Josette G Harris

Learn More
A series of human and animal investigations has suggested that altered expression and function of the alpha7-nicotinic cholinergic receptor may be responsible for the auditory sensory gating deficit characterized in schizophrenia patients and their relatives as diminished suppression of an auditory-evoked response (P50) to repeated stimuli. This finding, in(More)
CONTEXT The alpha7 nicotinic acetylcholine receptor gene, CHRNA7, is associated with genetic transmission of schizophrenia and related cognitive and neurophysiological sensory gating deficits. Cognitive dysfunction is responsible for significant psychosocial disability in schizophrenia. Nicotine, a low-potency agonist at the alpha7 receptor, has some(More)
Several lines of evidence suggest a pathophysiological role for nicotinic receptors in schizophrenia. Activation by nicotine alters physiological dysfunctions, such as eye movement and sensory gating abnormalities, but effects on neuropsychological performance are just beginning to be investigated. Nicotine-induced desensitization and the well-known(More)
Patients with schizophrenia often cannot respond to important features of their environment and filter out irrelevant stimuli. This dysfunction could be related to an underlying defect in inhibition--i.e., the brain's ability to alter its sensitivity to repeated stimuli. One of the neuronal mechanisms responsible for such inhibitory gating involves the(More)
OBJECTIVE Nicotinic acetylcholine receptors are possible therapeutic targets for schizophrenia, as shown by neurobiological and molecular evidence for deficiencies in expression of alpha(7)-nicotinic receptors. Patients' heavy smoking suggests attempted self-medication through this mechanism. The agent 3-(2,4-dimethoxybenzylidene) anabaseine (DMXB-A) is a(More)
OBJECTIVE Sensory gating deficits found in schizophrenia can be assessed by using a paired auditory stimulus paradigm to measure auditory evoked response. The ratio of the P50 response amplitude of the second or test stimulus to that of the first or conditioning stimulus is expressed as a percentage. Normal subjects generally suppress the second response(More)
The behavior of the P50 wave of the auditory evoked potential in a paired stimulus or conditioning-testing paradigm has been used as a measure of sensory gating disturbance in schizophrenia. Schizophrenics fail to decrement the P50 response to the second stimulus of the pair, so that the ratio of the test to the conditioning amplitude is elevated over(More)
BACKGROUND Smooth pursuit eye movement (SPEM) abnormalities are a putative marker of genetic risk for schizophrenia. Accurate SPEM performance requires the subject to activate neural systems responsible for smooth pursuit tracking, while simultaneously suppressing activity of neurons responsible for saccadic movements that would move the eye ahead of the(More)
Schizophrenia and attention deficit/hyperactivity disorder (ADHD) are both associated with deficits in inhibition and working memory, although in ADHD the working memory deficit is hypothesized to be secondary to the inhibitory deficit. This similarity in cognitive processes has been paralleled by similarities across the two groups in the performance of(More)
BACKGROUND Performance during a smooth pursuit eye movement (SPEM) task has been proposed as a marker of genetic risk for schizophrenia, although the precise component of SPEM tracking most associated with genetic risk remains undetermined. Normal adult aging is associated with deterioration on SPEM tasks; it remains unclear whether investigations of SPEM(More)