RESUMEN
BACKGROUND: People with Alzheimer disease (AD) are capable of new learning when cognitive support is provided, suggesting that there is plasticity even in a degenerating brain. However, it is unclear how a cognition-focused intervention operates on a neural level. OBJECTIVE: The present study examined the effects of cognitive rehabilitation (CR) on memory-related brain activation in people with early-stage AD, as measured by functional magnetic resonance imaging (fMRI). METHODS: A total of 19 participants either received 8 weeks of CR treatment (n = 7) or formed a control group (n = 12). We scanned participants pretreatment and posttreatment while they learned and recognized unfamiliar face-name pairs. RESULTS: Following treatment, the CR group showed higher brain activation during recognition of face-name pairs in the left middle and inferior frontal gyri, the left insula, and 2s regions in the right medial parietal cortex. The control group showed decreased activation in these areas during recognition after the intervention period. Neither group showed an activation change during encoding. Behavioral performance on face-name learning did not improve for either group. CONCLUSIONS: We suggest that CR may have operated on the process of recognition through partial restoration of function in frontal brain areas that are less compromised in early-stage AD and that physiological markers may be more sensitive indicators of brain plasticity than behavioral performance.
Asunto(s)
Enfermedad de Alzheimer/complicaciones , Encéfalo/irrigación sanguínea , Terapia Cognitivo-Conductual , Trastornos de la Memoria , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/rehabilitación , Análisis de Varianza , Aprendizaje por Asociación , Encéfalo/patología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/patología , Trastornos de la Memoria/rehabilitación , Escala del Estado Mental , Persona de Mediana Edad , Análisis Multivariante , Evaluación de Resultado en la Atención de Salud , Oxígeno , Reconocimiento Visual de Modelos , Estimulación Luminosa , Terapia por Relajación , Factores de TiempoRESUMEN
OBJECTIVES: To provide evidence regarding the clinical efficacy of cognitive rehabilitation (CR) in early-stage Alzheimer disease (AD). DESIGN: Single-blind randomized controlled trial comparing CR with relaxation therapy and no treatment. SETTING: Outpatient, community-based setting. PARTICIPANTS: Sixty-nine individuals (41 women, 28 men; mean age 77.78 years, standard deviation 6.32, range = 56-89) with a diagnosis of AD or mixed AD and vascular dementia and a Mini-Mental State Examination score of 18 or above, and receiving a stable dose of acetylcholinesterase-inhibiting medication. Forty-four family carers also contributed. INTERVENTION: Eight weekly individual sessions of CR consisting of personalized interventions to address individually relevant goals supported by components addressing practical aids and strategies, techniques for learning new information, practice in maintaining attention and concentration, and techniques for stress management. MEASUREMENTS: The primary outcomes were goal performance and satisfaction, assessed using the Canadian Occupational Performance Measure. Questionnaires assessing mood, quality of life and career strain, and a brief neuropsychological test battery were also administered. A subset of participants underwent functional magnetic resonance imaging (fMRI). RESULTS: CR produced significant improvement in ratings of goal performance and satisfaction, whereas scores in the other two groups did not change. Behavioral changes in the CR group were supported by fMRI data for a subset of participants. CONCLUSIONS: The findings support the clinical efficacy of CR in early-stage AD. CR offers a means of assisting people with early-stage AD and their families in managing the effects of the condition.
Asunto(s)
Enfermedad de Alzheimer/rehabilitación , Terapia Cognitivo-Conductual/métodos , Objetivos , Actividades Cotidianas , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/fisiopatología , Encéfalo/fisiopatología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Método Simple CiegoRESUMEN
Making the right choice depends crucially on the accurate valuation of the available options in the light of current needs and goals of an individual. Thus, the valuation of identical options can vary considerably with motivational context. The present study investigated the neural structures underlying context dependent evaluation. We instructed participants to choose from food menu items based on different criteria: on their anticipated taste or on ease of preparation. The aim of the manipulation was to assess which neural sites were activated during choice guided by incentive value, and which during choice based on a value-irrelevant criterion. To assess the impact of increased motivation, affect-guided choice and cognition-guided choice was compared during the sated and hungry states. During affective choice, we identified increased activity in structures representing primarily valuation and taste (medial prefrontal cortex, insula). During cognitive choice, structures showing increased activity included those implicated in suppression and conflict monitoring (lateral orbitofrontal cortex, anterior cingulate). Hunger influenced choice-related activity in the ventrolateral prefrontal cortex. Our results show that choice is associated with the use of distinct neural structures for the pursuit of different goals.
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Afecto/fisiología , Encéfalo/fisiología , Conducta de Elección/fisiología , Cognición/fisiología , Conducta Alimentaria/fisiología , Motivación , Adulto , Mapeo Encefálico , Femenino , Humanos , Hambre/fisiología , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Saciedad/fisiologíaRESUMEN
How much we desire a meal depends on both the constituent foods and how hungry we are, though not every meal becomes more desirable with increasing hunger. The brain therefore needs to be able to integrate hunger and meal properties to compute the correct incentive value of a meal. The present study investigated the functional role of the amygdala and the orbitofrontal cortex in mediating hunger and dish attractiveness. Furthermore, it explored neural responses to dish descriptions particularly susceptible to value-increase following fasting. We instructed participants to rate how much they wanted food menu items while they were either hungry or sated, and compared the rating differences in these states. Our results point to the representation of food value in the amygdala, and to an integration of attractiveness with hunger level in the orbitofrontal cortex. Dishes particularly desirable during hunger activated the thalamus and the insula. Our results specify the functions of evaluative structures in the context of food attractiveness, and point to a complex neural representation of dish qualities which contribute to state-dependent value.
Asunto(s)
Apetito , Encéfalo/fisiología , Hambre , Adulto , Ingestión de Alimentos , Femenino , Humanos , Imagen por Resonancia Magnética , MasculinoRESUMEN
The cortical and subcortical forebrain connections of the marmoset prefrontal cortex (PFC) were examined by injecting the retrograde tracer, choleratoxin, and the anterograde tracer, biotin dextran amine, into four sites within the PFC. Two of the sites, the lateral and orbital regions, had previously been shown to provide functionally dissociable contributions to distinct forms of behavioral flexibility, attentional set-shifting and discrimination reversal learning, respectively. The dysgranular and agranular regions lying on the orbital and medial surfaces of the frontal lobes were most closely connected with limbic structures including cingulate cortex, amygdala, parahippocampal cortex, subiculum, hippocampus, hypothalamus, medial caudate nucleus, and nucleus accumbens as well as the magnocellular division of the mediodorsal nucleus of the thalamus and midline thalamic nuclei, consistent with findings in the rhesus monkey. In contrast, the granular region on the dorsal surface closely resembled area 8Ad in macaques and had connections restricted to posterior parietal cortex primarily associated with visuospatial functions. However, it also had connections with limbic cortex, including retrosplenial and caudal cingulate cortex as well as auditory processing regions in the superior temporal cortex. The granular region on the lateral convexity had the most extensive connections. Based on its architectonics and functionality, it resembled areas 12/45 in macaques. It had connections with high-order visual processing regions in the inferotemporal cortex and posterior parietal cortex, higher-order auditory and polymodal processing regions in the superior temporal cortex. In addition it had extensive connections with limbic regions including the amygdala, parahippocampal cortex, cingulate, and retrosplenial cortex.