Actividad oscilatoria cerebral en tareas de memoria háptica implícita y explícita para objetos...

TESIS DOCTORAL

ACTIVIDAD OSCILATORIA CEREBRAL EN TAREAS DE MEMORIA HÁPTICA IMPLÍCITA Y EXPLÍCITA PARA OBJETOS FAMILIARES: UN ESTUDIO CON JÓVENES Y MAYORES

DOCTORANDO: MANUEL SEBASTIÁN CARRASCO Licenciado en Psicología

DIRECTORA: SOLEDAD BALLESTEROS JIMÉNEZ

Catedrática de Psicología Básica

Programa de Doctorado “Envejecimiento y Enfermedades Neurodegenerativas” Mención de Calidad de la Dirección General de Universidades Ref.MCD2003-00411

1 PhD dissertation Manuel Sebastián Carrasco

Manuel Sebastián Carrasco PhD dissertation 2

Multilevel systems analysis and modeling of somatosensory, memory, and affective maps of body and objects in multidimensional subjective space

FP6-2005-NEST-Path 043432 2007-2010 EU Funding: € 2 037 220

PARTNERS: University of Mannheim, Otto-Selz Institute (Germany) University of Mannheim, Institute for Computational Medicine (Germany) University of Aalborg (Denmark); University of Twente (The Netherlands) Universidad Nacional de Educación a Distancia (Spain) Central Institute of Mental Health, Mannheim (Germany)

Imagen multiparamétrica de la competencia vascular/ Multiparametric imaging of vascular competence . Ref. S2006/BIO-0170

http://www.madrid.org/cs/Satellite?pagename=ComunidadMadrid/Estructura

OUTLINE

Manuel Sebastián Carrasco 3 PhD dissertation

1. INTRODUCTION

2. STUDY 1: EEG & HAPTIC REPETITION PRIMING

1. HYPOTHESES 2. METHOD 3. RESULTS 4. CONCLUSIONS

3. STUDY 2: EEG & HAPTIC RECOGNITION MEMORY

1. HYPOTHESES 2. METHOD 3. RESULTS 4. CONCLUSIONS

4. FINAL CONCLUSIONS

1. INTRODUCTION


The aim of the present study was to investigate the effects of aging on the neural correlates of implicit (Study 1) and explicit (Study 2) haptic memory. We obtained evoked (ERP) and induced (ERSP) brain activity measures by recording EEG data during haptic object exploration. To our knowledge, no ERP studies have been conducted in haptics. Few studies have investigated induced EEG measures during haptic memory tasks, but using raised-line shapes (Grunwald et al., 1999, 2001, 2002). Based on the idea that the brain is “metamodal” (Lacey & Sathian, 2008) and because the similarities between vision and touch (e.g., James et al., 2002), we expect to find similar results in the haptic modality to those reported in vision.

2. EEG & HAPTIC PRIMING


2.1. HYPOTHESES

STUDY 1: EEG AND HAPTIC REPETITION PRIMING 1. In line with previous haptic studies (e.g., Ballesteros & Reales, 2008), we

predict response time facilitation for repeated objects as a signal of behavioural priming.

2. Based on previous visual studies (e.g., Friedman & Cycowicz, 2006), we expect to find an ERP repetition enhancement in both age groups.

3. Because we used an immediate repetition procedure, we also expect to observe a late ERP repetition reduction in young adults (Penney et al., 2001).

4. We anticipated theta power increases for young adults but decreases for older adults (Grunwald et al., 2002).

5. We also hypotesize larger alpha power reductions for older than young adults (Cabeza et al., 2002).

2.2. METHOD (PARTICIPANTS AND PROCEDURE)


IMPLICIT HAPTIC TASK: Speeded symmetry-asymmetry detection

20 Symmetric and 20 asymmetric 3D objects were randomly presented to touch 3 times each

VERBAL TASKS: Free-recall and Recognition


2.2. METHOD (STIMULI)

Symmetric (up) and asymmetric (bottom) objects presented to touch




HAPTIC TACHISTOSCHOPE NuAmps NEUROSCAN

2.2. METHOD (EEG RECORDINGS SET-UP)


2.2. METHOD (DATA ANALYSIS)


BEHAVIORAL DATA: MIXED FACTORIAL DESIGN: 2 GROUP (Young, Older adults) X 3 PRESENTATION (1, 2, 3) X 2 OBJECT TYPE (Symmetric, Asymmetric) EEG DATA MIXED FACTORIAL DESIGN: 2 GROUP (Young, Older adults) X 3 PRESENTATION (1, 2, 3) X 3 AXIS (Anterior, Central, Posterior) X LATERALITY 3 (Right, Midline, Left).



2.3. BEHAVIORAL RESULTS


Both age groups showed robust repetition priming



Both age groups performed similarly in the verbal tasks



100-400 ms 500-900 ms 1200-1500 ms

2.3. EVENT-RELATED POTENTIALS



2.3. ERPs AND SCALP MAPS

Mean voltage was higher for older than for young adults




Both age groups showed ERP repetition enhancement




Only the young group showed a reliable ERP repetition reduction



2.3. ERSP RESULTS: THETA BAND

Young adults showed theta enhancement, but older adults displayed power reduction between 600-1200 ms.



2.3. ERSP RESULTS: ALPHA & GAMMA BAND

The older participants displayed stronger alpha power reductions than younger adults during the haptic exploration.



2.4. CONCLUSIONS

The older adults needed longer time to explore symmetric objects, probably to gain confidence in their symmetric responses. The ERP repetition enhancement could reflect facilitation in the processing of object features. The group differences at frontal sites could reflect that younger adults had access to explicit information. The late ERP repetition reduction in young participants might reflect the influence of explicit recognition processes. Theta power modulations might reflect age related differences in memory encoding. The stronger alpha power reduction in the older adults suggest greater brain activation during haptic exploration. This might indicate the recruitment of additional neural resources.


3. EEG & HAPTIC RECOGNITION MEMORY


3.1. HYPOTHESES

STUDY 2: EEG AND HAPTIC RECOGNITION MEMORY 1. We expect similar accuracy in young and older adults (Ballesteros & Reales,

2004).

2. Based on previous visual studies, we hypotesized an ERP old/new effect for both age groups (Friedman et al., 2010; Duarte et al., 2006).

3. We also expect to observe a late negative going ERP effect for older adults (Friedman, 2010).

4. We anticipated theta power increases for young adults but decreases for older adults (Grunwald et al., 2002).

5. We also hypothesize larger age-related reductions in alpha power for older adults (Cabeza et al., 2002).


3.2. METHOD (PARTICIPANTS AND PROCEDURE)

EXPLICIT HAPTIC TASK: Old-New Recognition Paradigm

40 3D objects were randomly presented to touch 3 times each

VERBAL TASKS: Free-recall and Recognition


3.2. METHOD (DATA ANALYSIS)



BEHAVIORAL DATA: MIXED FACTORIAL DESIGN: 2 GROUP (Young, Older adults) X 3 PRESENTATION (1, 2, 3) EEG DATA MIXED FACTORIAL DESIGN: 2 GROUP (Young, Older adults) X 3 PRESENTATION (1, 2, 3) X 3 AXIS (Anterior, Central, Posterior) X 3 LATERALITY (Right, Midline, Left).



The young participants were more accurate than older adults in the free-recall task



200-400 ms 550-750 ms 1200-1500 ms

3.3. EVENT-RELATED POTENTIALS




Both age groups showed ERP repetition enhancement (Old/New) effect




The young adults showed higher amplitude than older participants



3.3. ERSP RESULTS: THETA BAND

Repetition effects in theta band for young and older participants



4.3. ERSP RESULTS: ALPHA BAND

The older participants displayed stronger alpha power reductions than younger adults during the haptic exploration.



4.4. CONCLUSIONS


Recognition memory is spared with age in both vision and touch, whereas explicit memory is age-impaired as measured by free-recall tasks. Although the ERP old/new effect temporarily overlaps the parietal old/new effect found in visual studies, it is unclear whether reflects either explicit recollection or familiarity processes. The late negativity displayed by older participants has been related to an attempt for neural compensation. The stronger alpha power reduction in the older adults suggest greater brain activation during the haptic exploration. This might reflect the recruitment of additional neural resources when enconding new objects.


5. FINAL CONCLUSIONS

To our knowledge, this is the first electrophysiological investigation recording brain activity measures while young and older participants performed implicit (Study 1) and explicit (Study 2) haptic memory tasks. We observed similar ERP effects to those reported in visual studies for young and older adults. The current investigation also extends previous findings in brain oscillations in the visual domain to the haptic modality. The stronger alpha power reductions in older participants suggest greater brain activation with age during haptic exploration. Overall, the present results suggest that, in spite of similar behavioral performance, young and older adults recruited different neural resources to perform the haptic memory tasks.


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Actividad oscilatoria cerebral en tareas de memoria háptica implícita y explícita para objetos...

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