Assignment: What is the role of a psychostimulant in learning and memory?

Assignment: What is the role of a psychostimulant in learning and memory?

Assignment: What is the role of a psychostimulant in learning and memory?

1. How can damage to Broca’s or Wernicke’s area affect speech? From speech patterns, how can you differentiate between which area was affected? How can this affect the quality of life?

2. What is the role of a psychostimulant in learning and memory? Psychostimulants have typically been prescribed to individuals with ADHD. What are some affects of taking a psychostimulant for a person who does not have ADHD? Should this medication be prescribed more widely? Why?

Please participate (respond) to the classmates answers with notable and educational input. (200 word minimum Reponses)

1. Kelly: The psychostimulant methylphenidate (MPH) has been used since 1955 as a cognitive enhancer and wake-promoting agent for a variety of disorders (Challman and Lipsky 2000). Over time, it has become the mainstay of treatment for attention deficit hyperactivity disorder (ADHD) as it improves executive control, reduces impulsivity, and improves cognitive function, including learning and memory (O’Toole et al. 1997; Aron et al. 2003; Mehta et al. 2004; Arnsten 2006; Swanson et al. 2011). MPH-induced memory enhancement is often viewed as incidental to improved attention and/or cognitive control (Barkley 1997).

Although many studies have modeled MPH’s effect on executive function, almost none have directly modeled its effect on long-term memory (LTM) acquisition or retention, per se. Improvement in LTM is a critical target of therapeutic intervention in ADHD, as ample evidence shows a deficit in LTM in ADHD (Rhodes et al. 2012). Psychostimulants are frequently prescribed to enhance classroom learning and are increasingly sought out by individuals without ADHD for the same reason. Indeed, stimulants also enhance learning in normal populations (Rapoport et al. 1980;Rapoport and Inoff-Germain 2002; Marshall et al. 2010).

Thus, the degree to which MPH directly enhances LTM warrants further examination. Drug development for ADHD would benefit from a simple, efficient animal model of MPH’s effects on LTM. We examined the effects of a wide range of doses of MPH on Pavlovian fear learning. In this task, an initially neutral tone conditional stimulus is paired with an aversive foot-shock unconditional stimulus. As the result of this pairing, the animal comes to fear both the tone and the place of conditioning, a phenomenon known as context conditioning. Tone and context fear memory are used generally to model long-lasting memory (Anagnostaras et al. 1999; Gale et al. 2004).  Drug development for ADHD would benefit from a simple, efficient animal model of MPH’s effects on LTM.  (“Learning And Memory”, 2014)

2. Bernice: Damage to a discrete part of the brain in the left frontal lobe (Broca’s area) of the language-dominant hemisphere has been shown to significantly affect use of spontaneous speech and motor speech control. Words may be uttered very slowly and poorly articulated. Speech may be labored and consist primarily of nouns, verbs or important adjectives. Speech takes on a telegraphic character. People suffering from Broca’s aphasia have great difficulty with repetition and a severe impairment in writing. In some patients, however, the understanding of spoken and written language may be relatively well-preserved.

The non-fluent variant of primary progressive aphasia (nfvPPA) is a type of expressive aphasia. Damage to the posterior superior areas of the language dominant temporal lobe (often called Wernicke’s area) has been shown to significantly affect speech comprehension. In other words, information is heard through an intact auditory cortex in the anterior temporal lobe, however, when it arrives at the posterior association areas, the information cannot be sufficiently “translated.” To differentiate between which area was affected; in contrast to Broca’s aphasia, the person with Wernicke’s aphasia talks volubly and gestures freely. Speech is produced without effort, and sentences are of normal length. However, the person’s speech is devoid of meaning.

How can this affect the quality of life? As communication is at the core of many of our daily activities aphasia can have a big impact. It affects the ability of a person to do everyday tasks that we take for granted, such as, reading a get well card, answering the telephone, watching TV, or shopping.  People can find it extremely hard to stay in employment, to fulfill their role in a family, or to keep up their usual social activities and hobbies.  They often feel extremely frustrated, and isolated, and there can be breakdown in relationships.  Many people with aphasia feel anxious and depressed and their wellbeing and quality of life suffer.