The Effect of Drugs and Alcohol on Cognitive Performance

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Let's take a closer look. I also attached a supporting article, some of which this response is drawn.

RESPONSE:

1. Describe the impact of the following drugs on the different aspects of cognitive performance.

(a) Ritalin

Ritalin is a stimulant. It is one of the drugs that have been prescribed for decades to treat attention deficit hyperactivity disorder (ADHD), and their popularity as "cognition enhancers" has recently surged among the healthy, as well. For example, Devilbiss and Berridge report that Ritalin (in small doses as prescribed) fine-tunes the functioning of neurons in the prefrontal cortex (PFC) - a brain region involved in attention, decision-making and impulse control - while having few effects outside it. This supposedly supports the use of today's ADHD drugs may be safer than people think, says Berridge. Mounting behavioral and neurochemical evidence suggests that clinically relevant doses of Ritalin primarily target the PFC, without affecting brain centers linked to over-arousal and addiction. In other words, Ritalin at low doses doesn't appear to act like a stimulant at all. "It's the higher doses of these drugs that are normally associated with their effects as stimulants, those that increase locomotor activity, impair cognition and target neurotransmitters all over the brain," says Berridge. "These lower doses are diametrically opposed to that. Instead, they help the PFC better do what it's supposed to do" (http://www.sciencedaily.com/releases/2008/06/080624115956.htm).

Ritalin at lower doses appears to cause the prefrontal cortex (PFC) to be more sensitive to signals coming in from the hippocampus. When they listened to individual PFC neurons, the scientists found that while cognition-enhancing doses of Ritalin had little effect on spontaneous activity, the neurons' sensitivity to signals coming from the hippocampus increased dramatically. Under higher, stimulatory doses, on the other hand, PFC neurons stopped responding to incoming information. "This suggests that the therapeutic effects of Ritalin likely stem from this fine-tuning of PFC sensitivity," says Berridge. "You're improving the ability of these neurons to respond to behaviorally relevant signals, and that translates into better cognition, attention and working memory." Higher doses associated with drug abuse and ...