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- Ankarberg, Emma, et al.
(författare)
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Neurobehavioural defects in adult mice neonatally exposed to nicotine: changes in nicotine-induced behaviour and maze learning performance
- 2001
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Ingår i: Behavioural Brain Research. - 0166-4328 .- 1872-7549. ; 123:2, s. 185-192
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Tidskriftsartikel (refereegranskat)abstract
- Neonatal exposure to low doses of nicotine has been shown to disturb the development of low-affinity nicotinic binding sites in the cerebral cortex and to elicit a deviant behavioural response to nicotine in adult mice. In this study, 10-day-old male NMRI mice were exposed to one of three different doses of nicotine (3.3, 33, or 66 μg nicotine-base/kg body wt.) s.c. twice daily on 5 consecutive days to study dose–response effects of nicotine on adult spontaneous and nicotine-induced motor behaviour. The nicotine-induced behaviour test revealed a hypoactive response to nicotine in 4-month-old mice neonatally exposed to 33 or 66 μg nicotine-base, whereas the response to nicotine in control animals and mice exposed to 3.3 μg nicotine-base was an increased activity. Learning and memory functions were also investigated in adult animals neonatally exposed to 66 μg nicotine-base/kg body wt. in the same manner, in the Morris water maze and in the Radial arm maze. In the swim maze and the Radial arm maze tests, no significant differences were observed between nicotine-treated and control animals at the age of 4 months. At 7 months, however, a significant difference in performance was evident, indicating a time-response/time-dependent effect. Furthermore, it was shown that in mice exposed neonatally to a nicotine dose known to inhibit the development of the nicotinic low affinity-binding site (LA), the response to nicotine could not cause any increase in spontaneous motor activity as seen in controls.
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| 2. |
- McGlone, Francis, et al.
(författare)
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Functional neuroimaging studies of human somatosensory cortex
- 2002
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Ingår i: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 135:1-2, s. 147-158, PII S0166-4328(02)00144-4
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Tidskriftsartikel (refereegranskat)abstract
- Two studies were carried out to assess the applicability of echoplanar fMRI at 3.0 T to the analysis of somatosensory mechanisms in humans. Vibrotactile stimulation of the tips of digits two and five reliably generated significant clusters of activation in primary (SI) and secondary (SII) somatosensory cortex, area 43, the pre-central gyrus, posterior insula, posterior parietal cortex and posterior cingulate. Separation of these responses by digit in SI was possible in all subjects and the activation sites reflected the known lateral position of the representation of digit 2 relative to that of digit 5. A second study employed microneurographic techniques in which individual median-nerve mechanoreceptive afferents were isolated, physiologically characterized, and microstimulated in conjunction with fMRI. Hemodynamic responses, observed in every case, were robust, focal, and physiologically orderly. These techniques will enable more detailed studies of the representation of the body surface in human somatosensory cortex, the relationship of that organization to short-term plasticity in responses to natural tactile stimuli, and effects of stimulus patterning and unimodal/cross-modal attentional manipulations. They also present unique opportunities to investigate the basic physiology of the BOLD effect, and to optimize the operating characteristics of two important human functional neuroimaging modalities-high-field fMRI and high-resolution EEG-in an unusually specific and well-characterized neurophysiological setting.
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| 3. |
- Trulsson, Mats, et al.
(författare)
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Orofacial mechanoreceptors in humans : encoding characteristics and responses during natural orofacial behaviors.
- 2002
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Ingår i: Behavioural Brain Research. - 0166-4328 .- 1872-7549. ; 135:1-2, s. 27-33
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Tidskriftsartikel (refereegranskat)abstract
- We used microneurography to characterize stimulus-encoding properties of low-threshold mechanoreceptive afferents in human orofacial tissues. Signals were recorded from single afferents in the infraorbital, lingual and inferior alveolar nerves while localized, controlled, mechanical stimuli were delivered to the facial skin, lips, oral mucosa and teeth. We likewise analyzed activity in these afferents during orofacial behaviors such as speech, chewing and biting. The afferents in the soft tissues functionally resemble four types described in the human hand: hair follicle afferents, slowly adapting (SA) type I and type II afferents and fast adapting (FA) type I afferents. Afferents in the facial skin, lips and buccal mucosa respond not only to contact with environmental objects, but also to contact between the lips, changes in air pressure generated for speech sounds, and to facial skin and mucosa deformations that accompany lip and jaw movements associated with chewing and swallowing. Hence, in addition to exteroceptive information, these afferents provide proprioceptive information. In contrast, afferents terminating superficially in the tongue do not signal proprioceptive information about tongue movements in this manner. They only respond when the receptive field is brought into contact with other intraoral structures or objects, e.g. the teeth or food. All human periodontal afferents adapt slowly to maintained tooth loads. Populations of periodontal afferents encode information about both which teeth are loaded and the direction of forces applied to individual teeth. Most afferents exhibit a markedly curved relationship between discharge rate and force amplitude, featuring the highest sensitivity to changes in tooth load at low forces (below 1 N). Accordingly, periodontal afferents efficiently encode tooth load when subjects first contact, hold, and gently manipulate food by the teeth. In contrast, only a minority of the afferents encodes the rapid and strong force increase generated when biting through food. We conclude, that humans use periodontal afferent signals to control jaw actions associated with intraoral manipulation of food rather than exertion of jaw power actions.
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| 14. |
- Mohammed, AH, et al.
(författare)
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Brain mechanisms of tactile perception
- 2002
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Ingår i: BEHAVIOURAL BRAIN RESEARCH. - 0166-4328. ; 135:1-2, s. 1-1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 21. |
- Werme, M, et al.
(författare)
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Running increases ethanol preference
- 2002
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Ingår i: Behavioural brain research. - : Elsevier BV. - 0166-4328. ; 133:2, s. 301-308
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Tidskriftsartikel (refereegranskat)
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| 24. |
- Lindqvist, Ann-Sophie, 1973, et al.
(författare)
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Anabolic androgenic steroid affects competitive behaviour, behavioural response to ethanol and brain serotonin levels.
- 2002
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Ingår i: Behavioural brain research. - 0166-4328. ; 133:1, s. 21-9
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigated whether anabolic androgenic steroid (AAS) treatment (daily subcutaneous injections during 2 weeks with nandrolone decanoate; 15 mg/kg) affects competitive behaviour, and locomotor activity response to a sedative dose of ethanol (0.5 g ethanol/kg). In addition, levels of brain monoamines were assessed. The results showed that AAS treated animals exhibited enhanced dominant behaviour in the competition test compared to controls. The AAS groups' locomotor activity was not affected by ethanol in contrast to the controls who showed a sedative locomotor activity. AAS animals had significant lower levels of serotonin in basal forebrain and dorsal striatum compared to controls. These findings further strengthen the fact that AAS affects behaviour, as well as biochemical parameters. Based on previous studies and results from the present study, we hypothesize that AAS abuse may constitute a risk factor for disinhibitory behaviour, partly by affecting the serotonergic system.
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| 25. |
- Nordberg, A, et al.
(författare)
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Preface
- 2000
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Ingår i: Behavioural brain research. - 1872-7549. ; 113:1-2, s. 1-1
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Tidskriftsartikel (refereegranskat)
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