour. Overall, this study provided evidence of single-trial spontaneous learning of novel odours in a teleost fish and the presence of multiple neural substrates involved in the process. These findings are promising for the development of zebrafish models to investigate cognitive functions.

The brain dynamics of visuospatial perspective-taking captured by intracranial EEG

Visuospatial perspective-taking (VPT) is the ability to imagine a scene from a position different from the one used in self-perspective judgments (SPJ). We typically use VPT to understand how others see the environment. VPT requires overcoming the self-perspective, and impairments in this process are implicated in various brain disorders, such as schizophrenia and autism. However, the underlying brain areas of VPT are not well distinguished from SPJ-related ones and from domain-general responses to both perspectives. In addition, hierarchical processing theory suggests that domain-specific processes emerge over time from domain-general ones. It mainly focuses on the sensory system, but outside of it, support for this hypothesis is lacking. Therefore, we aimed to spatiotemporally distinguish brain responses domain-specific to VPT from the specific ones to self-perspective, and domain-general responses to both perspectives. In particular, we intended to test whether VPT- and SPJ specific responses begin later than the general ones. We recorded intracranial EEG data from 30 patients with epilepsy who performed a task requiring laterality judgments during VPT and SPJ, and analyzed the spatiotemporal features of responses in the broad gamma band (50–150 Hz). We found VPT-specific processing in a more extensive brain network than SPJ-specific processing. Their dynamics were similar, but both differed from the general responses, which began earlier and lasted longer. Our results anatomically distinguish VPT-specific from SPJ-specific processing. Furthermore, we temporally differentiate between domain-specific and domain-general processes both inside and outside the sensory system, which serves as a novel example of hierarchical processing.

The quest for objectivity and measurements in phrenology's "bumpy" history.

Phrenology is based on correlating character traits with visible or palpable cranial bumps (or depressions) thought to reflect underlying brain areas differing in size and levels of activity. Franz Joseph Gall, who introduced the doctrine during the 1790s, relied heavily on seeing and feeling skulls when he formulated his theory, as did Johann Spurzheim, who served as his assistant until 1813 and then set forth on his own. But Peter Mark Roget, a British critic of the doctrine, first assailed these methods as too subjective in 1818, and never changed his mind. George Combe, a Scotsman who admired Spurzheim, introduced calipers and other measuring instruments during the 1820s, hoping to make phrenology more like the admired physical sciences. In the United States, the Fowlers also called for more numbers, including measuring distances between the cortical sites above the organs of mind. Nonetheless, phrenologists realized they faced formidable barriers when it came to measuring the physical organs of mind, as opposed to basic skull dimensions. This essay examines the subjectivity that left phrenology open to criticism and shows how some phrenologists tried to overcome it. It also shows how vision and touch remained features of phrenological examinations throughout the numbers-obsessed 19th century. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Phrenology’s frontal sinus problem: An insurmountable obstruction?

ABSTRACT Whereas some of Gall’s critics were quick to assail his organology as materialistic and fatalistic, others questioned his methods and scientific assumptions, especially his craniological tenets. The idea that the skull does not faithfully reflect the features of small, underlying brain areas was repeatedly brought up in the scientific debates. Critics pointed to the frontal sinuses above the eye orbits as evidence for the interior and exterior plates of the cranium not being in parallel—hence, for several or many phrenological organs being unknowable. This article traces the origins of the frontal sinus arguments and how Gall, Spurzheim, and later phrenologists responded to it. It reveals how the two sides fought and remained divided about the significance of the sinuses throughout the nineteenth century—that is, on whether the frontal sinus “problem” was an insurmountable obstacle or one that was merely an inconvenience.

1 Hz Repetitive Transcranial Magnetic Stimulation of the Primary Motor Cortex: Impact on Excitability and Task Performance in Healthy Subjects.

Neuronavigated repetitive transcranial stimulation (rTMS) at a frequency of 1 Hz was shown to reduce excitability in underlying brain areas while increasing excitability in the opposite hemisphere. In stroke patients, this principle is used to normalize activity between the lesioned and healthy hemispheres and to facilitate rehabilitation. However, standardization is lacking in applied protocols, and there is a poor understanding of the underlying physiologic mechanisms. Furthermore, the influence of hemispheric dominance on the intervention has not been studied before. A systematic evaluation of the effects in healthy subjects would deepen the understanding of these mechanisms and offer insights into ways to improve the intervention. Twenty healthy subjects underwent five 15-minute sessions of neuronavigated rTMS or sham stimulation over their dominant or nondominant motor cortex. Dominance was assessed with the Edinburgh Handedness Inventory. Changes in both hemispheres were measured using behavioral parameters (finger tapping, grip force, and finger dexterity) and TMS measures (resting motor threshold, recruitment curve, motor area, and cortical silent period). All subjects tolerated the stimulation well. A pronounced improvement was noted in finger tapping scores over the nonstimulated hemisphere as well as a nonsignificant reduction of the cortical silent period in the stimulated hemisphere, indicating a differential effect of the rTMS on both hemispheres. Grip force remained at the baseline level in the rTMS group while decreasing in the sham group, suggesting the rTMS counterbalanced the effects of fatigue. Lastly, dominance did not influence any of the observed effects. This study shows the capability of the applied low-frequency rTMS protocol to modify excitability of underlying brain areas as well as the contralateral hemisphere. It also highlights the need for a better understanding of underlying mechanisms and the identification of predictors for responsiveness to rTMS. However, results should be interpreted with caution because of the small sample size.

Birdsong as a window into language origins and evolutionary neuroscience.

Humans and songbirds share the key trait of vocal learning, manifested in speech and song, respectively. Striking analogies between these behaviours include that both are acquired during developmental critical periods when the brain's ability for vocal learning peaks. Both behaviours show similarities in the overall architecture of their underlying brain areas, characterized by cortico-striato-thalamic loops and direct projections from cortical neurons onto brainstem motor neurons that control the vocal organs. These neural analogies extend to the molecular level, with certain song control regions sharing convergent transcriptional profiles with speech-related regions in the human brain. This evolutionary convergence offers an unprecedented opportunity to decipher the shared neurogenetic underpinnings of vocal learning. A key strength of the songbird model is that it allows for the delineation of activity-dependent transcriptional changes in the brain that are driven by learned vocal behaviour. To capitalize on this advantage, we used previously published datasets from our laboratory that correlate gene co-expression networks to features of learned vocalization within and after critical period closure to probe the functional relevance of genes implicated in language. We interrogate specific genes and cellular processes through converging lines of evidence: human-specific evolutionary changes, intelligence-related phenotypes and relevance to vocal learning gene co-expression in songbirds. This article is part of the theme issue 'What can animal communication teach us about human language?'

Franz Joseph Gall on the Cerebellum as the Organ for the Reproductive Drive.

Franz Joseph Gall (1758–1828) is best remembered for his belief that bumps on the skull reflect the growth of small, underlying brain areas, though among some historians, more positively for introducing the concept of cortical localization of function. All but one of Gall’s 27 settled-upon cortical faculties involved the cerebral cortex, the exception being his most primitive faculty, reproductive instinct, which he associated with the cerebellar cortex. This article examines Gall’s earlier subcortical organs, with an emphasis on why he associated the cerebellum with this drive. It draws from accounts by several physicians, who attended his Vienna lectures or heard him speak in Germany and the Netherlands in 1805–1806 [i.e., before he published his finalized list in his Anatomie et Physiologie (1810–1819)]. These early accounts show that early on he localized at least four faculties in brainstem structures, including a reproductive drive in the cerebellar cortex. He based his structure–function association primarily on cranial differences between men and women, and what he found in males and females of other species, although cranioscopy was not his sole method. It is also shown that, in opposition to his cerebellar–reproductive drive association, Marie Jean Pierre Flourens linked coordinated skeletal movements to the cerebellum after conducting lesion experiments, mainly on birds. Flourens did not design his experiments to challenge Gall’s ideas on localization of function, but they did just that. Gall responded that ablation methods lack precision and lead to misguided conclusions. How Gall continued to associate the reproductive instinct with the cerebellar cortex, even after deleting his other brainstem-based associations from his faculties of mind, tells us much about him and the faith he had in his methods and doctrine.

The development and evolution of “cerebral thermometry”: The physiology underlying a nineteenth-century approach to cerebral localization and neurological diagnosis

ABSTRACTSurface thermometers were developed in the latter half of the nineteenth century. From the 1850s through the 1880s, collaborations between physicians, research scientists, and instrument makers produced clear improvements in the technology to measure cranial surface temperatures, with development of self-registering mercury surface thermometers resistant to pressure and little influenced by ambient temperature, apparatus for recording cranial surface temperatures from multiple stations simultaneously, and development of thermoelectric apparatus. Physiologic studies of cranial surface thermometry were conducted over a quarter century from 1861 to 1886. Beginning in the 1860s Albers in Bonn, Germany, and Lombard at Harvard and later in England systematically investigated surface temperatures on the head using surface thermometers and thermoelectric apparatus; they demonstrated that head temperatures were variable over time and across individuals and were not clearly influenced by thinking or muscular contraction but were influenced by ambient air temperature. In 1880 Amidon in the United States claimed that cranial surface thermometry during exertion produced localized increases in surface temperature on the contralateral scalp in a specific pattern (“external motive areas”) indicating underlying brain areas responsible for each movement. Amidon’s results were not reproduced by experienced physiologists in England or France. Contemporaries recognized that significant technical and practical problems limited the accuracy and reliability of cranial surface thermometry. Physiological studies of cranial surface thermometry ended in the mid 1880s, although some clinicians who were early advocates promoted its use in clinical contexts into the early twentieth century.

Supplementary motor area connectivity and dual-task walking variability in multiple sclerosis

BackgroundDespite the prevalence of dual-task (e.g., walking while talking) deficits in people with multiple sclerosis (MS), no neuroimaging studies to date have examined neuronal networks used for dual-task processing or specific brain areas related to dual-task performance in this population. A better understanding of the relationship among underlying brain areas and dual-task performance may improve targeted rehabilitation programs. The objective of this study was to examine relationships between neuroimaging measures and clinical measures of dual-task performance, and reported falls in persons with MS. Materials and methodsAll participants completed measures of dual-task performance, a fall history, and neuroimaging on a 3 T MRI scanner. Spearman correlations were used to examine relationships among dual-task performance, falls and neuroimaging measures. ResultsEighteen females with relapsing-remitting MS [mean age = 45.5 ± 8.2 SD; mean symptom duration = 12.3 ± 6.7 years; Expanded Disability Status Scale median 2.25 (range 1.5–4)] participated in this study. Structural imaging measures of supplementary motor area (SMA) interhemispheric connectivity were significantly related to dual-task walking variability. ConclusionsThe SMA interhemispheric tract may play a role in dual-task performance. Structural neuroimaging may be a useful adjunct to clinical measures to predict performance and provide information about recovery patterns in MS. Functional recovery can be challenging to objectively report in MS; diffusion tensor imaging could show microstructural improvements and suggest improved connectivity.

Depressive- and anxiety-like behaviors and stress-related neuronal activation in vasopressin-deficient female Brattleboro rats

Vasopressin can contribute to the development of stress-related psychiatric disorders, anxiety and depression. Although these disturbances are more common in females, most of the preclinical studies have been done in males.We compared female vasopressin-deficient and +/+ Brattleboro rats. To test anxiety we used open-field, elevated plus maze (EPM), marble burying, novelty-induced hypophagia, and social avoidance tests. Object and social recognition were used to assess short term memory. To test depression-like behavior consumption of sweet solutions (sucrose and saccharin) and forced swim test (FST) were studied. The stress–hormone levels were followed by radioimmunoassay and underlying brain areas were studied by c-Fos immunohistochemistry.In the EPM the vasopressin-deficient females showed more entries towards the open arms and less stretch attend posture, drank more sweet fluids and struggled more (in FST) than the +/+ rats. The EPM-induced stress-hormone elevations were smaller in vasopressin-deficient females without basal as well as open-field and FST-induced genotype-differences. On most studied brain areas the resting c-Fos levels were higher in vasopressin-deficient rats, but the FST-induced elevations were smaller than in the +/+ ones.Similarly to males, female vasopressin-deficient animals presented diminished depression- and partly anxiety-like behavior with significant contribution of stress-hormones. In contrast to males, vasopressin deficiency in females had no effect on object and social memory, and stressor-induced c-Fos elevations were diminished only in females. Thus, vasopressin has similar effect on anxiety- and depression-like behavior in males and females, while only in females behavioral alterations are associated with reduced neuronal reactivity in several brain areas.

Maternal neglect with reduced depressive-like behavior and blunted c-fos activation in Brattleboro mothers, the role of central vasopressin

Early mother–infant relationships exert important long-term effects in offspring and are disturbed by factors such as postpartum depression. We aimed to clarify if lack of vasopressin influences maternal behavior paralleled by the development of a depressive-like phenotype. We compared vasopressin-deficient Brattleboro mothers with heterozygous and homozygous normal ones. The following parameters were measured: maternal behavior (undisturbed and separation-induced); anxiety by the elevated plus maze; sucrose and saccharin preference and forced swim behavior. Underlying brain areas were examined by c-fos immunocytochemistry among rest and after swim-stress. In another group of rats, vasopressin 2 receptor agonist was used peripherally to exclude secondary changes due to diabetes insipidus. Results showed that vasopressin-deficient rats spend less time licking–grooming their pups through a centrally driven mechanism. There was no difference between genotypes during the pup retrieval test. Vasopressin-deficient mothers tended to explore more the open arms of the plus maze, showed more preference for sucrose and saccharin and struggled more in the forced swim test, suggesting that they act as less depressive. Under basal conditions, vasopressin-deficient mothers had more c-fos expression in the medial preoptic area, shell of nucleus accumbens, paraventricular nucleus of the hypothalamus and amygdala, but not in other structures. In these areas the swim-stress-induced activation was smaller. In conclusion, vasopressin-deficiency resulted in maternal neglect due to a central effect and was protective against depressive-like behavior probably as a consequence of reduced activation of some stress-related brain structures. The conflicting behavioral data underscores the need for more sex specific studies.

P-80 - Transcranial magnetic stimulation as potential therapeutic tool on alcohol disorders: evidences and proposals

Transcranial magnetic stimulation (TMS) is a non invasive technique of brain stimulation which could be an interesting therapeutic tool in addictive disorders, being offline repetitive TMS (rTMS) the main strategy used due to it allows to disrupt underlying brain areas and examine behavioral consequences, (Knoch et al., 2006). There are some evidences that rTMS over the dorso-lateral prefrontal (DLPF) cortex is effective reducing craving in several drugs, such as cocaine, tobacco and alcohol (Camprodon et al., 2007; Amiaz et al., 2009; Mishra et al. 2010). In fact, a decrease on cocaine craving could be observed with a single session of rTMS. Complementary, the application of single and paired-pulse TMS in controlled paradigms is a novel and promising strategy in this area: recent results showed that reward modulated TMS-induced motor-evoked potentials, showing greater cortical inhibition during reward expectation (Gupta and Aron, 2010). Regarding alcohol abuse, there is a narrow relation between alcohol consumption and impulsiveness. On one hand, alcohol consumption produces impulsive behavior and desinhibition (Marinkovic et al. 2011); and on the other hand, impulsiveness personality trait predisposes to abusive alcohol consumption (Magid et al. 2007). Considering these evidences and the effectiveness of rTMS as therapeutic tool, use rTMS to reduce impulsivity could be a new approach to alcohol disorders treatment. Prefrontal cortex is a good candidate for this purpose since its pivotal role in impulsiveness behavior (Crews and Boettinger, 2009). Thus, we suggest that high frequency rTMS stimulation could improve the ability of alcohol abusers for control their drinking impulse.

Medial temporal lobe memory in childhood: developmental transitions

The medial temporal lobes (MTL) support declarative memory and mature structurally and functionally during the postnatal years in humans. Although recent work has addressed the development of declarative memory in early childhood, less is known about continued development beyond this period of time. The purpose of this investigation was to explore MTL-dependent memory across middle childhood. Children (6 -10 years old) and adults completed two computerized tasks, place learning (PL) and transitive inference (TI), that each examined relational memory, as well as the flexible use of relational learning. Findings suggest that the development of relational memory precedes the development of the ability to use relational knowledge flexibly in novel situations. Implications for the development of underlying brain areas and ideas for future neuroimaging investigations are discussed.

Ten Percent Electrode System for Topographic Studies of Spontaneous and Evoked EEG Activities

ABSTRACT.An 81-electrode system is described which is designed for topographic studies of spontaneous and evoked EEG activities. This method combines the standard leads of the International 10–20 System with supplementary electrodes applied midway between leads of the 10–20 system or electrodes in turn situated between 10–20 leads. Auxiliary electrode designations refer to the underlying brain areas and to adjacent leads of the 10–20 method. The utilization of this “10% system” is suggested to promote standardization.