Cognitive Neuroscience (Fach) / Learning and Memory (Lektion)

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• Describe the classical memory dissociation (Squire & Zola-Morgan, 1991). The classical model is based on awareness for memorized content and thus differentiates between explicit (awareness) and implicit memory (no awareness). Explicit memory further divides into the subcategories episodic and semantic memory, whereas implicit memory divides into procedural memory, classical conditioning, priming and habituation.
• Is there a different way than the classical model to dissociate memory? Explain your answer. Another way to dissociate memory reflects information processing and is supported by neuroimaging data. Here the main distinction is based on the content of the memorized material (rather than the awareness of the content). Thus, memory is divided into perceptual content/stimulus-stimulus associations and motor content/stimulus-response associations, the former being represented in the Medial Temporal Lope, the latter being represented in the basalganglia. In a second step, the model also takes the amount of awareness into acount by sorting the different subcategories (episodic, semantic, procedural, etc.) by the degree of conscious access to memory.
• Name three experimental approaches for the examination of memory. Circumscribed lesions and description of memory deficits and intact skills. Correlation of recollection success with neuronal activity during encoding: DM-Effect Modeling of a Time x Condition (learn vs. no learn) interaction effect to control for unspecific effects.
• Describe the experiment of Rose et al. (2011). Serial Reaction Time Task with random trials and trials with sequence. Sequence could be a motor sequence (sequence of pressed buttons) or a perceptual sequence (sequence of colors). Explicit memory was controlled for (via a betting task that involved monetary reinforcement). Measured activity in hippocampus and basalganglia. For motor sequences the activation in the basalganglia increased (with trial) more than for perceptual sequences. For perceptual sequences activation in the hippocampus increased, but did not change for motor sequences.
• Describe the Face Recognition, Card Sorting and Mirror Drawing task by Milner et al. (1968). Which conclusions can be drawn? Face Recognition: Patients with hippocampal lesions and patients with frontal lesions performed a face-name learning task. Only patients with hippocampal lesions had problems with this task. Card Sorting: Patients with hippocampal lesions and patients with frontal lesions performed a cognitive task. Only patients with frontal lesions were impaired. --> double dissociation. Hippocampus --> memory function; Frontal Cortex --> Cognitive functions Mirror Drawing task: Task in which patients have to draw a figure while looking in a mirror. Task needs to be learned to improve performance. Even though patients with hippocampal lesions do not remember practicing this task, their performance improves with repeated practice. --> Hippocampus --> memory function for explicit memory, not for implicit memory. 
• Describe the memory gradient of amnestic patients (Bayley et al., 2006). Which theory can explain the findings? Amnestic patients with hippocampal lesions are not able to form new memory. However, they can retrieve past memories. The closer to the date of the lesion the memory lies, the less likely it is that the memory is retrieved (retrograde memory gradient).  These findings can be explained by the theory of the MTL as a switchboard or hub (Alvarez & Squire, 1994). In this model MTL stores new memory via fast changing connections. Memory is then transferred to areas of the cortex with slow changing connections. Old memories, once they're represented in cortex and independent of the MTL, can thus be remembered even when hippocampal lesions do not allow patients to form new memories.
• Explain the DM-Effect and name an example study. DM-Effect = Difference due to memory Neural activity (measured via EEG and fMRI) during encoding can predict memorized items during retrieval, as neuronal activity for those items is higher during encoding (activitynot memorized item - activitymemorized item = DM). Brewer et al. (1998) studied the DM-Effect for visual objects. They found that higher signal intensity (neuronal activity in parahippocampus) during encoding correlates with better memory for item.
• Explain the Two Process Model of Explicit Memory (Eichenbaum et al., 2007). The model differentiates between two processes: Familiarity and Recollection. In the parahippocampus parts of the object (like color, shape, texture) are put together to form a single object. The same with context. Thus, high parahippocampal activity during encoding should correlate with object/context familiarity (one knows to have seen the item or context before, but cannot retrieve information about what was seen in which context). In the hippocampus, object and context are put together and form a memory of the item in its context. (=Recollection).

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