UNIT 5: NEURAL BASES OF IMPLICIT MEMORY.

1. MULTIPLE SYSTEMS OF LEARNING AND MEMORY.

Memory can be classified in terms of different dimensions:

•Temporal categories.

•Qualitative categories.

•What is remembered.

2. PERCEPTUAL LEARNING.

Learning enables us to adapt to our environment and to respond to changes in it. It provides us with the ability to perform an

appropriate behavior in an appropriate situation. Perceptual learning involves learning to recognize things. Perceptual learning can

involve learning to recognize entirely new stimulus, or it can involve learning to recognize changes or variations in familiar

stimuli.

2.1. LEARNING TO RECOGNIZE STIMULI.

Objects are recognized visually by circuits of neurons in the visual association cortex. Visual learning can take place very rapidly.

The primary visual cortex receives information from the lateral geniculate nucleus of the thalamus. The information is sent to the

extrastriate cortex. After that, subregions of the extrastriate cortex send the result of their analysis to the “streams”. The ventral

stream (“what”) continues ventrally into the inferior temporal cortex. The dorsal stream (“where” “how”) continues dorsally into

the posterior parietal cortex.

Perceptual learning clearly involves changes in synaptic connections in the visual association cortex that establish new neural

circuits. When the same stimulus is seen again and the same pattern of activity is transmitted to the cortex, these circuits become

active again. This activity constitutes the recognition of the stimulus. Activation of neural circuits in the sensory association

cortex constitutes the “readout” of a perceptual memory.

Damage to regions of the brain involved in visual perception not only impair the ability to recognize visual stimuli but also

disrupt people’s memory of the visual properties of familiar stimuli.

The degree of activity of the visual association is related to experience. Memory retrieving activates specific regions in the

sensory association cortex.

2.2. PERCEPTUAL SHORT-TERM MEMORY.

Sometimes the situation demands that we make the appropriate response after a delay, even after the stimulus is no longer visible.

A short-term memory is the memory for a stimulus or an event that lasts for a short while.

The prefrontal cortex permits retaining the information of the perceived stimulus during the delay.

Recognition of a stimulus occurs when a sensory input activates these established sets of neural circuits. Short-term memory of a

stimulus involves activity of these circuits that continues even after the stimulus disappears.

Functional-imaging studies have shown that retention of specific types of short-term visual memories involves activity of specific

regions of the visual association cortex. In the ventral stream, the fusiform face area is involved in recognition of faces, and the

parahippocampal place area is involved in recognition of places.

Vista previa parcial del texto

¡Descarga Unit 5: implicit memory y más Apuntes en PDF de Psicología Fisiológica solo en Docsity!

UNIT 5: NEURAL BASES OF IMPLICIT MEMORY.

1. MULTIPLE SYSTEMS OF LEARNING AND MEMORY.

Memory can be classified in terms of different dimensions:

• Temporal categories.

• Qualitative categories.

• What is remembered.

2. PERCEPTUAL LEARNING.

Learning enables us to adapt to our environment and to respond to changes in it. It provides us with the ability to perform an appropriate behavior in an appropriate situation. Perceptual learning involves learning to recognize things. Perceptual learning can involve learning to recognize entirely new stimulus, or it can involve learning to recognize changes or variations in familiar stimuli.

2.1. LEARNING TO RECOGNIZE STIMULI.

Objects are recognized visually by circuits of neurons in the visual association cortex. Visual learning can take place very rapidly. The primary visual cortex receives information from the lateral geniculate nucleus of the thalamus. The information is sent to the extrastriate cortex. After that, subregions of the extrastriate cortex send the result of their analysis to the “streams”. The ventral stream (“what”) continues ventrally into the inferior temporal cortex. The dorsal stream (“where” “how”) continues dorsally into the posterior parietal cortex. Perceptual learning clearly involves changes in synaptic connections in the visual association cortex that establish new neural circuits. When the same stimulus is seen again and the same pattern of activity is transmitted to the cortex, these circuits become active again. This activity constitutes the recognition of the stimulus. Activation of neural circuits in the sensory association cortex constitutes the “readout” of a perceptual memory. Damage to regions of the brain involved in visual perception not only impair the ability to recognize visual stimuli but also disrupt people’s memory of the visual properties of familiar stimuli. The degree of activity of the visual association is related to experience. Memory retrieving activates specific regions in the sensory association cortex.

2.2. PERCEPTUAL SHORT-TERM MEMORY.

Sometimes the situation demands that we make the appropriate response after a delay, even after the stimulus is no longer visible. A short-term memory is the memory for a stimulus or an event that lasts for a short while. The prefrontal cortex permits retaining the information of the perceived stimulus during the delay. Recognition of a stimulus occurs when a sensory input activates these established sets of neural circuits. Short-term memory of a stimulus involves activity of these circuits that continues even after the stimulus disappears. Functional-imaging studies have shown that retention of specific types of short-term visual memories involves activity of specific regions of the visual association cortex. In the ventral stream, the fusiform face area is involved in recognition of faces, and the parahippocampal place area is involved in recognition of places.

Stimulating the ventral stream interfered with short-term memory for visual patterns and stimulating the dorsal stream interfered with short-term memory of location. The dorsal and the ventral visual streams project directly to the areas placed dorsally and ventrally to the Sulcus principal in the PFC. The neurons of the zone dorsal to the sulcus principal maintain the information concerning the location of the stimuli during the delay and the neurons of the zone ventral to the sulcus principal maintain the information concerning the identity of the stimulus during the delay. Although the neural circuits responsible for learning to recognize particular stimuli appear to reside in the sensory association cortex, perceptual short-term memories involve other brain regions as well. Patients with damage to the left basal ganglia had difficulty filtering out irrelevant information, and patients with damage to the right prefrontal cortex had difficulty retaining more than a few pieces of information in short-term memory. The size of the superior longitudinal fasciculus and performance on a test of spatial short-term memory, were both significantly influenced by the same genetic factors. This fiber tract is an important link between the parietal and frontal lobes, suggesting that communication between these two brain regions plays a role in spatial short-term memory.

3. NEURAL BASES OF MOTOR LEARNING AND PROCEDURAL MEMORY.

The neurons of the prefrontal cortex are active during the delay in delayed-response tasks.

4. NEURAL BASES OF ASSOCIATIVE LEARNING.

4.1. CLASSICAL CONDITIONING.

The amygdala is part of an important system involved in a particular form of stimulus-response learning: classical conditioned emotional responses. A classically conditioned emotional response is establish by paring a neutral stimulus with an aversive stimulus. Information about the CS reaches the lateral nucleus of the amygdala. This nucleus also receives information about the US from the somatosensory system. These two resources of information converge in the lateral nucleus. The lateral nucleus of the amygdala contains neuronal buttons from neurons that transmit auditory and somatosensory information to the lateral nucleus form synapses with dendritic spines on these neurons. The changes in the lateral amygdala responsible for acquisition of a conditioned emotional response involve LTP. LTP mediated by the NMDA receptors in the LA is necessary for emotional learning. NMDA receptor inactivation in the lateral amygdala blocks emotional learning. Administration of AP5 before initial training prevents acquisition learning. Administration of AP5 before extinction training prevents the extinction of the CS. The NMDA receptors containing the NR2B subunit are necessary for emotional learning. Blocking the NR2B subunit of the NMDA receptor: prevents LTP and the acquisition of a new conditioned emotional response. Increasing the amount of NR2B subunits: facilitate LTP and the acquisition of a conditioned emotional response.

4.2. INSTRUMENTAL (OPERANT) CONDITIONING.

Instrumental conditioning is the mean by which we profit from experience.

Basal Ganglia. The circuits that are responsible for instrumental conditioning begin in various regions of the sensory association cortex, and end in the motor association cortex of the frontal lobe. There are two major pathways between the sensory association cortex and the motor association cortex: direct transcortical connection and connection via the basal ganglia and thalamus. In conjunction with the hippocampal formation, the transcortical connections are involved in the acquisition of episodic memories. The transcortical connections are also involved in the acquisition of complex behaviors that involve deliberation or instruction. As learned behaviors become automatic and routine, they are “transferred” to the basal ganglia. The neostriatum receives sensory information from all regions of the cerebral cortex. It also receives information from the frontal lobes about movements that are planned or are actually in progress. The outputs of the caudate nucleus and the putamen are sent to another part of the basal ganglia: the globus pallidus. The outputs of this structure are sent to the frontal cortex: to the premotor and supplementary motor cortex and to the primary motor cortex. Lesions of the basal ganglia disrupt instrumental conditioning but do not affect other forms of learning. The transfer of memories from brain system involved in acquisition of behavior sequences to those involved in storage of automatic procedures can be seen in the basal ganglia. The caudate nucleus is reciprocally connected with the prefrontal cortex. The putamen is reciprocally connected to sensory and motor regions of the cortex. DM striatum was involved in early learning of new skills.

Unit 5: implicit memory, Apuntes de Psicología Fisiológica

Documentos relacionados

Vista previa parcial del texto

¡Descarga Unit 5: implicit memory y más Apuntes en PDF de Psicología Fisiológica solo en Docsity!

UNIT 5: NEURAL BASES OF IMPLICIT MEMORY.

1. MULTIPLE SYSTEMS OF LEARNING AND MEMORY.

• Temporal categories.

• Qualitative categories.

• What is remembered.

2. PERCEPTUAL LEARNING.

2.1. LEARNING TO RECOGNIZE STIMULI.

2.2. PERCEPTUAL SHORT-TERM MEMORY.

3. NEURAL BASES OF MOTOR LEARNING AND PROCEDURAL MEMORY.

4. NEURAL BASES OF ASSOCIATIVE LEARNING.

4.1. CLASSICAL CONDITIONING.

4.2. INSTRUMENTAL (OPERANT) CONDITIONING.